adapt to new nako version

.gitignore

@@ -1,5 +1,3 @@
-.pijul
 Cargo.lock
 /target
 *~
-\#*\#

Cargo.toml

@@ -1,10 +1,12 @@
 [workspace]
 members = [
     "nested",
-#    "terminal/display_server",
+    "terminal/display_server",
-#    "terminal/ansi_parser",
+    "terminal/ansi_parser",
-#    "math/str2int",
+    "shell",
-#    "math/int2str",
+    "sdf_editor",
-#    "math/radix_transform",
+    "math/str2int",
-#    "math/fib"
+    "math/int2str",
+    "math/radix_transform",
+    "math/fib"
 ]

math/fib/src/main.rs

@@ -1,7 +1,8 @@
+
 use std::{
     fs::File,
     io::{Read, Write},
-    os::unix::io::FromRawFd,
+    os::unix::io::FromRawFd
 };
 
 fn fib(n: u64) -> u64 {
@@ -9,7 +10,7 @@ fn fib(n: u64) -> u64 {
     let mut y1 = 1;
     let mut y2 = 0;
 
-    for _ in 0..n {
+    for _ in 0 .. n {
         y = y1 + y2;
         y2 = y1;
         y1 = y;
@@ -25,32 +26,26 @@ fn main() {
 
     nested::magic_header();
 
-    eprintln!(
+    eprintln!("
-        "
+interface (Sequence ℕ) 0 1");
-interface (Sequence ℕ) 0 1"
-    );
 
     let mut f0 = unsafe { File::from_raw_fd(0) };
-    eprintln!(
+    eprintln!("
-        "
 >0: n
   ( ℕ )
   ( MachineInt )
   ( MachineWord )
   ( Stream MachineSyllab )
-"
+");
-    );
 
     let mut f1 = unsafe { File::from_raw_fd(1) };
-    eprintln!(
+    eprintln!("
-        "
 <1: n'th fibonacci number
   ( ℕ )
   ( MachineInt )
   ( MachineWord )
   ( Stream MachineSyllab )
-"
+");
-    );
 
     nested::magic_header();
 
@@ -60,3 +55,4 @@ interface (Sequence ℕ) 0 1"
     bytes = fib(n).to_le_bytes();
     f1.write(&bytes).expect("");
 }
+

math/int2str/src/main.rs

@@ -1,4 +1,9 @@
-use std::{fs::File, io::Read, os::unix::io::FromRawFd};
+
+use std::{
+    fs::File,
+    io::{Read},
+    os::unix::io::FromRawFd
+};
 
 fn main() {
     nested::magic_header();
@@ -6,18 +11,15 @@ fn main() {
     nested::magic_header();
 
     let mut f0 = unsafe { File::from_raw_fd(0) };
-    eprintln!(
+    eprintln!("
-        "
 >0:
   ( ℕ )
   ( MachineInt )
   ( MachineWord )
   ( Stream MachineSyllab )
-"
+");
-    );
 
-    eprintln!(
+    eprintln!("
-        "
 <1:
   ( ℕ )
   ( PositionalInt 10 BigEndian )
@@ -25,8 +27,7 @@ fn main() {
   ( Sequence UTF-8-Char )
   ( Stream UTF-8-Char )
   ( Stream MachineSyllab )
-"
+");
-    );
 
     nested::magic_header();
 
@@ -34,3 +35,4 @@ fn main() {
     f0.read_exact(&mut bytes).expect("");
     println!("{}", u64::from_le_bytes(bytes));
 }
+

math/radix_transform/src/main.rs

@@ -1,68 +1,55 @@
-use nested::{
+
-    core::{TypeDict, ViewPort},
+use {
-    integer::RadixProjection,
+    nested::{
-    vec::VecBuffer,
+        core::{
+            ViewPort,
+            TypeDict
+        },
+        vec::{VecBuffer},
+        integer::{RadixProjection}
+    }
 };
 
 #[async_std::main]
 async fn main() {
     let mut td = TypeDict::new();
     for tn in vec![
-        "MachineWord",
+        "MachineWord", "MachineInt", "MachineSyllab",
-        "MachineInt",
+        "Vec", "Stream", "Json",
-        "MachineSyllab",
+        "Sequence", "UTF-8-Char",
-        "Vec",
+        "PositionalInt", "Digit", "LittleEndian", "BigEndian",
-        "Stream",
+        "DiffStream", "ℕ",
-        "Json",
+        "$src_radix", "$dst_radix"
-        "Sequence",
+    ] { td.add_typename(tn.into()); }
-        "UTF-8-Char",
-        "PositionalInt",
-        "Digit",
-        "LittleEndian",
-        "BigEndian",
-        "DiffStream",
-        "ℕ",
-        "$src_radix",
-        "$dst_radix",
-    ] {
-        td.add_typename(tn.into());
-    }
 
     let radix_types = vec![
         td.type_term_from_str("( ℕ )").unwrap(),
-        td.type_term_from_str("( PositionalInt 10 LittleEndian )")
+        td.type_term_from_str("( PositionalInt 10 LittleEndian )").unwrap(),
-            .unwrap(),
         td.type_term_from_str("( Sequence ( Digit 10 ) )").unwrap(),
         td.type_term_from_str("( Sequence UTF-8-Char )").unwrap(),
-        td.type_term_from_str("( Sequence MachineSyllab )").unwrap(),
+        td.type_term_from_str("( Sequence MachineSyllab )").unwrap()
     ];
 
     let src_types = vec![
         td.type_term_from_str("( ℕ )").unwrap(),
-        td.type_term_from_str("( PositionalInt $src_radix LittleEndian )")
+        td.type_term_from_str("( PositionalInt $src_radix LittleEndian )").unwrap(),
-            .unwrap(),
+        td.type_term_from_str("( Sequence ( Digit $src_radix ) )").unwrap(),
-        td.type_term_from_str("( Sequence ( Digit $src_radix ) )")
-            .unwrap(),
         td.type_term_from_str("( Sequence MachineInt )").unwrap(),
-        td.type_term_from_str("( DiffStream ( Vec MachineInt ) )")
+        td.type_term_from_str("( DiffStream ( Vec MachineInt ) )").unwrap(),
-            .unwrap(),
         td.type_term_from_str("( Json )").unwrap(),
         td.type_term_from_str("( Stream UTF-8-Char )").unwrap(),
-        td.type_term_from_str("( Stream MachineSyllab )").unwrap(),
+        td.type_term_from_str("( Stream MachineSyllab )").unwrap()
     ];
 
     let dst_types = vec![
         td.type_term_from_str("( ℕ )").unwrap(),
-        td.type_term_from_str("( PositionalInt $dst_radix LittleEndian )")
+        td.type_term_from_str("( PositionalInt $dst_radix LittleEndian )").unwrap(),
-            .unwrap(),
+        td.type_term_from_str("( Sequence ( Digit $dst_radix ) )").unwrap(),
-        td.type_term_from_str("( Sequence ( Digit $dst_radix ) )")
-            .unwrap(),
         td.type_term_from_str("( Sequence MachineInt )").unwrap(),
-        td.type_term_from_str("( DiffStream ( Vec MachineInt ) )")
+        td.type_term_from_str("( DiffStream ( Vec MachineInt ) )").unwrap(),
-            .unwrap(),
         td.type_term_from_str("( Json )").unwrap(),
         td.type_term_from_str("( Stream UTF-8-Char )").unwrap(),
-        td.type_term_from_str("( Stream MachineSyllab )").unwrap(),
+        td.type_term_from_str("( Stream MachineSyllab )").unwrap()
     ];
 
     nested::magic_header();
@@ -112,26 +99,27 @@ async fn main() {
         src_radix,
         dst_radix,
         src_digits_port.outer().to_sequence(),
-        dst_digits_port.inner(),
+        dst_digits_port.inner()
     );
 
     // output dst digits
     let writer = {
-        use std::os::unix::io::FromRawFd;
+        use std::{
+            os::unix::io::FromRawFd
+        };
 
-        dst_digits_port
+        dst_digits_port.outer().serialize_json(unsafe { std::fs::File::from_raw_fd(1) })
-            .outer()
-            .serialize_json(unsafe { std::fs::File::from_raw_fd(1) })
     };
 
     // start reading src digits
     {
-        use async_std::os::unix::io::FromRawFd;
+        use async_std::{
+            os::unix::io::FromRawFd
+        };
 
-        src_digits
+        src_digits.from_json(unsafe { async_std::fs::File::from_raw_fd(0) }).await;
-            .from_json(unsafe { async_std::fs::File::from_raw_fd(0) })
-            .await;
     }
 
     drop(writer);
 }
+

math/str2int/src/main.rs

@@ -1,7 +1,8 @@
+
 use std::{
     fs::File,
     io::{Read, Write},
-    os::unix::io::FromRawFd,
+    os::unix::io::FromRawFd
 };
 
 fn main() {
@@ -9,19 +10,16 @@ fn main() {
     eprintln!("       Parse MachineInt from String");
     nested::magic_header();
 
-    eprintln!(
+    eprintln!("
-        "
 $1: radix
   ( ℕ )
   ( PositionalInt 10 BigEndian )
   ( Sequence ( Digit 10 ) )
   ( Sequence UTF-8-Char )
   ( Sequence MachineSyllab )
-"
+");
-    );
 
-    eprintln!(
+    eprintln!("
-        "
 >0: n
   ( ℕ )
   ( PositionalInt $radix BigEndian )
@@ -29,18 +27,15 @@ $1: radix
   ( Sequence UTF-8-Char )
   ( Stream UTF-8-Char )
   ( Stream MachineSyllab )
-"
+");
-    );
 
-    eprintln!(
+    eprintln!("
-        "
 <1: n
   ( ℕ )
   ( MachineInt )
   ( MachineWord )
   ( Stream MachineSyllab )
-"
+");
-    );
 
     nested::magic_header();
 
@@ -60,10 +55,6 @@ $1: radix
     let mut chars = Vec::new();
     f0.read_to_end(&mut chars).expect("");
     chars.retain(|c| (*c as char).is_alphanumeric());
-    f1.write(
+    f1.write(&u64::from_str_radix(&String::from_utf8_lossy(&chars), radix).unwrap().to_le_bytes()).expect("");
-        &u64::from_str_radix(&String::from_utf8_lossy(&chars), radix)
-            .unwrap()
-            .to_le_bytes(),
-    )
-    .expect("");
 }
+

nested/Cargo.toml

@@ -5,12 +5,9 @@ name = "nested"
 version = "0.1.0"
 
 [dependencies]
-#r3vi = { git = "https://git.exobiont.de/senvas/lib-r3vi.git" }
-r3vi = { path = "../../lib-r3vi" }
-laddertypes = { path = "../../lib-laddertypes" }
 no_deadlocks = "*"
 cgmath = { version = "0.18.0", features = ["serde"] }
-termion = "2.0.1"
+termion = "1.5.5"
 vte = "0.10.1"
 ansi_colours = "1.0"
 signal-hook = "0.3.1"
@@ -19,6 +16,11 @@ serde = { version = "1.0", features = ["derive"] }
 bincode = "1.3.3"
 serde_json = "*"
 
+nako = {git= "https://git.exobiont.de/senvas/nako.git"}
+nako_std = {git= "https://git.exobiont.de/senvas/nako.git"}
+nakorender = {git="https://git.exobiont.de/senvas/nako.git", default-features = false}
+font-kit = "*"
+
 [dependencies.async-std]
 version = "1.9.0"
 features = ["unstable", "attributes"]

nested/src/bimap.rs

@@ -1,17 +1,20 @@
-use std::{collections::HashMap, hash::Hash};
+use std::{
+    collections::HashMap,
+    hash::Hash
+};
 
 //<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
 
 pub struct Bimap<V: Eq + Hash, Λ: Eq + Hash> {
-    pub mλ: HashMap<V, Λ>,
+    pub mλ: HashMap::<V, Λ>,
-    pub my: HashMap<Λ, V>,
+    pub my: HashMap::<Λ, V>
 }
 
 impl<V: Eq + Hash + Clone, Λ: Eq + Hash + Clone> Bimap<V, Λ> {
     pub fn new() -> Self {
         Bimap {
             mλ: HashMap::new(),
-            my: HashMap::new(),
+            my: HashMap::new()
         }
     }
 
@@ -22,3 +25,4 @@ impl<V: Eq + Hash + Clone, Λ: Eq + Hash + Clone> Bimap<V, Λ> {
 }
 
 //<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+

nested/src/commander.rs

@@ -1,17 +0,0 @@
-
-pub trait Commander {
-    type Cmd;
-
-    fn send_cmd(&mut self, cmd: &Self::Cmd);
-}
-
-use std::sync::{Arc, RwLock};
-use crate::{
-    type_system::ReprTree,
-    tree::{nav::TreeNavResult}
-};
-
-pub trait ObjCommander {
-    fn send_cmd_obj(&mut self, cmd_obj: Arc<RwLock<ReprTree>>) -> TreeNavResult;
-}
-

nested/src/core/channel.rs

@@ -0,0 +1,221 @@
+use {
+    core::{
+        task::{Poll, Context, Waker},
+        pin::Pin
+    },
+    std::{
+        sync::{Arc, Mutex},
+        collections::HashSet,
+        hash::Hash
+    },
+    async_std::{
+        stream::Stream
+    },
+
+    crate::{
+        core::{Observer}
+    }
+};
+
+
+                    /*\
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+                  Traits
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+                    \*/
+pub trait ChannelData : Default + IntoIterator + Send + Sync {
+    fn channel_insert(&mut self, x: Self::Item);
+}
+
+
+                    /*\
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+               Queue Channel
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+                    \*/
+impl<T> ChannelData for Vec<T>
+where T: Send + Sync {
+    fn channel_insert(&mut self, x: T) {
+        self.push(x);
+    }
+}
+
+                    /*\
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+                 Set Channel
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+                    \*/
+impl<T> ChannelData for HashSet<T>
+where T: Eq + Hash + Send + Sync {
+    fn channel_insert(&mut self, x: T) {
+        self.insert(x);
+    }
+}
+
+                    /*\
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+             Singleton Channel
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+                    \*/
+impl<T> ChannelData for Option<T>
+where T: Send + Sync {
+    fn channel_insert(&mut self, x: T) {
+        *self = Some(x);
+    }
+}
+
+                    /*\
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+                  Channel
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+                    \*/
+struct ChannelState<Data: ChannelData> {
+    send_buf: Option<Data>,
+    recv_iter: Option<Data::IntoIter>,
+    num_senders: usize,
+    waker: Option<Waker>
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct ChannelSender<Data: ChannelData>(Arc<Mutex<ChannelState<Data>>>);
+pub struct ChannelReceiver<Data: ChannelData>(Arc<Mutex<ChannelState<Data>>>);
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<Data: ChannelData> ChannelSender<Data>
+where Data::IntoIter: Send + Sync {
+    pub fn send(&self, msg: Data::Item) {
+        let mut state = self.0.lock().unwrap();
+
+        if state.send_buf.is_none() {
+            state.send_buf = Some(Data::default());
+        }
+
+        state.send_buf.as_mut().unwrap().channel_insert(msg);
+
+        if let Some(waker) = state.waker.take() {
+            waker.wake();
+        }
+    }
+}
+
+use crate::core::View;
+impl<V: View + ?Sized, Data: ChannelData<Item = V::Msg>> Observer<V> for ChannelSender<Data>
+where V::Msg: Clone, Data::IntoIter: Send + Sync {
+    fn notify(&mut self, msg: &V::Msg) {
+        self.send(msg.clone());
+    }
+}
+
+impl<Data: ChannelData> Clone for ChannelSender<Data> {
+    fn clone(&self) -> Self {
+        self.0.lock().unwrap().num_senders += 1;
+        ChannelSender(self.0.clone())
+    }
+}
+
+impl<Data: ChannelData> Drop for ChannelSender<Data> {
+    fn drop(&mut self) {
+        let mut state = self.0.lock().unwrap();
+        state.num_senders -= 1;
+        if let Some(waker) = state.waker.take() {
+            waker.wake();
+        }
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<Data: ChannelData> ChannelReceiver<Data> {
+    pub async fn recv(&self) -> Option<Data> {
+        ChannelRead(self.0.clone()).await
+    }
+
+    pub fn try_recv(&self) -> Option<Data> {
+        let mut state = self.0.lock().unwrap();
+        if let Some(buf) = state.send_buf.take() {
+            Some(buf)
+        } else {
+            None
+        }        
+    }
+}
+
+struct ChannelRead<Data: ChannelData>(Arc<Mutex<ChannelState<Data>>>);
+impl<Data: ChannelData> std::future::Future for ChannelRead<Data> {
+    type Output = Option<Data>;
+
+    fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
+        let mut state = self.0.lock().unwrap();
+        if let Some(buf) = state.send_buf.take() {
+            Poll::Ready(Some(buf))
+        } else if state.num_senders == 0 {
+            Poll::Ready(None)
+        } else {
+            state.waker = Some(cx.waker().clone());
+            Poll::Pending
+        }
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<Data: ChannelData> Stream for ChannelReceiver<Data> {
+    type Item = Data::Item;
+
+    fn poll_next(
+        self: Pin<&mut Self>,
+        cx: &mut Context<'_>
+    ) -> Poll<Option<Self::Item>> {
+        let mut state = self.0.lock().unwrap();
+
+        if let Some(recv_iter) = state.recv_iter.as_mut() {
+            if let Some(val) = recv_iter.next() {
+                return Poll::Ready(Some(val))
+            } else {
+                state.recv_iter = None
+            }
+        }
+
+        if let Some(send_buf) = state.send_buf.take() {
+            state.recv_iter = Some(send_buf.into_iter());
+            // recv_iter.next() is guaranteed to be Some(x)
+            Poll::Ready(state.recv_iter.as_mut().unwrap().next())
+        } else if state.num_senders == 0 {
+            Poll::Ready(None)
+        } else {
+            state.waker = Some(cx.waker().clone());
+            Poll::Pending
+        }
+    }
+}
+
+                    /*\
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+             Factory Functions
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+                    \*/
+pub fn channel<Data: ChannelData>() -> (ChannelSender<Data>, ChannelReceiver<Data>) {
+    let state = Arc::new(Mutex::new(ChannelState{
+        send_buf: None,
+        recv_iter: None,
+        num_senders: 1,
+        waker: None
+    }));
+
+    (ChannelSender(state.clone()), ChannelReceiver(state))
+}
+
+pub fn set_channel<T: Eq + Hash + Send + Sync>() -> (ChannelSender<HashSet<T>>, ChannelReceiver<HashSet<T>>) {
+    channel::<HashSet<T>>()
+}
+
+pub fn queue_channel<T: Send + Sync>() -> (ChannelSender<Vec<T>>, ChannelReceiver<Vec<T>>) {
+    channel::<Vec<T>>()
+}
+
+pub fn singleton_channel<T: Send + Sync>() -> (ChannelSender<Option<T>>, ChannelReceiver<Option<T>>) {
+    channel::<Option<T>>()
+}
+

nested/src/core/context.rs

@@ -0,0 +1,394 @@
+use {
+    std::{
+        collections::HashMap,
+        sync::{Arc, RwLock}
+    },
+    crate::{
+        core::{
+            type_term::{
+                TypeTerm,
+                TypeDict
+            },
+            View,
+            OuterViewPort,
+            AnyOuterViewPort
+        }
+    }
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+#[derive(Clone)]
+pub struct ReprTree {
+    port: Option<AnyOuterViewPort>,
+    branches: HashMap<TypeTerm, Arc<RwLock<ReprTree>>>
+}
+
+impl ReprTree {
+    pub fn new() -> Self {
+        ReprTree {
+            port: None,
+            branches: HashMap::new()
+        }
+    }
+
+    pub fn new_leaf(
+        port: AnyOuterViewPort
+    ) -> Arc<RwLock<Self>> {
+        let mut tree = ReprTree::new();
+        tree.insert_leaf(vec![].into_iter(), port);
+        Arc::new(RwLock::new(tree))
+    }
+
+    pub fn insert_branch(
+        &mut self,
+        type_tag: TypeTerm,
+        repr: Arc<RwLock<ReprTree>>
+    ) {
+        self.branches.insert(type_tag, repr);
+    }
+
+    pub fn insert_leaf(
+        &mut self,
+        mut type_ladder: impl Iterator<Item = TypeTerm>,
+        port: AnyOuterViewPort
+    ) {
+        if let Some(type_term) = type_ladder.next() {
+            if let Some(next_repr) = self.branches.get(&type_term) {
+                next_repr.write().unwrap().insert_leaf(type_ladder, port);
+            } else {
+                let mut next_repr = ReprTree::new();
+                next_repr.insert_leaf(type_ladder, port);
+                self.insert_branch(type_term, Arc::new(RwLock::new(next_repr)));
+            }
+        } else {
+            self.port = Some(port);
+        }
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+#[derive(Clone)]
+pub struct Object {
+    pub type_tag: TypeTerm,
+    pub repr: Arc<RwLock<ReprTree>>
+}
+
+impl Object {
+    pub fn get_port<V: View + ?Sized + 'static>(&self) -> Option<OuterViewPort<V>> where V::Msg: Clone {
+        Some(self.repr.read().unwrap().port.clone()?.downcast::<V>().ok().unwrap())
+    }
+
+    pub fn downcast(&self, dst_type: TypeTerm) -> Option<Object> {
+        if let Some(repr) = self.repr.read().unwrap().branches.get(&dst_type) {
+            Some(Object {
+                type_tag: dst_type,
+                repr: repr.clone()
+            })
+        } else {
+            None
+        }
+    }
+
+    fn downcast_ladder(
+        &self,
+        repr_ladder: impl Iterator<Item = TypeTerm>
+    ) -> Option<Object> {
+        repr_ladder.fold(
+            Some(self.clone()),
+            |s, t| s?.downcast(t.clone())
+        )
+    }
+
+    pub fn add_iso_repr(
+        &self,
+        type_ladder: impl Iterator<Item = TypeTerm>,
+        morphism_constructors: &HashMap<MorphismType, Box<dyn Fn(Object) -> Object>>
+    ) {
+        let mut cur_repr = self.repr.clone();
+
+        for dst_type in type_ladder {
+            if let Some(next_repr) = self.repr.read().unwrap().branches.get(&dst_type) {
+                // go deeper
+                cur_repr = next_repr.clone();
+            } else {
+                // search for morphism constructor and insert new repr
+                let mut obj = None;
+
+                for src_type in cur_repr.read().unwrap().branches.keys() {
+                    if let Some(ctor) = morphism_constructors.get(
+                        &MorphismType {
+                            mode: MorphismMode::Iso,
+                            src_type: src_type.clone(),
+                            dst_type: dst_type.clone()
+                        }
+                    ) {
+                        let new_obj = ctor(
+                            Object {
+                                type_tag: src_type.clone(),
+                                repr: cur_repr.read().unwrap()
+                                    .branches
+                                    .get(&src_type).unwrap().clone()
+                            }
+                        );
+
+                        assert!(new_obj.type_tag == dst_type);
+
+                        obj = Some(new_obj);
+                        break;
+                    }
+                }
+
+                if let Some(obj) = obj {
+                    cur_repr.write().unwrap().insert_branch(obj.type_tag, obj.repr);
+                } else {
+                    panic!("could not find matching isomorphism!");
+                }
+            }
+        }
+    }
+
+    pub fn add_mono_repr<'a>(
+        &self,
+        type_ladder: impl Iterator<Item = TypeTerm>,
+        morphism_constructors: &HashMap<MorphismType, Box<dyn Fn(Object) -> Object>>
+    ) {
+        let mut cur_type = self.type_tag.clone();
+        let mut cur_repr = self.repr.clone();
+
+        for dst_type in type_ladder {
+            if let Some(next_repr) = self.repr.read().unwrap().branches.get(&dst_type) {
+                // go deeper
+                cur_type = dst_type;
+                cur_repr = next_repr.clone();
+            } else {
+                if let Some(constructor) = morphism_constructors.get(
+                    &MorphismType {
+                        mode: MorphismMode::Mono,
+                        src_type: cur_type.clone(),
+                        dst_type: dst_type.clone()
+                    }
+                ) {
+                    let new_obj = constructor(
+                        Object {
+                            type_tag: cur_type.clone(),
+                            repr: cur_repr.read().unwrap()
+                                .branches
+                                .get(&cur_type).unwrap().clone()
+                        }
+                    );
+
+                    assert!(new_obj.type_tag == dst_type);
+                    cur_repr.write().unwrap().insert_branch(new_obj.type_tag.clone(), new_obj.repr.clone());
+
+                    cur_type = new_obj.type_tag;
+                    cur_repr = new_obj.repr;
+                }
+            }
+        }
+    }
+
+    // replace with higher-level type in which self is a repr branch
+    pub fn epi_cast<'a>(
+        &self,
+        _type_ladder: impl Iterator<Item = TypeTerm>,
+        _morphism_constructors: &HashMap<MorphismType, Box<dyn Fn(Object) -> Object>>
+    ) {
+        // todo        
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct TypeLadder(Vec<TypeTerm>);
+
+#[derive(Clone, Copy, Hash, PartialEq, Eq)]
+pub enum MorphismMode {
+    /// Isomorphism
+    /// e.g. `( PositionalInteger 10 BigEndian ) <~> ( PositionalInteger 16 LittleEndian )`
+    Iso,
+
+    /// Monomorphism, i.e. injective functions,
+    /// upcast-view, downcast-control, semantic gain
+    /// e.g. `( Sequence ( Digit 16 ) ) ~> ( PositionalInteger 16 LittleEndian )`
+    Mono,
+
+    /// Epimorphsim, i.e. surjective functions,
+    /// upcast-control, downcast-view, possible loss of entropy
+    /// e.g. `( Ascii ) ~> ( Digit 16 )`
+    Epi,
+
+    /// Any other function
+    Any
+}
+
+#[derive(Clone, Hash, PartialEq, Eq)]
+pub struct MorphismType {
+    pub mode: MorphismMode,
+    pub src_type: TypeTerm,
+    pub dst_type: TypeTerm
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct Context {
+    type_dict: TypeDict,
+    default_constructors: HashMap<TypeTerm, Box<dyn Fn() -> Object + Send + Sync>>,
+    morphism_constructors: HashMap<MorphismType, Box<dyn Fn(Object) -> Object + Send + Sync>>,
+    objects: HashMap<String, Object>,
+    parent: Option<Arc<RwLock<Context>>>
+}
+
+impl Context {
+    pub fn with_parent(parent: Option<Arc<RwLock<Context>>>) -> Self {
+        Context {
+            type_dict: TypeDict::new(),
+            default_constructors: HashMap::new(),
+            morphism_constructors: HashMap::new(),
+            objects: HashMap::new(),
+            parent
+        }
+    }
+
+    pub fn new() -> Self {
+        Context::with_parent(None)
+    }
+
+    pub fn add_typename(&mut self, tn: String) {
+        self.type_dict.add_typename(tn);
+    }
+
+    pub fn type_term_from_str(&self, tn: &str) -> Option<TypeTerm> {
+        self.type_dict.type_term_from_str(&tn)
+    }
+
+    pub fn add_morphism(
+        &mut self,
+        morph_type: MorphismType,
+        morph_fn: Box<dyn Fn(Object) -> Object + Send + Sync>
+    ) {
+        self.morphism_constructors.insert(morph_type, morph_fn);
+    }
+
+    /// adds an object without any representations
+    pub fn add_obj(
+        &mut self,
+        name: String,
+        typename: &str
+    ) {
+        let type_tag = self.type_dict.type_term_from_str(typename).unwrap();
+
+        self.objects.insert(
+            name,
+            if let Some(ctor) = self.default_constructors.get(&type_tag) {
+                ctor()
+            } else {
+                Object {
+                    type_tag,
+                    repr: Arc::new(RwLock::new(ReprTree::new()))
+                }
+            }
+        );
+    }
+
+    pub fn get_obj(
+        &self,
+        name: &String
+    ) -> Option<Object> {
+        if let Some(obj) = self.objects.get(name) {
+            Some(obj.clone())
+        } else if let Some(parent) = self.parent.as_ref() {
+            parent.read().unwrap().get_obj(name)
+        } else {
+            None
+        }
+    }
+ 
+    pub fn get_obj_port<
+        'a,
+        V: View + ?Sized + 'static
+    >(
+        &self,
+        name: &str,
+        type_ladder: impl Iterator<Item = &'a str>
+    ) -> Option<OuterViewPort<V>>
+    where V::Msg: Clone {
+        self.get_obj(&name.into())?
+            .downcast_ladder(
+                type_ladder.map(|tn| self.type_dict.type_term_from_str(tn).unwrap())
+            )?
+            .get_port()
+    }
+
+    pub fn insert_repr<'a>(
+        &mut self,
+        name: &str,
+        type_ladder: impl Iterator<Item = &'a str>,
+        port: AnyOuterViewPort
+    ) {
+        self.get_obj(&name.to_string()).unwrap()
+            .repr.write().unwrap()
+            .insert_leaf(
+                type_ladder.map(|tn| self.type_dict.type_term_from_str(tn).unwrap()),
+                port
+            );
+    }
+
+    pub fn epi_cast(
+        &mut self,
+        name: &str,
+        typename: &str
+    ) {
+        let dst_type = self.type_dict.type_term_from_str(typename).unwrap();
+        let old_obj = self.objects.get(&name.to_string()).unwrap().clone();
+        let new_obj =
+            if let Some(ctor) = self.morphism_constructors.get(
+                &MorphismType {
+                    mode: MorphismMode::Epi,
+                    src_type: old_obj.type_tag.clone(),
+                    dst_type: dst_type.clone()
+                }
+            ) {
+                ctor(old_obj.clone())
+            } else {
+                Object {
+                    type_tag: dst_type,
+                    repr: Arc::new(RwLock::new(ReprTree::new()))
+                }
+            };
+
+        new_obj.repr.write().unwrap().insert_branch(
+            old_obj.type_tag,
+            old_obj.repr
+        );
+
+        self.objects.insert(name.to_string(), new_obj);
+    }
+
+    pub fn mono_view<'a, V: View + ?Sized + 'static>(
+        &mut self,
+        name: &str,
+        type_ladder: impl Iterator<Item = &'a str>
+    ) -> Option<OuterViewPort<V>>
+    where V::Msg: Clone {
+        if let Some(p) = self.get_obj_port(name, type_ladder) {
+            Some(p)
+        } else {
+            // todo : add repr with morphism constructor (if one exists)
+            /*
+            if let Some(ctor) = self.morphism_constructors.get(
+                &MorphismType {
+                    mode: MorphismMode::Mono,
+                    src_type: old_obj.type_tag.clone(),
+                    dst_type: 
+                }
+            )
+            */
+            None
+        }
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+

nested/src/core/mod.rs

@@ -0,0 +1,47 @@
+
+pub mod view;
+pub mod observer;
+pub mod channel;
+pub mod port;
+pub mod type_term;
+pub mod context;
+
+pub use {
+    view::{View},
+    observer::{
+        Observer,
+        ObserverExt,
+        ObserverBroadcast,
+        NotifyFnObserver,
+        ResetFnObserver
+    },
+    channel::{
+        ChannelReceiver,
+        ChannelSender,
+        set_channel,
+        queue_channel,
+        singleton_channel
+    },
+    port::{
+        ViewPort,
+        InnerViewPort,
+        OuterViewPort,
+        AnyViewPort,
+        AnyOuterViewPort,
+        AnyInnerViewPort,
+    },
+    type_term::{
+        TypeID,
+        TypeTerm,
+        TypeDict,
+    },
+    context::{
+        ReprTree,
+        Object,
+        Context,
+        MorphismMode,
+        MorphismType
+    }
+};
+
+

nested/src/core/observer.rs

@@ -0,0 +1,166 @@
+use {
+    crate::{
+        core::{
+            View,
+            channel::{channel, ChannelSender, ChannelReceiver}
+        }
+    },
+    std::{
+        sync::{Arc, Weak}
+    },
+    std::sync::RwLock
+};
+
+                    /*\
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+                 Observer
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+                    \*/
+pub trait Observer<V: View + ?Sized> : Send + Sync {
+    fn reset(&mut self, _view: Option<Arc<V>>) {}
+    fn notify(&mut self, msg: &V::Msg);
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<V: View + ?Sized, O: Observer<V>> Observer<V> for Arc<RwLock<O>> {
+    fn reset(&mut self, view: Option<Arc<V>>) {
+        self.write().unwrap().reset(view);
+    }
+
+    fn notify(&mut self, msg: &V::Msg) {
+        self.write().unwrap().notify(msg);
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub trait ObserverExt<V: View + ?Sized> : Observer<V> {    
+    fn notify_each(&mut self, it: impl IntoIterator<Item = V::Msg>);
+}
+
+impl<V: View + ?Sized, T: Observer<V>> ObserverExt<V> for T {
+    fn notify_each(&mut self, it: impl IntoIterator<Item = V::Msg>) {
+        for msg in it {
+            self.notify(&msg);
+        }
+    }
+}
+
+                    /*\
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+                 Broadcast
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+                    \*/
+pub struct ObserverBroadcast<V: View + ?Sized>
+where V::Msg : Send + Sync {
+    rx: ChannelReceiver<Vec<V::Msg>>,
+    tx: ChannelSender<Vec<V::Msg>>,
+    observers: Vec<Weak<RwLock<dyn Observer<V>>>>
+}
+
+impl<V: View + ?Sized> ObserverBroadcast<V>
+where V::Msg : Clone + Send + Sync {
+    pub fn new() -> Self {
+        let (tx, rx) = channel::<Vec<V::Msg>>();
+        ObserverBroadcast {
+            rx, tx,
+            observers: Vec::new()
+        }
+    }
+
+    pub fn add_observer(&mut self, obs: Weak<RwLock<dyn Observer<V>>>) {
+        self.cleanup();
+        self.observers.push(obs);
+    }
+
+    fn cleanup(&mut self) {
+        self.observers.retain(|o| o.strong_count() > 0);
+    }
+
+    fn iter(&self) -> impl Iterator<Item = Arc<RwLock<dyn Observer<V>>>> + '_ {
+        self.observers.iter().filter_map(|o| o.upgrade())
+    }
+
+    pub fn update(&self) {
+        if let Some(msg_vec) = self.rx.try_recv() {
+            for msg in msg_vec {
+                for o in self.iter() {
+                    o.write().unwrap().notify(&msg);
+                }
+            }
+        }
+    }
+}
+
+impl<V: View + ?Sized> Observer<V> for ObserverBroadcast<V>
+where V::Msg: Clone {
+    fn reset(&mut self, view: Option<Arc<V>>) {
+        for o in self.iter() {
+            o.write().unwrap().reset(view.clone());
+        }
+    }
+
+    fn notify(&mut self, msg: &V::Msg) {
+        self.tx.send(msg.clone());
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct NotifyFnObserver<V, F>
+where V: View + ?Sized,
+      F: Fn(&V::Msg) + Send + Sync {
+    f: F,
+    _phantom: std::marker::PhantomData<V>
+}
+
+impl<V, F> NotifyFnObserver<V, F>
+where V: View + ?Sized,
+      F: Fn(&V::Msg) + Send + Sync {
+    pub fn new(f: F) -> Self {
+        NotifyFnObserver {
+            f,
+            _phantom: std::marker::PhantomData
+        }
+    }
+}
+
+impl<V, F> Observer<V> for NotifyFnObserver<V, F>
+where V: View + ?Sized,
+      F: Fn(&V::Msg) + Send + Sync {
+    fn notify(&mut self, msg: &V::Msg) {
+        (self.f)(msg);
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct ResetFnObserver<V, F>
+where V: View + ?Sized,
+      F: Fn(Option<Arc<V>>) + Send + Sync {
+    f: F,
+    _phantom: std::marker::PhantomData<V>
+}
+
+impl<V, F> ResetFnObserver<V, F>
+where V: View + ?Sized,
+      F: Fn(Option<Arc<V>>) + Send + Sync {
+    pub fn new(f: F) -> Self {
+        ResetFnObserver {
+            f,
+            _phantom: std::marker::PhantomData
+        }
+    }
+}
+
+impl<V, F> Observer<V> for ResetFnObserver<V, F>
+where V: View + ?Sized,
+      F: Fn(Option<Arc<V>>) + Send + Sync {
+    fn notify(&mut self, _msg: &V::Msg) {}
+    fn reset(&mut self, view: Option<Arc<V>>) {
+        (self.f)(view);
+    }
+}
+
+

nested/src/core/port.rs

@@ -0,0 +1,295 @@
+use {
+    std::sync::Arc,
+    std::any::Any,
+    std::sync::RwLock,
+    crate::core::{
+        View,
+        Observer,
+        ObserverBroadcast,
+        NotifyFnObserver,
+        ResetFnObserver
+    }
+};
+
+
+pub trait UpdateTask : Send + Sync {
+    fn update(&self);
+}
+
+                    /*\
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+                 View Port
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+                    \*/
+pub struct ViewPort<V: View + ?Sized> {
+    view: Arc<RwLock<Option<Arc<V>>>>,
+    cast: Arc<RwLock<ObserverBroadcast<V>>>,
+    pub update_hooks: Arc<RwLock<Vec<Arc<dyn UpdateTask>>>>
+}
+
+impl<V: View + ?Sized> ViewPort<V>
+where V::Msg: Clone {
+    pub fn new() -> Self {
+        ViewPort {
+            view: Arc::new(RwLock::new(None)),
+            cast: Arc::new(RwLock::new(ObserverBroadcast::new())),
+            update_hooks: Arc::new(RwLock::new(Vec::new()))
+        }
+    }
+
+    pub fn with_view(view: Arc<V>) -> Self {
+        let port = ViewPort::new();
+        port.set_view(Some(view));
+        port
+    }
+
+    pub fn set_view(&self, view: Option<Arc<V>>) {
+        self.update();
+        *self.view.write().unwrap() = view.clone();
+        self.cast.write().unwrap().reset(view);
+    }
+
+    pub fn add_observer(&self, observer: Arc<RwLock<dyn Observer<V>>>) {
+        self.update();
+        self.cast.write().unwrap().add_observer(Arc::downgrade(&observer));
+        observer.write().unwrap().reset(self.view.read().unwrap().clone());
+    }
+
+    pub fn add_update_hook(&self, hook_cast: Arc<dyn UpdateTask>) {
+        self.update_hooks.write().unwrap().push(hook_cast);
+    }
+
+    pub fn inner(&self) -> InnerViewPort<V> {
+        InnerViewPort(
+            ViewPort{
+                view: self.view.clone(),
+                cast: self.cast.clone(),
+                update_hooks: self.update_hooks.clone()
+            }
+        )
+    }
+
+    pub fn outer(&self) -> OuterViewPort<V> {
+        OuterViewPort(
+            ViewPort{
+                view: self.view.clone(),
+                cast: self.cast.clone(),
+                update_hooks: self.update_hooks.clone()
+            }
+        )
+    }
+
+    pub fn into_inner(self) -> InnerViewPort<V> {
+        InnerViewPort(
+            ViewPort{
+                view: self.view,
+                cast: self.cast,
+                update_hooks: self.update_hooks
+            }
+        )
+    }
+
+    pub fn into_outer(self) -> OuterViewPort<V> {
+        OuterViewPort(
+            ViewPort{
+                view: self.view,
+                cast: self.cast,
+                update_hooks: self.update_hooks
+            }
+        )
+    }
+}
+
+impl<V: View + ?Sized> UpdateTask for ViewPort<V> where V::Msg: Clone + Send + Sync{
+    fn update(&self) {
+        let v = {
+            let t = self.update_hooks.read().unwrap();
+            t.iter().cloned().collect::<Vec<_>>()
+        };
+
+        for hook in v {
+            hook.update();
+        }
+
+        self.cast.read().unwrap().update();
+    }
+}
+
+
+impl<V: View + ?Sized> Clone for ViewPort<V>
+where V::Msg: Clone {
+    fn clone(&self) -> Self {
+        ViewPort {
+            view: self.view.clone(),
+            cast: self.cast.clone(),
+            update_hooks: self.update_hooks.clone()
+        }
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct InnerViewPort<V: View + ?Sized>(pub ViewPort<V>) where V::Msg: Clone;
+pub struct OuterViewPort<V: View + ?Sized>(pub ViewPort<V>) where V::Msg: Clone;
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<V: View + ?Sized> InnerViewPort<V> where V::Msg: Clone {
+    pub fn get_broadcast(&self) -> Arc<RwLock<ObserverBroadcast<V>>> {
+        self.0.cast.clone()
+    }
+
+    pub fn set_view(&self, view: Option<Arc<V>>) -> Arc<RwLock<ObserverBroadcast<V>>> {
+        self.0.set_view(view);
+        self.get_broadcast()
+    }
+
+    pub fn get_view(&self) -> Option<Arc<V>> {
+        self.0.view.read().unwrap().clone()
+    }
+
+    pub fn notify(&self, msg: &V::Msg) {
+        self.0.cast.write().unwrap().notify(msg);
+    }
+}
+
+impl<V: View + ?Sized> Clone for InnerViewPort<V>
+where V::Msg: Clone {
+    fn clone(&self) -> Self {
+        InnerViewPort(self.0.clone())
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<V: View + ?Sized + 'static> OuterViewPort<V>
+where V::Msg: Clone {
+    pub fn get_view(&self) -> Option<Arc<V>> {
+        self.0.view.read().unwrap().clone()
+    }
+
+    pub fn get_view_arc(&self) -> Arc<RwLock<Option<Arc<V>>>> {
+        self.0.view.clone()
+    }
+
+    pub fn add_observer(&self, observer: Arc<RwLock<dyn Observer<V>>>) -> Arc<RwLock<Option<Arc<V>>>> {
+        self.0.add_observer(observer);
+        self.get_view_arc()
+    }
+
+    pub fn add_reset_fn<F: Fn(Option<Arc<V>>) + Send + Sync + 'static>(&self, reset: F) -> Arc<RwLock<ResetFnObserver<V, F>>> {
+        let obs = Arc::new(RwLock::new(ResetFnObserver::new(reset)));
+        self.add_observer(obs.clone());
+        obs
+    }
+
+    pub fn add_notify_fn<F: Fn(&V::Msg) + Send + Sync + 'static>(&self, notify: F) -> Arc<RwLock<NotifyFnObserver<V, F>>> {
+        let obs = Arc::new(RwLock::new(NotifyFnObserver::new(notify)));
+        self.add_observer(obs.clone());
+        obs
+    }
+}
+
+impl<V: View + ?Sized> Clone for OuterViewPort<V>
+where V::Msg: Clone {
+    fn clone(&self) -> Self {
+        OuterViewPort(self.0.clone())
+    }
+}
+
+/*
+impl<V: View + ?Sized + 'static> OuterViewPort<V>
+where V::Msg: Clone {
+    pub fn into_stream<Data>(
+        self,
+        reset: impl Fn(Option<Arc<V>>, ChannelSender<Data>) + Send + Sync + 'static
+    ) -> ChannelReceiver<Data>
+    where Data: ChannelData<Item = V::Msg> + 'static,
+          Data::IntoIter: Send + Sync + 'static
+    {
+        let (s, r) = crate::core::channel::channel::<Data>();
+        self.add_observer(Arc::new(s.clone()));
+        self.add_reset_fn(
+            move |view| { reset(view, s.clone()); }
+        );
+        r
+    }
+}
+*/
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+#[derive(Clone)]
+pub struct AnyViewPort {
+    view: Arc<dyn Any + Send + Sync + 'static>,
+    cast: Arc<dyn Any + Send + Sync + 'static>,
+    update_hooks: Arc<RwLock<Vec<Arc<dyn UpdateTask>>>>
+}
+
+impl AnyViewPort {
+    pub fn downcast<V: View + ?Sized + 'static>(self) -> Result<ViewPort<V>, AnyViewPort> {
+        match (
+            self.view.clone().downcast::<RwLock<Option<Arc<V>>>>(),
+            self.cast.clone().downcast::<RwLock<ObserverBroadcast<V>>>(),
+            self.update_hooks.clone()
+        ) {
+            (Ok(view), Ok(cast), update_hooks) => Ok(ViewPort{view, cast, update_hooks}),
+            _ => Err(self)
+        }
+    }
+}
+
+impl<V: View + ?Sized + 'static> From<ViewPort<V>> for AnyViewPort {
+    fn from(port: ViewPort<V>) -> Self {
+        AnyViewPort {
+            view: port.view as Arc<dyn Any + Send + Sync + 'static>,
+            cast: port.cast as Arc<dyn Any + Send + Sync + 'static>,
+            update_hooks: port.update_hooks
+        }
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+#[derive(Clone)]
+pub struct AnyOuterViewPort(AnyViewPort);
+
+#[derive(Clone)]
+pub struct AnyInnerViewPort(AnyViewPort);
+
+impl AnyOuterViewPort {
+    pub fn downcast<V: View + ?Sized + 'static>(self) -> Result<OuterViewPort<V>, AnyViewPort> where V::Msg: Clone {
+        Ok(OuterViewPort(self.0.downcast::<V>()?))
+    }
+}
+
+impl<V: View + ?Sized + 'static> From<OuterViewPort<V>> for AnyOuterViewPort
+where V::Msg: Clone {
+    fn from(port: OuterViewPort<V>) -> Self {
+        AnyOuterViewPort(AnyViewPort{
+            view: port.0.view as Arc<dyn Any + Send + Sync + 'static>,
+            cast: port.0.cast as Arc<dyn Any + Send + Sync + 'static>,
+            update_hooks: port.0.update_hooks
+        })
+    }
+}
+
+impl AnyInnerViewPort {
+    pub fn downcast<V: View + ?Sized + 'static>(self) -> Result<InnerViewPort<V>, AnyViewPort> where V::Msg: Clone {
+        Ok(InnerViewPort(self.0.downcast::<V>()?))
+    }
+}
+
+impl<V: View + ?Sized + 'static> From<InnerViewPort<V>> for AnyInnerViewPort
+where V::Msg: Clone {
+    fn from(port: InnerViewPort<V>) -> Self {
+        AnyInnerViewPort(AnyViewPort{
+            view: port.0.view as Arc<dyn Any + Send + Sync + 'static>,
+            cast: port.0.cast as Arc<dyn Any + Send + Sync + 'static>,
+            update_hooks: port.0.update_hooks
+        })
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+

nested/src/core/type_term.rs

@@ -0,0 +1,163 @@
+use {
+    std::{
+        collections::HashMap
+    },
+    crate::{
+        bimap::Bimap,
+    }
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub type TypeID = u64;
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+#[derive(Clone, PartialEq, Eq, Hash)]
+pub enum TypeTerm {
+    Type {
+        id: TypeID,
+        args: Vec<TypeTerm>
+    },
+    Num(i64)
+}
+
+impl TypeTerm {
+    pub fn new(id: TypeID) -> Self {
+        TypeTerm::Type{ id, args: vec![] }
+    }
+
+    pub fn arg(&mut self, t: TypeTerm) -> &mut Self {
+        if let TypeTerm::Type{ id: _, args } = self {
+            args.push(t);
+        }
+
+        self
+    }
+
+    pub fn num_arg(&mut self, v: i64) -> &mut Self {
+        self.arg(TypeTerm::Num(v))
+    }
+
+    pub fn from_str(s: &str, names: &HashMap<String, u64>) -> Option<Self> {
+        let mut term_stack = Vec::<Option<TypeTerm>>::new();
+
+        for token in s.split_whitespace() {
+            match token {
+                "(" => {
+                    term_stack.push(None);
+                },
+                ")" => {
+                    let t = term_stack.pop().unwrap();
+                    if term_stack.len() > 0 {
+                        let f = term_stack.last_mut().unwrap();
+                        if let Some(f) = f {
+                            f.arg(t.unwrap());
+                        } else {
+                            //error
+                        }
+                    } else {
+                        return t;
+                    }
+                },
+                atom => {
+                    let f = term_stack.last_mut().unwrap();
+
+                    match f {
+                        Some(f) =>
+                            if atom.chars().nth(0).unwrap().is_numeric() {
+                                f.num_arg(i64::from_str_radix(atom, 10).unwrap());
+                            } else {
+                                f.arg(TypeTerm::new(*names.get(atom).expect(&format!("invalid atom {}", atom))));
+                            }
+                        None => {
+                            *f = Some(TypeTerm::new(*names.get(atom).expect(&format!("invalid atom {}", atom))));
+                        }
+                    }
+                }
+            }
+        }
+
+        None
+    }
+
+    // only adds parenthesis where args.len > 0
+    pub fn to_str1(&self, names: &HashMap<u64, String>) -> String {
+        match self {
+            TypeTerm::Type{ id, args } =>
+                if args.len() > 0 {
+                    format!(
+                        "( {} {})",
+                        names[id],
+                        if args.len() > 0 {
+                            args.iter().fold(
+                                String::new(),
+                                |str, term| format!("{}{} ", str, term.to_str1(names) )
+                            )
+                        } else {
+                            String::new()
+                        }
+                    )
+                } else {
+                    names[id].clone()
+                },
+
+            TypeTerm::Num(n) =>
+                format!("{}", n)
+        }
+    }
+
+    // always adds an enclosing pair of parenthesis
+    pub fn to_str(&self, names: &HashMap<u64, String>) -> String {
+        match self {
+            TypeTerm::Type{ id, args } =>
+                format!(
+                    "( {} {})",
+                    names[id],
+                    if args.len() > 0 {
+                        args.iter().fold(
+                            String::new(),
+                            |str, term| format!("{}{} ", str, term.to_str1(names) )
+                        )
+                    } else {
+                        String::new()
+                    }),
+
+            TypeTerm::Num(n) =>
+                format!("{}", n)
+        }
+    }
+
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct TypeDict {
+    typenames: Bimap::<String, u64>,
+    type_id_counter: u64
+}
+
+impl TypeDict {
+    pub fn new() -> Self {
+        TypeDict {
+            typenames: Bimap::new(),
+            type_id_counter: 0
+        }
+    }
+
+    pub fn add_typename(&mut self, tn: String) {
+        self.typenames.insert(tn, self.type_id_counter);
+        self.type_id_counter += 1;
+    }
+
+    pub fn type_term_from_str(&self, typename: &str) -> Option<TypeTerm> {
+        TypeTerm::from_str(typename, &self.typenames.mλ)
+    }
+
+    pub fn type_term_to_str(&self, term: &TypeTerm) -> String {
+        term.to_str(&self.typenames.my)
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+

nested/src/core/view.rs

@@ -0,0 +1,28 @@
+
+                    /*\
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+                   View
+<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+                    \*/
+pub trait View : Send + Sync {
+    /// Notification message for the observers
+    type Msg : Send + Sync;
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+use std::sync::Arc;
+use std::sync::RwLock;
+
+impl<V: View + ?Sized> View for RwLock<V> {
+    type Msg = V::Msg;
+}
+
+impl<V: View + ?Sized> View for Arc<V> {
+    type Msg = V::Msg;
+}
+
+impl<V: View> View for Option<V> {
+    type Msg = V::Msg;
+}
+

nested/src/diagnostics.rs

@@ -1,113 +0,0 @@
-use {
-    r3vi::{
-        view::{OuterViewPort, sequence::*},
-        buffer::{vec::*, index_hashmap::*}
-    },
-    crate::{
-        terminal::{
-            TerminalView, TerminalStyle, make_label
-        }
-    },
-    cgmath::Point2
-};
-
-#[derive(Clone)]
-pub struct Message {
-    pub addr: Vec<usize>,
-    pub port: OuterViewPort<dyn TerminalView>
-}
-
-pub trait Diagnostics {
-    fn get_msg_port(&self) -> OuterViewPort<dyn SequenceView<Item = Message>> {
-        VecBuffer::new().get_port().to_sequence()
-    }
-}
-
-pub fn make_error(msg: OuterViewPort<dyn TerminalView>) -> Message {
-    let mut mb = IndexBuffer::new();
-    mb.insert_iter(vec![
-        (Point2::new(0, 0),
-         make_label("error: ")
-         .map_item(|_p,a| a
-                   .add_style_back(TerminalStyle::bold(true))
-                   .add_style_back(TerminalStyle::fg_color((200,0,0))))
-        ),
-        (Point2::new(1, 0),
-         msg
-         .map_item(|_p,a| a
-                   .add_style_back(TerminalStyle::fg_color((180,180,180))))
-        )
-    ]);
-
-    Message {
-        addr: vec![],
-        port: mb.get_port().flatten()
-    }
-}
-
-pub fn make_warn(msg: OuterViewPort<dyn TerminalView>) -> Message {
-    let mut mb = IndexBuffer::new();
-    mb.insert_iter(vec![
-        (Point2::new(0, 0),
-         make_label("warning: ")
-         .map_item(|_p,a| a
-                   .add_style_back(TerminalStyle::bold(true))
-                   .add_style_back(TerminalStyle::fg_color((200,200,0))))
-        ),
-        (Point2::new(1, 0),
-         msg
-         .map_item(|_p,a| a
-                   .add_style_back(TerminalStyle::fg_color((180,180,180))))
-        )
-    ]);
-
-    Message {
-        addr: vec![],
-        port: mb.get_port().flatten()
-    }
-}
-
-pub fn make_todo(msg: OuterViewPort<dyn TerminalView>) -> Message {
-    let mut mb = IndexBuffer::new();
-    mb.insert_iter(vec![
-        (Point2::new(0, 0),
-         make_label("todo: ")
-         .map_item(|_p,a| a
-                   .add_style_back(TerminalStyle::bold(true))
-                   .add_style_back(TerminalStyle::fg_color((180,180,250))))
-        ),
-        (Point2::new(1, 0),
-         msg
-         .map_item(|_p,a| a
-                   .add_style_back(TerminalStyle::fg_color((180,180,180))))
-        )
-    ]);
-
-    Message {
-        addr: vec![],
-        port: mb.get_port().flatten()
-    }
-}
-
-pub fn make_info(msg: OuterViewPort<dyn TerminalView>) -> Message {
-    let mut mb = IndexBuffer::new();
-    mb.insert_iter(vec![
-        (Point2::new(0, 0),
-         make_label("info: ")
-         .map_item(|_p,a| a
-                   .add_style_back(TerminalStyle::bold(true))
-                   .add_style_back(TerminalStyle::fg_color((180,180,250))))
-        ),
-        (Point2::new(1, 0),
-         msg
-         .map_item(|_p,a| a
-                   .add_style_back(TerminalStyle::fg_color((180,180,180))))
-        )
-    ]);
-
-    Message {
-        addr: vec![],
-        port: mb.get_port().flatten()
-    }
-}
-

nested/src/editors/char/mod.rs

@@ -1,102 +0,0 @@
-use {
-    r3vi::{
-        view::{
-            OuterViewPort,
-            singleton::*,
-        },
-        buffer::singleton::*
-    },
-    laddertypes::{TypeTerm},
-    crate::{
-        type_system::{Context, ReprTree},
-        terminal::{TerminalAtom},
-        tree::{NestedNode, TreeNavResult},
-        commander::{ObjCommander}
-    },
-    std::sync::Arc,
-    std::sync::RwLock
-};
-
-pub fn init_ctx( ctx: &mut Context ) {
-    ctx.add_node_ctor(
-        "Char",
-        Arc::new(|ctx: Arc<RwLock<Context>>, _ty: TypeTerm, depth: OuterViewPort<dyn SingletonView<Item = usize>>| {
-            Some(CharEditor::new_node(ctx, depth))
-        }));
-}
-
-pub struct CharEditor {
-    ctx: Arc<RwLock<Context>>,
-    data: SingletonBuffer<char>
-}
-
-impl ObjCommander for CharEditor {
-    fn send_cmd_obj(&mut self, cmd_obj: Arc<RwLock<ReprTree>>) -> TreeNavResult {
-        let cmd_obj = cmd_obj.read().unwrap();
-        let cmd_type = cmd_obj.get_type().clone();
-
-        if cmd_type == Context::parse(&self.ctx, "Char") {
-            if let Some(cmd_view) = cmd_obj.get_view::<dyn SingletonView<Item = char>>() {
-                let value = cmd_view.get();
-
-                if self.ctx.read().unwrap().meta_chars.contains(&value) {
-                    TreeNavResult::Exit
-                } else {
-                    self.data.set(value);
-                    TreeNavResult::Continue
-                }
-            } else {
-                TreeNavResult::Exit
-            }
-        } else {
-            TreeNavResult::Exit   
-        }
-    }
-}
-
-impl CharEditor {
-    pub fn new(ctx: Arc<RwLock<Context>>) -> Self {
-        CharEditor {
-            ctx,
-            data: SingletonBuffer::new('\0')
-        }
-    }
-
-    pub fn get_port(&self) -> OuterViewPort<dyn SingletonView<Item = char>> {
-        self.data.get_port()
-    }
-
-    pub fn get(&self) -> char {
-        self.get_port().get_view().unwrap().get()
-    }
-
-    pub fn new_node(ctx0: Arc<RwLock<Context>>, depth: OuterViewPort<dyn SingletonView<Item = usize>>) -> NestedNode {
-        let data = SingletonBuffer::new('\0');
-        let ctx = ctx0.clone();
-        let editor = Arc::new(RwLock::new(CharEditor{ ctx, data: data.clone() }));
-
-        NestedNode::new(
-            ctx0.clone(),
-            ReprTree::new_leaf(
-                ctx0.read().unwrap().type_term_from_str("Char").unwrap(),
-                data.get_port().into()
-            ),
-            depth
-        )
-            .set_view(data
-                      .get_port()
-                      .map(move |c| TerminalAtom::from(if c == '\0' { ' ' } else { c }))
-                      .to_grid()
-            )
-            .set_cmd( editor.clone() )
-            .set_editor( editor.clone() )
-    }
-}
-/*
-use crate::StringGen;
-impl StringGen for CharEditor {
-    fn get_string(&self)  -> String {
-        String::from(self.get())
-    }
-}
-*/

nested/src/editors/integer/add.rs

@@ -1,70 +0,0 @@
-use {
-    r3vi::{
-        view::{
-            InnerViewPort, OuterViewPort,
-            sequence::*,
-        },
-        buffer::{
-            vec::*
-        },
-        projection::projection_helper::*,
-    },
-    std::sync::{Arc, RwLock},
-};
-
-fn posint_add(
-    radix: usize,
-    a: impl SequenceView<Item = usize>,
-    b: impl SequenceView<Item = usize>,
-) -> Vec<usize> {
-    let mut carry = 0;
-    let mut result = Vec::new();
-
-    for digit_idx in 0..std::cmp::max(a.len().unwrap_or(0), b.len().unwrap_or(0)) {
-        let sum = a.get(&digit_idx).unwrap_or(0) + b.get(&digit_idx).unwrap_or(0) + carry;
-
-        result.push(sum % radix);
-
-        carry = if sum > radix { sum - radix } else { 0 };
-    }
-
-    if carry > 0 {
-        result.push(carry);
-    }
-
-    result
-}
-
-pub struct Add {
-    radix: usize,
-    a: Arc<dyn SequenceView<Item = usize>>, // PosInt, Little Endian
-    b: Arc<dyn SequenceView<Item = usize>>, // PosInt, Little Endian
-    c: VecBuffer<usize>,
-    _proj_helper: ProjectionHelper<usize, Self>,
-}
-
-impl Add {
-    pub fn new(
-        radix: usize,
-        a: OuterViewPort<dyn SequenceView<Item = usize>>,
-        b: OuterViewPort<dyn SequenceView<Item = usize>>,
-        c: InnerViewPort<RwLock<Vec<usize>>>, //<dyn SequenceView<Item = usize>>
-    ) -> Arc<RwLock<Self>> {
-        let mut proj_helper = ProjectionHelper::new(c.0.update_hooks.clone());
-        let add = Arc::new(RwLock::new(Add {
-            radix,
-            a: proj_helper.new_sequence_arg(0, a, |s: &mut Self, _digit_idx| s.update()),
-            b: proj_helper.new_sequence_arg(1, b, |s: &mut Self, _digit_idx| s.update()),
-            c: VecBuffer::with_port(c),
-            _proj_helper: proj_helper,
-        }));
-        add
-    }
-
-    fn update(&mut self) {
-        self.c.clear();
-        for digit in posint_add(self.radix, self.a.clone(), self.b.clone()) {
-            self.c.push(digit);
-        }
-    }
-}

nested/src/editors/integer/ctx.rs

@@ -1,139 +0,0 @@
-
-use {
-    r3vi::{
-        view::{OuterViewPort, singleton::*}
-    },
-    laddertypes::{TypeTerm},
-    crate::{
-        type_system::{Context},
-        editors::{
-            list::*,
-            integer::*
-        },
-        type_system::{MorphismTypePattern},
-    },
-    std::sync::{Arc, RwLock}
-};
-
-pub fn init_ctx(ctx: &mut Context) {
-    ctx.add_typename("MachineInt".into());
-    ctx.add_typename("u32".into());
-    ctx.add_typename("u64".into());
-    ctx.add_typename("LittleEndian".into());
-    ctx.add_typename("BigEndian".into());
-
-    ctx.add_node_ctor(
-        "Digit", Arc::new(
-            |ctx: Arc<RwLock<Context>>, ty: TypeTerm, depth: OuterViewPort<dyn SingletonView<Item = usize>>| {
-                match ty {
-                    TypeTerm::App(args) => {
-                        if args.len() > 1 {
-                            match args[1] {
-                                TypeTerm::Num(radix) => {
-                                    let node = DigitEditor::new(ctx.clone(), radix as u32).into_node(depth);
-                                    Some(
-                                        node
-                                    )
-                                },
-                                _ => None
-                            }
-                        } else {
-                            None
-                        }
-                    }
-                    _ => None
-                }
-            }
-        )
-    );
-
-    ctx.add_list_typename("PosInt".into());
-    let pattern = MorphismTypePattern {
-        src_tyid: ctx.get_typeid("List"),
-        dst_tyid: ctx.get_typeid("PosInt").unwrap()
-    };
-    ctx.add_morphism(pattern,
-        Arc::new(
-            |mut node, dst_type| {
-                // todo: check src_type parameter to be ( Digit radix )
-
-                match dst_type {
-                    TypeTerm::App(args) => {
-                        if args.len() > 1 {
-                            match args[1] {
-                                TypeTerm::Num(_radix) => {
-                                    PTYListController::for_node(
-                                        &mut node,
-                                        Some(','),
-                                        None,
-                                    );
-
-                                    PTYListStyle::for_node(
-                                        &mut node,
-                                        ("0d", "", "")
-                                    );
-
-                                    Some(node)
-                                },
-                                _ => None
-                            }
-                        } else {
-                            None
-                        }
-                    }
-                    _ => None
-                }
-            }
-        )
-    );
-
-    ctx.add_node_ctor(
-        "PosInt", Arc::new(
-            |ctx0: Arc<RwLock<Context>>, dst_typ: TypeTerm, depth: OuterViewPort<dyn SingletonView<Item = usize>>| {
-                match dst_typ.clone() {
-                    TypeTerm::App(args) => {
-                        if args.len() > 1 {
-                            match args[1] {
-                                TypeTerm::Num(radix) => {
-                                    let ctx = ctx0.read().unwrap();
-                                    let mut node = Context::make_node(
-                                        &ctx0,
-                                        TypeTerm::App(vec![
-                                            TypeTerm::TypeID(ctx.get_typeid("List").unwrap()),
-                                            TypeTerm::TypeID(
-                                                ctx.get_typeid("Digit").unwrap()
-                                            )
-                                                .num_arg(radix)
-                                                .clone()
-                                                .into()
-                                        ]),
-                                        depth.map(|d| d+1)
-                                    ).unwrap();
-
-                                    node = node.morph(dst_typ);
-
-                                    Some(node)
-                                }
-                                _ => None
-                            }
-                        } else {
-                            None
-                        }
-                    }
-                    _ => None
-                }
-            }
-        )
-    );
-    
-    ctx.add_typename("Date".into());
-    ctx.add_typename("ISO-8601".into());
-    ctx.add_typename("TimeSince".into());
-    ctx.add_typename("UnixEpoch".into());
-    ctx.add_typename("AnnoDomini".into());
-    ctx.add_typename("Epoch".into());
-    ctx.add_typename("Duration".into());
-    ctx.add_typename("Seconds".into());
-    ctx.add_typename("ℕ".into());
-}
-

nested/src/editors/integer/editor.rs

@@ -1,239 +0,0 @@
-use {
-    r3vi::{
-        view::{
-            OuterViewPort,
-            singleton::*,
-        },
-        buffer::{
-            singleton::*,
-            vec::*,
-            index_hashmap::*
-        }
-    },
-    laddertypes::{TypeTerm},
-    crate::{
-        type_system::{Context, ReprTree},
-        editors::list::{ListCmd, PTYListController, PTYListStyle},
-        terminal::{
-            TerminalAtom, TerminalStyle, make_label
-        },
-        diagnostics::{Message},
-        tree::{NestedNode, TreeNav, TreeNavResult, TreeCursor},
-        commander::ObjCommander
-    },
-    std::sync::Arc,
-    std::sync::RwLock,
-    std::iter::FromIterator,
-    cgmath::{Point2}
-};
-
-//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
-
-pub struct DigitEditor {
-    ctx: Arc<RwLock<Context>>,
-    radix: u32,
-    data: SingletonBuffer<Option<char>>,
-    msg: VecBuffer<Message>,
-}
-
-impl ObjCommander for DigitEditor {
-    fn send_cmd_obj(&mut self, cmd_obj: Arc<RwLock<ReprTree>>) -> TreeNavResult {
-        let cmd_obj = cmd_obj.read().unwrap();
-        let cmd_type = cmd_obj.get_type().clone();
-
-        if cmd_type == Context::parse(&self.ctx, "Char") {
-            if let Some(cmd_view) = cmd_obj.get_view::<dyn SingletonView<Item = char>>() {
-                let c = cmd_view.get();
-
-                self.msg.clear();
-
-                if self.ctx.read().unwrap().meta_chars.contains(&c) {
-                    eprintln!("digitedit: meta char");
-                    return TreeNavResult::Exit;
-
-                } else if c.to_digit(self.radix).is_none() {
-                    /* in case the character c is not in the range of digit-chars,
-                       add a message to the diagnostics view
-                     */
-
-                    let message = IndexBuffer::from_iter(vec![
-                        (Point2::new(1, 0), make_label("invalid digit '")),
-                        (Point2::new(2, 0), make_label(&format!("{}", c))
-                         .map_item(|_p,a| a.add_style_back(TerminalStyle::fg_color((140,140,250))))),
-                        (Point2::new(3, 0), make_label("'"))
-                    ]);
-
-                    self.msg.push(crate::diagnostics::make_error(message.get_port().flatten()));
-                    self.data.set(Some(c));
-                } else {
-                    self.data.set(Some(c));
-                }
-            }
-        }
-
-        TreeNavResult::Continue
-    }
-}
-
-impl DigitEditor {
-    pub fn new(ctx: Arc<RwLock<Context>>, radix: u32) -> Self {
-        DigitEditor {
-            ctx,
-            radix,
-            data: SingletonBuffer::new(None),
-            msg: VecBuffer::new(),
-        }
-    }
-
-    pub fn into_node(self, depth: OuterViewPort<dyn SingletonView<Item = usize>>) -> NestedNode {
-        let data = self.get_data();        
-        let editor = Arc::new(RwLock::new(self));
-        let ed = editor.write().unwrap();
-        let r = ed.radix;
-
-        NestedNode::new(ed.ctx.clone(), data, depth)
-            .set_cmd(editor.clone())
-            .set_view(
-                ed.data
-                    .get_port()
-                    .map(move |c| {
-                        TerminalAtom::new(
-                            c.unwrap_or('?'),
-                            if c.unwrap_or('?').to_digit(r).is_some() {
-                                TerminalStyle::fg_color((90, 160, 90))
-                            } else {
-                                //TerminalStyle::bg_color((90, 10, 10))
-                                TerminalStyle::fg_color((200, 40, 40))
-                            },
-                        )
-                    })
-                    .to_grid()
-            )
-            .set_diag(
-                ed.msg.get_port().to_sequence()
-            )
-    }
-
-    pub fn get_data_port(&self) -> OuterViewPort<dyn SingletonView<Item = Option<u32>>> {
-        let radix = self.radix;
-        self.data.get_port().map(move |c| c?.to_digit(radix))
-    }
-
-    pub fn get_type(&self) -> TypeTerm {
-        TypeTerm::TypeID(self.ctx.read().unwrap().get_typeid("Digit").unwrap())
-    }
-
-    pub fn get_data(&self) -> Arc<RwLock<ReprTree>> {
-        ReprTree::ascend(
-            &ReprTree::new_leaf(
-                self.ctx.read().unwrap().type_term_from_str("<Seq u32>").unwrap(),
-                self.get_data_port().into()
-            ),
-            self.get_type()
-        )
-    }
-}
-
-
-pub struct PosIntEditor {
-    radix: u32,
-    digits: NestedNode,
-
-    // todo: endianness
-}
-
-impl PosIntEditor {
-    pub fn new(ctx: Arc<RwLock<Context>>, radix: u32) -> Self {
-        let mut node = Context::make_node(
-            &ctx,
-            Context::parse(&ctx, format!("<List <Digit {}>>", radix).as_str()),
-            r3vi::buffer::singleton::SingletonBuffer::new(0).get_port()
-        ).unwrap();
-
-        // Set Type
-        node.data = ReprTree::ascend(
-            &node.data.clone(),
-            TypeTerm::App(vec![
-                TypeTerm::TypeID(ctx.read().unwrap().get_typeid("PosInt").unwrap()),
-                TypeTerm::Num(radix as i64).into(),
-                TypeTerm::TypeID(ctx.read().unwrap().get_typeid("BigEndian").unwrap())
-            ]
-        ));
-
-        PTYListController::for_node( &mut node, Some(' '), None );
-        PTYListStyle::for_node( &mut node,
-            (
-                match radix {
-                    2 => "0b".into(),
-                    8 => "0o".into(),
-                    10 => "0d".into(),
-                    16 => "0x".into(),
-                    _ => "".into()
-                },
-                "".into(),
-                "".into()
-            )
-        );
-
-        PosIntEditor {
-            radix,
-            digits: node
-        }
-    }
-
-    pub fn from_u64(ctx: Arc<RwLock<Context>>, radix: u32, value: u64) -> Self {
-        let mut edit = PosIntEditor::new(ctx, radix);
-        edit.set_value_u64( value );
-        edit
-    }
-
-    pub fn set_value_u64(&mut self, mut value: u64) {
-        self.digits.send_cmd_obj(ListCmd::Clear.into_repr_tree(&self.digits.ctx));
-
-        while value > 0 {
-            let digit_val = (value % self.radix as u64) as u32;
-            value /= self.radix as u64;
-
-            // if BigEndian
-            self.digits.goto(TreeCursor::home());
-
-            self.digits.send_cmd_obj(ReprTree::from_char(&self.digits.ctx, char::from_digit(digit_val, self.radix).expect("invalid digit"))); 
-        }
-        self.digits.goto(TreeCursor::none());
-    }
-
-    pub fn into_node(self) -> NestedNode {
-        self.digits
-    }
-
-/*
-    pub fn get_data_port(&self) -> OuterViewPort<dyn SequenceView<Item = u32>> {
-        let radix = self.radix;
-        self.digits
-            .get_data_port()
-            .filter_map(move |digit_editor| {
-                digit_editor.read().unwrap().data.get()?.to_digit(radix)
-            })
-    }
-
-    pub fn get_value(&self) -> u32 {
-        let mut value = 0;
-        let mut weight = 1;
-        for digit_value in self
-            .get_data_port()
-            .get_view()
-            .unwrap()
-            .iter()
-            .collect::<Vec<_>>()
-            .into_iter()
-            .rev()
-        {
-            value += digit_value * weight;
-            weight *= self.radix;
-        }
-
-        value
-}
-*/
-}
-

nested/src/editors/list/cmd.rs

@@ -1,170 +0,0 @@
-use {
-    r3vi::{
-        view::{singleton::*}
-    },
-    crate::{
-        editors::list::{ListEditor, ListCursor, ListCursorMode},
-        type_system::{Context, ReprTree},
-        tree::{NestedNode, TreeNav, TreeNavResult, TreeCursor},
-        commander::{ObjCommander}
-    },
-    std::sync::{Arc, RwLock}
-};
-
-#[derive(Copy, Clone, PartialEq, Eq)]
-pub enum ListCmd {
-    DeletePxev,
-    DeleteNexd,
-    JoinNexd,
-    JoinPxev,
-    Split,
-    Clear,
-    Close,
-}
-
-impl ListCmd {
-    pub fn into_repr_tree(self, ctx: &Arc<RwLock<Context>>) -> Arc<RwLock<ReprTree>> {
-        let buf = r3vi::buffer::singleton::SingletonBuffer::new(self);
-        ReprTree::new_leaf(
-            Context::parse(ctx, "ListCmd"),
-            buf.get_port().into()
-        )
-    }
-}
-
-impl ObjCommander for ListEditor {
-    fn send_cmd_obj(&mut self, cmd_obj: Arc<RwLock<ReprTree>>) -> TreeNavResult {
-        let cmd_repr = cmd_obj.read().unwrap();
-
-        if let Some(view) = cmd_repr.get_view::<dyn SingletonView<Item = NestedNode>>() {
-            let node = view.get();
-            let cur = self.cursor.get();
-
-            if let Some(idx) = cur.idx {
-                match cur.mode {
-                    ListCursorMode::Select => {
-                        *self.data.get_mut(idx as usize) = Arc::new(RwLock::new(node));
-                        TreeNavResult::Exit
-                    }
-                    ListCursorMode::Insert => {
-                        self.insert(Arc::new(RwLock::new(node)));
-                        self.cursor.set(ListCursor{ idx: Some(idx+1),  mode: ListCursorMode::Insert });
-                        TreeNavResult::Continue
-                    }
-                }
-            } else {
-                TreeNavResult::Exit
-            }
-        }
-
-        else if let Some(cmd) = cmd_repr.get_view::<dyn SingletonView<Item = ListCmd>>() {
-            eprintln!("pty-list-editor some list cmmd");
-
-            let cur = self.cursor.get();
-            drop(cmd_repr);
-
-            match cmd.get() {
-                ListCmd::Clear => {
-                    self.clear();
-                    TreeNavResult::Continue
-                }
-                _ => {
-                    if let Some(idx) = cur.idx {
-                        match cur.mode {
-                            ListCursorMode::Select => {                        
-                                if let Some(mut item) = self.get_item().clone() {
-                                    let item_cur = item.get_cursor();
-                                    
-                                    match cmd.get() {
-                                        ListCmd::DeletePxev => {
-                                            eprintln!("SELECT: delete pxev");
-                                            if idx > 0
-                                                && item_cur.tree_addr.iter().fold(
-                                                    true,
-                                                    |is_zero, x| is_zero && (*x == 0)
-                                                )
-                                            {
-                                                self.listlist_join_pxev(idx);
-                                                TreeNavResult::Continue
-                                            } else {
-                                                item.send_cmd_obj(cmd_obj)
-                                            }
-                                        }
-
-                                        ListCmd::DeleteNexd => {
-                                            let item_cur = item.get_cursor_warp();
-                                            let next_idx = idx as usize + 1;
-
-                                            if next_idx < self.data.len()
-                                                && item_cur.tree_addr.iter().fold(
-                                                    true,
-                                                    |is_end, x| is_end && (*x == -1)
-                                                )
-                                            {
-                                                self.listlist_join_nexd(idx as usize);
-                                                TreeNavResult::Continue
-                                            } else {
-                                                item.send_cmd_obj(cmd_obj)
-                                            }
-                                        }
-
-                                        ListCmd::Split => {
-                                            self.listlist_split();
-                                            TreeNavResult::Continue
-                                        }
-
-                                        _ => {
-                                            item.send_cmd_obj(cmd_obj);
-                                            TreeNavResult::Continue
-                                        }
-                                    }
-                                } else {
-                                    eprintln!("ptylist: no item");
-                                    TreeNavResult::Exit
-                                }
-                            },
-
-                            ListCursorMode::Insert => {
-                                match cmd.get() {
-                                    ListCmd::DeletePxev => {
-                                        eprintln!("INSERT: delete pxev");
-                                        self.delete_pxev();
-                                        TreeNavResult::Continue
-                                    }
-                                    ListCmd::DeleteNexd => {
-                                        self.delete_nexd();
-                                        TreeNavResult::Continue
-                                    }
-                                    ListCmd::Split => {
-                                        self.split();
-                                        TreeNavResult::Exit
-                                    }
-                                    ListCmd::Close => {
-                                        self.goto(TreeCursor::none());
-                                        TreeNavResult::Exit
-                                    }
-                                    _ =>{
-                                        TreeNavResult::Continue
-                                    }
-                                }
-                            }
-                        }
-                    } else {
-                        eprintln!("ptylist: cursor has no idx");
-                        TreeNavResult::Exit
-                    }
-                }
-            }
-
-        } else {
-            if let Some(cur_item) = self.get_item_mut() {
-                drop(cmd_repr);
-                cur_item.write().unwrap().send_cmd_obj(cmd_obj);
-                TreeNavResult::Continue
-            } else {
-                TreeNavResult::Exit
-            }
-        }
-    }
-}
-

nested/src/editors/list/ctx.rs

@@ -1,41 +0,0 @@
-use {
-    r3vi::{view::{OuterViewPort, singleton::*}},
-    laddertypes::{TypeTerm},
-    crate::{
-        type_system::{Context},
-        editors::list::{ListEditor, PTYListController, PTYListStyle}
-    },
-    std::sync::{Arc, RwLock}
-};
-
-//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
-
-pub fn init_ctx(ctx: &mut Context) {
-    ctx.add_typename("ListCmd".into());
-    ctx.add_list_typename("List".into());
-
-    ctx.add_node_ctor(
-        "List", Arc::new(
-            |ctx: Arc<RwLock<Context>>, ty: TypeTerm, depth: OuterViewPort<dyn SingletonView<Item = usize>>| {
-                match ty {
-                    TypeTerm::App(args) => {
-                        if args.len() > 1 {
-                            let typ = args[1].clone();
-
-                            let mut node = ListEditor::new(ctx.clone(), typ).into_node(depth);
-
-                            PTYListController::for_node( &mut node, Some(','), Some('}') );
-                            PTYListStyle::for_node( &mut node, ("{",", ","}") );
-
-                            Some(node)
-                        } else {
-                            None
-                        }
-                    }
-                    _ => None
-                }
-            }
-        )
-    );
-}
-

nested/src/editors/list/cursor.rs

@@ -1,40 +0,0 @@
-#[derive(Clone, Copy, Eq, PartialEq, Debug)]
-pub enum ListCursorMode {
-    Insert,
-    Select
-}
-
-impl Default for ListCursorMode {
-    fn default() -> Self {
-        ListCursorMode::Select
-    }
-}
-
-#[derive(Clone, Copy, Eq, PartialEq, Debug)]
-pub struct ListCursor {
-    pub mode: ListCursorMode,
-    pub idx: Option<isize>,
-}
-
-impl ListCursor {
-    pub fn home() -> Self {
-        ListCursor {
-            mode: ListCursorMode::Insert,
-            idx: Some(0)
-        }
-    }
-
-    pub fn none() -> Self {
-        ListCursor {
-            mode: ListCursorMode::Insert,
-            idx: None,
-        }        
-    }
-}
-
-impl Default for ListCursor {
-    fn default() -> Self {
-        ListCursor::home()
-    }
-}
-

nested/src/editors/list/editor.rs

@@ -1,494 +0,0 @@
-use {
-    r3vi::{
-        view::{ViewPort, OuterViewPort, singleton::*, sequence::*},
-        buffer::{singleton::*, vec::*}
-    },
-    laddertypes::{TypeTerm},
-    crate::{
-        type_system::{Context, ReprTree},
-        editors::list::{ListCursor, ListCursorMode, ListCmd},
-        tree::{NestedNode, TreeNav, TreeCursor},
-        diagnostics::Diagnostics,
-        commander::ObjCommander
-    },
-    std::sync::{Arc, RwLock}
-};
-
-//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
-
-pub struct ListEditor {
-    pub(super) cursor: SingletonBuffer<ListCursor>,
-
-    // todo: (?) remove RwLock<..> around NestedNode ??
-    pub data: VecBuffer< Arc<RwLock<NestedNode>> >,
-
-    pub spillbuf: Arc<RwLock<Vec<Arc<RwLock<NestedNode>>>>>,
-
-    pub(super) addr_port: OuterViewPort<dyn SequenceView<Item = isize>>,
-    pub(super) mode_port: OuterViewPort<dyn SingletonView<Item = ListCursorMode>>,
-
-    depth: OuterViewPort<dyn SingletonView<Item = usize>>,
-
-    pub(crate) ctx: Arc<RwLock<Context>>,
-
-    /// item type
-    pub(super) typ: TypeTerm,
-}
-
-impl ListEditor {
-    pub fn new(
-        ctx: Arc<RwLock<Context>>,
-        typ: TypeTerm,
-    ) -> Self {
-        let cursor = SingletonBuffer::new(ListCursor::default());
-        let data : VecBuffer<Arc<RwLock<NestedNode>>> = VecBuffer::new();
-
-        ListEditor {
-            mode_port: cursor
-                .get_port()
-                .map({
-                    let data = data.clone();
-                    move |c| {
-                        let ip = SingletonBuffer::new(c.mode).get_port();
-                        match c.mode {
-                            ListCursorMode::Insert => ip,
-                            ListCursorMode::Select => {
-                                if let Some(idx) = c.idx {
-                                    if idx >= 0 && idx < data.len() as isize {
-                                        data.get(idx as usize).read().unwrap().get_mode_view()
-                                    } else {
-                                        eprintln!("ListEditor::mode_port invalid cursor idx");
-                                        ip
-                                    }
-                                } else {
-                                    ip
-                                }
-                            }
-                        }
-                    }
-                })
-                .flatten(),
-
-            addr_port: VecBuffer::<OuterViewPort<dyn SequenceView<Item = isize>>>::with_data(
-                vec![
-                    cursor.get_port()
-                        .to_sequence()
-                        .filter_map(|cur| cur.idx),
-                    cursor.get_port()
-                        .map({
-                            let data = data.clone();
-                            move |cur| {
-                                if cur.mode == ListCursorMode::Select {
-                                    if let Some(idx) = cur.idx {
-                                        if idx >= 0 && idx < data.len() as isize {
-                                            return data.get(idx as usize).read().unwrap().get_addr_view();
-                                        }
-                                    }
-                                }
-                                OuterViewPort::default()
-                            }
-                        })
-                        .to_sequence()
-                        .flatten()                
-                ])
-                .get_port()
-                .to_sequence()
-                .flatten(),
-            cursor,
-            data,
-            spillbuf: Arc::new(RwLock::new(Vec::new())),
-            ctx,
-            typ,
-            depth: SingletonBuffer::new(0).get_port()
-        }
-    }
-
-    pub fn into_node(mut self, depth: OuterViewPort<dyn SingletonView<Item = usize>>) -> NestedNode {
-        let data = self.get_data();
-        let ctx = self.ctx.clone();
-
-        self.depth = depth.clone();
-        let editor = Arc::new(RwLock::new(self));
-
-        let e = editor.read().unwrap();
-
-        let mut node = NestedNode::new(ctx, data, depth)
-            .set_editor(editor.clone())
-            .set_nav(editor.clone())
-            .set_cmd(editor.clone())
-            .set_diag(e
-                      .get_data_port()
-                      .enumerate()
-                      .map(
-                          |(idx, item_editor)| {
-                              let idx = *idx;
-                              item_editor
-                                  .get_msg_port()
-                                  .map(
-                                      move |msg| {
-                                          let mut msg = msg.clone();
-                                          msg.addr.insert(0, idx);
-                                          msg
-                                      }
-                                  )
-                          }
-                      )
-                      .flatten()
-            );
-
-        node.spillbuf = e.spillbuf.clone();
-        node
-    }
-
-    pub fn get_item_type(&self) -> TypeTerm {
-        self.typ.clone()
-    }
-
-    pub fn get_seq_type(&self) -> TypeTerm {
-        TypeTerm::App(vec![
-            TypeTerm::TypeID(self.ctx.read().unwrap().get_typeid("List").unwrap()),
-            self.get_item_type().into()
-        ])
-    }
-
-    pub fn get_cursor_port(&self) -> OuterViewPort<dyn SingletonView<Item = ListCursor>> {
-        self.cursor.get_port()
-    }
-
-    pub fn get_data_port(&self) -> OuterViewPort<dyn SequenceView<Item = NestedNode>> {
-        self.data.get_port().to_sequence().map(
-            |x| x.read().unwrap().clone()
-        )
-    }
-
-    pub fn get_data(&self) -> Arc<RwLock<ReprTree>> {
-        let data_view = self.get_data_port();
-        ReprTree::new_leaf(
-            self.get_seq_type(),
-            data_view.into()
-        )
-    }
-
-    pub fn get_item(&self) -> Option<NestedNode> {
-        if let Some(idx) = self.cursor.get().idx {
-            let idx = crate::utils::modulo(idx as isize, self.data.len() as isize) as usize;
-            if idx < self.data.len() {
-                Some(self.data.get(idx).read().unwrap().clone())
-            } else {
-                None
-            }
-        } else {
-            None
-        }
-    }
-
-    pub fn get_item_mut(&mut self) -> Option<MutableVecAccess<Arc<RwLock<NestedNode>>>> {
-        if let Some(idx) = self.cursor.get().idx {
-            let idx = crate::utils::modulo(idx as isize, self.data.len() as isize) as usize;
-            if idx < self.data.len() {
-                Some(self.data.get_mut(idx))
-            } else {
-                None
-            }
-        } else {
-            None
-        }
-    }
-
-    /// is the element-type also a list-like editor (i.e. impls TreeNav)
-    pub fn is_listlist(&self) -> bool {
-        self.ctx.read().unwrap().is_list_type(&self.typ)
-    }
-
-    /// delete all items
-    pub fn clear(&mut self) {
-        let mut b = self.spillbuf.write().unwrap();
-        for i in 0..self.data.len() {
-            b.push( self.data.get(i) );
-        }
-        
-        self.data.clear();
-        self.cursor.set(ListCursor::home());
-    }
-
-    /// delete item before the cursor
-    pub fn delete_pxev(&mut self) {
-        let mut cur = self.cursor.get();
-        if let Some(idx) = cur.idx {
-            if idx > 0 && idx <= self.data.len() as isize {
-                cur.idx = Some(idx as isize - 1);
-                self.cursor.set(cur);
-                self.data.remove(idx as usize - 1);
-            }
-        }
-    }
-
-    /// delete item after the cursor
-    pub fn delete_nexd(&mut self) {
-        if let Some(idx) = self.cursor.get().idx {
-            if idx < self.data.len() as isize {
-                self.data.remove(idx as usize);
-            }
-        }
-    }
-
-    /// insert a new element
-    pub fn insert(&mut self, item: Arc<RwLock<NestedNode>>) {
-        eprintln!("list insert");
-
-        item.read().unwrap().depth.0.set_view(
-            self.depth.map(|d| d+1).get_view()
-        );
-
-        let mut cur = self.cursor.get();
-        if let Some(idx) = cur.idx {
-            match cur.mode {
-                ListCursorMode::Insert => {
-                    self.data.insert(idx as usize, item.clone());
-                    if self.is_listlist() {
-                        cur.mode = ListCursorMode::Select;
-                    } else {
-                        eprintln!("list insert: is not a listlist ({:?})", self.typ);
-                        item.write().unwrap().goto(TreeCursor::none());
-                        cur.idx = Some(idx + 1);
-                    }
-                }
-
-                ListCursorMode::Select => {
-                    self.data.insert(1 + idx as usize, item.clone());                    
-                    if self.is_listlist() {
-                        cur.idx = Some(idx + 1);
-                    }
-                }
-            }
-
-            self.cursor.set(cur);
-        } else {
-            //eprintln!("insert: no cursor");
-        }
-    }
-
-    /// split the list off at the current cursor position and return the second half
-    pub fn split(&mut self) {
-        eprintln!("split");
-        let cur = self.cursor.get();
-        if let Some(idx) = cur.idx {
-            let idx = idx as usize;
-            for _ in idx .. self.data.len() {
-                self.spillbuf.write().unwrap().push(
-                    self.data.get(idx)
-                );
-                self.data.remove(idx);
-            }
-
-            /* in case the split leaves an empty item-list
-             * as a last element, remove it
-             */
-/*
-            if self.is_listlist() {
-                if idx > 0 && idx < self.data.len()+1 {
-                    /* we are in insert mode,
-                     * get element before cursor
-                     */
-                    let prev_idx = idx - 1;
-                    let prev_node = self.data.get(prev_idx);
-                    let prev_node = prev_node.read().unwrap();
-
-                    if prev_node.get_data_view::<dyn SequenceView<Item = NestedNode>>(vec![].into_iter()).iter().count() == 0 {
-                        drop(prev_node);
-                        self.data.remove(prev_idx);
-                    }
-                }
-        }
-            */
-        }
-    }
-
-    pub fn listlist_split(&mut self) {
-        eprintln!("listlist split");
-        let cur = self.get_cursor();
-
-        if let Some(mut item) = self.get_item().clone() {
-            item.send_cmd_obj(ListCmd::Split.into_repr_tree(&self.ctx));
-
-            if cur.tree_addr.len() < 3 {
-                item.goto(TreeCursor::none());
-
-                self.set_leaf_mode(ListCursorMode::Insert);
-                self.nexd();
-
-                let mut b = item.spillbuf.write().unwrap();
-                let mut tail_node = Context::make_node(&self.ctx, self.typ.clone(), self.depth.map(|d| d+1)).unwrap();
-                tail_node.goto(TreeCursor::home());
-
-                for node in b.iter() {
-                    eprintln!("splid :send to tail node");
-                    tail_node
-                        .send_cmd_obj(
-                            ReprTree::new_leaf(
-                                Context::parse(&self.ctx, "NestedNode"),
-                                SingletonBuffer::<NestedNode>::new(
-                                    node.read().unwrap().clone()
-                                ).get_port().into()
-                            )
-                        );
-                }
-                b.clear();
-                drop(b);
-                drop(item);
-
-                tail_node.goto(TreeCursor::home());
-                if cur.tree_addr.len() > 1 {
-                    tail_node.dn();
-                }
-
-                self.insert(
-                    Arc::new(RwLock::new(tail_node))
-                );
-
-            } else {
-                self.up();
-                self.listlist_split();
-                self.dn();
-            }
-        }
-    }
-
-    pub fn listlist_join_pxev(&mut self, idx: isize) {
-        {
-            let cur_editor = self.data.get(idx as usize);
-            let pxv_editor = self.data.get(idx as usize-1);
-            let mut cur_editor = cur_editor.write().unwrap();
-            let mut pxv_editor = pxv_editor.write().unwrap();
-
-            let oc0 = cur_editor.get_cursor();
-
-            // tell cur_editor move all its elements into its spill-buffer
-            cur_editor.goto(TreeCursor::none());
-            cur_editor.send_cmd_obj(
-                ListCmd::Clear.into_repr_tree( &self.ctx )
-            );
-            
-            pxv_editor.goto(TreeCursor {
-                tree_addr: vec![-1],
-                leaf_mode: ListCursorMode::Insert
-            });
-
-            let old_cur = pxv_editor.get_cursor();
-
-            let data = cur_editor.spillbuf.read().unwrap();
-            for x in data.iter() {
-                pxv_editor.send_cmd_obj(
-                    ReprTree::new_leaf(
-                        Context::parse(&self.ctx, "NestedNode"),
-                        SingletonBuffer::<NestedNode>::new(
-                            x.read().unwrap().clone()
-                        ).get_port().into()
-                    )
-                );
-            }
-
-
-            // fixme: is it oc0 or old_cur ??
-            if oc0.tree_addr.len() > 1 {
-                pxv_editor.goto(TreeCursor {
-                    tree_addr: vec![ old_cur.tree_addr[0], 0 ],
-                    leaf_mode: ListCursorMode::Insert                
-                });
-                pxv_editor.send_cmd_obj(ListCmd::DeletePxev.into_repr_tree( &self.ctx ));
-            } else if oc0.tree_addr.len() > 0 {
-                pxv_editor.goto(TreeCursor {
-                    tree_addr: vec![ old_cur.tree_addr[0] ],
-                    leaf_mode: ListCursorMode::Insert                
-                });
-            }
-        }
-
-        self.cursor.set(ListCursor {
-            idx: Some(idx as isize - 1),
-            mode: ListCursorMode::Select
-        });
-
-        // remove cur_editor from top list, its elements are now in pxv_editor
-        self.data.remove(idx as usize);
-    }
-
-    pub fn listlist_join_nexd(&mut self, idx: usize) {
-        {
-            let cur_editor = self.data.get(idx);
-            let nxd_editor = self.data.get(idx + 1);
-            let mut cur_editor = cur_editor.write().unwrap();
-            let mut nxd_editor = nxd_editor.write().unwrap();
-
-            let oc0 = cur_editor.get_cursor();
-
-            // tell next_editor move all its elements into its spill-buffer
-            nxd_editor.goto(TreeCursor::none());
-            nxd_editor.send_cmd_obj(
-                ListCmd::Clear.into_repr_tree( &self.ctx )
-            );
-
-            let old_cur = cur_editor.get_cursor();
-            cur_editor.goto(TreeCursor {
-                tree_addr: vec![-1],
-                leaf_mode: ListCursorMode::Insert
-            });
- 
-            let data = nxd_editor.spillbuf.read().unwrap();
-
-            for x in data.iter() {
-                cur_editor.send_cmd_obj(
-                    ReprTree::new_leaf(
-                        Context::parse(&self.ctx, "NestedNode"),
-                        SingletonBuffer::<NestedNode>::new(
-                            x.read().unwrap().clone()
-                        ).get_port().into()
-                    )
-                );
-            }
-
-            // fixme: is it oc0 or old_cur ??
-            if oc0.tree_addr.len() > 1 {
-                cur_editor.goto(TreeCursor {
-                    tree_addr: vec![ old_cur.tree_addr[0], -1 ],
-                    leaf_mode: ListCursorMode::Insert                
-                });
-                cur_editor.send_cmd_obj(ListCmd::DeleteNexd.into_repr_tree( &self.ctx ));
-            } else if oc0.tree_addr.len() > 0 {
-                cur_editor.goto(TreeCursor {
-                    tree_addr: vec![ old_cur.tree_addr[0] ],
-                    leaf_mode: ListCursorMode::Insert
-                });
-            } else {
-                cur_editor.goto(TreeCursor::none());
-            }
-        }
-
-        // remove next_editor from top list, its elements are now in cur_editor
-        self.data.remove(idx+1);
-    }
-}
-
-/*
-use crate::{
-    type_system::TypeLadder,
-    tree::{TreeType, TreeAddr}
-};
-
-impl TreeType for ListEditor {
-    fn get_type(&self, addr: &TreeAddr) -> TypeLadder {
-        let idx = crate::utils::modulo::modulo(addr.0[0] as isize, self.data.len() as isize) as usize;
-
-        let mut addr = addr.clone();
-        
-        if self.data.len() > 0 {
-            addr.0.remove(0);
-            self.data.get(idx).get_type(addr)
-        } else {
-            vec![]
-        }
-    }
-}
- */
-
-

nested/src/editors/list/mod.rs

@@ -1,19 +0,0 @@
-
-
-pub mod cursor;
-pub mod editor;
-pub mod nav;
-pub mod segment;
-pub mod pty_editor;
-pub mod cmd;
-pub mod ctx;
-
-pub use {
-    cursor::{ListCursor, ListCursorMode},
-    editor::ListEditor,
-    segment::{ListSegment, ListSegmentSequence},
-    pty_editor::{PTYListStyle, PTYListController},
-    cmd::ListCmd,
-    ctx::init_ctx
-};
-

nested/src/editors/list/nav.rs

@@ -1,429 +0,0 @@
-use {
-    r3vi::{
-        view::{
-            OuterViewPort,
-            singleton::*,
-            sequence::*
-        }
-    },
-    crate::{
-        editors::list::{
-            ListCursor, ListCursorMode,
-            editor::ListEditor
-        },
-        tree::{TreeCursor, TreeNav, TreeNavResult, TreeHeightOp}
-    },
-    cgmath::Vector2
-};
-
-//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
-
-impl TreeNav for ListEditor {
-    fn get_addr_view(&self) -> OuterViewPort<dyn SequenceView<Item = isize>> {
-        self.addr_port.clone()
-    }
-
-    fn get_mode_view(&self) -> OuterViewPort<dyn SingletonView<Item = ListCursorMode>> {
-        self.mode_port.clone()
-    }
-    
-    fn get_height(&self, op: &TreeHeightOp) -> usize {
-        match op {
-            TreeHeightOp::P | TreeHeightOp::Q => {
-                if self.data.len() > 0 {
-                    1 + self.data.get(match op {
-                        TreeHeightOp::P => 0,
-                        TreeHeightOp::Q => self.data.len() - 1,
-                        _ => 0
-                    }).read().unwrap().get_height(op)
-                } else {
-                    1
-                }
-            }
-            TreeHeightOp::Max => {
-                1 + (0..self.data.len() as usize)
-                    .map(|i| self.data
-                         .get(i).read().unwrap()
-                         .get_height(&TreeHeightOp::Max)
-                    )
-                    .max()
-                    .unwrap_or(0)
-            }
-        }
-    }
-
-    fn get_cursor_warp(&self) -> TreeCursor {
-        let cur = self.cursor.get();
-        match cur.mode {
-            ListCursorMode::Insert => TreeCursor {
-                leaf_mode: cur.mode,
-                tree_addr: if let Some(i) = cur.idx {
-                    vec![
-                        i - self.data.len() as isize - 1
-                    ]
-                } else {
-                    vec![]
-                }
-            },
-            ListCursorMode::Select => {
-                if let Some(i) = cur.idx {
-                    if i < self.data.len() as isize {
-                        let mut sub_cur = self.data.get(i as usize).read().unwrap().get_cursor_warp();
-                        sub_cur.tree_addr.insert(0, i as isize - self.data.len() as isize);
-                        return sub_cur;
-                    } else {
-                        return TreeCursor {
-                            leaf_mode: ListCursorMode::Select,
-                            tree_addr: vec![ i as isize - self.data.len() as isize ],
-                        };
-                    }
-                }
-                TreeCursor {
-                    leaf_mode: cur.mode,
-                    tree_addr: vec![],
-                }
-            }
-        }
-    }
-
-    fn get_cursor(&self) -> TreeCursor {
-        let cur = self.cursor.get();
-        match cur.mode {
-            ListCursorMode::Insert => TreeCursor {
-                leaf_mode: cur.mode,
-                tree_addr: if let Some(i) = cur.idx {
-                    vec![i]
-                } else {
-                    vec![]
-                },
-            },
-            ListCursorMode::Select => {
-                if let Some(i) = cur.idx {
-                    if i < self.data.len() as isize {
-                        let mut sub_cur = self.data.get(i as usize).read().unwrap().get_cursor();
-                        if sub_cur.tree_addr.len() > 0 {
-                            sub_cur.tree_addr.insert(0, i as isize);
-                            return sub_cur;
-                        } else {                            
-                            return TreeCursor {
-                                leaf_mode: ListCursorMode::Select,
-                                tree_addr: vec![ i ],
-                            };
-                        }
-                    }
-                }
-                TreeCursor {
-                    leaf_mode: ListCursorMode::Select,
-                    tree_addr: vec![],
-                }
-            }
-        }
-    }
-
-    fn goto(&mut self, new_cur: TreeCursor) -> TreeNavResult {
-        let old_cur = self.cursor.get();
-        if let Some(i) = old_cur.idx {
-            if i < self.data.len() as isize {
-                self.data.get_mut(i as usize).write().unwrap().goto(TreeCursor::none());
-            }
-        }
-
-        match new_cur.tree_addr.len() {
-            0 => {
-                self.cursor.set(ListCursor {
-                    mode: new_cur.leaf_mode,
-                    idx: None,
-                });
-                TreeNavResult::Continue
-            }
-            1 => {
-                let idx = crate::utils::modulo(new_cur.tree_addr[0], if new_cur.leaf_mode == ListCursorMode::Insert { 1 } else { 0 } + self.data.len() as isize);
-
-                self.cursor.set(ListCursor {
-                    mode: new_cur.leaf_mode,
-                    idx: Some(idx),
-                });
-
-                if new_cur.leaf_mode == ListCursorMode::Select && self.data.len() > 0 {
-                    self.data
-                        .get_mut(idx as usize)
-                        .write().unwrap()
-                        .goto(TreeCursor {
-                            leaf_mode: ListCursorMode::Select,
-                            tree_addr: vec![]
-                        });
-                }
-
-                TreeNavResult::Continue
-            }
-            _ => {
-                if self.data.len() > 0 {
-                    let idx = crate::utils::modulo(new_cur.tree_addr[0], self.data.len() as isize);
-
-                    self.cursor.set(ListCursor {
-                        mode: ListCursorMode::Select,
-                        idx: Some(idx),
-                    });
-
-                    self.data
-                        .get_mut(idx as usize)
-                        .write().unwrap()
-                        .goto(TreeCursor {
-                            leaf_mode: new_cur.leaf_mode,
-                            tree_addr: new_cur.tree_addr[1..].iter().cloned().collect(),
-                        });
-                } else {
-                    self.cursor.set(ListCursor::home());
-                }
-
-                TreeNavResult::Continue                
-            }
-        }
-    }
-
-    fn goby(&mut self, direction: Vector2<isize>) -> TreeNavResult {
-        let mut cur = self.get_cursor();
-
-        let gravity = true;
-
-        match cur.tree_addr.len() {
-            0 => {
-
-                if direction.y < 0 {
-                    // up
-                    self.cursor.set(ListCursor::none());
-                    TreeNavResult::Exit
-                } else if direction.y > 0 {
-                    // dn
-                    eprintln!("dn: data.len() = {}", self.data.len());
-                    self.cursor.set(ListCursor {
-                        mode: if self.data.len() > 0 { cur.leaf_mode } else { ListCursorMode::Insert },
-                        idx: Some(0)
-                    });
-
-                    self.goby(Vector2::new(direction.x, direction.y-1));
-                    TreeNavResult::Continue
-                } else {
-                    TreeNavResult::Continue
-                }
-            },
-
-            1 => {
-                if direction.y > 0 {
-                    // dn
-
-                    if cur.tree_addr[0] < self.data.len() as isize {
-                        if self.data
-                            .get_mut(cur.tree_addr[0] as usize)
-                            .write().unwrap()
-                            .goby(Vector2::new(direction.x, direction.y))
-                            == TreeNavResult::Continue {
-                                self.cursor.set(ListCursor {
-                                    mode: ListCursorMode::Select,
-                                    idx: Some(cur.tree_addr[0])
-                                });
-                                self.set_leaf_mode(cur.leaf_mode);
-                            }
-                    }
-
-                    TreeNavResult::Continue
-
-                } else if direction.y < 0 {
-                    // up
-                    self.cursor.set(ListCursor {
-                        mode: cur.leaf_mode,
-                        idx: None
-                    });
-                    TreeNavResult::Exit
-                } else {
-                    // horizontal
-
-                    if (cur.tree_addr[0]+direction.x >= 0) &&
-                        (cur.tree_addr[0]+direction.x <
-                         self.data.len() as isize
-                         + if cur.leaf_mode == ListCursorMode::Insert { 1 } else { 0 })
-                    {
-                        let idx = cur.tree_addr[0] + direction.x;
-                        let mut new_addr = Vec::new();
-
-                        match cur.leaf_mode {
-                            ListCursorMode::Select => {
-                                let cur_item = self.data.get(cur.tree_addr[0] as usize);
-                                let cur_height = cur_item.read().unwrap().get_height(&TreeHeightOp::Max);
-
-                                let new_item = self.data
-                                    .get_mut(idx as usize);
-
-                                let height = new_item.read().unwrap().get_height(
-                                    if direction.x < 0 {
-                                        &TreeHeightOp::Q
-                                    } else {
-                                        &TreeHeightOp::P
-                                    }
-                                );
-
-                                new_addr.push(idx);
-                                if gravity && cur_height < 2 {
-                                    for _ in 1..height {
-                                        new_addr.push( if direction.x >= 0 {
-                                            0
-                                        } else {
-                                            -1
-                                        });
-                                    }
-                                }
-                            }
-                            ListCursorMode::Insert => {
-                                let gravity = false;
-                                if direction.x > 0
-                                {
-                                    if (cur.tree_addr[0] as usize) < self.data.len() {
-                                        let cur_item = self.data.get(cur.tree_addr[0] as usize);
-                                        let cur_height = cur_item.read().unwrap().get_height(&TreeHeightOp::P);
-
-                                        if gravity && cur_height > 1 {
-                                            new_addr.push( cur.tree_addr[0] );
-                                            new_addr.push(0);
-                                        } else {
-                                            new_addr.push( idx );           
-                                        }
-                                    }
-                                } else {
-                                    if (idx as usize) < self.data.len() {
-                                        let pxv_item = self.data.get(idx as usize);
-                                        let pxv_height = pxv_item.read().unwrap().get_height(&TreeHeightOp::P);
-
-                                        if gravity && pxv_height > 1 {
-                                            new_addr.push( idx );
-                                            new_addr.push( -1 );
-                                        } else {
-                                            new_addr.push( idx );           
-                                        }
-                                    }                                    
-                                }
-                            }
-                        }
-
-                        if self.data.len() == 0 {
-                            cur.leaf_mode = ListCursorMode::Insert
-                        }
-                        cur.tree_addr = new_addr;
-                        self.goto(cur);
-
-                        TreeNavResult::Continue
-                    } else {
-                        self.cursor.set(ListCursor {
-                            mode: cur.leaf_mode,
-                            idx: None
-                        });
-                        self.cursor.set(ListCursor::none());
-                        TreeNavResult::Exit
-                    }
-                }
-            },
-            depth => {
-                // nested
-
-                if cur.tree_addr[0] < self.data.len() as isize {
-
-                    let cur_item = self.data
-                        .get_mut(cur.tree_addr[0] as usize);
-
-                    let result = cur_item.write().unwrap().goby(direction);
-
-                    match result
-                    {
-                        TreeNavResult::Exit => {
-                            if direction.y < 0 {
-                                // up
-                                self.cursor.set(ListCursor {
-                                    mode: cur.leaf_mode,
-                                    idx: Some(cur.tree_addr[0])
-                                });
-
-                                TreeNavResult::Continue
-                            } else if direction.y > 0 {
-                                // dn
-
-                                TreeNavResult::Continue
-                            } else {
-                                // horizontal
-                                if (cur.tree_addr[0]+direction.x >= 0) &&
-                                    (cur.tree_addr[0]+direction.x < self.data.len() as isize)
-                                {
-                                    let mut new_addr = Vec::new();
-
-                                    if direction.x < 0 {
-                                        let pxv_item = self.data
-                                            .get_mut(cur.tree_addr[0] as usize - 1);
-
-                                        let pxv_height = pxv_item.read().unwrap().get_height(&TreeHeightOp::Q) as isize;
-                                        let cur_height = cur_item.read().unwrap().get_height(&TreeHeightOp::P) as isize;
-                                        let dist_from_ground = cur_height - (depth as isize - 1);
-                                        let n_steps_down =
-                                            if gravity {
-                                                pxv_height - dist_from_ground
-                                            } else {
-                                                depth as isize - 1
-                                            };
-
-                                        eprintln!("<- LEFT CROSS: pxv_height = {}, cur_height = {}, dist_from_ground = {}, n_steps_down = {}", pxv_height, cur_height, dist_from_ground, n_steps_down);
-                                        new_addr.push( cur.tree_addr[0] - 1 );
-                                        for _i in 0..n_steps_down {
-                                            new_addr.push( -1 );
-                                        }
-                                        
-                                    } else {
-                                        let nxd_item = self.data
-                                            .get_mut(cur.tree_addr[0] as usize + 1);
-
-                                        let cur_height = cur_item.read().unwrap().get_height(&TreeHeightOp::Q) as isize;
-                                        let nxd_height = nxd_item.read().unwrap().get_height(&TreeHeightOp::P) as isize;
-                                        let dist_from_ground = cur_height - (depth as isize - 1);
-                                        let n_steps_down =
-                                            if gravity {
-                                                nxd_height - dist_from_ground
-                                            } else {
-                                                depth as isize - 1
-                                            };
-
-                                        eprintln!("-> RIGHT CROSS: cur_height = {}, nxd_height = {}, dist_from_ground = {}, n_steps_down = {}", cur_height, nxd_height, dist_from_ground, n_steps_down);
-                                        new_addr.push( cur.tree_addr[0] + 1 );
-                                        for _i in 0..n_steps_down {
-                                            new_addr.push( 0 );
-                                        }
-                                    }
-
-                                    drop(cur_item);
-
-                                    eprintln!("CROSS: goto {:?}", new_addr);
-                                    cur.tree_addr = new_addr;
-                                    self.goto(cur)
-                                } else {
-                                    self.cursor.set(ListCursor {
-                                        mode: cur.leaf_mode,
-                                        idx: None
-                                    });
-                                    self.cursor.set(ListCursor::none());
-                                    TreeNavResult::Exit
-                                }
-                            }
-                        }
-                        TreeNavResult::Continue => TreeNavResult::Continue
-                    }
-
-
-                } else {
-                    self.cursor.set(
-                        ListCursor {
-                            mode: ListCursorMode::Insert,
-                            idx: Some(0)
-                        }
-                    );
-                    TreeNavResult::Continue
-                }
-            }
-        }
-    }
-}
-

nested/src/editors/list/pty_editor.rs

@@ -1,250 +0,0 @@
-use {
-    r3vi::{
-        view::{ViewPort, OuterViewPort, sequence::*},
-        projection::decorate_sequence::*,
-    },
-    crate::{
-        type_system::{Context, ReprTree},
-        editors::list::*,
-        terminal::{TerminalEvent, TerminalView, make_label},
-        tree::{TreeCursor, TreeNav, TreeNavResult},
-        tree::NestedNode,
-        PtySegment
-    },
-    std::sync::{Arc, RwLock},
-    termion::event::{Event, Key}
-};
-
-//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
-
-pub struct PTYListStyle {
-    style: (String, String, String)
-}
-
-impl PTYListStyle {
-    pub fn new(style: (&str, &str, &str)) -> PTYListStyle {
-        PTYListStyle {
-            style: (style.0.into(), style.1.into(), style.2.into())
-        }
-    }
-
-    pub fn get_seg_seq_view(&self, editor: &ListEditor) -> OuterViewPort<dyn SequenceView<Item = OuterViewPort<dyn TerminalView>>> {
-        let seg_seq = ListSegmentSequence::new(
-            editor.get_cursor_port(),
-            editor.get_data_port()
-        );
-        let se = seg_seq.read().unwrap();
-        se.get_view().map(move |segment| segment.pty_view())
-    }
-
-    pub fn pty_view(&self, editor: &ListEditor) -> OuterViewPort<dyn TerminalView> {
-        let seg_seq = ListSegmentSequence::new(
-            editor.get_cursor_port(),
-            editor.get_data_port()
-        );
-        let seg_seq = seg_seq.read().unwrap();
-
-        seg_seq
-            .get_view()
-            .map(move |segment| segment.pty_view())
-            .separate(make_label(&self.style.1))
-            .wrap(make_label(&self.style.0), make_label(&self.style.2))
-            .to_grid_horizontal()
-            .flatten()
-    }
-
-    pub fn for_node(node: &mut NestedNode, style: (&str, &str, &str)) {
-        node.view = Some(
-            Self::new(style)
-                .pty_view(
-                    &node.get_edit::<ListEditor>().unwrap().read().unwrap()
-                )
-        );
-    }
-}
-
-//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
-
-// todo: rename to CharController
-
-pub struct PTYListController {
-    pub editor: Arc<RwLock<ListEditor>>,
-
-    split_char: Option<char>,
-    close_char: Option<char>,
-
-    depth: OuterViewPort<dyn SingletonView<Item = usize>>
-}
-
-//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
-
-impl PTYListController {
-    pub fn from_editor(
-        editor: Arc<RwLock<ListEditor>>,
-        split_char: Option<char>,
-        close_char: Option<char>,
-        depth: OuterViewPort<dyn SingletonView<Item = usize>>
-    ) -> Self {
-        PTYListController {
-            editor,
-            split_char,
-            close_char,
-            depth
-        } 
-    }
-
-    pub fn for_node(
-        node: &mut NestedNode,
-        split_char: Option<char>,
-        close_char: Option<char>
-    ) {
-        {
-            let ctx = node.ctx.as_ref();
-            let mut ctx = ctx.write().unwrap();
-
-            if let Some(c) = split_char.as_ref() {
-                ctx.meta_chars.push(*c);
-            }
-            if let Some(c) = close_char.as_ref() {
-                ctx.meta_chars.push(*c);
-            }
-        }
-        
-        let editor = node.get_edit::<ListEditor>().unwrap();
-        let controller = Arc::new(RwLock::new(PTYListController::from_editor( editor, split_char, close_char, node.depth.clone() )));
-
-        node.cmd.set(Some(controller.clone()));
-        node.close_char.set(close_char);
-    }
-
-    pub fn get_data_port(&self) -> OuterViewPort<dyn SequenceView<Item = NestedNode>> {
-        self.editor.read().unwrap().get_data_port()
-    }
-
-    pub fn clear(&mut self) {
-        self.editor.write().unwrap().clear();
-    }
-
-    pub fn get_item(&self) -> Option<NestedNode> {
-        self.editor.read().unwrap().get_item()
-    }
-
-    pub fn handle_term_event(&mut self, event: &TerminalEvent, _cmd_obj: Arc<RwLock<ReprTree>>) -> TreeNavResult {
-        let mut e = self.editor.write().unwrap();
-        match event {
-            TerminalEvent::Input(Event::Key(Key::Insert)) => {
-                e.toggle_leaf_mode();
-                TreeNavResult::Continue
-            }
-            _  => TreeNavResult::Continue
-        }        
-    }
-
-    pub fn handle_meta_char(&mut self, c: char, child_close_char: Option<char>) -> TreeNavResult {
-        eprintln!("handle meta char: got '{}', child_close={:?}, self.close={:?}, split={:?}", c, child_close_char, self.close_char, self.split_char);
-        let mut e = self.editor.write().unwrap();
-        let cur = e.cursor.get();
-        
-        if Some(c) == self.split_char
-//            || Some(c) == child_close_char
-        {
-            e.listlist_split();
-            eprintln!("done listlist split");
-            TreeNavResult::Continue
-        } else if Some(c) == child_close_char {
-            e.goto(TreeCursor::none());
-            e.cursor.set(ListCursor {
-                mode: ListCursorMode::Insert,
-                idx: Some(cur.idx.unwrap_or(0)+1)
-            });
-            TreeNavResult::Continue
-        } else {
-            TreeNavResult::Exit
-        }
-    }
-
-    pub fn handle_any_event(&mut self, cmd_obj: Arc<RwLock<ReprTree>>) -> TreeNavResult {
-        let mut e = self.editor.write().unwrap();
-        let cur = e.cursor.get();
-        let ctx = e.ctx.clone();
-        let ctx = ctx.read().unwrap();
-
-        match cur.mode {
-            ListCursorMode::Insert => {
-                let mut new_edit = Context::make_node(&e.ctx, e.typ.clone(), self.depth.map(|d| d+1)).unwrap();
-                new_edit.goto(TreeCursor::home());
-
-                match new_edit.send_cmd_obj(cmd_obj.clone()) {
-                    TreeNavResult::Continue => {
-                        e.insert(Arc::new(RwLock::new(new_edit.clone())));
-                        TreeNavResult::Continue
-                    }
-                    TreeNavResult::Exit => {
-                        TreeNavResult::Exit
-                    }
-                }
-            },
-            ListCursorMode::Select => {
-                if let Some(item) = e.get_item_mut() {
-                    let res = item.write().unwrap().send_cmd_obj(cmd_obj.clone());
-                    let child_close_char = item.read().unwrap().close_char.get();
-
-                   match res {
-                        TreeNavResult::Continue => TreeNavResult::Continue,
-                        TreeNavResult::Exit => {
-                            // child editor returned control, probably for meta-char handling..
-
-                            if cmd_obj.read().unwrap().get_type().clone() == ctx.type_term_from_str("Char").unwrap() {
-                                let co = cmd_obj.read().unwrap();
-                                if let Some(cmd_view) = co.get_view::<dyn SingletonView<Item = char>>() {
-                                    drop(co);
-                                    drop(e);
-                                    self.handle_meta_char(cmd_view.get(), child_close_char)
-                                } else {
-                                    TreeNavResult::Exit
-                                }
-                            } else {
-                                TreeNavResult::Exit
-                            }
-                        }
-                    }
-                } else {
-                    // cursor selects non existent item
-                    TreeNavResult::Exit
-                }
-            }
-        }
-    }
-}
-
-use r3vi::view::singleton::SingletonView;
-use crate::commander::ObjCommander;
-
-impl ObjCommander for PTYListController {
-    fn send_cmd_obj(&mut self, cmd_obj: Arc<RwLock<ReprTree>>) -> TreeNavResult {
-        let mut e = self.editor.write().unwrap();
-        let cmd_type = cmd_obj.read().unwrap().get_type().clone();
-
-        if cmd_type == Context::parse(&e.ctx, "ListCmd").into()
-        || cmd_type == Context::parse(&e.ctx, "NestedNode").into()
-        {
-            e.send_cmd_obj( cmd_obj )
-        }
-
-        else if cmd_type == Context::parse(&e.ctx, "TerminalEvent").into() {
-            let co = cmd_obj.read().unwrap();
-            if let Some(view) = co.get_view::<dyn SingletonView<Item = TerminalEvent>>() {
-                drop( co );
-                drop( e );
-                self.handle_term_event( &view.get(), cmd_obj )
-            } else {
-                TreeNavResult::Exit
-            }
-        }
-
-        else {
-            drop( e );
-            self.handle_any_event( cmd_obj )
-        }
-    }
-}

nested/src/editors/list/segment.rs

@@ -1,174 +0,0 @@
-use {
-    r3vi::{
-        view::{
-            Observer, ObserverBroadcast, ObserverExt, OuterViewPort, View, ViewPort,
-            singleton::*,
-            sequence::*,
-        },
-        projection::projection_helper::*
-    },
-    crate::{
-        editors::list::{ListCursor, ListCursorMode},
-        terminal::{TerminalView, TerminalStyle, make_label},
-        tree::{NestedNode, TreeNav},
-        utils::color::{bg_style_from_depth, fg_style_from_depth},
-        PtySegment
-    },
-    std::sync::Arc,
-    std::sync::RwLock,
-};
-
-pub enum ListSegment {
-    InsertCursor,
-    Item {
-        editor: NestedNode,
-        cur_dist: isize,
-    }
-}
-
-impl PtySegment for ListSegment {
-    fn pty_view(&self) -> OuterViewPort<dyn TerminalView> {
-        match self {
-            ListSegment::InsertCursor => {
-                make_label("|")
-                    .map_item(move |_pt, atom| {
-                     atom.add_style_front(TerminalStyle::fg_color((150,80,230)))
-                        .add_style_front(TerminalStyle::bold(true))
-                    })
-            }
-            ListSegment::Item{ editor, cur_dist } => {
-                let e = editor.clone();
-                let cur_dist = *cur_dist;
-                editor.get_view().map_item(move |_pt, atom| {
-                    let c = e.get_cursor();
-                    let cur_depth = c.tree_addr.len();
-                    let select =
-                        if cur_dist == 0 {
-                            cur_depth
-                        } else {
-                            usize::MAX
-                        };
-                    
-                    atom
-                        .add_style_back(bg_style_from_depth(select))
-                        .add_style_back(TerminalStyle::bold(select==1))
-                        .add_style_back(fg_style_from_depth(e.depth.get_view().get()))
-                })
-            }
-        }
-    }
-}
-
-pub struct ListSegmentSequence {
-    data: Arc<dyn SequenceView<Item = NestedNode>>,
-    cursor: Arc<dyn SingletonView<Item = ListCursor>>,
-
-    cur_cursor: ListCursor,
-
-    port: ViewPort<dyn SequenceView<Item = ListSegment>>,
-    cast: Arc<RwLock<ObserverBroadcast<dyn SequenceView<Item = ListSegment>>>>,
-    proj_helper: ProjectionHelper<usize, Self>,
-}
-
-impl View for ListSegmentSequence {
-    type Msg = usize;
-}
-
-impl SequenceView for ListSegmentSequence {
-    type Item = ListSegment;
-
-    fn len(&self) -> Option<usize> {
-        match self.cur_cursor.mode {
-            ListCursorMode::Insert => {
-                Some(self.data.len()? + if self.cur_cursor.idx.is_some() { 1 } else { 0 })
-            }
-            _ => self.data.len(),
-        }
-    }
-
-    fn get(&self, idx: &usize) -> Option<Self::Item> {
-        let c = self.cursor.get();
-        Some(if let Some(cur) = c.idx {
-            match c.mode {
-                ListCursorMode::Select => {
-                    ListSegment::Item {
-                        editor: self.data.get(idx)?,
-                        cur_dist: cur - *idx as isize
-                    }
-                }
-                ListCursorMode::Insert => {
-                    if *idx < cur as usize {
-                        ListSegment::Item {
-                            editor: self.data.get(idx)?,
-                            cur_dist: cur - *idx as isize
-                        }
-                    } else if *idx == cur as usize {
-                        ListSegment::InsertCursor
-                    } else {
-                        ListSegment::Item {
-                            editor: self.data.get(&(*idx - 1))?,
-                            cur_dist: cur - *idx as isize
-                        }
-                    }
-                }
-            }
-        } else {
-            ListSegment::Item {
-                editor: self.data.get(&idx)?,
-                cur_dist: *idx as isize + 1
-            }
-        })
-    }
-}
-
-impl ListSegmentSequence {
-    pub fn new(
-        cursor_port: OuterViewPort<dyn SingletonView<Item = ListCursor>>,
-        data_port: OuterViewPort<dyn SequenceView<Item = NestedNode>>,
-    ) -> Arc<RwLock<Self>> {
-        let out_port = ViewPort::new();
-        let mut proj_helper = ProjectionHelper::new(out_port.update_hooks.clone());
-        let proj = Arc::new(RwLock::new(ListSegmentSequence {
-            cur_cursor: cursor_port.get_view().get(),
-            port: out_port.clone(),
-
-            cursor: proj_helper.new_singleton_arg(0, cursor_port, |s: &mut Self, _msg| {
-                let _old_cursor = s.cur_cursor;
-                s.cur_cursor = s.cursor.get();
-
-                // todo: optimize
-                s.cast.notify_each(0..=s.data.len().unwrap_or(0) + 1);
-            }),
-
-            data: proj_helper.new_sequence_arg(1, data_port, |s: &mut Self, idx| {
-                if let Some(cur_idx) = s.cur_cursor.idx {
-                    match s.cur_cursor.mode {
-                        ListCursorMode::Insert => {
-                            if *idx < cur_idx as usize {
-                                s.cast.notify(idx);
-                            } else {
-                                s.cast.notify(&(*idx + 1));
-                            }
-                        }
-                        _ => {
-                            s.cast.notify(idx);
-                        }
-                    }
-                } else {
-                    s.cast.notify(idx);
-                }
-            }),
-            cast: out_port.inner().get_broadcast(),
-            proj_helper,
-        }));
-
-        proj.write().unwrap().proj_helper.set_proj(&proj);
-        out_port.inner().set_view(Some(proj.clone()));
-
-        proj
-    }
-
-    pub fn get_view(&self) -> OuterViewPort<dyn SequenceView<Item = ListSegment>> {
-        self.port.outer()
-    }
-}

nested/src/editors/mod.rs

@@ -1,9 +0,0 @@
-
-pub mod list;
-pub mod product;
-pub mod sum;
-
-pub mod char;
-pub mod integer;
-pub mod typeterm;
-

nested/src/editors/product/editor.rs

@@ -1,280 +0,0 @@
-use {
-    r3vi::{
-        view::{
-            OuterViewPort,
-            sequence::*
-        },
-        buffer::{
-            vec::*,
-            index_hashmap::*
-        }
-    },
-    laddertypes::{TypeTerm},
-    crate::{
-        type_system::{Context},
-        terminal::{
-            TerminalEditor, TerminalEditorResult,
-            TerminalEvent, TerminalView
-        },
-        editors::{
-            list::ListCursorMode,
-            product::{
-                segment::ProductEditorSegment
-            }
-        },
-        tree::{TreeNav, TreeNavResult},
-        diagnostics::{Diagnostics},
-        terminal::{TerminalStyle},
-        tree::NestedNode
-    },
-    cgmath::{Point2},
-    std::sync::{Arc, RwLock},
-    termion::event::{Event, Key},
-    std::ops::{DerefMut}
-};
-
-pub struct ProductEditor {
-    msg_buf: VecBuffer<Option<OuterViewPort<dyn SequenceView<Item = crate::diagnostics::Message>>>>,
-    msg_port:  OuterViewPort<dyn SequenceView<Item = crate::diagnostics::Message>>,
-    segments: IndexBuffer<Point2<i16>, ProductEditorSegment>,
-    pub(super) n_indices: Vec<Point2<i16>>,
-
-    pub(super) ctx: Arc<RwLock<Context>>,    
-    pub(super) cursor: Option<isize>,
-    pub(super) depth: usize,
-}
-
-impl ProductEditor {
-    pub fn new(depth: usize, ctx: Arc<RwLock<Context>>) -> Self {
-        let msg_buf = VecBuffer::new();
-        ProductEditor {
-            segments: IndexBuffer::new(),
-            msg_port: msg_buf.get_port()
-                .to_sequence()
-                .enumerate()
-                .filter_map(|(idx, msgs): &(usize, Option<OuterViewPort<dyn SequenceView<Item = crate::diagnostics::Message>>>)| {
-                    let idx = *idx;
-                    if let Some(msgs) = msgs {
-                        Some(msgs.map(
-                            move |msg| {
-                                let mut msg = msg.clone();
-                                msg.addr.insert(0, idx);
-                                msg
-                            }))
-                    } else {
-                        None
-                    }
-                })
-                .flatten(),
-            msg_buf,
-
-            n_indices: Vec::new(),
-            ctx,
-            cursor: None,
-            depth
-        }
-    }
-
-    pub fn with_t(mut self, pos: Point2<i16>, t: &str) -> Self {
-        self.segments.insert(pos, ProductEditorSegment::T(t.to_string(), self.depth));
-        self
-    }   
-
-    pub fn with_n(mut self, pos: Point2<i16>, n: &TypeTerm) -> Self {
-        self.segments.insert(pos, ProductEditorSegment::N{
-            t: n.clone(),
-            editor: None,
-            ed_depth: self.depth + 1,
-            cur_depth: 0,
-            cur_dist: isize::MAX
-        });
-        self.n_indices.push(pos);
-
-        let mut b = VecBuffer::new();
-        b.push(crate::diagnostics::make_todo(crate::terminal::make_label(&format!("complete {}", self.ctx.read().unwrap().type_term_to_str(n)))));
-        self.msg_buf.push(Some(b.get_port().to_sequence()));
-        self
-    }
-
-    pub fn get_editor_segment(&self, mut idx: isize) -> ProductEditorSegment {
-        idx = crate::utils::modulo(idx, self.n_indices.len() as isize);
-        if let Some(pos) = self.n_indices.get(idx as usize) {
-            self.segments.get(pos).unwrap()
-        } else {
-            unreachable!()
-        }
-    }
-
-    pub fn get_editor_segment_mut(&mut self, mut idx: isize) -> MutableIndexAccess<Point2<i16>, ProductEditorSegment> {
-        idx = crate::utils::modulo(idx, self.n_indices.len() as isize);
-        if let Some(pos) = self.n_indices.get(idx as usize) {
-            self.segments.get_mut(pos)
-        } else {
-            unreachable!()
-        }
-    }
-
-    pub fn get_cur_segment(&self) -> Option<ProductEditorSegment> {
-        Some(self.get_editor_segment(self.cursor?))
-    }
-
-    pub fn get_cur_segment_mut(&mut self) -> Option<MutableIndexAccess<Point2<i16>, ProductEditorSegment>> {
-        Some(self.get_editor_segment_mut(self.cursor?))
-    }
-
-    pub fn get_editor(&self, idx: isize) -> Option<NestedNode> {
-        if let ProductEditorSegment::N{ t: _, editor, ed_depth: _, cur_depth: _, cur_dist: _ } = self.get_editor_segment(idx) {
-            editor
-        } else {
-            unreachable!()
-        }
-    }
-
-    pub fn get_cur_editor(&self) -> Option<NestedNode> {
-        self.get_editor(self.cursor?)
-    }
-
-    pub fn set_leaf_mode(&mut self, mode: ListCursorMode) {
-        let mut c = self.get_cursor();
-        c.leaf_mode = mode;
-        self.goto(c);
-    }
-
-    pub fn update_segment(&mut self, idx: isize) {
-        if let Some(ProductEditorSegment::N{ t, editor, ed_depth: _, cur_depth, cur_dist }) = self.get_editor_segment_mut(idx).deref_mut() {
-            let cur = self.get_cursor();
-
-            if cur.tree_addr.len() > 0 {
-                if cur.tree_addr[0] == idx {
-                    *cur_depth = cur.tree_addr.len();
-                }
-                
-                *cur_dist = cur.tree_addr[0] - idx
-            } else {
-                *cur_dist = isize::MAX;
-            };
-
-            if let Some(e) = editor {
-                self.msg_buf.update(idx as usize, Some(e.get_msg_port()));
-            } else {
-                let mut b = VecBuffer::new();
-                b.push(crate::diagnostics::make_todo(crate::terminal::make_label(&format!("complete {}", self.ctx.read().unwrap().type_term_to_str(&t)))));
-
-                self.msg_buf.update(idx as usize, Some(b.get_port().to_sequence()));
-
-                if cur.tree_addr.len() > 0 {
-                    if cur.tree_addr[0] == idx {
-                        self.msg_buf.update(idx as usize, Some(b.get_port().to_sequence().map(
-                            |msg| {
-                                let mut msg = msg.clone();
-                                msg.port = msg.port.map_item(|_p,a| a.add_style_back(TerminalStyle::bg_color((40,40,40))));
-                                msg
-                            }
-                        )));
-
-                    }
-                }
-            }
-
-        } else {
-            unreachable!()
-        }
-    }
-
-    pub fn update_cur_segment(&mut self) {
-        if let Some(c) = self.cursor {
-            self.update_segment(c);
-        }
-    }
-
-    pub fn get_term_view(&self) -> OuterViewPort<dyn TerminalView> {
-        let ctx = self.ctx.clone();
-        self.segments
-            .get_port()
-            .map_item(move |_pos, e: &ProductEditorSegment| { e.get_view(ctx.clone()) })
-            .flatten()
-    }
-}
-
-use r3vi::view::singleton::SingletonView;
-use crate::{commander::ObjCommander, type_system::ReprTree};
-
-impl ObjCommander for ProductEditor {
-    fn send_cmd_obj(&mut self, cmd_obj: Arc<RwLock<ReprTree>>) -> TreeNavResult {
-        let co = cmd_obj.read().unwrap();
-        let cmd_type = co.get_type().clone();
-        let term_event_type = Context::parse(&self.ctx, "TerminalEvent").into();
-
-        if cmd_type == term_event_type {
-            if let Some(te_view) = co.get_view::<dyn SingletonView<Item = TerminalEvent>>() {
-                drop(co);
-                let event = te_view.get();
-
-                let mut update_segment = false;
-
-                let _result = if let Some(mut segment) = self.get_cur_segment_mut().as_deref_mut() {
-                    if let Some(ProductEditorSegment::N{ t, editor, ed_depth, cur_depth, cur_dist: _ }) = segment.deref_mut() {
-                        *cur_depth = self.get_cursor().tree_addr.len();
-
-                        if let Some(mut e) = editor.clone() {
-                            match e.handle_terminal_event(&event) {
-                                TerminalEditorResult::Exit =>
-                                    match event {
-                                        TerminalEvent::Input(Event::Key(Key::Backspace)) => {
-                                            *editor = None;
-                                            update_segment = true;
-                                            TerminalEditorResult::Continue
-                                        }
-                                        _ => {
-                                            *cur_depth = e.get_cursor().tree_addr.len();
-                                            match self.nexd() {
-                                                TreeNavResult::Continue => TerminalEditorResult::Continue,
-                                                TreeNavResult::Exit => TerminalEditorResult::Exit
-                                            }
-                                        }
-                                    },
-                                TerminalEditorResult::Continue => {
-                                    *cur_depth = e.get_cursor().tree_addr.len();
-                                    TerminalEditorResult::Continue
-                                }
-                            }
-                        } else {
-                            let mut e = Context::make_node(&self.ctx, t.clone(), r3vi::buffer::singleton::SingletonBuffer::new(*ed_depth).get_port()).unwrap();
-                            *editor = Some(e.clone());
-                            update_segment = true;
-
-                            e.dn();
-                            let x = e.handle_terminal_event(&event);
-                            x
-                        }
-                    } else {
-                        unreachable!();
-                    }
-                } else {
-                    TerminalEditorResult::Exit
-                };
-
-                if update_segment {
-                    self.update_cur_segment();
-                }
-            }
-
-            TreeNavResult::Continue
-        } else {
-            drop(co);
-            if let Some(mut node) = self.get_cur_editor() {
-                node.send_cmd_obj(cmd_obj)
-            } else {
-                TreeNavResult::Exit
-            }
-        }
-    }
-}
-
-impl Diagnostics for ProductEditor {
-    fn get_msg_port(&self) -> OuterViewPort<dyn SequenceView<Item = crate::diagnostics::Message>> {
-        self.msg_port.clone()
-    }
-}
-
-

nested/src/editors/product/mod.rs

@@ -1,7 +0,0 @@
-
-pub mod editor;
-pub mod segment;
-pub mod nav;
-
-pub use editor::ProductEditor;
-

nested/src/editors/product/nav.rs

@@ -1,247 +0,0 @@
-use {
-    crate::{
-        type_system::Context,
-        tree::{TreeNav, TreeNavResult, TreeCursor},
-        editors::{
-            list::ListCursorMode,
-            product::{segment::ProductEditorSegment, ProductEditor},
-        }
-    },
-    cgmath::{Vector2},
-    std::{ops::{DerefMut}},
-};
-
-impl TreeNav for ProductEditor {
-    fn get_cursor(&self) -> TreeCursor {
-        if let Some(i) = self.cursor {
-            if let Some(e) = self.get_editor(i) {
-                let mut c = e.get_cursor();
-                if c.tree_addr.len() == 0 {
-                    c.leaf_mode = ListCursorMode::Select;
-                }
-                c.tree_addr.insert(0, i);                
-                c
-            } else {
-                TreeCursor {
-                    leaf_mode: ListCursorMode::Select,
-                    tree_addr: vec![ i ]
-                }
-            }
-        } else {
-            TreeCursor::none()
-        }
-    }
-
-    fn get_cursor_warp(&self) -> TreeCursor {
-        if let Some(i) = self.cursor {
-            if let Some(e) = self.get_editor(i) {
-                let mut c = e.get_cursor_warp();
-                if c.tree_addr.len() == 0 {
-                    c.leaf_mode = ListCursorMode::Select;
-                }
-                c.tree_addr.insert(0, i as isize - self.n_indices.len() as isize);
-                c
-            } else {
-                TreeCursor {
-                    leaf_mode: ListCursorMode::Select,
-                    tree_addr: vec![ i as isize - self.n_indices.len() as isize ]
-                }
-            }
-        } else {
-            TreeCursor::none()
-        }
-    }
-
-    fn goto(&mut self, mut c: TreeCursor) -> TreeNavResult {
-        let old_cursor = self.cursor;
-
-        if let Some(mut segment) = self.get_cur_segment_mut() {
-            if let Some(ProductEditorSegment::N{ t: _t, editor, ed_depth: _, cur_depth: _, cur_dist:_ }) = segment.deref_mut() {
-                if let Some(e) = editor {
-                    e.goto(TreeCursor::none());
-                }
-            }
-        }
-
-        if c.tree_addr.len() > 0 {
-            self.cursor = Some(crate::utils::modulo(c.tree_addr.remove(0), self.n_indices.len() as isize));
-            if let Some(mut element) = self.get_cur_segment_mut() {
-                if let Some(ProductEditorSegment::N{ t, editor, ed_depth, cur_depth: _, cur_dist:_ }) = element.deref_mut() {
-                    if let Some(e) = editor {
-                        e.goto(c.clone());
-                    } else if c.tree_addr.len() > 0 {
-                        // create editor
-                        let mut e = Context::make_node(&self.ctx, t.clone(), r3vi::buffer::singleton::SingletonBuffer::new(*ed_depth+1).get_port()).unwrap();
-                        *editor = Some(e.clone());
-                        e.goto(c.clone());
-                    }
-                }
-            }
-
-            if let Some(i) = old_cursor{
-                self.update_segment(i);
-            }
-
-            if let Some(i) = self.cursor {
-                self.update_segment(i);
-            }
-
-            TreeNavResult::Continue
-        } else {
-            if let Some(mut ed) = self.get_cur_editor() {
-                ed.goto(TreeCursor::none());
-            }
-
-            self.cursor = None;
-
-            if let Some(i) = old_cursor {
-                self.update_segment(i);
-            }
-            TreeNavResult::Exit
-        }
-    }
-
-    fn goby(&mut self, direction: Vector2<isize>) -> TreeNavResult {
-        let mut cur = self.get_cursor();
-        
-        match cur.tree_addr.len() {
-            0 => {
-                if direction.y > 0 {
-                    self.cursor = Some(0);
-                    self.update_segment(0);
-
-                    self.goby(Vector2::new(direction.x, direction.y-1));
-                    TreeNavResult::Continue
-                } else if direction.y < 0 {
-                    TreeNavResult::Exit
-                } else {
-                    TreeNavResult::Continue
-                }
-            }
-            1 => {
-                if direction.y > 0 {
-                    // dn
-                    if let Some(mut element) = self.get_cur_segment_mut() {
-                        if let Some(ProductEditorSegment::N{ t, editor, ed_depth, cur_depth: _, cur_dist:_ }) = element.deref_mut() {
-                            if let Some(e) = editor {
-                                e.goby(direction);
-                            } else {
-                                // create editor
-
-                                let mut e = Context::make_node(&self.ctx, t.clone(), r3vi::buffer::singleton::SingletonBuffer::new(*ed_depth+1).get_port()).unwrap();
-                                *editor = Some(e.clone());
-                                e.goby(direction);
-                            }
-                        }
-                    }
-
-                    self.update_segment(cur.tree_addr[0]);
-                    TreeNavResult::Continue
-                } else if direction.y < 0 {
-                    // up
-                    let old_cursor = self.cursor;
-                    self.cursor = None;
-                    if let Some(i) = old_cursor {
-                        self.update_segment(i);
-                    }
-                    TreeNavResult::Exit
-                } else {
-                    let old_cursor = self.cursor;
-
-                    if (cur.tree_addr[0]+direction.x >= 0) &&
-                        (cur.tree_addr[0]+direction.x < self.n_indices.len() as isize)
-                    {
-                        self.cursor = Some(cur.tree_addr[0] + direction.x);
-
-                        self.update_cur_segment();
-                        if let Some(i) = old_cursor {
-                            self.update_segment(i);
-                        }
-                        TreeNavResult::Continue
-                    } else {
-                        self.cursor = None;
-                        if let Some(i) = old_cursor {
-                            self.update_segment(i);
-                        }
-                        TreeNavResult::Exit
-                    }
-                }
-            }
-            depth => {
-                let old_cursor = self.cursor;
-                let nav_result =
-                    if let Some(mut element) = self.get_cur_segment_mut() {
-                        if let Some(ProductEditorSegment::N{ t: _, editor, ed_depth: _, cur_depth, cur_dist:_ }) = element.deref_mut() {
-                            if let Some(e) = editor.as_mut() {
-                                //\\//\\//\\//\\
-                                // horizontal //
-                                //\\//\\//\\//\\
-                                match e.goby(direction) {
-                                    TreeNavResult::Exit => {
-                                       // *cur_depth = 1;
-
-                                        if direction.y < 0 {
-                                            if depth <= (1-direction.y) as usize {
-                                                // up
-                                                TreeNavResult::Continue
-                                            } else {
-                                                panic!("unplausible direction.y on exit");
-                                            }
-                                        } else if direction.y > 0 {
-                                            // dn
-                                            TreeNavResult::Continue
-                                        } else if direction.y == 0 {
-                                            // horizontal
-                                            if direction.x != 0 {
-                                                *cur_depth = 0;
-                                            }
-
-                                            if (cur.tree_addr[0]+direction.x >= 0) &&
-                                                (cur.tree_addr[0]+direction.x < self.n_indices.len() as isize)
-                                            {
-                                                if direction.x < 0 {
-                                                    cur.tree_addr[0] -= 1;
-                                                    for i in 1..depth {
-                                                        cur.tree_addr[i] = -1;
-                                                    }
-                                                } else {
-                                                    cur.tree_addr[0] += 1;
-                                                    for i in 1..depth {
-                                                        cur.tree_addr[i] = 0;
-                                                    }
-                                                }
-
-                                                self.goto(cur)
-                                            } else {
-                                                self.cursor = None;
-                                                TreeNavResult::Exit
-                                            }
-                                        } else {
-                                            TreeNavResult::Continue
-                                        }
-                                    }
-                                    TreeNavResult::Continue => {
-                                        TreeNavResult::Continue
-                                    }
-                                }
-                            } else {
-                                TreeNavResult::Continue
-                            }
-                        } else {
-                            TreeNavResult::Continue
-                        }
-                    } else {
-                        TreeNavResult::Continue
-                    };
-
-                if let Some(i) = old_cursor {
-                    self.update_segment(i);
-                }
-
-                self.update_cur_segment();
-                return nav_result;
-            }
-        }
-    }
-}
-

nested/src/editors/product/segment.rs

@@ -1,83 +0,0 @@
-use {
-    r3vi::{
-        view::{
-            OuterViewPort
-        }
-    },
-    laddertypes::{TypeTerm},
-    crate::{
-        type_system::{Context},
-        terminal::{
-            TerminalStyle, TerminalView,
-            make_label
-        },
-        utils::color::{bg_style_from_depth, fg_style_from_depth},
-        tree::{NestedNode, TreeNav}
-    },
-    std::{sync::{Arc, RwLock}},
-};
-
-#[derive(Clone)]
-pub enum ProductEditorSegment {
-    T( String, usize ),
-    N {
-        t: TypeTerm,
-        editor: Option<NestedNode>,
-        ed_depth: usize,
-        cur_depth: usize,
-        cur_dist: isize
-    }
-}
-
-impl ProductEditorSegment {
-    pub fn get_view(&self, ctx: Arc<RwLock<Context>>) -> OuterViewPort<dyn TerminalView> {
-        match self {
-            ProductEditorSegment::T(t, depth) =>
-                make_label(t.as_str())
-                .map_item({
-                    let depth = *depth;
-                    move |_i, x|
-                    x.add_style_back(fg_style_from_depth(depth)).add_style_back(TerminalStyle::italic(true))
-                }
-            ),
-
-            ProductEditorSegment::N { t: _, editor: Some(e), ed_depth, cur_depth: _, cur_dist } =>
-                e.get_view()
-                .map_item({
-                    let e = e.clone();
-                    let d = *ed_depth;
-                    let cur_dist = *cur_dist;
-
-                    move |_i, x| {
-                        let c = e.get_cursor();
-                        let cur_depth = c.tree_addr.len();
-                        let select =
-                            if cur_dist == 0 {
-                                cur_depth
-                            } else {
-                                usize::MAX
-                            };
-
-                        return x
-                            .add_style_back(bg_style_from_depth(select))
-                            .add_style_back(TerminalStyle::bold(select==1))
-                            .add_style_back(fg_style_from_depth(d));
-                    }
-                }),
-
-            ProductEditorSegment::N{ t, editor: None, ed_depth, cur_depth, cur_dist } =>
-                make_label(&ctx.read().unwrap().type_term_to_str(t))
-                .map_item({
-                    let _cur_depth = *cur_depth;
-                    let _ed_depth = *ed_depth;
-                    let cur_dist = *cur_dist;
-
-                    move |_i, x|
-                    x.add_style_back(TerminalStyle::fg_color((215,140,95)))
-                        .add_style_back(bg_style_from_depth(if cur_dist == 0 { 0 } else { usize::MAX }))
-                        .add_style_back(TerminalStyle::bold(cur_dist == 0))
-                })
-        }        
-    }
-}
-

nested/src/editors/sum/editor.rs

@@ -1,142 +0,0 @@
-use {
-    r3vi::{
-        view::{
-            ViewPort, OuterViewPort,
-            singleton::*,
-            sequence::*,            
-        }
-    },
-    laddertypes::{TypeTerm},
-    crate::{
-        terminal::TerminalView,
-        editors::list::ListCursorMode,
-        type_system::{Context, ReprTree},
-        tree::{TreeNav, TreeCursor, TreeNavResult},
-        diagnostics::{Diagnostics, Message},
-        tree::NestedNode,
-        commander::{ObjCommander},
-        PtySegment
-    },
-    cgmath::{Vector2},
-    std::sync::{Arc, RwLock}
-};
-
-pub struct SumEditor {
-    cur: usize,
-    pub editors: Vec< NestedNode >,
-
-    addr_port: ViewPort< dyn SequenceView<Item = isize> >,
-    mode_port: ViewPort< dyn SingletonView<Item = ListCursorMode> >,
-
-    port: ViewPort< dyn TerminalView >,
-    diag_port: ViewPort< dyn SequenceView<Item = Message> >
-}
-
-impl SumEditor {
-    pub fn new(
-        editors: Vec< NestedNode >
-    ) -> Self {
-        let port = ViewPort::new();
-
-        SumEditor {
-            cur: 0,
-            editors,
-            port,
-            diag_port: ViewPort::new(),
-
-
-            addr_port: ViewPort::new(),
-            mode_port: ViewPort::new()
-        }
-    }
-
-    pub fn init_ctx(ctx: &Arc<RwLock<Context>>) {
-        ctx.write().unwrap().add_typename("Sum".into());
-    }
-
-    pub fn into_node(self, ctx: Arc<RwLock<Context>>) -> NestedNode {
-        let view = self.pty_view();
-        let editor = Arc::new(RwLock::new(self));
-
-        NestedNode::new(
-            ctx.clone(),
-            ReprTree::new_arc(TypeTerm::TypeID(ctx.read().unwrap().get_typeid("Sum").unwrap())),
-            r3vi::buffer::singleton::SingletonBuffer::new(0).get_port()
-        )
-            .set_view(view)
-            .set_editor(editor.clone())
-            .set_cmd(editor.clone())
-            .set_nav(editor.clone())
-//            .set_diag(editor.read().unwrap().diag.clone())
-    }
-
-    pub fn get(&self) -> NestedNode {
-        self.editors[ self.cur ].clone()
-    }
-
-    pub fn select(&mut self, idx: usize) {
-        self.cur = idx;
-
-        let tv = self.editors[ self.cur ].get_view();
-        tv.add_observer( self.port.get_cast() );
-        self.port.update_hooks.write().unwrap().clear();
-        self.port.add_update_hook( Arc::new(tv.0.clone()) );
-        self.port.set_view( Some(tv.get_view_arc()) );
-
-        let dv = self.editors[ self.cur ].get_msg_port();
-        dv.add_observer( self.diag_port.get_cast() );
-        self.diag_port.update_hooks.write().unwrap().clear();
-        self.diag_port.add_update_hook( Arc::new(dv.0.clone()) );
-        self.diag_port.set_view( Some(dv.get_view_arc()) );
-
-        let dv = self.editors[ self.cur ].get_addr_view();
-        dv.add_observer( self.addr_port.get_cast() );
-        self.addr_port.update_hooks.write().unwrap().clear();
-        self.addr_port.add_update_hook( Arc::new(dv.0.clone()) );
-        self.addr_port.set_view( Some(dv.get_view_arc()) );
-        
-        let dv = self.editors[ self.cur ].get_mode_view();
-        dv.add_observer( self.mode_port.get_cast() );
-        self.mode_port.update_hooks.write().unwrap().clear();
-        self.mode_port.add_update_hook( Arc::new(dv.0.clone()) );
-        self.mode_port.set_view( Some(dv.get_view_arc()) );
-    }
-}
-
-impl TreeNav for SumEditor {
-    fn get_cursor(&self) -> TreeCursor {
-        self.editors[ self.cur ].get_cursor()
-    }
-
-    fn get_cursor_warp(&self) -> TreeCursor {
-        self.editors[ self.cur ].get_cursor_warp()
-    }
-
-    fn goby(&mut self, direction: Vector2<isize>) -> TreeNavResult {
-        self.editors[ self.cur ].goby( direction )
-    }
-
-    fn goto(&mut self, new_cursor: TreeCursor) -> TreeNavResult {
-        self.editors[ self.cur ].goto( new_cursor )
-    }
-
-    fn get_addr_view(&self) -> OuterViewPort<dyn SequenceView<Item = isize>> {
-        self.addr_port.outer()
-    }
-
-    fn get_mode_view(&self) -> OuterViewPort<dyn SingletonView<Item = ListCursorMode>> {
-        self.mode_port.outer()
-    }
-}
-
-impl PtySegment for SumEditor {
-    fn pty_view(&self) -> OuterViewPort<dyn TerminalView> {
-        self.port.outer()
-    }
-}
-
-impl ObjCommander for SumEditor {
-    fn send_cmd_obj(&mut self, obj: Arc<RwLock<ReprTree>>) -> TreeNavResult {
-        self.editors[ self.cur ].send_cmd_obj( obj )
-    }
-}

nested/src/editors/sum/mod.rs

@@ -1,4 +0,0 @@
-
-pub mod editor;
-pub use editor::SumEditor;
-

nested/src/editors/typeterm/cmd.rs

@@ -1,277 +0,0 @@
-use {
-    r3vi::{
-        view::{singleton::*}
-    },
-    crate::{
-        type_system::{Context, ReprTree},
-        editors::{list::{ListEditor, ListCmd, ListCursorMode}},
-        tree::{NestedNode, TreeNav, TreeNavResult, TreeCursor},
-        commander::ObjCommander
-    },
-    std::{sync::{Arc, RwLock}},
-
-    super::{TypeTermEditor, State}
-};
-
-impl ObjCommander for TypeTermEditor {
-    fn send_cmd_obj(&mut self, co: Arc<RwLock<ReprTree>>) -> TreeNavResult {
-        let _cur = self.get_cursor();
-
-        let cmd_obj = co.clone();
-        let cmd_obj = cmd_obj.read().unwrap();
-
-        if cmd_obj.get_type().clone() == Context::parse(&self.ctx, "Char") {
-            if let Some(cmd_view) = cmd_obj.get_view::<dyn SingletonView<Item = char>>() {
-                let c = cmd_view.get();
-
-                match &self.state {
-                    State::Any => {
-                        match c {
-                            '<' => {
-                                self.set_state( State::App );
-                                TreeNavResult::Continue
-                            }
-                            '0'|'1'|'2'|'3'|'4'|'5'|'6'|'7'|'8'|'9' => {
-                                self.set_state( State::Num );
-                                self.send_child_cmd( co );
-                                TreeNavResult::Continue
-                            }
-                            '\'' => {
-                                self.set_state( State::Char );
-                                TreeNavResult::Continue
-                            }
-                            '~' => {
-                                TreeNavResult::Exit
-                            }
-                            _ => {
-                                self.set_state( State::FunSymbol );
-                                self.cur_node.get_mut().goto(TreeCursor::home());
-                                self.send_child_cmd( co )
-                            }
-                        }
-                    }
-
-                    State::Char => {
-                        match self.send_child_cmd( co ) {
-                            TreeNavResult::Exit => {
-                                match c {
-                                    '\'' => {
-                                        self.cur_node.get_mut().goto(TreeCursor::none());
-                                    }
-                                    _ => {}
-                                }
-                                TreeNavResult::Exit
-                            },
-                            TreeNavResult::Continue => TreeNavResult::Continue
-                        }
-                    }
-
-                    State::Ladder => {
-
-                        match self.get_cursor().tree_addr.len() {
-
-                            // entire term is selected
-                            0 => {
-                                match c {
-                                    '<' => {
-                                        self.morph_to_list(State::App);
-                                        TreeNavResult::Continue
-                                    }
-                                    _ => { TreeNavResult::Exit }
-                                }
-                            }
-
-                            // entire item selected or insert mode
-                            1 => {
-                                match c {
-                                    '~' => {
-                                        // ignore '~' since we are already in a ladder
-                                        // and cant split current item
-                                        TreeNavResult::Continue
-                                    }
-                                    _ => {
-                                        self.send_child_cmd( co.clone() )
-                                    }
-                                }
-                            }
-
-                            // some subterm
-                            _ => {
-                                match c {
-                                    '~' => {
-                                        let i0 = self.cur_node.get().get_edit::<ListEditor>().unwrap();
-                                        let cur_it = i0.clone().read().unwrap().get_item().clone();
-                                        if let Some(i) = cur_it {
-                                            let cur_tte = i.get_edit::<TypeTermEditor>().unwrap();
-                                            if cur_tte.read().unwrap().state == State::App || cur_tte.read().unwrap().get_cursor().tree_addr.len() > 1 {
-                                                self.send_child_cmd( co.clone() )
-                                            } else {
-                                                drop(cur_tte);
-                                                drop(i);
-
-                                                self.send_child_cmd(
-                                                    ListCmd::Split.into_repr_tree( &self.ctx )
-                                                )
-                                            }
-                                        } else {
-                                            self.send_child_cmd( co.clone() )
-                                        }
-                                    }
-                                    _ => {
-                                        self.send_child_cmd( co.clone() )
-                                    }
-                                }
-                            }
-                        }
-                    }
-
-                    State::App => {
-
-                        match self.get_cursor().tree_addr.len() {
-
-                            // entire Term is selected
-                            0 => {
-                                
-                                match c {
-                                    '~' => {
-                                        self.morph_to_list(State::Ladder);
-                                        self.goto(TreeCursor {
-                                            tree_addr: vec![ -1 ],
-                                            leaf_mode: ListCursorMode::Insert
-                                        });
-                                        TreeNavResult::Continue
-                                    }
-                                    '<' => {
-                                        self.morph_to_list(State::App);
-                                        TreeNavResult::Continue
-                                    }
-                                    _ => {
-                                        TreeNavResult::Exit
-                                    }
-                                }
-
-                            },
-
-                            // some item is selected
-                            _ => {
-                                match self.send_child_cmd( co.clone() ) {
-                                    TreeNavResult::Exit => {
-                                        match c {
-                                            '~' => {
-                                                self.previous_item_into_ladder();
-                                                TreeNavResult::Continue
-                                            },
-                                            _ => {TreeNavResult::Exit}
-                                        }
-                                    },
-                                    TreeNavResult::Continue => {
-                                        match c {
-                                            '>'|
-                                            ' ' => {
-                                                let i = self.cur_node.get().get_edit::<ListEditor>().unwrap();
-                                                let i = i.read().unwrap();
-                                                if let Some(i) = i.get_item() {
-                                                    let tte = i.get_edit::<TypeTermEditor>().unwrap();
-                                                    let mut tte = tte.write().unwrap();
-
-                                                    if tte.state == State::Ladder {
-                                                        tte.normalize_singleton();
-                                                    }
-                                                }
-                                            },
-                                            _ => {}
-                                        }
-                                        TreeNavResult::Continue
-                                    }
-                                }
-                            }
-                        }
-                    }
-
-                    State::AnySymbol |
-                    State::FunSymbol |
-                    State::VarSymbol => {
-                        let res = self.send_child_cmd( co );
-                        match res {
-                            TreeNavResult::Exit => {
-                                match c {
-                                    '<' => {
-                                        self.goto(TreeCursor::none());
-                                        self.morph_to_list(State::App);
-                                        TreeNavResult::Continue
-                                    }
-                                    '~' => {
-                                        self.morph_to_list(State::Ladder);
-                                        self.set_addr(0);
-                                        self.dn();
-                                        self.send_cmd_obj(
-                                            ListCmd::Split.into_repr_tree( &self.ctx )
-                                        );
-                                        TreeNavResult::Continue
-                                    }
-                                    _ => {
-                                        TreeNavResult::Exit
-                                    }
-                                }
-                            }
-                            TreeNavResult::Continue => {
-                                TreeNavResult::Continue
-                            }
-                        }
-                    }
-
-                    _ => {
-                        self.send_child_cmd( co )
-                    }
-                }
-            } else {
-                TreeNavResult::Exit
-            }
-        } else {
-            match &self.state {
-                State::Any => {
-                    let cmd_repr = co.read().unwrap();
-                    if cmd_repr.get_type().clone() == Context::parse(&self.ctx, "NestedNode") {
-                        if let Some(view) = cmd_repr.get_view::<dyn SingletonView<Item = NestedNode>>() {
-                            let node = view.get();
-
-                            if node.data.read().unwrap().get_type().clone() == Context::parse(&self.ctx, "Char") {
-                                self.set_state( State::AnySymbol );
-                            } else {
-                                self.set_state( State::Ladder );
-                            }
-                        } else {
-                            eprintln!("ERROR");
-                        }
-                    } else {
-                        self.set_state( State::AnySymbol );
-                    }
-
-                    self.cur_node.get_mut().goto(TreeCursor::home());
-                }
-                State::Ladder | State::App => {
-                    // todo: if backspace cmd and empty list, reset to Any
-                }
-                _ => {
-                }
-            }
-
-            let res = self.send_child_cmd( co.clone() );
-
-            self.normalize_empty();
-            if let Some(cmd) = co.read().unwrap().get_view::<dyn SingletonView<Item = ListCmd>>() {
-                match cmd.get() {
-                    ListCmd::Split => {
-                        if self.state == State::Ladder {
-                            self.normalize_singleton();
-                        }
-                    }
-                    _ =>{}
-                }
-            }
-
-            res
-        }
-    }
-}
-

nested/src/editors/typeterm/ctx.rs

@@ -1,144 +0,0 @@
-use {
-    r3vi::{
-        view::{OuterViewPort, singleton::*}
-    },
-    laddertypes::{TypeTerm},
-    crate::{
-        type_system::{Context, MorphismTypePattern},
-        terminal::{TerminalStyle, TerminalProjections},
-        editors::{
-            list::{PTYListStyle, PTYListController, ListEditor, ListSegmentSequence},
-            typeterm::{State, TypeTermEditor}
-        },
-        PtySegment
-    },
-    std::{sync::{Arc, RwLock}},
-    cgmath::{Point2}
-};
-
-pub fn init_ctx(ctx: &mut Context) {
-    ctx.add_list_typename("Type".into()); // = Lit | Sym | App | Ladder
-    ctx.add_list_typename("Type::Lit".into()); // = Num | char
-    ctx.add_list_typename("Type::Lit::Num".into());  // [0-9]*
-    ctx.add_list_typename("Type::Lit::Char".into()); // .
-    ctx.add_list_typename("Type::Sym".into()); // = Fun | Var
-    ctx.add_list_typename("Type::Sym::Fun".into());  // [a-zA-Z][a-zA-Z0-9]*
-    ctx.add_list_typename("Type::Sym::Var".into());  // [a-zA-Z][a-zA-Z0-9]*
-    ctx.add_list_typename("Type::App".into()); // = <T1 T2 ...>
-    ctx.add_list_typename("Type::Ladder".into()); // = T1~T2~...
-
-    ctx.add_morphism(
-        MorphismTypePattern { src_tyid: ctx.get_typeid("List"), dst_tyid: ctx.get_typeid("Type").unwrap() },
-        Arc::new(move |node, _dst_type:_| {
-            let ctx : Arc<RwLock<Context>> = Arc::new(RwLock::new(Context::with_parent(Some(node.ctx.clone()))));
-            ctx.write().unwrap().meta_chars.push('~');
-
-            let new_node = TypeTermEditor::with_node( ctx, node.clone(), State::Any );
-            Some(new_node)
-        }));
-
-    ctx.add_morphism(
-        MorphismTypePattern { src_tyid: ctx.get_typeid("List"), dst_tyid: ctx.get_typeid("Type::Ladder").unwrap() },
-        Arc::new(|mut node, _dst_type: _| {
-            PTYListController::for_node( &mut node, Some('~'), None );
-
-            let vertical_view = true;
-            if vertical_view {
-                let editor = node.get_edit::<crate::editors::list::ListEditor>().unwrap();
-                let mut e = editor.write().unwrap();
-                let seg_view = PTYListStyle::new( ("","~","") ).get_seg_seq_view( &mut e );
-
-                node = node.set_view(
-                    seg_view.to_grid_vertical()
-                        .map_item(
-                            |pt,x|
-                            if pt.y > 0 {
-                                r3vi::buffer::vec::VecBuffer::with_data(vec![
-                                    crate::terminal::make_label("~"),
-                                    x.clone()
-                                ])
-                                    .get_port()
-                                    .to_sequence()
-                                    .to_grid_horizontal()
-                                    .flatten()
-                            } else {
-                                x.clone()
-                            }
-                    ).flatten()
-                );
-            } else {
-                PTYListStyle::for_node( &mut node, ("","~","") );
-            }
-
-            Some(node)
-        }));
-
-    ctx.add_morphism(
-        MorphismTypePattern { src_tyid: ctx.get_typeid("List"), dst_tyid: ctx.get_typeid("Type::App").unwrap() },
-        Arc::new( |mut node, _dst_type: _| {
-            PTYListController::for_node( &mut node, Some(' '), Some('>') );
-            PTYListStyle::for_node( &mut node, ("<"," ",">") );
-            Some(node)
-        }));
-
-    ctx.add_morphism(
-        MorphismTypePattern { src_tyid: ctx.get_typeid("List"), dst_tyid: ctx.get_typeid("Type::Sym").unwrap() },
-        Arc::new(|mut node, _dst_type:_| {
-            PTYListController::for_node( &mut node, Some(' '), None );
-            PTYListStyle::for_node( &mut node, ("","","") );
-            Some(node)
-        }));
-
-    ctx.add_morphism(
-        MorphismTypePattern { src_tyid: ctx.get_typeid("List"), dst_tyid: ctx.get_typeid("Type::Sym::Fun").unwrap() },
-        Arc::new(|mut node, _dst_type:_| {
-            PTYListController::for_node( &mut node, Some(' '), None );
-            PTYListStyle::for_node( &mut node, ("","","") );
-
-            Some(node)
-        }));
-
-    ctx.add_morphism(
-        MorphismTypePattern { src_tyid: ctx.get_typeid("List"), dst_tyid: ctx.get_typeid("Type::Sym::Var").unwrap() },
-        Arc::new(|mut node, _dst_type:_| {
-            PTYListController::for_node( &mut node, Some(' '), None );
-            PTYListStyle::for_node( &mut node, ("","","") );
-
-            Some(node)
-        }));
-
-    ctx.add_morphism(
-        MorphismTypePattern { src_tyid: ctx.get_typeid("PosInt"), dst_tyid: ctx.get_typeid("Type::Lit::Num").unwrap() },
-        Arc::new(|node, _dst_type:_| {
-            Some(node)
-        }));
-
-    ctx.add_morphism(
-        MorphismTypePattern { src_tyid: ctx.get_typeid("Char"), dst_tyid: ctx.get_typeid("Type::Lit::Char").unwrap() },
-        Arc::new(|mut node, _dst_type:_| {
-            node.ctx.write().unwrap().meta_chars = vec![ '\'' ];
-            let mut grid = r3vi::buffer::index_hashmap::IndexBuffer::new();
-
-            grid.insert_iter(
-                vec![
-                    (Point2::new(0,0), crate::terminal::make_label("'")),
-                    (Point2::new(1,0), node.view.clone().unwrap_or( crate::terminal::make_label(".").with_fg_color((220,200,20))) ),
-                    (Point2::new(2,0), crate::terminal::make_label("'")),
-                ]
-            );
-            
-            node.close_char.set(Some('\''));
-            node = node.set_view(
-                grid.get_port()
-                    .flatten()
-            );
-
-            Some(node)
-        }));
-
-    ctx.add_node_ctor("Type", Arc::new(
-        |ctx: Arc<RwLock<Context>>, _ty: TypeTerm, depth: OuterViewPort<dyn SingletonView<Item = usize>>| {
-            Some(TypeTermEditor::new_node(ctx, depth))
-        }));
-}
-

nested/src/editors/typeterm/mod.rs

@@ -1,394 +0,0 @@
-mod ctx;
-mod nav;
-mod cmd;
-
-pub use ctx::init_ctx;
-
-use {
-    r3vi::{
-        view::{OuterViewPort, singleton::*},
-        buffer::{singleton::*}
-    },
-    laddertypes::{TypeID, TypeTerm},
-    crate::{
-        type_system::{Context, ReprTree},
-        editors::{list::{ListCursorMode, ListEditor, ListCmd}},
-        tree::{NestedNode, TreeNav, TreeNavResult, TreeCursor},
-        commander::ObjCommander
-    },
-    std::{sync::{Arc, RwLock}}
-};
-
-#[derive(PartialEq, Eq, Clone, Copy, Debug)]
-pub(super) enum State {
-    Any,
-    Num,
-    Char,
-    AnySymbol,
-    FunSymbol,
-    VarSymbol,
-    App,
-    Ladder,
-}
-
-pub struct TypeTermEditor {
-
-    // shared with NestedNode that contains self
-    ctx: Arc<RwLock<Context>>,
-    data: Arc<RwLock<ReprTree>>,
-    close_char: SingletonBuffer<Option<char>>,
-    spillbuf: Arc<RwLock<Vec<Arc<RwLock<NestedNode>>>>>,
-    depth: OuterViewPort<dyn SingletonView<Item = usize>>,
-
-    buf: SingletonBuffer< TypeTerm >,
-
-    // editing/parsing state
-    state: State,
-
-    // child node
-    cur_node: SingletonBuffer< NestedNode >
-}
-
-impl TypeTermEditor {
-    pub fn from_type_term(ctx: Arc<RwLock<Context>>, depth: OuterViewPort<dyn SingletonView<Item = usize>>, term: &TypeTerm) -> NestedNode {
-        let mut node = TypeTermEditor::new_node(ctx.clone(), depth.clone());
-        node.goto(TreeCursor::home());
-
-        match term {
-            TypeTerm::TypeID( tyid ) => {
-                let editor = node.get_edit::<TypeTermEditor>().expect("typ term edit");
-                editor.write().unwrap().set_state(match tyid {
-                    TypeID::Fun(_) => State::FunSymbol,
-                    TypeID::Var(_) => State::VarSymbol
-                });
-
-                let typename = ctx.read().unwrap().get_typename(&tyid).unwrap_or("UNNAMED TYPE".into());
-                for x in typename.chars() {
-                    node.send_cmd_obj(
-                        ReprTree::from_char( &ctx, x )
-                    );
-                }
-            },
-
-            TypeTerm::App( args ) => {
-                let editor = node.get_edit::<TypeTermEditor>().expect("typ term edit");
-                editor.write().unwrap().set_state( State::App );
-
-                let parent_ctx = editor.read().unwrap().cur_node.get().ctx.clone();
-
-                for x in args.iter() {                    
-                    let arg_node = TypeTermEditor::from_type_term( parent_ctx.clone(), depth.map(|d| d+1), x );
-
-                    node.send_cmd_obj(
-                        ReprTree::new_leaf(
-                            Context::parse(&ctx, "NestedNode"),
-                            SingletonBuffer::new(arg_node).get_port().into()
-                        )
-                    );
-                }
-            }
-
-            TypeTerm::Ladder( args ) => {
-                let editor = node.get_edit::<TypeTermEditor>().expect("typ term edit");
-                editor.write().unwrap().set_state( State::Ladder );
-
-                let parent_ctx = editor.read().unwrap().cur_node.get().ctx.clone();
-
-                for x in args.iter() {
-                    let arg_node = TypeTermEditor::from_type_term( parent_ctx.clone(), depth.map(|d| d+1), x );
-
-                    node.send_cmd_obj(
-                        ReprTree::new_leaf(
-                            Context::parse(&ctx, "NestedNode"),
-                            SingletonBuffer::new(arg_node).get_port().into()
-                        )
-                    );
-                }
-            }
-
-            TypeTerm::Num( n ) => {
-                let editor = node.get_edit::<TypeTermEditor>().expect("typ term edit");
-                let parent_ctx = editor.read().unwrap().cur_node.get().ctx.clone();
-
-                let mut editor = editor.write().unwrap();
-                editor.cur_node.set(
-                    crate::editors::integer::PosIntEditor::from_u64(parent_ctx, 10, *n as u64)
-                        .into_node()
-                );
-                editor.state = State::Num;
-            }
-
-            TypeTerm::Char( c ) => {
-                let editor = node.get_edit::<TypeTermEditor>().expect("typ term edit");
-                let mut editor = editor.write().unwrap();
-                editor.set_state( State::Char );
-                editor.send_cmd_obj(ReprTree::from_char(&ctx, *c));
-            }
-        }
- 
-        node.goto(TreeCursor::none());
-        node
-    }
-
-    fn set_state(&mut self, new_state: State) {
-        let mut node = match new_state {
-            State::Any => {
-                Context::make_node( &self.ctx, Context::parse(&self.ctx, "<List Char>"), self.depth.map(|x| x) ).unwrap()
-                    .morph( Context::parse(&self.ctx, "Type::Sym") )
-            }
-            State::App => {
-                Context::make_node( &self.ctx, Context::parse(&self.ctx, "<List Type>"), self.depth.map(|x| x) ).unwrap()
-                    .morph( Context::parse(&self.ctx, "Type::App") )
-            }
-            State::Ladder => {
-                Context::make_node( &self.ctx, Context::parse(&self.ctx, "<List Type>"), self.depth.map(|x| x) ).unwrap()
-                    .morph( Context::parse(&self.ctx, "Type::Ladder") )
-            }
-            State::AnySymbol => {
-                Context::make_node( &self.ctx, Context::parse(&self.ctx, "<List Char>"), self.depth.map(|x| x) ).unwrap()
-                    .morph( Context::parse(&self.ctx, "Type::Sym") )
-            },
-            State::FunSymbol => {
-                Context::make_node( &self.ctx, Context::parse(&self.ctx, "<List Char>"), self.depth.map(|x| x) ).unwrap()
-                    .morph( Context::parse(&self.ctx, "Type::Sym::Fun") )
-            },
-            State::VarSymbol => {
-                Context::make_node( &self.ctx, Context::parse(&self.ctx, "<List Char>"), self.depth.map(|x| x) ).unwrap()
-                    .morph( Context::parse(&self.ctx, "Type::Sym::Var") )
-            }
-            State::Num => {
-                crate::editors::integer::PosIntEditor::new(self.ctx.clone(), 10)
-                    .into_node()
-                    .morph( Context::parse(&self.ctx, "Type::Lit::Num") )
-            }
-            State::Char => {
-                Context::make_node( &self.ctx, Context::parse(&self.ctx, "Char"), self.depth.map(|x| x) ).unwrap()
-                    .morph( Context::parse(&self.ctx, "Type::Lit::Char") )
-            }
-        };
-
-        node.goto(TreeCursor::home());
-
-        let _editor = node.editor.get();
-        self.close_char.set(node.close_char.get());
-        self.cur_node.set(node);
-        self.state = new_state;
-    }
-
-    pub fn new_node(ctx: Arc<RwLock<Context>>, depth: OuterViewPort<dyn SingletonView<Item = usize>>) -> NestedNode {
-        let ctx : Arc<RwLock<Context>> = Arc::new(RwLock::new(Context::with_parent(Some(ctx))));
-        ctx.write().unwrap().meta_chars.push('~');
-        ctx.write().unwrap().meta_chars.push('<');
-
-        let mut symb_node = Context::make_node( &ctx, Context::parse(&ctx, "<List Char>"), depth ).unwrap();
-        symb_node = symb_node.morph( Context::parse(&ctx, "Type::Sym") );
-
-        Self::with_node(
-            ctx.clone(),
-            symb_node,
-            State::Any
-        )
-    }
-
-    fn with_node(ctx: Arc<RwLock<Context>>, cur_node: NestedNode, state: State) -> NestedNode {
-        let buf = SingletonBuffer::<TypeTerm>::new( TypeTerm::unit() );
-
-        let data = Arc::new(RwLock::new(ReprTree::new(
-            Context::parse(&ctx, "Type")
-        )));
-
-        let editor = TypeTermEditor {
-            ctx: ctx.clone(),
-            data: data.clone(),
-            state,
-            buf,
-            cur_node: SingletonBuffer::new(cur_node.clone()),
-            close_char: SingletonBuffer::new(None),
-            spillbuf: Arc::new(RwLock::new(Vec::new())),
-            depth: cur_node.depth.clone()
-        };
-
-        let view = editor.cur_node
-            .get_port()
-            .map(|node| {
-                node.view.clone().unwrap_or(r3vi::view::ViewPort::new().into_outer())
-            })
-            .to_grid()
-            .flatten();
-        let _cc = editor.cur_node.get().close_char;
-        let editor = Arc::new(RwLock::new(editor));
-
-        let mut super_node = NestedNode::new(ctx, data, cur_node.depth)
-            .set_view(view)
-            .set_nav(editor.clone())
-            .set_cmd(editor.clone())
-            .set_editor(editor.clone());
-
-        editor.write().unwrap().close_char = super_node.close_char.clone();
-        super_node.spillbuf = editor.read().unwrap().spillbuf.clone();
-
-        super_node
-    }
-
-    fn forward_spill(&mut self) {
-        let node = self.cur_node.get();
-        let mut buf = node.spillbuf.write().unwrap();
-        for n in buf.iter() {
-            self.spillbuf.write().unwrap().push(n.clone());
-        }
-        buf.clear();
-    }
-
-    fn send_child_cmd(&mut self, cmd: Arc<RwLock<ReprTree>>) -> TreeNavResult {
-        let res = self.cur_node.get_mut().send_cmd_obj( cmd );
-        self.forward_spill();
-        res
-    }
-
-    fn get_typeterm(&self) -> Option<TypeTerm> {
-        match self.state {
-            State::Any => None,
-
-            State::AnySymbol => {
-                /*
-                let x = self.data.descend_ladder(vec![
-                    (&ctx, "( FunctionID )").into(),
-                    (&ctx, "( Symbol )").into(),
-                    (&ctx, "( List Char )").into(),
-                ].into_iter());
-
-                let fun_name = /* x...*/ "PosInt";
-                let fun_id = self.ctx.read().unwrap().get_typeid( fun_name );
-
-                self.data.add_repr(
-                    vec![
-                        (&ctx, "( FunctionID )").into(),
-                        (&ctx, "( MachineInt )").into()
-                    ]
-                );
-                 */
-                Some(TypeTerm::new(TypeID::Fun(0)))
-            },
-
-            State::App => {
-                Some(TypeTerm::new(TypeID::Fun(0)))
-            },
-
-            State::Char => {
-                Some(TypeTerm::Char('c'))
-            }
-            State::Num => {
-                Some(TypeTerm::Num(44))
-            }
-            _ => {None}
-        }
-    }
-
-    pub fn normalize_empty(&mut self) {
-        eprintln!("normalize singleton");
-        let subladder_list_node = self.cur_node.get().clone();
-        let subladder_list_edit = subladder_list_node.get_edit::<ListEditor>().unwrap();
-
-        let subladder_list_edit = subladder_list_edit.read().unwrap();
-        if subladder_list_edit.data.len() == 0 {
-            self.set_state( State::Any );
-        }
-    }
-    
-    /* unwrap a ladder if it only contains one element
-     */
-    pub fn normalize_singleton(&mut self) {
-        eprintln!("normalize singleton");
-
-        if self.state == State::Ladder {           
-            let subladder_list_node = self.cur_node.get().clone();
-            let subladder_list_edit = subladder_list_node.get_edit::<ListEditor>().unwrap();
-
-            let subladder_list_edit = subladder_list_edit.read().unwrap();
-            if subladder_list_edit.data.len() == 1 {
-                let it_node = subladder_list_edit.data.get(0);
-                let it_node = it_node.read().unwrap();
-                if it_node.get_type() == Context::parse(&self.ctx, "Type") {
-                    let other_tt = it_node.get_edit::<TypeTermEditor>().unwrap();
-
-                    let mut other_tt = other_tt.write().unwrap();
-
-                    other_tt.normalize_singleton();
-                    other_tt.depth.0.set_view( self.depth.map(|x| x).get_view() );
-
-                    self.close_char.set(other_tt.close_char.get());
-                    self.cur_node.set(other_tt.cur_node.get());
-                    self.state = other_tt.state;
-                }
-            }
-        }
-    }
-
-    /* in insert mode, morph the previous element into a ladder and continue there
-     */
-    pub fn previous_item_into_ladder(&mut self) {
-        let app_edit = self.cur_node.get().get_edit::<ListEditor>().expect("editor");
-        let mut app_edit = app_edit.write().unwrap();
-
-        let cur = app_edit.get_cursor();
-
-        if cur.tree_addr.len() <= 2 && cur.tree_addr.len() > 0 {
-            if cur.tree_addr.len() == 2 {
-                app_edit.delete_nexd();
-            }
-
-            // select previous element
-            app_edit.goto(TreeCursor{
-                tree_addr: vec![ cur.tree_addr[0]-1 ],
-                leaf_mode: ListCursorMode::Select
-            });
-
-            // get selected element
-            if let Some(item_node) = app_edit.get_item() {
-                let item_typterm = item_node.get_edit::<TypeTermEditor>().expect("typetermedit");
-                let mut item_typterm = item_typterm.write().unwrap();
-                if item_typterm.state != State::Ladder {
-                    item_typterm.morph_to_list( State::Ladder );
-                }
-
-                item_typterm.goto(TreeCursor {
-                    tree_addr: vec![ -1 ],
-                    leaf_mode: ListCursorMode::Insert
-                });
-            }
-        }
-    }
-    
-    /* replace with new list-node (ladder/app) with self as first element
-     */
-     pub(super) fn morph_to_list(&mut self, state: State) {
-        eprintln!("morph into ladder");
-
-        let mut old_node = self.cur_node.get().clone();
-
-        /* reconfigure current node to display new_node list-editor
-         */
-        self.set_state( state );
-
-        /* create a new NestedNode with TerminaltypeEditor,
-         * that has same state & child-node as current node.
-         */
-        let old_edit_node = TypeTermEditor::new_node( self.ctx.clone(), SingletonBuffer::new(0).get_port() );
-        old_node.depth.0.set_view( old_edit_node.depth.map(|x|x).get_view() );
-        
-        let old_edit_clone = old_edit_node.get_edit::<TypeTermEditor>().unwrap();
-        old_edit_clone.write().unwrap().set_state( self.state );
-        old_edit_clone.write().unwrap().cur_node.set( old_node );
-
-        /* insert old node and split
-         */
-        self.goto(TreeCursor::home());
-        self.send_child_cmd(
-            ReprTree::new_leaf(
-                Context::parse(&self.ctx, "NestedNode"),
-                SingletonBuffer::new( old_edit_node ).get_port().into()
-            )
-        );
-    }
-}
-

nested/src/editors/typeterm/nav.rs

@@ -1,44 +0,0 @@
-use {
-    r3vi::{
-        view::{
-            OuterViewPort,
-            singleton::*,
-            sequence::*
-        }
-    },
-    crate::{
-        tree::{TreeNav, TreeCursor, TreeNavResult, TreeHeightOp},
-        editors::{typeterm::TypeTermEditor, list::ListCursorMode}
-    },
-    cgmath::Vector2
-};
-
-impl TreeNav for TypeTermEditor {
-    fn get_cursor(&self) -> TreeCursor {
-        self.cur_node.get().get_cursor()
-    }
-
-    fn get_addr_view(&self) -> OuterViewPort<dyn SequenceView<Item = isize>> {
-        self.cur_node.get_port().map(|x| x.get_addr_view()).to_sequence().flatten()   
-    }
-
-    fn get_mode_view(&self) -> OuterViewPort<dyn SingletonView<Item = ListCursorMode>> {
-        self.cur_node.get_port().map(|x| x.get_mode_view()).flatten()
-    }
-
-    fn get_cursor_warp(&self) -> TreeCursor {
-        self.cur_node.get().get_cursor_warp()
-    }
-
-    fn get_height(&self, op: &TreeHeightOp) -> usize {
-        self.cur_node.get().get_height(op)
-    }
-
-    fn goby(&mut self, dir: Vector2<isize>) -> TreeNavResult {
-        self.cur_node.get_mut().goby(dir)
-    }
-
-    fn goto(&mut self, new_cur: TreeCursor) -> TreeNavResult {
-        self.cur_node.get_mut().goto(new_cur)
-    }
-}

nested/src/grid/flatten.rs

@@ -0,0 +1,236 @@
+use {
+    std::{
+        sync::Arc,
+        cmp::max,
+        collections::HashMap
+    },
+    std::sync::RwLock,
+    cgmath::{Point2, Vector2},
+    crate::{
+        core::{
+            View, Observer, ObserverBroadcast,
+            ViewPort, InnerViewPort, OuterViewPort,
+            port::UpdateTask
+        },
+        grid::{GridView, GridWindowIterator},
+        index::{IndexArea, IndexView},
+        projection::ProjectionHelper
+    }
+};
+
+impl<Item> OuterViewPort<dyn GridView<Item = OuterViewPort<dyn GridView<Item = Item>>>>
+where Item: 'static{
+    pub fn flatten(&self) -> OuterViewPort<dyn GridView<Item = Item>> {
+        let port = ViewPort::new();
+        port.add_update_hook(Arc::new(self.0.clone()));
+        Flatten::new(self.clone(), port.inner());
+        port.into_outer()
+    }
+}
+
+pub struct Chunk<Item>
+where Item: 'static
+{
+    offset: Vector2<i16>,
+    limit: Point2<i16>,
+    view: Arc<dyn GridView<Item = Item>>
+}
+
+pub struct Flatten<Item>
+where Item: 'static
+{
+    limit: Point2<i16>,
+    top: Arc<dyn GridView<Item = OuterViewPort<dyn GridView<Item = Item>>>>,
+    chunks: HashMap<Point2<i16>, Chunk<Item>>,
+    cast: Arc<RwLock<ObserverBroadcast<dyn GridView<Item = Item>>>>,
+    proj_helper: ProjectionHelper<Point2<i16>, Self>
+}
+
+impl<Item> View for Flatten<Item>
+where Item: 'static
+{
+    type Msg = IndexArea<Point2<i16>>;
+}
+
+impl<Item> IndexView<Point2<i16>> for Flatten<Item>
+where Item: 'static
+{
+    type Item = Item;
+
+    fn get(&self, idx: &Point2<i16>) -> Option<Self::Item> {
+        let chunk_idx = self.get_chunk_idx(*idx)?;
+        let chunk = self.chunks.get(&chunk_idx)?;
+        chunk.view.get(&(*idx - chunk.offset))
+    }
+
+    fn area(&self) -> IndexArea<Point2<i16>> {
+        IndexArea::Range(
+            Point2::new(0, 0) ..= self.limit
+        )
+    }
+}
+
+/* TODO: remove unused projection args (bot-views) if they get replaced by a new viewport  */
+impl<Item> Flatten<Item>
+where Item: 'static
+{
+    pub fn new(
+        top_port: OuterViewPort<dyn GridView<Item = OuterViewPort<dyn GridView<Item = Item>>>>,
+        out_port: InnerViewPort<dyn GridView<Item = Item>>
+    ) -> Arc<RwLock<Self>> {
+        let mut proj_helper = ProjectionHelper::new(out_port.0.update_hooks.clone());
+
+        let flat = Arc::new(RwLock::new(
+            Flatten {
+                limit: Point2::new(0, 0),
+                top: proj_helper.new_index_arg(
+                    Point2::new(-1, -1),
+                    top_port,
+                    |s: &mut Self, chunk_area| {
+                        for chunk_idx in chunk_area.iter() {
+                            s.update_chunk(chunk_idx);
+                        }
+                    }
+                ),
+                chunks: HashMap::new(),
+                cast: out_port.get_broadcast(),
+                proj_helper
+            }));
+
+        flat.write().unwrap().proj_helper.set_proj(&flat);
+        out_port.set_view(Some(flat.clone()));
+        flat
+    }
+
+    /// the top-sequence has changed the item at chunk_idx,
+    /// create a new observer for the contained sub sequence
+    fn update_chunk(&mut self, chunk_idx: Point2<i16>) {
+        if let Some(chunk_port) = self.top.get(&chunk_idx) {
+            let view = self.proj_helper.new_index_arg(
+                chunk_idx,
+                chunk_port.clone(),
+                move |s: &mut Self, area| {
+                    if let Some(chunk) = s.chunks.get(&chunk_idx) {
+                        if chunk.limit != *chunk.view.area().range().end() {
+                            s.update_all_offsets();
+                        }
+                    }
+
+                    if let Some(chunk) = s.chunks.get(&chunk_idx) {
+                        s.cast.notify(
+                            &area.map(|pt| pt + chunk.offset)
+                        );
+                    }
+                }
+            );
+
+            if let Some(chunk) = self.chunks.get_mut(&chunk_idx) {
+                chunk.view = view;
+                self.cast.notify(
+                    &chunk.view.area().map(|pt| pt + chunk.offset)
+                );
+            } else {
+                self.chunks.insert(
+                    chunk_idx,
+                    Chunk {
+                        offset: Vector2::new(-1, -1),
+                        limit: Point2::new(-1, -1),
+                        view
+                    }
+                );
+            }
+
+            self.update_all_offsets();
+        } else {
+            self.proj_helper.remove_arg(&chunk_idx);
+
+            if let Some(chunk) = self.chunks.remove(&chunk_idx) {
+                self.update_all_offsets();
+            }
+        }
+    }
+
+    /// recalculate all chunk offsets
+    /// and update size of flattened grid
+    fn update_all_offsets(&mut self) {
+        let top_range = self.top.area().range();
+        let mut col_widths = vec![0 as i16; (top_range.end().x+1) as usize];
+        let mut row_heights = vec![0 as i16; (top_range.end().y+1) as usize];
+
+        for chunk_idx in GridWindowIterator::from(top_range.clone()) {
+            if let Some(chunk) = self.chunks.get_mut(&chunk_idx) {
+                let chunk_range = chunk.view.area().range();
+                let lim = *chunk_range.end();
+
+                col_widths[chunk_idx.x as usize] =
+                    max(
+                        col_widths[chunk_idx.x as usize],
+                        if lim.x < 0 { 0 } else { lim.x+1 }
+                    );
+                row_heights[chunk_idx.y as usize] =
+                    max(
+                        row_heights[chunk_idx.y as usize],
+                        if lim.y < 0 { 0 } else { lim.y+1 }
+                    );
+            }
+        }
+
+        for chunk_idx in GridWindowIterator::from(top_range.clone()) {
+            if let Some(chunk) = self.chunks.get_mut(&chunk_idx) {
+                let old_offset = chunk.offset;
+                let old_limit = chunk.limit;
+
+                chunk.limit = *chunk.view.area().range().end();
+                chunk.offset = Vector2::new(
+                    (0 .. chunk_idx.x as usize).map(|x| col_widths[x]).sum(),
+                    (0 .. chunk_idx.y as usize).map(|y| row_heights[y]).sum()
+                );
+/*
+                if old_offset != chunk.offset {
+                    self.cast.notify(
+                        &IndexArea::Range(
+                            Point2::new(
+                                std::cmp::min(old_offset.x, chunk.offset.x),
+                                std::cmp::min(old_offset.y, chunk.offset.y)
+                            )
+                                ..= Point2::new(
+                                    std::cmp::max(old_offset.x + old_limit.x, chunk.offset.x + chunk.limit.x),
+                                    std::cmp::max(old_offset.y + old_limit.y, chunk.offset.y + chunk.limit.y)
+                                )
+                        )
+                    );
+                }
+*/
+            }
+        }
+
+        let old_limit = self.limit;
+        self.limit = Point2::new(
+            (0 ..= top_range.end().x as usize).map(|x| col_widths[x]).sum::<i16>() - 1,
+            (0 ..= top_range.end().y as usize).map(|y| row_heights[y]).sum::<i16>() - 1,
+        );
+
+        self.cast.notify(
+            &IndexArea::Range(
+                Point2::new(0, 0) ..= Point2::new(max(self.limit.x, old_limit.x), max(self.limit.y, old_limit.y))
+            )
+        );
+    }
+
+    /// given an index in the flattened sequence,
+    /// which sub-sequence does it belong to?
+    fn get_chunk_idx(&self, glob_pos: Point2<i16>) -> Option<Point2<i16>> {
+        for chunk_idx in GridWindowIterator::from(self.top.area().range()) {
+            if let Some(chunk) = self.chunks.get(&chunk_idx) {
+                let end = chunk.limit + chunk.offset;
+
+                if glob_pos.x <= end.x && glob_pos.y <= end.y {
+                    return Some(chunk_idx);
+                }
+            }
+        }
+
+        None
+    }
+}
+

nested/src/grid/mod.rs

@@ -0,0 +1,82 @@
+
+use {
+    std::{
+        ops::RangeInclusive,
+        cmp::{min, max}
+    },
+    cgmath::{Point2},
+    crate::index::{IndexArea, IndexView}
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub trait GridView = IndexView<Point2<i16>>;
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub mod offset;
+pub mod flatten;
+pub mod window_iterator;
+
+pub use window_iterator::GridWindowIterator;
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl IndexArea<Point2<i16>> {
+
+    // todo: this is not perfect (e.g. diagonals are inefficient)
+    pub fn iter(&self) -> GridWindowIterator {
+        GridWindowIterator::from(self.range())
+    }
+
+    pub fn range(&self) -> RangeInclusive<Point2<i16>> {
+        match self {
+            IndexArea::Empty => Point2::new(i16::MAX, i16::MAX) ..= Point2::new(i16::MIN, i16::MIN),
+            IndexArea::Full => panic!("range from full grid area"),
+            IndexArea::Set(v) =>
+                Point2::new(
+                    v.iter().map(|p| p.x).min().unwrap_or(0),
+                    v.iter().map(|p| p.y).min().unwrap_or(0)
+                ) ..=
+                Point2::new(
+                    v.iter().map(|p| p.x).max().unwrap_or(0),
+                    v.iter().map(|p| p.y).max().unwrap_or(0)
+                ),
+            IndexArea::Range(r) => r.clone()
+        }
+    }
+
+    pub fn union(self, other: IndexArea<Point2<i16>>) -> IndexArea<Point2<i16>> {
+        match (self, other) {
+            (IndexArea::Empty, a) |
+            (a, IndexArea::Empty) => a,
+
+            (IndexArea::Full, _) |
+            (_, IndexArea::Full) => IndexArea::Full,
+
+            (IndexArea::Set(mut va), IndexArea::Set(mut vb)) => {
+                va.extend(vb.into_iter());
+                IndexArea::Set(va)
+            },
+
+            (IndexArea::Range(r), IndexArea::Set(mut v)) |
+            (IndexArea::Set(mut v), IndexArea::Range(r)) => {
+                v.extend(GridWindowIterator::from(r));
+                IndexArea::Set(v)
+            },
+
+            (IndexArea::Range(ra), IndexArea::Range(rb)) => IndexArea::Range(
+                Point2::new(
+                    min(ra.start().x, rb.start().x),
+                    min(ra.start().y, rb.start().y)
+                )
+                    ..=
+                    Point2::new(
+                        max(ra.end().x, rb.end().x),
+                        max(ra.end().y, rb.end().y)
+                    )
+            )
+        }
+    }
+}
+

nested/src/grid/offset.rs

@@ -0,0 +1,20 @@
+use {
+    cgmath::Vector2,
+    crate::{
+        core::OuterViewPort,
+        grid::GridView
+    }
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<Item> OuterViewPort<dyn GridView<Item = Item>>
+where Item: 'static {
+    pub fn offset(&self, offset: Vector2<i16>) -> OuterViewPort<dyn GridView<Item = Item>> {
+        self.map_key(
+            move |pt| pt + offset,
+            move |pt| Some(pt - offset)
+        )
+    }
+}
+

nested/src/grid/window_iterator.rs

@@ -0,0 +1,60 @@
+
+use {
+    std::ops::{Range, RangeInclusive},
+    cgmath::{Point2}
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct GridWindowIterator {
+    next: Point2<i16>,
+    range: Range<Point2<i16>>
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl From<Range<Point2<i16>>> for GridWindowIterator {
+    fn from(range: Range<Point2<i16>>) -> Self {
+        GridWindowIterator {
+            next: range.start,
+            range
+        }
+    }
+}
+
+impl From<RangeInclusive<Point2<i16>>> for GridWindowIterator {
+    fn from(range: RangeInclusive<Point2<i16>>) -> Self {
+        GridWindowIterator {
+            next: *range.start(),
+            range: *range.start() .. Point2::new(range.end().x+1, range.end().y+1)
+        }
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl Iterator for GridWindowIterator {
+    type Item = Point2<i16>;
+
+    fn next(&mut self) -> Option<Point2<i16>> {
+        if self.next.y < self.range.end.y {
+            if self.next.x < self.range.end.x {
+                let next = self.next;
+
+                if self.next.x+1 < self.range.end.x {
+                    self.next.x += 1;
+                } else {
+                    self.next.x = self.range.start.x;
+                    self.next.y += 1;
+                }
+
+                Some(next)
+            } else {
+                None
+            }
+        } else {
+            None
+        }
+    }
+}
+

nested/src/index/buffer.rs

@@ -0,0 +1,85 @@
+
+use {
+    std::{
+        sync::Arc,
+        collections::HashMap,
+        hash::Hash
+    },
+    std::sync::RwLock,
+    crate::{
+        core::{
+            Observer,
+            ObserverBroadcast,
+            View,
+            InnerViewPort
+        },
+        index::{IndexArea, IndexView}
+    }
+};
+
+pub struct IndexBufferView<Key, Item>(Arc<RwLock<HashMap<Key, Item>>>)
+where Key: Clone + Hash + Eq + Send + Sync + 'static,
+      Item: Clone + Send + Sync + 'static;
+
+impl<Key, Item> View for IndexBufferView<Key, Item>
+where Key: Clone + Hash + Eq + Send + Sync + 'static,
+      Item: Clone + Send + Sync + 'static
+{
+    type Msg = IndexArea<Key>;
+}
+
+impl<Key, Item> IndexView<Key> for IndexBufferView<Key, Item>
+where Key: Clone + Hash + Eq + Send + Sync + 'static,
+      Item: Clone + Send + Sync + 'static
+{
+    type Item = Item;
+
+    fn get(&self, key: &Key) -> Option<Self::Item> {
+        self.0.read().unwrap().get(key).cloned()
+    }
+
+    fn area(&self) -> IndexArea<Key> {
+        IndexArea::Set(self.0.read().unwrap().keys().cloned().collect())
+    }
+}
+
+pub struct IndexBuffer<Key, Item>
+where Key: Clone + Hash + Eq + Send + Sync + 'static,
+      Item: Clone + Send + Sync + 'static
+{
+    data: Arc<RwLock<HashMap<Key, Item>>>,
+    cast: Arc<RwLock<ObserverBroadcast<dyn IndexView<Key, Item = Item>>>>
+}
+
+impl<Key, Item> IndexBuffer<Key, Item>
+where Key: Clone + Hash + Eq + Send + Sync + 'static,
+      Item: Clone + Send + Sync + 'static
+{
+    pub fn new(port: InnerViewPort<dyn IndexView<Key, Item = Item>>) -> Self {
+        let data = Arc::new(RwLock::new(HashMap::<Key, Item>::new()));
+        port.set_view(Some(Arc::new(IndexBufferView(data.clone()))));
+
+        IndexBuffer {
+            data,
+            cast: port.get_broadcast()
+        }
+    }
+
+    pub fn insert(&mut self, key: Key, item: Item) {
+        self.data.write().unwrap().insert(key.clone(), item);
+        self.cast.notify(&IndexArea::Set(vec![ key ]));
+    }
+
+    pub fn insert_iter<T>(&mut self, iter: T)
+    where T: IntoIterator<Item = (Key, Item)> {
+        for (key, item) in iter {
+            self.insert(key, item);
+        }
+    }
+
+    pub fn remove(&mut self, key: Key) {
+        self.data.write().unwrap().remove(&key);
+        self.cast.notify(&IndexArea::Set(vec![ key ]));
+    }
+}
+

nested/src/index/map_item.rs

@@ -0,0 +1,116 @@
+pub use {
+    std::{
+        sync::Arc,
+        boxed::Box
+    },
+    std::sync::RwLock,
+    crate::{
+        core::{
+            View,
+            Observer,
+            ObserverExt,
+            ObserverBroadcast,
+            ViewPort,
+            InnerViewPort,
+            OuterViewPort
+        },
+        index::{IndexArea, IndexView}
+    }
+};
+
+impl<Key, Item> OuterViewPort<dyn IndexView<Key, Item = Item>>
+where Key: Clone + Send + Sync + 'static,
+      Item: Send + Sync + 'static
+{
+    pub fn map_item<
+        DstItem: 'static,
+        F: Fn(&Key, &Item) -> DstItem + Send + Sync + 'static
+    >(
+        &self,
+        f: F
+    ) -> OuterViewPort<dyn IndexView<Key, Item = DstItem>> {
+        let port = ViewPort::new();
+        port.add_update_hook(Arc::new(self.0.clone()));
+
+        let map = MapIndexItem::new(port.inner(), f);
+        self.add_observer(map.clone());
+        port.into_outer()
+    }
+}
+
+pub struct MapIndexItem<Key, DstItem, SrcView, F>
+where Key: Clone + Send + Sync,
+      SrcView: IndexView<Key> + ?Sized,
+      F: Fn(&Key, &SrcView::Item) -> DstItem + Send + Sync
+{
+    src_view: Option<Arc<SrcView>>,
+    f: F,
+    cast: Arc<RwLock<ObserverBroadcast<dyn IndexView<Key, Item = DstItem>>>>
+}
+
+impl<Key, DstItem, SrcView, F> MapIndexItem<Key, DstItem, SrcView, F>
+where Key: Clone + Send + Sync + 'static,
+      DstItem: 'static,
+      SrcView: IndexView<Key> + ?Sized + 'static,
+      F: Fn(&Key, &SrcView::Item) -> DstItem + Send + Sync + 'static
+{
+    fn new(
+        port: InnerViewPort<dyn IndexView<Key, Item = DstItem>>,
+        f: F
+    ) -> Arc<RwLock<Self>> {
+        let map = Arc::new(RwLock::new(
+            MapIndexItem {
+                src_view: None,
+                f,
+                cast: port.get_broadcast()
+            }
+        ));
+
+        port.set_view(Some(map.clone()));
+        map
+    }
+}
+
+impl<Key, DstItem, SrcView, F> View for MapIndexItem<Key, DstItem, SrcView, F>
+where Key: Clone + Send + Sync,
+      SrcView: IndexView<Key> + ?Sized,
+      F: Fn(&Key, &SrcView::Item) -> DstItem + Send + Sync
+{
+    type Msg = IndexArea<Key>;
+}
+
+impl<Key, DstItem, SrcView, F> IndexView<Key> for MapIndexItem<Key, DstItem, SrcView, F>
+where Key: Clone + Send + Sync,
+      SrcView: IndexView<Key> + ?Sized,
+      F: Fn(&Key, &SrcView::Item) -> DstItem + Send + Sync
+{
+    type Item = DstItem;
+
+    fn get(&self, key: &Key) -> Option<Self::Item> {
+        self.src_view.get(key).as_ref().map(|item| (self.f)(key, item))
+    }
+
+    fn area(&self) -> IndexArea<Key> {
+        self.src_view.area()
+    }
+}
+
+impl<Key, DstItem, SrcView, F> Observer<SrcView> for MapIndexItem<Key, DstItem, SrcView, F>
+where Key: Clone + Send + Sync,
+      SrcView: IndexView<Key> + ?Sized,
+      F: Fn(&Key, &SrcView::Item) -> DstItem + Send + Sync
+{
+    fn reset(&mut self, view: Option<Arc<SrcView>>) {
+        let old_area = self.area();
+
+        self.src_view = view;
+
+        self.cast.notify(&old_area);
+        self.cast.notify(&self.src_view.area())
+    }
+
+    fn notify(&mut self, area: &IndexArea<Key>) {
+        self.cast.notify(area);
+    }
+}
+

nested/src/index/map_key.rs

@@ -0,0 +1,148 @@
+pub use {
+    std::{
+        sync::Arc,
+        boxed::Box
+    },
+    std::sync::RwLock,
+    crate::{
+        core::{
+            View,
+            Observer,
+            ObserverExt,
+            ObserverBroadcast,
+            ViewPort,
+            InnerViewPort,
+            OuterViewPort
+        },
+        index::{IndexArea, IndexView},
+        grid::{GridView}
+    }
+};
+
+impl<SrcKey, Item> OuterViewPort<dyn IndexView<SrcKey, Item = Item>>
+where SrcKey: Clone + Send + Sync + 'static,
+      Item: 'static
+{
+    pub fn map_key<
+        DstKey: Clone + Send + Sync + 'static,
+        F1: Fn(&SrcKey) -> DstKey + Send + Sync + 'static,
+        F2: Fn(&DstKey) -> Option<SrcKey> + Send + Sync + 'static,
+    >(
+        &self,
+        f1: F1,
+        f2: F2
+    ) -> OuterViewPort<dyn IndexView<DstKey, Item = Item>> {
+        let port = ViewPort::new();
+        port.add_update_hook(Arc::new(self.0.clone()));
+
+        let map = MapIndexKey::new(port.inner(), f1, f2);
+        self.add_observer(map.clone());
+        port.into_outer()
+    }
+}
+
+impl<Item> OuterViewPort<dyn IndexView<usize, Item = Item>>
+where Item: 'static
+{
+    pub fn to_grid_horizontal(&self) -> OuterViewPort<dyn GridView<Item = Item>> {
+        self.map_key(
+            |idx| cgmath::Point2::new(*idx as i16, 0),
+            |pt| if pt.y == 0 { Some(pt.x as usize) } else { None }
+        )
+    }
+
+    pub fn to_grid_vertical(&self) -> OuterViewPort<dyn GridView<Item = Item>> {
+        self.map_key(
+            |idx| cgmath::Point2::new(0, *idx as i16),
+            |pt| if pt.x == 0 { Some(pt.y as usize) } else { None }
+        )        
+    }
+}
+
+pub struct MapIndexKey<DstKey, SrcKey, SrcView, F1, F2>
+where DstKey: Clone + Send + Sync,
+      SrcKey: Clone + Send + Sync,
+      SrcView: IndexView<SrcKey> + ?Sized,
+      F1: Fn(&SrcKey) -> DstKey + Send + Sync,
+      F2: Fn(&DstKey) -> Option<SrcKey> + Send + Sync,
+{
+    src_view: Option<Arc<SrcView>>,
+    f1: F1,
+    f2: F2,
+    cast: Arc<RwLock<ObserverBroadcast<dyn IndexView<DstKey, Item = SrcView::Item>>>>
+}
+
+impl<DstKey, SrcKey, SrcView, F1, F2> MapIndexKey<DstKey, SrcKey, SrcView, F1, F2>
+where DstKey: Clone + Send + Sync + 'static,
+      SrcKey: Clone + Send + Sync + 'static,
+      SrcView: IndexView<SrcKey> + ?Sized + 'static,
+      SrcView::Item: 'static,
+      F1: Fn(&SrcKey) -> DstKey + Send + Sync + 'static,
+      F2: Fn(&DstKey) -> Option<SrcKey> + Send + Sync + 'static,
+{
+    fn new(
+        port: InnerViewPort<dyn IndexView<DstKey, Item = SrcView::Item>>,
+        f1: F1,
+        f2: F2
+    ) -> Arc<RwLock<Self>> {
+        let map = Arc::new(RwLock::new(
+            MapIndexKey {
+                src_view: None,
+                f1,
+                f2,
+                cast: port.get_broadcast()
+            }
+        ));
+
+        port.set_view(Some(map.clone()));
+        map
+    }
+}
+
+impl<DstKey, SrcKey, SrcView, F1, F2> View for MapIndexKey<DstKey, SrcKey, SrcView, F1, F2>
+where DstKey: Clone + Send + Sync,
+      SrcKey: Clone + Send + Sync,
+      SrcView: IndexView<SrcKey> + ?Sized,
+      F1: Fn(&SrcKey) -> DstKey + Send + Sync,
+      F2: Fn(&DstKey) -> Option<SrcKey> + Send + Sync,
+{
+    type Msg = IndexArea<DstKey>;
+}
+
+impl<DstKey, SrcKey, SrcView, F1, F2> IndexView<DstKey> for MapIndexKey<DstKey, SrcKey, SrcView, F1, F2>
+where DstKey: Clone + Send + Sync,
+      SrcKey: Clone + Send + Sync,
+      SrcView: IndexView<SrcKey> + ?Sized,
+      F1: Fn(&SrcKey) -> DstKey + Send + Sync,
+      F2: Fn(&DstKey) -> Option<SrcKey> + Send + Sync,
+{
+    type Item = SrcView::Item;
+
+    fn get(&self, key: &DstKey) -> Option<Self::Item> {
+        self.src_view.get(&(self.f2)(key)?)
+    }
+
+    fn area(&self) -> IndexArea<DstKey> {
+        self.src_view.area().map(&self.f1)
+    }
+}
+
+impl<DstKey, SrcKey, SrcView, F1, F2> Observer<SrcView> for MapIndexKey<DstKey, SrcKey, SrcView, F1, F2>
+where DstKey: Clone + Send + Sync,
+      SrcKey: Clone + Send + Sync,
+      SrcView: IndexView<SrcKey> + ?Sized,
+      F1: Fn(&SrcKey) -> DstKey + Send + Sync,
+      F2: Fn(&DstKey) -> Option<SrcKey> + Send + Sync,
+{
+    fn reset(&mut self, view: Option<Arc<SrcView>>) {
+        let old_area = self.area();
+        self.src_view = view;
+        self.cast.notify(&old_area);
+        self.cast.notify(&self.area());
+    }
+
+    fn notify(&mut self, msg: &IndexArea<SrcKey>) {
+        self.cast.notify(&msg.map(&self.f1));
+    }
+}
+

nested/src/index/mod.rs

@@ -0,0 +1,126 @@
+
+pub mod map_item;
+pub mod map_key;
+pub mod buffer;
+
+use {
+    std::{
+        sync::Arc,
+        ops::{Deref, RangeInclusive},
+    },
+    std::sync::RwLock,
+    crate::core::View
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+#[derive(Clone)]
+pub enum IndexArea<Key> {
+    Empty,
+    Full,
+    Set(Vec<Key>),
+    Range(RangeInclusive<Key>),
+    //Procedural(Arc<dyn Fn() -> Box<dyn Iterator<Item = Key>>>)
+}
+
+impl<Key> IndexArea<Key> {
+    pub fn map<T>(&self, f: impl Fn(&Key) -> T) -> IndexArea<T> {
+        match self {
+            IndexArea::Empty => IndexArea::Empty,
+            IndexArea::Full => IndexArea::Full,
+            IndexArea::Set(v) => IndexArea::Set(v.iter().map(&f).collect()),
+            IndexArea::Range(r) => IndexArea::Range(f(&r.start()) ..= f(&r.end()))
+        }
+    }
+}
+
+pub trait IndexView<Key> : View<Msg = IndexArea<Key>>
+where Key: Send + Sync {
+    type Item;
+
+    fn get(&self, key: &Key) -> Option<Self::Item>;
+
+    fn area(&self) -> IndexArea<Key> {
+        IndexArea::Full
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<Key, V> IndexView<Key> for RwLock<V>
+where Key: Send + Sync,
+      V: IndexView<Key> + ?Sized
+{
+    type Item = V::Item;
+
+    fn get(&self, key: &Key) -> Option<Self::Item> {
+        self.read().unwrap().get(key)
+    }
+
+    fn area(&self) -> IndexArea<Key> {
+        self.read().unwrap().area()
+    }
+}
+
+impl<Key, V> IndexView<Key> for Arc<V>
+where Key: Send + Sync,
+      V: IndexView<Key> + ?Sized
+{
+    type Item = V::Item;
+
+    fn get(&self, key: &Key) -> Option<Self::Item> {
+        self.deref().get(key)
+    }
+
+    fn area(&self) -> IndexArea<Key> {
+        self.deref().area()
+    }
+}
+
+impl<Key, V> IndexView<Key> for Option<V>
+where Key: Send + Sync,
+      V: IndexView<Key>
+{
+    type Item = V::Item;
+
+    fn get(&self, key: &Key) -> Option<Self::Item> {
+        self.as_ref()?.get(key)
+    }
+
+    fn area(&self) -> IndexArea<Key> {
+        if let Some(v) = self.as_ref() {
+            v.area()
+        } else {
+            IndexArea::Empty
+        }
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+/*
+pub trait ImplIndexView : Send + Sync {
+    type Key : Send + Sync;
+    type Value;
+
+    fn get(&self, key: &Self::Key) -> Option<Self::Value>;
+    fn area(&self) -> Option<Vec<Self::Key>> {
+        None
+    }    
+}
+
+impl<V: ImplIndexView> View for V {
+    type Msg = V::Key;
+}
+
+impl<V: ImplIndexView> IndexView<V::Key> for V {
+    type Item = V::Value;
+
+    fn get(&self, key: &V::Key) -> Option<Self::Item> {
+        (self as &V).get(key)
+    }
+
+    fn area(&self) -> Option<Vec<V::Key>> {
+        (self as &V).area()
+    }
+}
+*/

nested/src/integer/add.rs

@@ -0,0 +1,76 @@
+use {
+    std::sync::{Arc, RwLock},
+    crate::{
+        core::{InnerViewPort, OuterViewPort},
+        sequence::SequenceView,
+        vec::VecBuffer,
+        projection::ProjectionHelper
+    }
+};
+
+fn posint_add(
+    radix: usize,
+    a: impl SequenceView<Item = usize>,
+    b: impl SequenceView<Item = usize>
+) -> Vec<usize> {
+    let mut carry = 0;
+    let mut result = Vec::new();
+
+    for digit_idx in 0 .. std::cmp::max(a.len().unwrap_or(0), b.len().unwrap_or(0)) {
+        let sum =
+            a.get(&digit_idx).unwrap_or(0) +
+            b.get(&digit_idx).unwrap_or(0) +
+            carry;
+
+        result.push(sum % radix);
+
+        carry =
+            if sum > radix {
+                sum - radix
+            } else {
+                0
+            };
+    }
+
+    if carry > 0 {
+        result.push(carry);
+    }
+
+    result
+}
+
+pub struct Add {
+    radix: usize,
+    a: Arc<dyn SequenceView<Item = usize>>, // PosInt, Little Endian
+    b: Arc<dyn SequenceView<Item = usize>>, // PosInt, Little Endian
+    c: VecBuffer<usize>,
+    _proj_helper: ProjectionHelper<usize, Self>
+}
+
+impl Add {
+    pub fn new(
+        radix: usize,
+        a: OuterViewPort<dyn SequenceView<Item = usize>>,
+        b: OuterViewPort<dyn SequenceView<Item = usize>>,
+        c: InnerViewPort<RwLock<Vec<usize>>>//<dyn SequenceView<Item = usize>>
+    ) -> Arc<RwLock<Self>> {
+        let mut proj_helper = ProjectionHelper::new(c.0.update_hooks.clone());
+        let add = Arc::new(RwLock::new(
+            Add {
+                radix,
+                a: proj_helper.new_sequence_arg(0, a, |s: &mut Self, _digit_idx| s.update()),
+                b: proj_helper.new_sequence_arg(1, b, |s: &mut Self, _digit_idx| s.update()),
+                c: VecBuffer::new(c),
+                _proj_helper: proj_helper
+            }
+        ));
+        add
+    }
+
+    fn update(&mut self) {
+        self.c.clear();
+        for digit in posint_add(self.radix, self.a.clone(), self.b.clone()) {
+            self.c.push(digit);
+        }
+    }
+}

nested/src/integer/editor.rs

@@ -0,0 +1,161 @@
+use {
+    std::sync::Arc,
+    std::sync::RwLock,
+    termion::event::{Key, Event},
+    cgmath::Point2,
+    crate::{
+        core::{ViewPort, OuterViewPort, Observer},
+        singleton::{SingletonView, SingletonBuffer},
+        sequence::{SequenceView, SequenceViewExt},
+        vec::VecBuffer,
+        terminal::{TerminalAtom, TerminalStyle, TerminalView, TerminalEvent, TerminalEditor, TerminalEditorResult},
+        tree_nav::{TreeNav, TreeNavResult, TerminalTreeEditor, TreeCursor},
+        list::{ListEditor, ListEditorStyle, sexpr::ListDecoration}
+    }
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct DigitEditor {
+    radix: u32,
+    data: SingletonBuffer<Option<char>>,
+    data_port: ViewPort<dyn SingletonView<Item = Option<char>>>,
+}
+
+impl DigitEditor {
+    pub fn new(radix: u32) -> Self {
+        let mut data_port = ViewPort::new();
+        DigitEditor {
+            radix,
+            data: SingletonBuffer::new(None, data_port.inner()),
+            data_port
+        }
+    }
+
+    pub fn get_data_port(&self) -> OuterViewPort<dyn SingletonView<Item = Option<u32>>> {
+        let radix = self.radix;
+        self.data_port.outer().map(
+            move |c| c?.to_digit(radix)
+        )
+    }
+}
+
+impl TreeNav for DigitEditor {}
+impl TerminalEditor for DigitEditor {
+    fn get_term_view(&self) -> OuterViewPort<dyn TerminalView> {
+        let radix = self.radix;
+        self.data_port.outer().map(
+            move |c| TerminalAtom::new(
+                c.unwrap_or('?'),
+                if c.unwrap_or('?').to_digit(radix).is_some() {
+                    TerminalStyle::fg_color((100, 140, 100))
+                } else {
+                    //TerminalStyle::bg_color((90, 10, 10))
+                    TerminalStyle::fg_color((200, 40, 40))
+                }
+            )
+        ).to_grid()
+    }
+
+    fn handle_terminal_event(&mut self, event: &TerminalEvent) -> TerminalEditorResult {
+        match event {
+            TerminalEvent::Input(Event::Key(Key::Char(' '))) |
+            TerminalEvent::Input(Event::Key(Key::Char('\n'))) =>
+                TerminalEditorResult::Exit,
+            TerminalEvent::Input(Event::Key(Key::Char(c))) => {
+                self.data.set(Some(*c));
+                TerminalEditorResult::Exit
+            }
+            TerminalEvent::Input(Event::Key(Key::Backspace)) |
+            TerminalEvent::Input(Event::Key(Key::Delete)) => {
+                self.data.set(None);
+                TerminalEditorResult::Exit
+            }
+            _ => TerminalEditorResult::Continue
+        }
+    }
+}
+
+pub struct PosIntEditor {
+    radix: u32,
+    digits_editor: ListEditor< DigitEditor,
+                               Box<dyn Fn() -> Arc<RwLock<DigitEditor>> + Send + Sync + 'static> >
+}
+
+impl PosIntEditor {
+    pub fn new(radix: u32) -> Self {
+        PosIntEditor {
+            radix,
+            digits_editor: ListEditor::new(
+                Box::new(
+                    move || {
+                        Arc::new(RwLock::new(DigitEditor::new(radix)))
+                    }
+                ),
+                crate::list::ListEditorStyle::Hex
+            )
+        }
+    }
+
+    pub fn get_data_port(&self) -> OuterViewPort<dyn SequenceView<Item = u32>> {
+        let radix = self.radix;
+        self.digits_editor.get_data_port()
+            .filter_map(move |digit_editor| digit_editor.read().unwrap().data.get()?.to_digit(radix))
+    }
+
+    pub fn get_value(&self) -> u32 {
+        let mut value = 0;
+        let mut weight = 1;
+        for digit_value in self.get_data_port().get_view().unwrap().iter().collect::<Vec<_>>().into_iter().rev() {
+            value += digit_value * weight;
+            weight *= self.radix;
+        }
+
+        value
+    }
+}
+
+impl TreeNav for PosIntEditor {
+    fn get_cursor(&self) -> TreeCursor { self.digits_editor.get_cursor() }
+    fn goto(&mut self, cur: TreeCursor) -> TreeNavResult  { self.digits_editor.goto(cur) }
+    fn goto_home(&mut self) -> TreeNavResult  { self.digits_editor.goto_home() }
+    fn goto_end(&mut self) -> TreeNavResult  { self.digits_editor.goto_end() }
+    fn pxev(&mut self) -> TreeNavResult  { self.digits_editor.pxev() }
+    fn nexd(&mut self) -> TreeNavResult  { self.digits_editor.nexd() }
+    fn up(&mut self) -> TreeNavResult { self.digits_editor.up() }
+    fn dn(&mut self) -> TreeNavResult { self.digits_editor.dn() }
+}
+
+impl TerminalEditor for PosIntEditor {
+    fn get_term_view(&self) -> OuterViewPort<dyn TerminalView> {
+        self.digits_editor
+            .get_seg_seq_view()
+            .decorate(
+                match self.radix {
+                    2 => "0b",
+                    8 => "0o",
+                    10 => "0d",
+                    16 => "0x",
+                    _ => ""
+                },
+                "",
+                "",
+                0
+            )
+            .to_grid_horizontal()
+            .flatten()
+    }
+
+    fn handle_terminal_event(&mut self, event: &TerminalEvent) -> TerminalEditorResult {
+        match event {
+            TerminalEvent::Input(Event::Key(Key::Char(' '))) |
+            TerminalEvent::Input(Event::Key(Key::Char('\n'))) => {
+                self.digits_editor.up();
+                TerminalEditorResult::Exit
+            }
+
+            event => self.digits_editor.handle_terminal_event(event)
+        }
+    }
+}
+

nested/src/integer/mod.rs

@@ -1,12 +1,11 @@
+
+pub mod radix;
 pub mod add;
 pub mod editor;
-pub mod radix;
-pub mod ctx;
 
 pub use {
-    add::Add,
-    editor::{DigitEditor, PosIntEditor},
     radix::RadixProjection,
-    ctx::init_ctx
+    add::Add,
+    editor::{DigitEditor, PosIntEditor}
 };
 

nested/src/integer/radix.rs

@@ -1,44 +1,39 @@
 use {
-    r3vi::{
-        view::{
-            InnerViewPort, Observer, OuterViewPort,
-            sequence::*,
-        },
-        buffer::{vec::*}
-    },
     std::sync::{Arc, RwLock},
+    crate::{
+        core::{
+            Observer,
+            InnerViewPort,
+            OuterViewPort
+        },
+        sequence::SequenceView,
+        vec::VecBuffer
+    }
 };
 
 pub struct RadixProjection {
     src_radix: usize,
     dst_radix: usize,
     src_digits: Option<Arc<dyn SequenceView<Item = usize>>>,
-    dst_digits: RwLock<VecBuffer<usize>>,
+    dst_digits: RwLock<VecBuffer<usize>>
 }
 
 impl RadixProjection {
     pub fn new(
-        // static parameters
-        //---
         src_radix: usize,
         dst_radix: usize,
-        //---
-
-        // dynamic parameters
-        //---
-        // input
         src_digits: OuterViewPort<dyn SequenceView<Item = usize>>,
-        // output
+        dst_digits: InnerViewPort<RwLock<Vec<usize>>>
-        dst_digits: InnerViewPort<RwLock<Vec<usize>>>,
-        //---
     ) -> Arc<RwLock<Self>> {
         dst_digits.0.add_update_hook(Arc::new(src_digits.0.clone()));
-        let proj = Arc::new(RwLock::new(RadixProjection {
+        let proj = Arc::new(RwLock::new(
+            RadixProjection {
                 src_radix,
                 dst_radix,
                 src_digits: None,
-            dst_digits: RwLock::new(VecBuffer::with_port(dst_digits)),
+                dst_digits: RwLock::new(VecBuffer::new(dst_digits))
-        }));
+            }
+        ));
         src_digits.add_observer(proj.clone());
         proj
     }
@@ -46,7 +41,7 @@ impl RadixProjection {
     fn machine_int(&self) -> usize {
         let mut val = 0;
         let mut r = 1;
-        for i in 0..self.src_digits.len().unwrap_or(0) {
+        for i in 0 .. self.src_digits.len().unwrap_or(0) {
             val += r * self.src_digits.get(&i).unwrap();
             r *= self.src_radix;
         }
@@ -80,7 +75,7 @@ impl RadixProjection {
         } else {
             // error
         }
-        */
+*/
     }
 }
 

nested/src/lib.rs

@@ -1,34 +1,26 @@
 #![feature(trait_alias)]
 
+pub mod core;
+pub mod projection;
+
+pub mod singleton;
+pub mod index;
+pub mod grid;
+pub mod sequence;
+pub mod vec;
 pub mod terminal;
+pub mod integer;
+pub mod list;
 
-pub mod utils;
+pub mod tree_nav;
-pub mod editors;
-pub mod tree;
-pub mod type_system;
 
-pub mod diagnostics;
+pub mod string_editor;
-pub mod commander;
+
-//pub mod product;
+pub mod bimap;
-//pub mod sum;
+
-//pub mod list;
+pub mod sdf;
 
 pub fn magic_header() {
     eprintln!("<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>");
 }
 
-/*
-pub trait StringGen {
-    fn get_string(&self) -> String;    
-}
-
-use crate::{tree::{TreeNav}, diagnostics::Diagnostics, terminal::TerminalView, core::{OuterViewPort}};
- */
-
-use r3vi::view::OuterViewPort;
-use crate::terminal::TerminalView;
-
-pub trait PtySegment {
-    fn pty_view(&self) -> OuterViewPort<dyn TerminalView>;
-}
-

nested/src/list/cursor.rs

@@ -0,0 +1,35 @@
+
+#[derive(Clone, Copy, Eq, PartialEq)]
+pub enum ListCursorMode {
+    Insert,
+    Select,
+    Modify
+}
+
+#[derive(Clone, Copy, Eq, PartialEq)]
+pub struct ListCursor {
+    pub mode: ListCursorMode,
+    pub idx: Option<usize>
+}
+
+impl Default for ListCursor {
+    fn default() -> Self {
+        ListCursor {
+            mode: ListCursorMode::Select,
+            idx: None
+        }
+    }
+}
+
+/*
+pub trait ListNav {
+    fn pxev(&mut self) -> ListNavResult;
+    fn nexd(&mut self) -> ListNavResult;
+    fn pua(&mut self) -> ListNavResult;
+    fn end(&mut self) -> ListNavResult;
+
+    fn set_cursor(&mut self, new_cursor: Option<ListCursor>) -> ListNavResult;
+    fn get_cursor(&self) -> Option<ListCursor>;
+}
+*/
+

nested/src/list/editor.rs

@@ -0,0 +1,757 @@
+use {
+    std::sync::{Arc, RwLock},
+    termion::event::{Event, Key},
+    crate::{
+        core::{
+            ViewPort,
+            OuterViewPort,
+        },
+        singleton::{SingletonView, SingletonBuffer},
+        sequence::{SequenceView},
+        vec::{VecBuffer},
+        terminal::{
+            TerminalView,
+            TerminalStyle,
+            TerminalEvent,
+            TerminalEditor,
+            TerminalEditorResult,
+            make_label
+        },
+        list::{SExprView, ListDecoration, ListCursor, ListCursorMode, editor_view::{ListEditorView, ListEditorViewSegment}},
+        tree_nav::{TreeCursor, TreeNav, TreeNavResult, TerminalTreeEditor}
+    }
+};
+
+#[derive(Clone, Copy)]
+pub enum ListEditorStyle {
+    HorizontalSexpr,
+    VerticalSexpr,
+    Path,
+    String,
+    Clist,
+    Hex,
+    Plain
+}
+
+pub struct ListEditor<ItemEditor, FnMakeItemEditor>
+where ItemEditor: TerminalEditor + ?Sized + Send + Sync + 'static,
+      FnMakeItemEditor: Fn() -> Arc<RwLock<ItemEditor>>
+{
+    cursor: SingletonBuffer<ListCursor>,
+    data: VecBuffer<Arc<RwLock<ItemEditor>>>,
+
+    cursor_port: ViewPort<dyn SingletonView<Item = ListCursor>>,
+    data_port: ViewPort<RwLock<Vec<Arc<RwLock<ItemEditor>>>>>,
+
+    make_item_editor: FnMakeItemEditor,
+
+    style: ListEditorStyle,
+    level: usize,
+    cur_dist: Arc<RwLock<usize>>,
+}
+
+impl<ItemEditor, FnMakeItemEditor> TreeNav for ListEditor<ItemEditor, FnMakeItemEditor>
+where ItemEditor: TerminalTreeEditor + ?Sized + Send + Sync + 'static,
+      FnMakeItemEditor: Fn() -> Arc<RwLock<ItemEditor>>
+{
+    fn get_cursor(&self) -> TreeCursor {
+        let cur = self.cursor.get();
+        match cur.mode {
+            ListCursorMode::Insert |
+            ListCursorMode::Select => {
+                TreeCursor {
+                    leaf_mode: cur.mode,
+                    tree_addr: if let Some(i) = cur.idx { vec![ i ] } else { vec![] }
+                }
+            },
+            ListCursorMode::Modify => {
+                if let Some(i) = cur.idx {
+                    if i < self.data.len() {
+                        let mut sub_cur = self.data.get(i).read().unwrap().get_cursor();
+                        sub_cur.tree_addr.insert(0, i);
+                        return sub_cur;
+                    }
+                }
+                TreeCursor {
+                    leaf_mode: cur.mode,
+                    tree_addr: vec![]
+                }
+            }
+        }
+    }
+
+    fn goto(&mut self, new_cur: TreeCursor) -> TreeNavResult {
+        let old_cur = self.cursor.get();
+        if old_cur.mode == ListCursorMode::Modify {
+            if let Some(i) = old_cur.idx {
+                let ce = self.data.get_mut(i);
+                let mut cur_edit = ce.write().unwrap();
+                cur_edit.goto(TreeCursor::default());
+            }
+        }
+
+        if new_cur.tree_addr.len() == 1 {
+            self.cursor.set(ListCursor{
+                mode: new_cur.leaf_mode,
+                idx: Some(new_cur.tree_addr[0])
+            });
+            TreeNavResult::Continue
+        } else if new_cur.tree_addr.len() > 1 && new_cur.tree_addr[0] < self.data.len() {
+            self.cursor.set(ListCursor {
+                mode: ListCursorMode::Modify,
+                idx: Some(new_cur.tree_addr[0])
+            });
+
+            let ne = self.data.get_mut(new_cur.tree_addr[0]);
+            let mut nxt_edit = ne.write().unwrap();
+
+            nxt_edit.goto(
+                TreeCursor {
+                    leaf_mode: new_cur.leaf_mode,
+                    tree_addr: new_cur.tree_addr[1..].iter().cloned().collect()
+                });
+
+            TreeNavResult::Continue
+        } else {
+            self.cursor.set(ListCursor {
+                mode: new_cur.leaf_mode,
+                idx: None
+            });
+            TreeNavResult::Continue
+        }
+    }
+
+    fn goto_end(&mut self) -> TreeNavResult {
+        let mut cur = self.cursor.get();
+        let i = cur.idx.unwrap_or(0);
+
+        if self.data.len() == 0 && cur.idx.is_none() {
+            self.cursor.set(
+                ListCursor {
+                    mode: ListCursorMode::Insert,
+                    idx: Some(0)
+                }
+            );
+            return TreeNavResult::Continue;
+        }
+
+        if i < self.data.len() {
+            match cur.mode {
+                ListCursorMode::Insert => {
+                    if i < self.data.len() || cur.idx.is_none() {
+                        cur.idx = Some(self.data.len());
+                        self.cursor.set(cur);
+                        TreeNavResult::Continue
+                    } else {
+                        self.cursor.set(ListCursor::default());
+                        TreeNavResult::Exit
+                    }
+                }
+                ListCursorMode::Select => {
+                    if self.data.len() == 0 && cur.idx.is_none() {
+                        self.cursor.set(
+                            ListCursor {
+                                mode: ListCursorMode::Insert,
+                                idx: Some(0)
+                            }
+                        );
+                        return TreeNavResult::Continue;
+                    }
+
+                    if i+1 < self.data.len() || cur.idx.is_none() {
+                        cur.idx = Some(self.data.len()-1);
+                        self.cursor.set(cur);
+                        TreeNavResult::Continue
+                    } else {
+                        self.cursor.set(ListCursor::default());
+                        TreeNavResult::Exit
+                    }
+                }
+                ListCursorMode::Modify => {
+                    let ce = self.data.get_mut(i);
+                    let mut cur_edit = ce.write().unwrap();
+                    let cur_mode = cur_edit.get_cursor().leaf_mode;
+                    let depth = cur_edit.get_cursor().tree_addr.len();
+                    match cur_edit.goto_end() {
+                        TreeNavResult::Continue => {
+                            TreeNavResult::Continue
+                        }
+                        TreeNavResult::Exit => {
+                            drop(cur_edit);
+
+                            self.up();
+
+                            if i+1 < self.data.len() {
+                                self.set_mode(ListCursorMode::Select);
+                                self.nexd();
+
+                                for x in 1 .. depth {
+                                    self.dn();
+                                    self.goto_home();
+                                }
+
+                                self.set_leaf_mode(cur_mode);
+                                self.dn();
+                                self.goto_end();
+
+                                return TreeNavResult::Continue;
+                            }
+
+                            TreeNavResult::Exit
+                        }
+                    }
+                }
+            }
+        } else {
+            self.cursor.set(ListCursor::default());
+            TreeNavResult::Exit
+        }
+    }
+
+    fn goto_home(&mut self) -> TreeNavResult {
+        let cur = self.cursor.get();
+        if self.data.len() == 0 && cur.idx.is_none() {
+            self.cursor.set(
+                ListCursor {
+                    mode: ListCursorMode::Insert,
+                    idx: Some(0)
+                }
+            );
+            return TreeNavResult::Continue;
+        }
+
+        match cur.mode {
+            ListCursorMode::Insert |
+            ListCursorMode::Select => {
+                if cur.idx != Some(0) {
+                    self.cursor.set(
+                        ListCursor {
+                            mode: if self.data.len() == 0 { ListCursorMode::Insert } else { cur.mode },
+                            idx: Some(0)
+                        }
+                    );
+                    TreeNavResult::Continue
+                } else {
+                    self.cursor.set(ListCursor::default());
+                    TreeNavResult::Exit
+                }
+            }
+            ListCursorMode::Modify => {
+                let ce = self.get_item().unwrap();
+                let mut cur_edit = ce.write().unwrap();
+                let cur_mode = cur_edit.get_cursor().leaf_mode;
+                let depth = cur_edit.get_cursor().tree_addr.len();
+
+                match cur_edit.goto_home() {
+                    TreeNavResult::Exit => {
+                        drop(cur_edit);
+
+                        if let Some(i) = cur.idx {
+                            self.up();
+
+                            if i > 0 {
+                                self.set_mode(ListCursorMode::Select);
+                                self.pxev();
+
+                                for x in 1 .. depth {
+                                    self.dn();
+                                    self.goto_end();
+                                }
+
+                                self.set_leaf_mode(cur_mode);
+                                self.dn();
+                                self.goto_home();
+                                return TreeNavResult::Continue;
+                            }
+                        }
+
+                        TreeNavResult::Exit
+                    }
+                    TreeNavResult::Continue => TreeNavResult::Continue
+                }
+            }
+        }
+    }
+
+    fn up(&mut self) -> TreeNavResult {
+        let cur = self.cursor.get();
+        if cur.mode == ListCursorMode::Modify {
+            if let Some(i) = cur.idx {
+                let ce = self.data.get_mut(i);
+                let mut cur_edit = ce.write().unwrap();
+                let mode = cur_edit.get_cursor().leaf_mode;
+
+                match cur_edit.up() {
+                    TreeNavResult::Exit => {
+                        self.set_mode(mode);
+                    }
+                    TreeNavResult::Continue => {}
+                }
+
+                return TreeNavResult::Continue;
+            }
+        }
+
+        self.cursor.set(ListCursor {
+            mode: cur.mode,
+            idx: None
+        });
+        TreeNavResult::Exit
+    }
+
+    fn dn(&mut self) -> TreeNavResult {
+        let cur = self.cursor.get();
+        match cur.mode {
+            ListCursorMode::Insert |
+            ListCursorMode::Select => {
+                if let Some(i) = cur.idx {
+                    if i < self.data.len() {
+                        self.set_mode(ListCursorMode::Modify);
+                        self.data.get_mut(i).write().unwrap().goto(
+                            TreeCursor {
+                                leaf_mode: cur.mode,
+                                tree_addr: vec![]
+                            }
+                        );
+                        *self.cur_dist.write().unwrap() += 1;
+                    }
+                }
+                TreeNavResult::Continue
+            }
+            ListCursorMode::Modify => {
+                self.get_item().unwrap().write().unwrap().dn()
+            }
+        }
+    }
+
+    fn pxev(&mut self) -> TreeNavResult {
+        let mut cur = self.cursor.get();
+        if let Some(i) = cur.idx {
+            match cur.mode {
+                ListCursorMode::Insert |
+                ListCursorMode::Select => {
+                    if i > 0 {
+                        cur.idx = Some(i - 1);
+                        self.cursor.set(cur);
+                        TreeNavResult::Continue
+                    } else {
+                        self.cursor.set(ListCursor::default());
+                        TreeNavResult::Exit
+                    }
+                }
+                ListCursorMode::Modify => {
+                    let ce = self.get_item().unwrap();
+                    let mut cur_edit = ce.write().unwrap();
+
+                    let cur_mode = cur_edit.get_cursor().leaf_mode;
+                    let depth = cur_edit.get_cursor().tree_addr.len();
+
+                    match cur_edit.pxev() {
+                        TreeNavResult::Exit => {
+                            drop(cur_edit);
+                            self.up();
+
+                            if i > 0 {
+                                self.set_mode(ListCursorMode::Select);
+                                self.pxev();
+
+                                for x in 1 .. depth {
+                                    self.dn();
+                                    self.goto_end();
+                                }
+
+                                self.set_leaf_mode(cur_mode);
+                                self.dn();
+                                self.goto_end();
+                                TreeNavResult::Continue
+                            } else {
+                                TreeNavResult::Exit
+                            }
+                        },
+                        TreeNavResult::Continue => TreeNavResult::Continue
+                    }
+                }
+            }
+        } else {
+            TreeNavResult::Exit
+        }
+    }
+
+    fn nexd(&mut self) -> TreeNavResult {
+        let mut cur = self.cursor.get();
+        if let Some(i) = cur.idx {
+            match cur.mode {
+                ListCursorMode::Insert => {
+                    if i < self.data.len() {
+                        cur.idx = Some(i + 1);
+                        self.cursor.set(cur);
+                        TreeNavResult::Continue
+                    } else {
+                        self.cursor.set(ListCursor::default());
+                        TreeNavResult::Exit
+                    }
+                }
+                ListCursorMode::Select => {
+                    if i+1 < self.data.len() {
+                        cur.idx = Some(i + 1);
+                        self.cursor.set(cur);
+                        TreeNavResult::Continue
+                    } else {
+                        self.cursor.set(ListCursor::default());
+                        TreeNavResult::Exit
+                    }
+                }
+                ListCursorMode::Modify => {
+                    let ce = self.data.get(i);
+                    let mut cur_edit = ce.write().unwrap();
+
+                    let depth = cur_edit.get_cursor().tree_addr.len();
+                    let cur_mode = cur_edit.get_cursor().leaf_mode;
+
+                    match cur_edit.nexd() {
+                        TreeNavResult::Exit => {
+                            drop(cur_edit);
+                            drop(ce);
+                            self.up();
+
+                            if i+1 < self.data.len() {
+
+                                self.set_mode(ListCursorMode::Select);
+                                self.nexd();
+
+                                for x in 1 .. depth {
+                                    self.dn();
+                                    self.goto_home();
+                                }
+
+                                self.set_leaf_mode(cur_mode);
+                                self.dn();
+                                self.goto_home();
+                                TreeNavResult::Continue
+                            } else {
+                                TreeNavResult::Exit
+                            }
+                        }
+                        TreeNavResult::Continue => TreeNavResult::Continue
+                    }
+                }
+            }
+        } else {
+            TreeNavResult::Exit
+        }
+    }
+}
+
+impl<ItemEditor, FnMakeItemEditor> TerminalEditor for ListEditor<ItemEditor, FnMakeItemEditor>
+where ItemEditor: TerminalTreeEditor + ?Sized + Send + Sync + 'static,
+      FnMakeItemEditor: Fn() -> Arc<RwLock<ItemEditor>>
+{
+    fn get_term_view(&self) -> OuterViewPort<dyn TerminalView> {
+        match self.style {
+            ListEditorStyle::HorizontalSexpr => self.horizontal_sexpr_view(),
+            ListEditorStyle::VerticalSexpr => self.vertical_sexpr_view(),
+            ListEditorStyle::Path => self.path_view(),
+            ListEditorStyle::String => self.string_view(),
+            ListEditorStyle::Clist => self.clist_view(),
+            ListEditorStyle::Hex => self.hex_view(),
+            ListEditorStyle::Plain => self.plain_view()
+        }
+    }
+
+    fn handle_terminal_event(&mut self, event: &TerminalEvent) -> TerminalEditorResult {
+        let mut cur = self.cursor.get();
+        if let Some(idx) = cur.idx {
+            match cur.mode {
+                ListCursorMode::Insert => {
+                    match event {
+                        TerminalEvent::Input(Event::Key(Key::Backspace)) => {
+                            if idx > 0 && idx <= self.data.len() {
+                                cur.idx = Some(idx-1);
+                                self.cursor.set(cur);
+                                self.data.remove(idx-1);
+                                TerminalEditorResult::Continue
+                            } else {
+                                TerminalEditorResult::Exit
+                            }
+                        }
+                        TerminalEvent::Input(Event::Key(Key::Delete)) => {
+                            if idx < self.data.len() {
+                                self.data.remove(idx);
+                                TerminalEditorResult::Continue
+                            } else {
+                                TerminalEditorResult::Exit
+                            }
+                        }
+                        TerminalEvent::Input(Event::Key(Key::Char('\t'))) |
+                        TerminalEvent::Input(Event::Key(Key::Insert)) => {
+                            self.set_mode(ListCursorMode::Select);
+                            TerminalEditorResult::Continue
+                        }
+                        _ => {
+                            let new_edit = (self.make_item_editor)();
+                            self.data.insert(idx, new_edit.clone());
+                            self.dn();
+                            self.goto_home();
+
+                            match new_edit.write().unwrap().handle_terminal_event(event) {
+                                TerminalEditorResult::Exit => {
+                                    self.cursor.set(ListCursor {
+                                        mode: ListCursorMode::Insert,
+                                        idx: Some(idx+1)
+                                    });
+                                }
+                                _ => {}
+                            }
+                            TerminalEditorResult::Continue
+                        }
+                    }
+                }
+                ListCursorMode::Select => {
+                    match event {
+                        TerminalEvent::Input(Event::Key(Key::Char('\t'))) |
+                        TerminalEvent::Input(Event::Key(Key::Insert)) => {
+                            self.set_mode(ListCursorMode::Insert);
+                            TerminalEditorResult::Continue
+                        }
+                        TerminalEvent::Input(Event::Key(Key::Delete)) => {
+                            self.data.remove(idx);
+
+                            if self.data.len() == 0 {
+                                self.cursor.set(ListCursor::default());
+                            } else if idx == self.data.len() {
+                                self.cursor.set(ListCursor {
+                                    mode: ListCursorMode::Select,
+                                    idx: Some(idx-1)
+                                });
+                            }
+                            TerminalEditorResult::Continue
+                        }
+                        _ => {
+                            TerminalEditorResult::Continue
+                        }
+                    }
+                }
+                ListCursorMode::Modify => {
+                    let mut ce = self.data.get_mut(idx);
+                    let mut cur_edit = ce.write().unwrap();
+
+                    match cur_edit.handle_terminal_event(event) {
+                        TerminalEditorResult::Exit => {
+                            cur_edit.up();
+                            drop(cur_edit);
+                            drop(ce);
+
+                            match event {
+                                TerminalEvent::Input(Event::Key(Key::Backspace)) => {
+                                    // todo: join instead of remove
+                                    self.cursor.set(ListCursor {
+                                        mode: ListCursorMode::Insert,
+                                        idx: Some(idx)
+                                    });
+
+                                    self.data.remove(idx);
+                                }
+                                _ => {
+                                    // todo: split
+
+                                    self.cursor.set(ListCursor {
+                                        mode: ListCursorMode::Insert,
+                                        idx: Some(idx+1)
+                                    });
+                                }
+                            }
+                        },
+                        TerminalEditorResult::Continue => {}
+                    }
+
+                    TerminalEditorResult::Continue
+                }
+            }
+        } else {
+            TerminalEditorResult::Continue
+        }
+    }
+}
+
+impl<ItemEditor, FnMakeItemEditor> ListEditor<ItemEditor, FnMakeItemEditor>
+where ItemEditor: TerminalTreeEditor + ?Sized + Send + Sync + 'static,
+      FnMakeItemEditor: Fn() -> Arc<RwLock<ItemEditor>>
+{
+    pub fn get_seg_seq_view(&self) -> OuterViewPort<dyn SequenceView<Item = OuterViewPort<dyn TerminalView>>> {
+        let segment_view_port = ViewPort::<dyn SequenceView<Item = ListEditorViewSegment>>::new();
+        ListEditorView::new(
+            self.cursor_port.outer(),
+            self.data_port.outer().to_sequence().map(|ed| ed.read().unwrap().get_term_view()),
+            segment_view_port.inner()
+        );
+
+        segment_view_port.into_outer()
+            .map(
+                move |segment| {
+                    let cursor_col = (90, 60, 200);
+                match segment {
+                    ListEditorViewSegment::InsertCursor =>
+                        make_label("|")
+                        .map_item(
+                            move |_pt, atom|
+                            atom.add_style_back(TerminalStyle::fg_color(cursor_col))
+                                .add_style_back(TerminalStyle::bold(true))
+                        ),
+                    ListEditorViewSegment::Select(sub_view) =>
+                        sub_view.map_item(
+                            move |_pt, atom| {
+                                let old_col = atom.style.bg_color.unwrap_or(cursor_col);
+                                atom.add_style_front(TerminalStyle::bg_color(((old_col.0 as f32 * 0.4) as u8, (old_col.1 as f32 * 0.4) as u8, (old_col.2 as f32 * 0.4) as u8)))
+                            }
+                        ),
+                    ListEditorViewSegment::Modify(sub_view) => {
+                        sub_view.clone().map_item(
+                            move |_pt, atom| {
+                                let old_col = atom.style.bg_color.unwrap_or(cursor_col);
+                                atom.add_style_front(TerminalStyle::bg_color(((old_col.0 as f32 * 0.4) as u8, (old_col.1 as f32 * 0.4) as u8, (old_col.2 as f32 * 0.4) as u8)))
+                            }
+                                //.add_style_back(TerminalStyle::bold(true))
+                        )
+                    },
+                    ListEditorViewSegment::View(sub_view) =>
+                        sub_view.clone()
+                }
+                }
+            )
+    }
+
+    pub fn horizontal_sexpr_view(&self) -> OuterViewPort<dyn TerminalView> {
+        self.get_seg_seq_view().horizontal_sexpr_view(1)
+    }
+
+    pub fn vertical_sexpr_view(&self) -> OuterViewPort<dyn TerminalView> {
+        self.get_seg_seq_view().vertical_sexpr_view(0)
+    }
+
+    pub fn path_view(&self) -> OuterViewPort<dyn TerminalView> {
+        self.get_seg_seq_view()
+            .decorate("<", ">", "/", 0)
+            .to_grid_horizontal()
+            .flatten()
+    }
+
+    pub fn string_view(&self) -> OuterViewPort<dyn TerminalView> {
+        self.get_seg_seq_view()
+            .decorate("\"", "\"", "", 1)
+            .to_grid_horizontal()
+
+            .flatten()
+    }
+
+    pub fn clist_view(&self) -> OuterViewPort<dyn TerminalView> {
+        self.get_seg_seq_view()
+            .decorate("{", "}", ", ", 1)
+            .to_grid_horizontal()
+            .flatten()
+    }
+
+    pub fn hex_view(&self) -> OuterViewPort<dyn TerminalView> {
+        self.get_seg_seq_view()
+            .decorate("0x", "", "", 0)
+            .to_grid_horizontal()
+            .flatten()
+    }
+
+    pub fn plain_view(&self) -> OuterViewPort<dyn TerminalView> {
+        self.get_seg_seq_view()
+            .to_grid_horizontal()
+            .flatten()
+    }
+
+    pub fn new(make_item_editor: FnMakeItemEditor, style: ListEditorStyle) -> Self {
+        let cursor_port = ViewPort::new();
+        let data_port = ViewPort::new();
+        let mut cursor = SingletonBuffer::new(ListCursor::default(), cursor_port.inner());
+        let mut data = VecBuffer::<Arc<RwLock<ItemEditor>>>::new(data_port.inner());
+
+        let mut le = ListEditor {
+            data,
+            data_port,
+            cursor,
+            cursor_port,
+
+            style,
+            make_item_editor,
+            level: 0,
+            cur_dist: Arc::new(RwLock::new(0))
+        };
+        le.set_style(style);
+        le
+    }
+
+    pub fn set_style(&mut self, style: ListEditorStyle) {
+        self.style = style;
+    }
+
+    pub fn get_data_port(&self) -> OuterViewPort<dyn SequenceView<Item = Arc<RwLock<ItemEditor>>>> {
+        self.data_port.outer().to_sequence()
+    }
+
+    pub fn get_list_cursor_port(&self) -> OuterViewPort<dyn SingletonView<Item = ListCursor>> {
+        self.cursor_port.outer()
+    }
+
+    pub fn get_item(&self) -> Option<Arc<RwLock<ItemEditor>>> {
+        if let Some(idx) = self.cursor.get().idx {
+            if idx < self.data.len() {
+                Some(self.data.get(idx))
+            } else {
+                None
+            }
+        } else {
+            None
+        }
+    }
+
+    fn set_idx(&mut self, idx: isize) {
+        let cur = self.cursor.get();
+        let mode = cur.mode;
+
+        if idx < 0 {
+            self.cursor.set(ListCursor {
+                mode,
+                idx: Some((self.data.len() as isize + idx) as usize)
+            });
+        } else {
+            self.cursor.set(ListCursor {
+                mode,
+                idx: Some(idx as usize)
+            });
+        }
+    }
+
+    fn set_mode(&mut self, mode: ListCursorMode) {
+        let mut cur = self.cursor.get();
+
+        if cur.mode == ListCursorMode::Insert &&
+            mode != ListCursorMode::Insert
+        {
+            if let Some(idx) = cur.idx {
+                if idx == self.data.len() && idx > 0 {
+                    cur.idx = Some(idx-1);
+                }
+            }
+        }
+
+        cur.mode = mode;
+
+        self.cursor.set(cur);
+    }
+}
+
+impl<ItemEditor, FnMakeItemEditor> ListEditor<ItemEditor, FnMakeItemEditor>
+where ItemEditor: TerminalTreeEditor + ?Sized + Send + Sync + 'static,
+      FnMakeItemEditor: Fn() -> Arc<RwLock<ItemEditor>>
+{
+    fn set_leaf_mode(&mut self, mode: ListCursorMode) {
+        let mut c = self.get_cursor();
+        c.leaf_mode = mode;
+        self.goto(c);
+    }
+}
+

nested/src/list/editor_view.rs

@@ -0,0 +1,142 @@
+use {
+    std::sync::Arc,
+    std::sync::RwLock,
+    crate::{
+        core::{
+            View,
+            InnerViewPort,
+            OuterViewPort,
+            Observer,
+            ObserverExt,
+            ObserverBroadcast
+        },
+        projection::ProjectionHelper,
+
+        singleton::SingletonView,
+        sequence::SequenceView,
+        terminal::TerminalView,
+
+        list::{ListCursor, ListCursorMode}
+    }
+};
+
+pub enum ListEditorViewSegment {
+    InsertCursor,
+    View(OuterViewPort<dyn TerminalView>),
+    Select(OuterViewPort<dyn TerminalView>),
+    Modify(OuterViewPort<dyn TerminalView>)
+}
+
+pub struct ListEditorView {
+    cursor: Arc<dyn SingletonView<Item = ListCursor>>,
+    data: Arc<dyn SequenceView<Item = OuterViewPort<dyn TerminalView>>>,
+    cur_cursor: ListCursor,
+
+    cast: Arc<RwLock<ObserverBroadcast<dyn SequenceView<Item = ListEditorViewSegment>>>>,
+    proj_helper: ProjectionHelper<usize, Self>
+}
+
+impl View for ListEditorView {
+    type Msg = usize;
+}
+
+impl SequenceView for ListEditorView {
+    type Item = ListEditorViewSegment;
+
+    fn len(&self) -> Option<usize> {
+        match self.cursor.get().mode {
+            ListCursorMode::Insert => Some(self.data.len()? + if self.cur_cursor.idx.is_some() { 1 } else { 0 }),
+            _ => self.data.len()
+        }
+    }
+
+    fn get(&self, idx: &usize) -> Option<Self::Item> {
+        Some(
+            if let Some(cur) = self.cur_cursor.idx {
+                match self.cur_cursor.mode {
+                    ListCursorMode::Select => {
+                        if *idx == cur {
+                            ListEditorViewSegment::Select(self.data.get(&idx)?)
+                        } else {
+                            ListEditorViewSegment::View(self.data.get(&idx)?)
+                        }
+                    }
+                    ListCursorMode::Insert => {
+                        if *idx < cur {
+                            ListEditorViewSegment::View(self.data.get(&idx)?)
+                        } else if *idx == cur {
+                            ListEditorViewSegment::InsertCursor
+                        } else {
+                            ListEditorViewSegment::View(self.data.get(&(idx-1))?)
+                        }
+                    }
+                    ListCursorMode::Modify => {
+                        if *idx == cur {
+                            ListEditorViewSegment::Modify(self.data.get(&idx)?)
+                        } else {
+                            ListEditorViewSegment::View(self.data.get(&idx)?)
+                        }
+                    }
+                }
+            } else {
+                ListEditorViewSegment::View(self.data.get(&idx)?)
+            }
+        )
+    }
+}
+
+impl ListEditorView {
+    pub fn new(
+        cursor_port: OuterViewPort<dyn SingletonView<Item = ListCursor>>,
+        data_port: OuterViewPort<dyn SequenceView<Item = OuterViewPort<dyn TerminalView>>>,
+        out_port: InnerViewPort<dyn SequenceView<Item = ListEditorViewSegment>>
+    ) -> Arc<RwLock<Self>> {
+        let mut proj_helper = ProjectionHelper::new(out_port.0.update_hooks.clone());
+        let proj = Arc::new(RwLock::new(
+                ListEditorView {
+                    cur_cursor: ListCursor::default(),
+                    cursor: proj_helper.new_singleton_arg(
+                        0,
+                        cursor_port,
+                        |s: &mut Self, _msg| {
+                            let old_cursor = s.cur_cursor;
+                            let new_cursor = s.cursor.get();
+                            s.cur_cursor = new_cursor;
+
+                            s.cast.notify_each(
+                                0 ..= s.data.len().unwrap_or(0)+1
+                            );
+                        }),
+                    data: proj_helper.new_sequence_arg(
+                        1,
+                        data_port,
+                        |s: &mut Self, idx| {
+                            if let Some(cur_idx) = s.cur_cursor.idx {
+                                match s.cur_cursor.mode {
+                                    ListCursorMode::Insert => {
+                                        if *idx < cur_idx {
+                                            s.cast.notify(idx);
+                                        } else {
+                                            s.cast.notify(&(*idx + 1));
+                                        }
+                                    },
+                                    _ => {
+                                        s.cast.notify(idx);
+                                    }
+                                }
+                            } else {
+                                s.cast.notify(idx);
+                            }
+                        }),
+                    cast: out_port.get_broadcast(),
+                    proj_helper
+                }
+            ));
+
+        proj.write().unwrap().proj_helper.set_proj(&proj);
+        out_port.set_view(Some(proj.clone()));
+
+        proj
+    }
+}
+

nested/src/list/mod.rs

@@ -0,0 +1,10 @@
+
+pub mod sexpr;
+pub mod cursor;
+pub mod editor;
+pub mod editor_view;
+
+pub use sexpr::{SExprView, ListDecoration};
+pub use cursor::{ListCursorMode, ListCursor};
+pub use editor::{ListEditor, ListEditorStyle};
+

nested/src/list/sexpr.rs

@@ -0,0 +1,270 @@
+use {
+    crate::{
+        core::{InnerViewPort, Observer, ObserverBroadcast, OuterViewPort, View, ViewPort},
+        projection::ProjectionHelper,
+        sequence::SequenceView,
+        index::{IndexArea},
+        terminal::{make_label, TerminalStyle, TerminalView},
+    },
+    cgmath::Point2,
+    std::sync::Arc,
+    std::sync::RwLock,
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct ListDecorator {
+    opening_port: OuterViewPort<dyn TerminalView>,
+    closing_port: OuterViewPort<dyn TerminalView>,
+    delim_port: OuterViewPort<dyn TerminalView>,
+    items: Arc<dyn SequenceView<Item = OuterViewPort<dyn TerminalView>>>,
+
+    list_style: TerminalStyle,
+    item_style: TerminalStyle,
+
+    cast: Arc<RwLock<ObserverBroadcast<dyn SequenceView<Item = OuterViewPort<dyn TerminalView>>>>>,
+    proj_helper: ProjectionHelper<(), Self>,
+}
+
+impl View for ListDecorator {
+    type Msg = usize;
+}
+
+impl SequenceView for ListDecorator {
+    type Item = OuterViewPort<dyn TerminalView>;
+
+    fn len(&self) -> Option<usize> {
+        let l = self.items.len()?;
+        Some(if l == 0 { 2 } else { 2 * l + 1 })
+    }
+
+    fn get(&self, idx: &usize) -> Option<Self::Item> {
+        let item_idx = idx / 2;
+        let list_style = self.list_style.clone();
+        let item_style = self.item_style.clone();
+        let l = self.items.len().unwrap_or(0);
+        Some(if *idx == 0 {
+            self.opening_port
+                .clone()
+                .map_item(move |_, atom| atom.add_style_back(list_style))
+        } else if (l == 0 && *idx == 1) || *idx == 2 * l {
+            self.closing_port
+                .clone()
+                .map_item(move |_, atom| atom.add_style_back(list_style))
+        } else if idx % 2 == 0 {
+            self.delim_port
+                .clone()
+                .map_item(move |_, atom| atom.add_style_back(list_style))
+        } else {
+            self.items
+                .get(&item_idx)?
+                .map_item(move |_, atom| atom.add_style_back(item_style))
+        })
+    }
+}
+
+impl ListDecorator {
+    pub fn new(
+        opening: &str,
+        closing: &str,
+        delim: &str,
+        level: usize,
+        items_port: OuterViewPort<dyn SequenceView<Item = OuterViewPort<dyn TerminalView>>>,
+        out_port: InnerViewPort<dyn SequenceView<Item = OuterViewPort<dyn TerminalView>>>,
+    ) -> Arc<RwLock<Self>> {
+        let mut proj_helper = ProjectionHelper::new(out_port.0.update_hooks.clone());
+
+        let li = Arc::new(RwLock::new(ListDecorator {
+            opening_port: make_label(opening),
+            closing_port: make_label(closing),
+            delim_port: make_label(delim),
+            items: proj_helper.new_sequence_arg((), items_port, |s: &mut Self, item_idx| {
+                s.cast.notify(&(*item_idx * 2 + 1));
+                s.cast.notify(&(*item_idx * 2 + 2));
+            }),
+            list_style: TerminalStyle::fg_color(match level {
+                0 => (200, 120, 10),
+                1 => (120, 200, 10),
+                _ => (255, 255, 255),
+            }),
+            item_style: TerminalStyle::fg_color(match level {
+                _ => (255, 255, 255),
+            }),
+            cast: out_port.get_broadcast(),
+            proj_helper,
+        }));
+
+        li.write().unwrap().proj_helper.set_proj(&li);
+
+        out_port.set_view(Some(li.clone()));
+        li
+    }
+}
+
+pub trait ListDecoration {
+    fn decorate(
+        &self,
+        opening: &str,
+        closing: &str,
+        delim: &str,
+        level: usize,
+    ) -> OuterViewPort<dyn SequenceView<Item = OuterViewPort<dyn TerminalView>>>;
+}
+
+impl ListDecoration for OuterViewPort<dyn SequenceView<Item = OuterViewPort<dyn TerminalView>>> {
+    fn decorate(
+        &self,
+        opening: &str,
+        closing: &str,
+        delim: &str,
+        level: usize,
+    ) -> OuterViewPort<dyn SequenceView<Item = OuterViewPort<dyn TerminalView>>> {
+        let port = ViewPort::new();
+        ListDecorator::new(opening, closing, delim, level, self.clone(), port.inner());
+        port.into_outer()
+    }    
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+use crate::{grid::GridView, index::IndexView};
+
+pub struct VerticalSexprDecorator {
+    opening_port: OuterViewPort<dyn TerminalView>,
+    closing_port: OuterViewPort<dyn TerminalView>,
+    items: Arc<dyn SequenceView<Item = OuterViewPort<dyn TerminalView>>>,
+
+    list_style: TerminalStyle,
+    item_style: TerminalStyle,
+
+    cast: Arc<RwLock<ObserverBroadcast<dyn GridView<Item = OuterViewPort<dyn TerminalView>>>>>,
+    proj_helper: ProjectionHelper<(), Self>,
+}
+
+impl View for VerticalSexprDecorator {
+    type Msg = IndexArea<Point2<i16>>;
+}
+
+impl IndexView<Point2<i16>> for VerticalSexprDecorator {
+    type Item = OuterViewPort<dyn TerminalView>;
+
+    fn area(&self) -> IndexArea<Point2<i16>> {
+        IndexArea::Range(
+            Point2::new(0, 0) ..= Point2::new(2, std::cmp::max(self.items.len().unwrap() as i16 - 1, 0))
+        )
+    }
+
+    fn get(&self, pt: &Point2<i16>) -> Option<Self::Item> {
+        if pt.y < 0 {
+            return None;
+        }
+        let item_idx = pt.y as usize;
+        let list_style = self.list_style.clone();
+        let item_style = self.item_style.clone();
+        let l = self.items.len().unwrap_or(0);
+
+        match pt.x {
+            0 => {
+                if pt.y == 0 {
+                    Some(
+                        self.opening_port
+                            .clone()
+                            .map_item(move |_, atom| atom.add_style_back(list_style)),
+                    )
+                } else {
+                    None
+                }
+            }
+            1 => {
+                if item_idx < l {
+                    Some(
+                        self.items
+                            .get(&item_idx)?
+                            .map_item(move |_, atom| atom.add_style_back(item_style)),
+                    )
+                } else {
+                    None
+                }
+            }
+            2 => {
+                if (l == 0 && pt.y == 0) || (item_idx + 1 == l) {
+                    Some(
+                        self.closing_port
+                            .clone()
+                            .map_item(move |_, atom| atom.add_style_back(list_style)),
+                    )
+                } else {
+                    None
+                }
+            }
+            _ => None,
+        }
+    }
+}
+
+impl VerticalSexprDecorator {
+    pub fn new(
+        opening: &str,
+        closing: &str,
+        level: usize,
+        items_port: OuterViewPort<dyn SequenceView<Item = OuterViewPort<dyn TerminalView>>>,
+        out_port: InnerViewPort<dyn GridView<Item = OuterViewPort<dyn TerminalView>>>,
+    ) -> Arc<RwLock<Self>> {
+        let mut proj_helper = ProjectionHelper::new(out_port.0.update_hooks.clone());
+
+        let li = Arc::new(RwLock::new(VerticalSexprDecorator {
+            opening_port: make_label(opening),
+            closing_port: make_label(closing),
+            items: proj_helper.new_sequence_arg((), items_port, |s: &mut Self, item_idx| {
+                s.cast.notify(
+                    &IndexArea::Range(
+                        Point2::new(0, *item_idx as i16) ..= Point2::new(2, *item_idx as i16)
+                    )
+                );
+            }),
+            list_style: TerminalStyle::fg_color(match level {
+                0 => (200, 120, 10),
+                1 => (120, 200, 10),
+                _ => (255, 255, 255),
+            }),
+            item_style: TerminalStyle::fg_color(match level {
+                _ => (255, 255, 255),
+            }),
+            cast: out_port.get_broadcast(),
+            proj_helper,
+        }));
+
+        li.write().unwrap().proj_helper.set_proj(&li);
+
+        out_port.set_view(Some(li.clone()));
+        li
+    }
+}
+
+pub trait SExprView {
+    fn horizontal_sexpr_view(&self, level: usize) -> OuterViewPort<dyn TerminalView>;
+    fn vertical_bar_view(&self, level: usize) -> OuterViewPort<dyn TerminalView>;
+    fn vertical_sexpr_view(&self, level: usize) -> OuterViewPort<dyn TerminalView>;
+}
+
+impl SExprView for OuterViewPort<dyn SequenceView<Item = OuterViewPort<dyn TerminalView>>> {
+    fn horizontal_sexpr_view(&self, level: usize) -> OuterViewPort<dyn TerminalView> {
+        let port = ViewPort::new();
+        ListDecorator::new("(", ")", " ", level, self.clone(), port.inner());
+
+        port.into_outer().to_grid_horizontal().flatten()
+    }
+
+    fn vertical_bar_view(&self, level: usize) -> OuterViewPort<dyn TerminalView> {
+        let port = ViewPort::new();
+        ListDecorator::new("Λ", "V", "|", level, self.clone(), port.inner());
+
+        port.into_outer().to_grid_vertical().flatten()
+    }
+
+    fn vertical_sexpr_view(&self, level: usize) -> OuterViewPort<dyn TerminalView> {
+        let port = ViewPort::new();
+        VerticalSexprDecorator::new("(", ")", level, self.clone(), port.inner());
+        port.into_outer().flatten()
+    }
+}

nested/src/projection.rs

@@ -0,0 +1,242 @@
+use {
+    std::{
+        cmp::{max},
+        any::Any,
+        sync::{Arc, Weak},
+        hash::Hash,
+        collections::HashMap
+    },
+    std::sync::RwLock,
+    crate::{
+        core::{
+            View,
+            Observer, ObserverExt,
+            port::UpdateTask,
+            OuterViewPort,
+            channel::{
+                ChannelSender, ChannelReceiver,
+                ChannelData,
+                set_channel,
+                queue_channel
+            }
+        },
+        singleton::{SingletonView},
+        sequence::{SequenceView},
+        index::{IndexArea, IndexView}
+    }
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct ProjectionHelper<ArgKey, P>
+where ArgKey: Clone + Hash + Eq,
+      P: Send + Sync + 'static
+{
+    keepalive: HashMap<ArgKey, (usize, Arc<dyn Any + Send + Sync>)>,
+    proj: Arc<RwLock<Weak<RwLock<P>>>>,
+    update_hooks: Arc<RwLock<Vec<Arc<dyn UpdateTask>>>>
+}
+
+impl<ArgKey, P> ProjectionHelper<ArgKey, P>
+where ArgKey: Clone + Hash + Eq,
+      P: Send + Sync + 'static
+{
+    pub fn new(update_hooks: Arc<RwLock<Vec<Arc<dyn UpdateTask>>>>) -> Self {
+        ProjectionHelper {
+            keepalive: HashMap::new(),
+            proj: Arc::new(RwLock::new(Weak::new())),
+            update_hooks
+        }
+    }
+
+    pub fn set_proj(&mut self, proj: &Arc<RwLock<P>>) {
+        *self.proj.write().unwrap() = Arc::downgrade(proj);
+    }
+
+    // todo: make this functions generic over the View
+    // this does currently not work because Observer<V> is not implemented for ProjectionArg for *all* V.
+
+    pub fn new_singleton_arg<Item: 'static>(
+        &mut self,
+        arg_key: ArgKey,
+        port: OuterViewPort<dyn SingletonView<Item = Item>>,
+        notify: impl Fn(&mut P, &()) + Send + Sync + 'static
+    ) -> Arc<RwLock<Option<Arc<dyn SingletonView<Item = Item>>>>> {
+        port.add_observer(self.new_arg(arg_key, Arc::new(port.0.clone()), notify, set_channel()));
+        port.get_view_arc()
+    }
+
+    pub fn new_sequence_arg<Item: 'static>(
+        &mut self,
+        arg_key: ArgKey,
+        port: OuterViewPort<dyn SequenceView<Item = Item>>,
+        notify: impl Fn(&mut P, &usize) + Send + Sync + 'static
+    ) -> Arc<RwLock<Option<Arc<dyn SequenceView<Item = Item>>>>> {
+        port.add_observer(self.new_arg(arg_key, Arc::new(port.0.clone()), notify, set_channel()));
+        port.get_view_arc()
+    }
+
+    pub fn new_index_arg<Key: Clone + Send + Sync + 'static, Item: 'static>(
+        &mut self,
+        arg_key: ArgKey,
+        port: OuterViewPort<dyn IndexView<Key, Item = Item>>,
+        notify: impl Fn(&mut P, &IndexArea<Key>) + Send + Sync + 'static
+    ) -> Arc<RwLock<Option<Arc<dyn IndexView<Key, Item = Item>>>>> {
+        port.add_observer(self.new_arg(arg_key, Arc::new(port.0.clone()), notify, queue_channel()));
+        port.get_view_arc()
+    }
+
+    pub fn new_arg<
+        V: View + ?Sized + 'static,
+        D: ChannelData<Item = V::Msg> + 'static
+    >(
+        &mut self,
+        arg_key: ArgKey,
+        src_update: Arc<dyn UpdateTask>,
+        notify: impl Fn(&mut P, &V::Msg) + Send + Sync + 'static,
+        (tx, rx): (ChannelSender<D>, ChannelReceiver<D>)
+    )
+        -> Arc<RwLock<ProjectionArg<P, V, D>>>
+    where V::Msg: Send + Sync,
+          D::IntoIter: Send + Sync + 'static
+    {
+        self.remove_arg(&arg_key);
+
+        let arg = Arc::new(RwLock::new(
+            ProjectionArg {
+                src: None,
+                notify: Box::new(notify),
+                proj: self.proj.clone(),
+                rx, tx
+            }));
+
+        let mut hooks = self.update_hooks.write().unwrap();
+        let idx = hooks.len();
+        hooks.push(src_update);
+        hooks.push(arg.clone());
+        self.keepalive.insert(arg_key, (idx, arg.clone()));
+
+        arg
+    }
+
+    pub fn remove_arg(&mut self, arg_key: &ArgKey) {
+        let mut hooks = self.update_hooks.write().unwrap();
+        if let Some((idx, arg)) = self.keepalive.remove(arg_key) {
+            hooks.remove(idx);
+            hooks.remove(idx);
+            for (_, (j, _)) in self.keepalive.iter_mut() {
+                if *j > idx {
+                    *j -= 2;
+                }
+            }
+        }
+    }
+}
+
+/// Special Observer which can access the state of the projection on notify
+/// also handles the reset()
+pub struct ProjectionArg<P, V, D>
+where P: Send + Sync + 'static,
+      V: View + ?Sized,
+      D: ChannelData<Item = V::Msg>,
+      D::IntoIter: Send + Sync
+{
+    src: Option<Arc<V>>,
+    notify: Box<dyn Fn(&mut P, &V::Msg) + Send + Sync + 'static>,
+    proj: Arc<RwLock<Weak<RwLock<P>>>>,
+    rx: ChannelReceiver<D>,
+    tx: ChannelSender<D>
+}
+
+impl<P, V, D> UpdateTask for ProjectionArg<P, V, D>
+where P: Send + Sync + 'static,
+      V: View + ?Sized,
+      D: ChannelData<Item = V::Msg>,
+      D::IntoIter: Send + Sync
+{
+    fn update(&self) {
+        if let Some(p) = self.proj.read().unwrap().upgrade() {
+            if let Some(data) = self.rx.try_recv() {
+                for msg in data {
+                    //eprintln!("proj update {:?}", msg);
+                    (self.notify)(
+                        &mut *p.write().unwrap(),
+                        &msg
+                    );
+                }
+            }
+        } else {
+            eprintln!("proj update: upgrade fail");
+        }
+    }
+}
+
+impl<P, V, D> UpdateTask for RwLock<ProjectionArg<P, V, D>>
+where P: Send + Sync + 'static,
+      V: View + ?Sized,
+      D: ChannelData<Item = V::Msg>,
+      D::IntoIter: Send + Sync
+{
+    fn update(&self) {
+        self.read().unwrap().update();
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<P, Item, D> Observer<dyn SingletonView<Item = Item>> for ProjectionArg<P, dyn SingletonView<Item = Item>, D>
+where P: Send + Sync + 'static,
+      D: ChannelData<Item = ()>,
+      D::IntoIter: Send + Sync
+{
+    fn reset(&mut self, new_src: Option<Arc<dyn SingletonView<Item = Item>>>) {
+        self.src = new_src;
+        self.notify(&());
+    }
+
+    fn notify(&mut self, msg: &()) {
+        self.tx.send(msg.clone());
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<P, Item, D> Observer<dyn SequenceView<Item = Item>> for ProjectionArg<P, dyn SequenceView<Item = Item>, D>
+where P: Send + Sync + 'static,
+      D: ChannelData<Item = usize>,
+      D::IntoIter: Send + Sync
+{
+    fn reset(&mut self, new_src: Option<Arc<dyn SequenceView<Item = Item>>>) {
+        let old_len = self.src.len().unwrap_or(0);
+        self.src = new_src;
+        let new_len = self.src.len().unwrap_or(0);
+
+        self.notify_each(0 .. max(old_len, new_len));
+    }
+
+    fn notify(&mut self, msg: &usize) {
+        self.tx.send(*msg);
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<P, Key, Item, D> Observer<dyn IndexView<Key, Item = Item>> for ProjectionArg<P, dyn IndexView<Key, Item = Item>, D>
+where P: Send + Sync + 'static,
+      Key: Clone + Send + Sync,
+      D: ChannelData<Item = IndexArea<Key>>,
+      D::IntoIter: Send + Sync
+{
+    fn reset(&mut self, new_src: Option<Arc<dyn IndexView<Key, Item = Item>>>) {
+        let old_area = self.src.area();
+        self.src = new_src;
+
+        self.notify(&old_area);
+        self.notify(&self.src.area())
+    }
+
+    fn notify(&mut self, msg: &IndexArea<Key>) {
+        self.tx.send(msg.clone());
+    }
+}
+

nested/src/sdf/mod.rs

@@ -0,0 +1,4 @@
+pub mod term;
+
+pub use term::SdfTerm;
+

nested/src/sdf/term.rs

@@ -0,0 +1,202 @@
+
+use {
+    std::{
+        sync::{Arc, RwLock, Mutex},
+        collections::HashMap
+    },
+    cgmath::{Point2, Vector2},
+    termion::event::{Event, Key},
+    crate::{
+        core::{
+            View,
+            ViewPort,
+            Observer,
+            ObserverExt,
+            OuterViewPort,
+            port::UpdateTask
+        },
+        index::{IndexArea},
+        terminal::{TerminalView}
+    },
+    nako::{
+        stream::{SecondaryStream2d, PrimaryStream2d},
+        glam::{Vec2, Vec3, UVec2, IVec2},
+        operations::{
+            planar::primitives2d::Box2d,
+            volumetric::{Color, Union, Round},
+        },
+    },
+    nakorender::{
+        backend::{Backend, LayerId, LayerId2d, LayerInfo, LayerSampling},
+        marp::MarpBackend,
+        winit, camera::Camera2d
+    },
+    nako_std::{
+        text::Character
+    },
+    std::{fs::File, io::Read, mem::needs_drop, path::Path},
+    font_kit::font::Font,
+};
+
+pub struct SdfTerm {
+    src_view: Option<Arc<dyn TerminalView>>,
+    bg_layers: HashMap<Point2<i16>, (bool, LayerId2d)>,
+    fg_layers: HashMap<Point2<i16>, (bool, LayerId2d)>,
+
+    font_height: u32,
+    font: Arc<Vec<u8>>,
+
+    renderer: Arc<Mutex<MarpBackend>>
+}
+
+impl SdfTerm {
+    pub fn new(renderer: Arc<Mutex<MarpBackend>>) -> Self {
+
+        let font_path = Path::new("/usr/share/fonts/TTF/FiraCode-Medium.ttf");
+        let mut font_file = File::open(font_path).unwrap();
+        let mut font_data = Vec::new();
+        font_file.read_to_end(&mut font_data).unwrap();
+
+        SdfTerm {
+            src_view: None,
+            bg_layers: HashMap::new(),
+            fg_layers: HashMap::new(),
+            font_height: 30,
+            font: Arc::new(font_data),
+            renderer
+        }
+    }
+
+    pub fn get_order(&self) -> Vec<LayerId> {
+        vec![
+            self.bg_layers.iter(),
+            self.fg_layers.iter()
+        ]
+            .into_iter()
+            .flatten()
+            .filter_map(
+                |(_pt,(active,id))|
+                if *active {
+                    Some((*id).into())
+                } else {
+                    None
+                })
+            .collect::<Vec<_>>()
+    }
+
+    pub fn update(&mut self, pt: &Point2<i16>) {
+        if self.bg_layers.get(pt).is_none() {
+            let id = self.renderer.lock().unwrap().new_layer_2d();
+
+            self.renderer.lock().unwrap().update_camera_2d(
+                id.into(),
+                Camera2d {
+                    extent: Vec2::new(0.5, 1.0),
+                    location: Vec2::new(0.0, 0.0),
+                    rotation: 0.0
+                });
+            self.renderer.lock().unwrap().set_layer_info(
+                id.into(),
+                LayerInfo {
+                    extent: UVec2::new(1 + self.font_height / 2, self.font_height),
+                    location: IVec2::new(pt.x as i32 * self.font_height as i32 / 2, pt.y as i32 * self.font_height as i32),
+                    sampling: LayerSampling::OverSampling(1),
+                });
+
+            self.bg_layers.insert(*pt, (false, id));
+        }
+        if self.fg_layers.get(pt).is_none() {
+            let id = self.renderer.lock().unwrap().new_layer_2d();
+
+            self.renderer.lock().unwrap().update_camera_2d(
+                id.into(),
+                Camera2d {
+                    extent: Vec2::new(0.5, 1.0),
+                    location: Vec2::new(0.0, 0.0),
+                    rotation: 0.0
+                });
+            self.renderer.lock().unwrap().set_layer_info(
+                id.into(),
+                LayerInfo {
+                    extent: UVec2::new(1 + self.font_height / 2, self.font_height),
+                    location: IVec2::new(pt.x as i32 * self.font_height as i32 / 2, pt.y as i32 * self.font_height as i32),
+                    sampling: LayerSampling::OverSampling(4),
+                });
+
+            self.fg_layers.insert(*pt, (false, id));
+        }
+
+        if let Some(atom) = self.src_view.get(pt) {
+
+            // background layer
+            if let Some((r,g,b)) = atom.style.bg_color {
+                let mut stream = PrimaryStream2d::new()
+                    .push(
+                        SecondaryStream2d::new(
+                            Union,
+                            Box2d {
+                                extent: Vec2::new(0.6, 1.0)
+                            }
+                        ).push_mod(
+                            Color(
+                                Vec3::new(
+                                    (r as f32 / 255.0).clamp(0.0, 1.0),
+                                    (g as f32 / 255.0).clamp(0.0, 1.0),
+                                    (b as f32 / 255.0).clamp(0.0, 1.0),
+                                )
+                            )
+                        ).build()
+                    );
+
+                self.renderer.lock().unwrap().update_sdf_2d(self.bg_layers.get(pt).unwrap().1, stream.build());
+                self.bg_layers.get_mut(pt).unwrap().0 = true;
+            } else {
+                self.bg_layers.get_mut(pt).unwrap().0 = false;                
+            }
+
+            // foreground layer
+            if let Some(c) = atom.c {
+                let font_index = 0;
+                let fontkit = Font::from_bytes(self.font.clone(), font_index).unwrap();
+                let mut ch = Character::from_font(&fontkit, c);//.with_size(1.0);
+
+                let (r,g,b) = atom.style.fg_color.unwrap_or((0, 0, 0));
+
+                let mut stream = PrimaryStream2d::new();
+                stream = ch.record_modifier_character(
+                    stream,
+                    Vec2::new(0.0, 0.0),
+                    1.0,
+                    Color(Vec3::new(
+                        (r as f32 / 255.0).clamp(0.0, 1.0),
+                        (g as f32 / 255.0).clamp(0.0, 1.0),
+                        (b as f32 / 255.0).clamp(0.0, 1.0),
+                    ))
+                );
+
+                self.renderer.lock().unwrap().update_sdf_2d(self.fg_layers.get(pt).unwrap().1, stream.build());
+                self.fg_layers.get_mut(pt).unwrap().0 = true;
+            } else {
+                self.fg_layers.get_mut(pt).unwrap().0 = false;                
+            }
+
+        } else {
+            self.bg_layers.get_mut(pt).unwrap().0 = false;
+            self.fg_layers.get_mut(pt).unwrap().0 = false;
+        }
+    }
+}
+
+impl Observer<dyn TerminalView> for SdfTerm {
+    fn reset(&mut self, new_view: Option<Arc<dyn TerminalView>>) {
+        self.src_view = new_view;
+        self.notify(&self.src_view.area());
+    }
+
+    fn notify(&mut self, area: &IndexArea<Point2<i16>>) {
+        for pt in area.iter() {
+            self.update(&pt);
+        }
+    }
+}
+

nested/src/sequence/filter.rs

@@ -0,0 +1,156 @@
+use {
+    std::sync::Arc,
+    std::sync::RwLock,
+    crate::{
+        sequence::{SequenceView},
+        core::{
+            Observer, ObserverExt, ObserverBroadcast,
+            View, ViewPort, OuterViewPort
+        }
+    }
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<V: SequenceView + ?Sized + 'static> OuterViewPort<V>
+{
+    pub fn filter<
+        P: Fn(&V::Item) -> bool + Send + Sync + 'static
+    >(&self, pred: P) -> OuterViewPort<dyn SequenceView<Item = V::Item>> {
+        let port = ViewPort::new();
+        port.add_update_hook(Arc::new(self.0.clone()));
+
+        let filter = Arc::new(RwLock::new(
+            Filter {
+                src_view: None,
+                pred,
+                old_preds: RwLock::new(Vec::new()),
+                cast: port.inner().get_broadcast()
+            }
+        ));
+
+        self.add_observer(filter.clone());
+        port.inner().set_view(Some(filter));
+        port.into_outer()
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+struct Filter<SrcView, P>
+where SrcView: SequenceView + ?Sized + 'static,
+      P: Fn(&SrcView::Item) -> bool + Send + Sync + 'static
+{
+    src_view: Option<Arc<SrcView>>,
+    pred: P,
+    old_preds: RwLock<Vec<bool>>,
+    cast: Arc<RwLock<ObserverBroadcast<dyn SequenceView<Item = SrcView::Item>>>>
+}
+
+impl<SrcView, P> Filter<SrcView, P>
+where SrcView: SequenceView + ?Sized + 'static,
+      P: Fn(&SrcView::Item) -> bool + Send + Sync + 'static
+{
+    fn get_offset(&self, idx: usize) -> usize {
+        if let Some(v) = self.src_view.clone() {
+            let mut i = 0;
+            let mut j = 0;
+            let mut offset = 0;
+
+            while let (Some(x), true) = (v.get(&i), j <= idx) {
+                if (self.pred)(&x) {
+                    j += 1;
+                } else {
+                    offset += 1;
+                }
+                i+=1;
+            }
+
+            offset
+        } else {
+           0
+        }
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<SrcView, P> View for Filter<SrcView, P>
+where SrcView: SequenceView + ?Sized + 'static,
+      P: Fn(&SrcView::Item) -> bool + Send + Sync + 'static
+{
+    type Msg = usize;
+}
+
+impl<SrcView, P> SequenceView for Filter<SrcView, P>
+where SrcView: SequenceView + ?Sized + 'static,
+      P: Fn(&SrcView::Item) -> bool + Send + Sync + 'static
+{
+    type Item = SrcView::Item;
+
+    fn len(&self) -> Option<usize> {
+        if let Some(src_len) = self.src_view.len() {
+            Some(src_len - self.get_offset(src_len) )
+        } else {
+            None
+        }
+    }
+
+    fn get(&self, idx: &usize) -> Option<Self::Item> {
+        self.src_view.get(&( idx + self.get_offset(*idx) ))
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<SrcView, P> Observer<SrcView> for Filter<SrcView, P>
+where SrcView: SequenceView + ?Sized + 'static,
+      P: Fn(&SrcView::Item) -> bool + Send + Sync + 'static
+{
+    fn reset(&mut self, new_src: Option<Arc<SrcView>>) {
+        let old_len = self.len();
+        self.src_view = new_src;
+        self.old_preds = RwLock::new(Vec::new());
+        let new_len = self.len();
+
+        if let Some(len) = old_len { self.cast.notify_each(0 .. len); }
+        if let Some(len) = new_len { self.cast.notify_each(0 .. len); }
+    }
+
+    fn notify(&mut self, idx: &usize) {
+        let l = self.len().unwrap_or(0)+1;
+        let np = 
+            if let Some(x) = self.src_view.get(idx) {
+                (self.pred)(&x)
+            } else {
+                false
+            };
+
+        let mut opds = self.old_preds.write().unwrap();
+
+        opds.resize_with(1+*idx, || false);
+        let op = opds.get(*idx).cloned().unwrap_or(false);
+        *opds.get_mut(*idx).unwrap() = np;
+
+        drop(opds);
+
+        let i =
+            (0 .. *idx)
+            .map(
+                |j|
+                if let Some(x) = self.src_view.get(&j) {
+                    if (self.pred)(&x) { 1 } else { 0 }
+                } else {
+                    0
+                }
+            )
+            .sum();
+
+        if np != op {
+            self.cast.notify_each(i .. l);
+        } else {
+            self.cast.notify(&i);
+        }
+    }
+}
+

nested/src/sequence/flatten.rs

@@ -0,0 +1,182 @@
+use {
+    std::{
+        sync::Arc,
+        collections::BTreeMap
+    },
+    std::sync::RwLock,
+    crate::{
+        core::{
+            View, Observer, ObserverBroadcast, ObserverExt,
+            ViewPort, InnerViewPort, OuterViewPort,
+            port::UpdateTask
+        },
+        sequence::SequenceView,
+        projection::ProjectionHelper
+    }
+};
+
+impl<Item> OuterViewPort<dyn SequenceView<Item = OuterViewPort<dyn SequenceView<Item = Item>>>>
+where Item: 'static{
+    pub fn flatten(&self) -> OuterViewPort<dyn SequenceView<Item = Item>> {
+        let port = ViewPort::new();
+        Flatten::new(self.clone(), port.inner());
+        port.into_outer()
+    }
+}
+
+pub struct Chunk<Item>
+where Item: 'static
+{
+    offset: usize,
+    len: usize,
+    view: Arc<dyn SequenceView<Item = Item>>
+}
+
+pub struct Flatten<Item>
+where Item: 'static
+{
+    length: usize,
+    top: Arc<dyn SequenceView<Item = OuterViewPort<dyn SequenceView<Item = Item>>>>,
+    chunks: BTreeMap<usize, Chunk<Item>>,
+    cast: Arc<RwLock<ObserverBroadcast<dyn SequenceView<Item = Item>>>>,
+    proj_helper: ProjectionHelper<usize, Self>
+}
+
+impl<Item> View for Flatten<Item>
+where Item: 'static
+{
+    type Msg = usize;
+}
+
+impl<Item> SequenceView for Flatten<Item>
+where Item: 'static
+{
+    type Item = Item;
+
+    fn get(&self, idx: &usize) -> Option<Self::Item> {
+        let chunk = self.chunks.get(&self.get_chunk_idx(*idx)?)?;
+        chunk.view.get(&(*idx - chunk.offset))
+    }
+
+    fn len(&self) -> Option<usize> {
+        Some(self.length)
+    }
+}
+
+/* TODO: remove unused projection args (bot-views) if they get replaced by a new viewport  */
+impl<Item> Flatten<Item>
+where Item: 'static
+{
+    pub fn new(
+        top_port: OuterViewPort<dyn SequenceView<Item = OuterViewPort<dyn SequenceView<Item = Item>>>>,
+        out_port: InnerViewPort<dyn SequenceView<Item = Item>>
+    ) -> Arc<RwLock<Self>> {
+        let mut proj_helper = ProjectionHelper::new(out_port.0.update_hooks.clone());
+
+        let flat = Arc::new(RwLock::new(
+            Flatten {
+                length: 0,
+                top: proj_helper.new_sequence_arg(
+                    usize::MAX,
+                    top_port,
+                    |s: &mut Self, chunk_idx| {
+                        s.update_chunk(*chunk_idx);
+                    }
+                ),
+                chunks: BTreeMap::new(),
+                cast: out_port.get_broadcast(),
+                proj_helper
+            }));
+
+        flat.write().unwrap().proj_helper.set_proj(&flat);
+        out_port.set_view(Some(flat.clone()));
+        flat
+    }
+
+    /// the top-sequence has changed the item at chunk_idx,
+    /// create a new observer for the contained sub sequence
+    fn update_chunk(&mut self, chunk_idx: usize) {
+        if let Some(chunk_port) = self.top.get(&chunk_idx) {
+            self.chunks.insert(
+                chunk_idx,
+                Chunk {
+                    offset: 0, // will be adjusted by update_offsets() later
+                    len: 0,
+                    view: self.proj_helper.new_sequence_arg(
+                        chunk_idx,
+                        chunk_port.clone(),
+                        move |s: &mut Self, idx| {
+                            if let Some(chunk) = s.chunks.get(&chunk_idx) {
+                                let chunk_offset = chunk.offset;
+                                let chunk_len = chunk.view.len().unwrap_or(0);
+
+                                let mut dirty_idx = Vec::new();
+                                if chunk.len != chunk_len {
+                                    dirty_idx = s.update_all_offsets();
+                                }
+
+                                s.cast.notify(&(idx + chunk_offset));
+                                s.cast.notify_each(dirty_idx);
+                            }
+                        }
+                    )
+                }
+            );
+
+            chunk_port.0.update();
+
+            let dirty_idx = self.update_all_offsets();
+            self.cast.notify_each(dirty_idx);
+        } else {
+            // todo:
+            self.proj_helper.remove_arg(&chunk_idx);
+
+            self.chunks.remove(&chunk_idx);
+
+            let dirty_idx = self.update_all_offsets();
+            self.cast.notify_each(dirty_idx);
+        }
+    }
+
+    /// recalculate all chunk offsets beginning at start_idx
+    /// and update length of flattened sequence
+    fn update_all_offsets(&mut self) -> Vec<usize> {
+        let mut dirty_idx = Vec::new();
+        let mut cur_offset = 0;
+
+        for (_chunk_idx, chunk) in self.chunks.iter_mut() {
+            let old_offset = chunk.offset;
+            chunk.offset = cur_offset;
+            chunk.len = chunk.view.len().unwrap_or(0);
+
+            if old_offset != cur_offset {
+                dirty_idx.extend(
+                    std::cmp::min(old_offset, cur_offset)
+                        .. std::cmp::max(old_offset, cur_offset) + chunk.len
+                );
+            }
+
+            cur_offset += chunk.len;
+        }
+
+        let old_length = self.length;
+        self.length = cur_offset;
+
+        dirty_idx.extend(self.length .. old_length);
+        dirty_idx
+    }
+
+    /// given an index in the flattened sequence,
+    /// which sub-sequence does it belong to?
+    fn get_chunk_idx(&self, glob_idx: usize) -> Option<usize> {        
+        let mut offset = 0;
+        for (chunk_idx, chunk) in self.chunks.iter() {
+            offset += chunk.view.len().unwrap_or(0);
+            if glob_idx < offset {
+                return Some(*chunk_idx);
+            }
+        }
+        None
+    }
+}
+

nested/src/sequence/map.rs

@@ -0,0 +1,104 @@
+use {
+    std::sync::Arc,
+    std::sync::RwLock,
+    crate::{
+        sequence::{SequenceView},
+        core::{
+            Observer, ObserverExt, ObserverBroadcast,
+            View, ViewPort, OuterViewPort
+        }
+    }
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<Item: 'static> OuterViewPort<dyn SequenceView<Item = Item>> {
+    pub fn map<
+        DstItem: 'static,
+        F: Fn(&Item) -> DstItem + Send + Sync + 'static
+    >(
+        &self,
+        f: F
+    ) -> OuterViewPort<dyn SequenceView<Item = DstItem>> {
+        let port = ViewPort::new();
+        port.add_update_hook(Arc::new(self.0.clone()));
+
+        let map = Arc::new(RwLock::new(MapSequenceItem {
+            src_view: None,
+            f,
+            cast: port.inner().get_broadcast()
+        }));
+
+        self.add_observer(map.clone());
+        port.inner().set_view(Some(map));
+        port.into_outer()
+    }
+
+    pub fn filter_map<
+        DstItem: Clone + 'static,
+        F: Fn(&Item) -> Option<DstItem> + Send + Sync + 'static
+    >(
+        &self,
+        f: F
+    ) -> OuterViewPort<dyn SequenceView<Item = DstItem>> {
+        self.map(f)
+            .filter(|x| x.is_some())
+            .map(|x| x.clone().unwrap())
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct MapSequenceItem<DstItem, SrcView, F>
+where SrcView: SequenceView + ?Sized,
+      F: Fn(&SrcView::Item) -> DstItem + Send + Sync
+{
+    src_view: Option<Arc<SrcView>>,
+    f: F,
+    cast: Arc<RwLock<ObserverBroadcast<dyn SequenceView<Item = DstItem>>>>
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<DstItem, SrcView, F> View for MapSequenceItem<DstItem, SrcView, F>
+where SrcView: SequenceView + ?Sized,
+      F: Fn(&SrcView::Item) -> DstItem + Send + Sync
+{
+    type Msg = usize;
+}
+
+impl<DstItem, SrcView, F> SequenceView for MapSequenceItem<DstItem, SrcView, F>
+where SrcView: SequenceView + ?Sized,
+      F: Fn(&SrcView::Item) -> DstItem + Send + Sync
+{
+    type Item = DstItem;
+
+    fn len(&self) -> Option<usize> {
+        self.src_view.len()
+    }
+
+    fn get(&self, idx: &usize) -> Option<DstItem> {
+        self.src_view.get(idx).as_ref().map(|item| (self.f)(item))
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<DstItem, SrcView, F> Observer<SrcView> for MapSequenceItem<DstItem, SrcView, F>
+where SrcView: SequenceView + ?Sized,
+      F: Fn(&SrcView::Item) -> DstItem + Send + Sync
+{
+    fn reset(&mut self, view: Option<Arc<SrcView>>) {
+        let old_len = self.len();
+        self.src_view = view;
+        let new_len = self.len();
+
+        if let Some(len) = old_len { self.cast.notify_each(0 .. len ); }
+        if let Some(len) = new_len { self.cast.notify_each(0 .. len ); }
+    }
+
+    fn notify(&mut self, msg: &usize) {
+        self.cast.notify(msg);
+    }
+}
+

nested/src/sequence/mod.rs

@@ -0,0 +1,101 @@
+
+pub mod seq2idx;
+pub mod map;
+pub mod filter;
+pub mod flatten;
+
+pub use seq2idx::{Sequence2Index};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+use crate::core::View;
+
+pub trait SequenceView : View<Msg = usize> {
+    type Item;
+
+    fn get(&self, idx: &usize) -> Option<Self::Item>;
+    fn len(&self) -> Option<usize>;
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub trait SequenceViewExt : SequenceView {
+    fn iter<'a>(&'a self) -> SequenceViewIter<'a, Self> {
+        SequenceViewIter {
+            view: self,
+            cur: 0
+        }
+    }
+}
+
+impl<V: SequenceView + ?Sized> SequenceViewExt for V {}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct SequenceViewIter<'a, V>
+where V: SequenceView + ?Sized
+{
+    view: &'a V,
+    cur: usize
+}
+
+impl<'a, V> Iterator for SequenceViewIter<'a, V>
+where V: SequenceView + ?Sized
+{
+    type Item = V::Item;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let i = self.cur;
+        self.cur += 1;
+        self.view.get(&i)
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+use std::{
+    sync::Arc,
+    ops::{Deref}
+};
+use std::sync::RwLock;
+
+impl<V: SequenceView + ?Sized> SequenceView for RwLock<V> {
+    type Item = V::Item;
+
+    fn get(&self, idx: &usize) -> Option<Self::Item> {
+        self.read().unwrap().get(idx)
+    }
+
+    fn len(&self) -> Option<usize> {
+        self.read().unwrap().len()
+    }
+}
+
+impl<V: SequenceView + ?Sized> SequenceView for Arc<V> {
+    type Item = V::Item;
+
+    fn get(&self, idx: &usize) -> Option<Self::Item> {
+        self.deref().get(idx)
+    }
+
+    fn len(&self) -> Option<usize> {
+        self.deref().len()
+    }
+}
+
+impl<V: SequenceView> SequenceView for Option<V> {
+    type Item = V::Item;
+
+    fn get(&self, idx: &usize) -> Option<Self::Item> {
+        (self.as_ref()? as &V).get(idx)
+    }
+
+    fn len(&self) -> Option<usize> {
+        if let Some(v) = self.as_ref() {
+            v.len()
+        } else {
+            Some(0)
+        }
+    }
+}
+

nested/src/sequence/seq2idx.rs

@@ -0,0 +1,97 @@
+use {
+    std::{
+        sync::Arc
+    },
+    std::sync::RwLock,
+    crate::{
+        core::{
+            View, Observer, ObserverBroadcast,
+            ViewPort, InnerViewPort, OuterViewPort
+        },
+        sequence::SequenceView,
+        index::{IndexArea, IndexView},
+        grid::GridView
+    }
+};
+
+/// Transforms a SequenceView into IndexView<usize>
+pub struct Sequence2Index<SrcView>
+where SrcView: SequenceView + ?Sized + 'static {
+    src_view: Option<Arc<SrcView>>,
+    cast: Arc<RwLock<ObserverBroadcast<dyn IndexView<usize, Item = SrcView::Item>>>>
+}
+
+impl<SrcView> Sequence2Index<SrcView>
+where SrcView: SequenceView + ?Sized + 'static {
+    pub fn new(
+        port: InnerViewPort<dyn IndexView<usize, Item = SrcView::Item>>
+    ) -> Arc<RwLock<Self>> {
+        let s2i = Arc::new(RwLock::new(
+            Sequence2Index {
+                src_view: None,
+                cast: port.get_broadcast()
+            }
+        ));
+        port.set_view(Some(s2i.clone()));
+        s2i
+    }
+}
+
+impl<Item: 'static> OuterViewPort<dyn SequenceView<Item = Item>> {
+    pub fn to_index(&self) -> OuterViewPort<dyn IndexView<usize, Item = Item>> {
+        let port = ViewPort::new();
+        port.add_update_hook(Arc::new(self.0.clone()));
+        self.add_observer(Sequence2Index::new(port.inner()));
+        port.into_outer()
+    }
+
+    pub fn to_grid_horizontal(&self) -> OuterViewPort<dyn GridView<Item = Item>> {
+        self.to_index().to_grid_horizontal()
+    }
+
+    pub fn to_grid_vertical(&self) -> OuterViewPort<dyn GridView<Item = Item>> {
+        self.to_index().to_grid_vertical()
+    }
+}
+
+impl<SrcView> View for Sequence2Index<SrcView>
+where SrcView: SequenceView + ?Sized + 'static {
+    type Msg = IndexArea<usize>;
+}
+
+impl<SrcView> IndexView<usize> for Sequence2Index<SrcView>
+where SrcView: SequenceView + ?Sized + 'static {
+    type Item = SrcView::Item;
+
+    fn get(&self, key: &usize) -> Option<Self::Item> {
+        self.src_view.get(key)
+    }
+
+    fn area(&self) -> IndexArea<usize> {
+        if let Some(len) = self.src_view.len() {
+            if len > 0 {
+                IndexArea::Range(0 ..= len-1)
+            } else {
+                IndexArea::Empty
+            }
+        } else {
+            IndexArea::Full
+        }
+    }
+}
+
+impl<SrcView> Observer<SrcView> for Sequence2Index<SrcView>
+where SrcView: SequenceView + ?Sized + 'static {
+    fn reset(&mut self, view: Option<Arc<SrcView>>) {
+        let old_area = self.area();
+        self.src_view = view;
+
+        self.cast.notify(&old_area);
+        self.cast.notify(&self.area());
+    }
+
+    fn notify(&mut self, idx: &usize) {
+        self.cast.notify(&IndexArea::Set(vec![ *idx ]));
+    }
+}
+

nested/src/singleton/buffer.rs

@@ -0,0 +1,70 @@
+use {
+    std::{
+        sync::{Arc}
+    },
+    std::sync::RwLock,
+    crate::{
+        core::{
+            Observer,
+            ObserverBroadcast,
+            View,
+            InnerViewPort
+        },
+        singleton::{SingletonView}
+    }
+};
+
+pub struct SingletonBufferView<T: Clone + Eq + Send + Sync + 'static>(Arc<RwLock<T>>);
+
+impl<T> View for SingletonBufferView<T>
+where T: Clone + Eq + Send + Sync + 'static {
+    type Msg = ();
+}
+
+impl<T> SingletonView for SingletonBufferView<T>
+where T: Clone + Eq + Send + Sync + 'static {
+    type Item = T;
+
+    fn get(&self) -> Self::Item {
+        self.0.read().unwrap().clone()
+    }
+}
+
+#[derive(Clone)]
+pub struct SingletonBuffer<T>
+where T: Clone + Eq + Send + Sync + 'static {
+    value: Arc<RwLock<T>>,
+    cast: Arc<RwLock<ObserverBroadcast<dyn SingletonView<Item = T>>>>
+}
+
+impl<T> SingletonBuffer<T>
+where T: Clone + Eq + Send + Sync + 'static {
+    pub fn new(
+        value: T,
+        port: InnerViewPort<dyn SingletonView<Item = T>>
+    ) -> Self {
+        let value = Arc::new(RwLock::new(value));
+        port.set_view(Some(Arc::new(SingletonBufferView(value.clone()))));
+
+        SingletonBuffer {
+            value,
+            cast: port.get_broadcast()
+        }
+    }
+
+    pub fn get(&self) -> T {
+        self.value.read().unwrap().clone()
+    }
+
+    pub fn set(&mut self, new_value: T) {
+        let mut v = self.value.write().unwrap();
+        if *v != new_value {
+            *v = new_value;
+            drop(v);
+            self.cast.notify(&());
+        }
+    }
+}
+
+// TODO: impl Deref & DerefMut
+

nested/src/singleton/map.rs

@@ -0,0 +1,84 @@
+use {
+    std::sync::Arc,
+    std::sync::RwLock,
+    crate::{
+        singleton::{SingletonView},
+        core::{
+            Observer, ObserverBroadcast,
+            View, ViewPort, OuterViewPort
+        }
+    }
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<Item: 'static> OuterViewPort<dyn SingletonView<Item = Item>> {
+    pub fn map<
+        DstItem: 'static,
+        F: Fn(Item) -> DstItem + Send + Sync + 'static
+    >(
+        &self,
+        f: F
+    ) -> OuterViewPort<dyn SingletonView<Item = DstItem>> {
+        let port = ViewPort::new();
+        port.add_update_hook(Arc::new(self.0.clone()));
+
+        let map = Arc::new(RwLock::new(MapSingleton {
+            src_view: None,
+            f,
+            cast: port.inner().get_broadcast()
+        }));
+
+        self.add_observer(map.clone());
+        port.inner().set_view(Some(map));
+        port.into_outer()
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct MapSingleton<DstItem, SrcView, F>
+where SrcView: SingletonView + ?Sized,
+      F: Fn(SrcView::Item) -> DstItem + Send + Sync
+{
+    src_view: Option<Arc<SrcView>>,
+    f: F,
+    cast: Arc<RwLock<ObserverBroadcast<dyn SingletonView<Item = DstItem>>>>
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<DstItem, SrcView, F> View for MapSingleton<DstItem, SrcView, F>
+where SrcView: SingletonView + ?Sized,
+      F: Fn(SrcView::Item) -> DstItem + Send + Sync
+{
+    type Msg = ();
+}
+
+impl<DstItem, SrcView, F> SingletonView for MapSingleton<DstItem, SrcView, F>
+where SrcView: SingletonView + ?Sized,
+      F: Fn(SrcView::Item) -> DstItem + Send + Sync
+{
+    type Item = DstItem;
+
+    fn get(&self) -> DstItem {
+        (self.f)(self.src_view.as_ref().unwrap().get())
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<DstItem, SrcView, F> Observer<SrcView> for MapSingleton<DstItem, SrcView, F>
+where SrcView: SingletonView + ?Sized,
+      F: Fn(SrcView::Item) -> DstItem + Send + Sync
+{
+    fn reset(&mut self, view: Option<Arc<SrcView>>) {
+        self.src_view = view;
+        self.cast.notify(&());
+    }
+
+    fn notify(&mut self, msg: &()) {
+        self.cast.notify(msg);
+    }
+}
+

nested/src/singleton/mod.rs

@@ -0,0 +1,68 @@
+
+pub mod buffer;
+pub mod map;
+pub mod to_index;
+//pub mod unwrap;
+
+use {
+    std::{
+        sync::Arc,
+        ops::Deref
+    },
+    std::sync::RwLock,
+    crate::core::{View}
+};
+
+pub use buffer::SingletonBuffer;
+
+// TODO: #[ImplForArc, ImplForRwLock]
+pub trait SingletonView : View<Msg = ()> {
+    type Item;
+
+    fn get(&self) -> Self::Item;
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<V: SingletonView + ?Sized> SingletonView for RwLock<V> {
+    type Item = V::Item;
+
+    fn get(&self) -> Self::Item {
+        self.read().unwrap().get()
+    }
+}
+
+impl<V: SingletonView + ?Sized> SingletonView for Arc<V> {
+    type Item = V::Item;
+
+    fn get(&self) -> Self::Item {
+        self.deref().get()
+    }
+}
+
+impl<V: SingletonView> SingletonView for Option<V>
+where V::Item: Default{
+    type Item = V::Item;
+
+    fn get(&self) -> Self::Item {
+        if let Some(s) = self.as_ref() {
+            s.get()
+        } else {
+            V::Item::default()
+        }
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+/*
+impl<T> OuterViewPort<dyn SingletonView<Item = T>> {
+    pub fn get(&self) -> T {
+        self.get_view().unrwap().read().unwrap().get();
+    }
+
+    pub fn map<U: Send + Sync + 'static>(&self, f: impl Fn(T) -> U) -> OuterViewPort<dyn SingletonView<Item = U>> {
+        
+    }
+}
+ */
+

nested/src/singleton/to_index.rs

@@ -0,0 +1,86 @@
+use {
+    std::sync::Arc,
+    std::sync::RwLock,
+    crate::{
+        singleton::{SingletonView},
+        index::{IndexArea, IndexView},
+        grid::{GridView},
+        core::{
+            Observer, ObserverBroadcast,
+            View, ViewPort, OuterViewPort
+        }
+    }
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<Item: 'static> OuterViewPort<dyn SingletonView<Item = Item>> {
+    pub fn to_index(&self) -> OuterViewPort<dyn IndexView<(), Item = Item>> {
+        let port = ViewPort::new();
+        port.add_update_hook(Arc::new(self.0.clone()));
+
+        let map = Arc::new(RwLock::new(Singleton2Index {
+            src_view: None,
+            cast: port.inner().get_broadcast()
+        }));
+
+        self.add_observer(map.clone());
+        port.inner().set_view(Some(map));
+        port.into_outer()
+    }
+
+    pub fn to_grid(&self) -> OuterViewPort<dyn GridView<Item = Item>> {
+        self.to_index()
+            .map_key(
+                |_msg: &()| cgmath::Point2::new(0, 0),
+                |pt| if pt.x == 0 && pt.y == 0 { Some(()) } else { None }
+            )
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct Singleton2Index<SrcView>
+where SrcView: SingletonView + ?Sized
+{
+    src_view: Option<Arc<SrcView>>,
+    cast: Arc<RwLock<ObserverBroadcast<dyn IndexView<(), Item = SrcView::Item>>>>
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<SrcView> View for Singleton2Index<SrcView>
+where SrcView: SingletonView + ?Sized
+{
+    type Msg = IndexArea<()>;
+}
+
+impl<SrcView> IndexView<()> for Singleton2Index<SrcView>
+where SrcView: SingletonView + ?Sized
+{
+    type Item = SrcView::Item;
+
+    fn area(&self) -> IndexArea<()> {
+        IndexArea::Full
+    }
+
+    fn get(&self, _msg: &()) -> Option<Self::Item> {
+        Some(self.src_view.as_ref().unwrap().get())
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<SrcView> Observer<SrcView> for Singleton2Index<SrcView>
+where SrcView: SingletonView + ?Sized
+{
+    fn reset(&mut self, view: Option<Arc<SrcView>>) {
+        self.src_view = view;
+        self.cast.notify(&IndexArea::Full);
+    }
+
+    fn notify(&mut self, _: &()) {
+        self.cast.notify(&IndexArea::Full);
+    }
+}
+

nested/src/string_editor.rs

@@ -0,0 +1,128 @@
+use {
+    std::sync::Arc,
+    std::sync::RwLock,
+    termion::event::{Key, Event},
+    crate::{
+        core::{ViewPort, OuterViewPort},
+        singleton::{SingletonView, SingletonBuffer},
+        sequence::{SequenceView},
+        terminal::{TerminalView, TerminalStyle, TerminalEvent, TerminalEditor, TerminalEditorResult},
+        list::{ListEditor, sexpr::ListDecoration},
+        tree_nav::{TreeNav, TreeNavResult, TreeCursor}
+    }
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct CharEditor {
+    data: SingletonBuffer<Option<char>>,
+    data_port: ViewPort<dyn SingletonView<Item = Option<char>>>
+}
+
+impl CharEditor {
+    pub fn new() -> Self {
+        let mut data_port = ViewPort::new();
+        CharEditor {
+            data: SingletonBuffer::new(None, data_port.inner()),
+            data_port
+        }
+    }
+
+    pub fn get_data_port(&self) -> OuterViewPort<dyn SingletonView<Item = Option<char>>> {
+        self.data_port.outer()
+    }
+}
+
+impl TreeNav for CharEditor {}
+impl TerminalEditor for CharEditor {
+    fn get_term_view(&self) -> OuterViewPort<dyn TerminalView> {
+        crate::terminal::make_label(
+            &if let Some(c) = self.data.get() {
+                c.to_string()
+            } else {
+                "".to_string()
+            })
+    }
+
+    fn handle_terminal_event(&mut self, event: &TerminalEvent) -> TerminalEditorResult {
+        match event {
+            TerminalEvent::Input(Event::Key(Key::Char('\n'))) =>
+                TerminalEditorResult::Continue,
+            TerminalEvent::Input(Event::Key(Key::Char(c))) => {
+                self.data.set(Some(*c));
+                TerminalEditorResult::Exit
+            }
+            TerminalEvent::Input(Event::Key(Key::Backspace)) |
+            TerminalEvent::Input(Event::Key(Key::Delete)) => {
+                self.data.set(None);
+                TerminalEditorResult::Exit
+            }
+            _ => TerminalEditorResult::Continue
+        }
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct StringEditor {
+    chars_editor: ListEditor< CharEditor,
+                              Box<dyn Fn() -> Arc<RwLock<CharEditor>> + Send + Sync + 'static> >
+}
+
+impl StringEditor {
+    pub fn new() -> Self {
+        StringEditor {
+            chars_editor: ListEditor::new(
+                Box::new(
+                    move || {
+                        Arc::new(RwLock::new(CharEditor::new()))
+                    }
+                ),
+                crate::list::ListEditorStyle::String
+            )
+        }
+    }
+
+    pub fn get_data_port(&self) -> OuterViewPort<dyn SequenceView<Item = char>> {
+        self.chars_editor.get_data_port()
+            .map(
+                |char_editor| char_editor.read().unwrap().data.get().unwrap()
+            )
+    }
+}
+
+impl TreeNav for StringEditor {
+    fn get_cursor(&self) -> TreeCursor { self.chars_editor.get_cursor() }
+    fn goto(&mut self, cur: TreeCursor) -> TreeNavResult  { self.chars_editor.goto(cur) }
+    fn goto_home(&mut self) -> TreeNavResult  { self.chars_editor.goto_home() }
+    fn goto_end(&mut self) -> TreeNavResult  { self.chars_editor.goto_end() }
+    fn pxev(&mut self) -> TreeNavResult  { self.chars_editor.pxev() }
+    fn nexd(&mut self) -> TreeNavResult  { self.chars_editor.nexd() }
+    fn up(&mut self) -> TreeNavResult { self.chars_editor.up() }
+    fn dn(&mut self) -> TreeNavResult { TreeNavResult::Exit }
+}
+
+impl TerminalEditor for StringEditor {
+    fn get_term_view(&self) -> OuterViewPort<dyn TerminalView> {
+        self.chars_editor
+            .get_seg_seq_view()
+            .decorate("\"", "\"", "", 1)
+            .to_grid_horizontal()
+            .flatten()
+            .map_item(
+                |_idx, atom|
+                atom.add_style_back(TerminalStyle::fg_color((120, 200, 10)))
+            )
+    }
+
+    fn handle_terminal_event(&mut self, event: &TerminalEvent) -> TerminalEditorResult {
+        match event {
+            TerminalEvent::Input(Event::Key(Key::Char('\n'))) => {
+                self.chars_editor.up();
+                TerminalEditorResult::Exit
+            }
+            event => self.chars_editor.handle_terminal_event(event)
+        }
+    }
+}
+

nested/src/terminal/atom.rs

@@ -1,12 +1,12 @@
 use {
     super::TerminalStyle,
-    serde::{Deserialize, Serialize},
+    serde::{Serialize, Deserialize}
 };
 
 #[derive(Clone, Copy, Serialize, Deserialize, Debug)]
 pub struct TerminalAtom {
     pub c: Option<char>,
-    pub style: TerminalStyle,
+    pub style: TerminalStyle
 }
 
 impl TerminalAtom {
@@ -15,10 +15,7 @@ impl TerminalAtom {
     }
 
     pub fn new_bg(bg_color: (u8, u8, u8)) -> Self {
-        TerminalAtom {
+        TerminalAtom { c: None, style: TerminalStyle::bg_color(bg_color) }
-            c: None,
-            style: TerminalStyle::bg_color(bg_color),
-        }
     }
 
     pub fn add_style_front(mut self, style: TerminalStyle) -> Self {
@@ -36,7 +33,7 @@ impl From<char> for TerminalAtom {
     fn from(c: char) -> Self {
         TerminalAtom {
             c: Some(c),
-            style: TerminalStyle::default(),
+            style: TerminalStyle::default()
         }
     }
 }
@@ -45,7 +42,7 @@ impl From<Option<char>> for TerminalAtom {
     fn from(c: Option<char>) -> Self {
         TerminalAtom {
             c,
-            style: TerminalStyle::default(),
+            style: TerminalStyle::default()
         }
     }
 }
@@ -54,7 +51,8 @@ impl From<&char> for TerminalAtom {
     fn from(c: &char) -> Self {
         TerminalAtom {
             c: Some(*c),
-            style: TerminalStyle::default(),
+            style: TerminalStyle::default()
         }
     }
 }
+

nested/src/terminal/compositor.rs

@@ -1,15 +1,15 @@
 use {
-    r3vi::{
+    std::{
-        view::{
+        sync::{Arc}
-            InnerViewPort, Observer, ObserverBroadcast, OuterViewPort, View,
-            index::*,
     },
-        projection::projection_helper::*,
-    },
-    crate::{terminal::{TerminalAtom, TerminalView}},
-    cgmath::Point2,
-    std::sync::Arc,
     std::sync::RwLock,
+    cgmath::Point2,
+    crate::{
+        core::{InnerViewPort, OuterViewPort, View, Observer, ObserverBroadcast},
+        index::{IndexArea, IndexView},
+        terminal::{TerminalAtom, TerminalView},
+        projection::ProjectionHelper
+    }
 };
 
 //<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
@@ -17,18 +17,22 @@ use {
 pub struct TerminalCompositor {
     layers: Vec<Arc<dyn TerminalView>>,
     cast: Arc<RwLock<ObserverBroadcast<dyn TerminalView>>>,
-    proj_helper: ProjectionHelper<usize, Self>,
+    proj_helper: ProjectionHelper<usize, Self>
 }
 
 //<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
 
 impl TerminalCompositor {
-    pub fn new(port: InnerViewPort<dyn TerminalView>) -> Arc<RwLock<Self>> {
+    pub fn new(
-        let comp = Arc::new(RwLock::new(TerminalCompositor {
+        port: InnerViewPort<dyn TerminalView>
+    ) -> Arc<RwLock<Self>> {
+        let comp = Arc::new(RwLock::new(
+            TerminalCompositor {
                 layers: Vec::new(),
                 cast: port.get_broadcast(),
-            proj_helper: ProjectionHelper::new(port.0.update_hooks.clone()),
+                proj_helper: ProjectionHelper::new(port.0.update_hooks.clone())
-        }));
+            }
+        ));
 
         comp.write().unwrap().proj_helper.set_proj(&comp);
         port.set_view(Some(comp.clone()));
@@ -39,10 +43,13 @@ impl TerminalCompositor {
     pub fn push(&mut self, v: OuterViewPort<dyn TerminalView>) {
         let idx = self.layers.len();
         self.layers.push(
-            self.proj_helper
+            self.proj_helper.new_index_arg(
-                .new_index_arg(idx, v, |s: &mut Self, area| {
+                idx,
+                v,
+                |s: &mut Self, area| {
                     s.cast.notify(area);
-                }),
+                }
+            )
         );
     }
 }
@@ -80,3 +87,4 @@ impl IndexView<Point2<i16>> for TerminalCompositor {
         area
     }
 }
+

nested/src/terminal/mod.rs

@@ -1,18 +1,21 @@
-pub mod ansi_parser;
-pub mod atom;
-pub mod compositor;
 pub mod style;
+pub mod atom;
 pub mod terminal;
-pub mod widgets;
+pub mod compositor;
+pub mod ansi_parser;
 
 pub use {
-    atom::TerminalAtom,
+    style::{TerminalStyle},
-    compositor::TerminalCompositor,
+    atom::{TerminalAtom},
-    style::TerminalStyle,
     terminal::{Terminal, TerminalEvent},
+    compositor::TerminalCompositor,
 };
 
-use r3vi::view::grid::*;
+use {
+    crate::{
+        grid::GridView
+    }
+};
 
 //<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
 
@@ -22,7 +25,7 @@ pub trait TerminalView = GridView<Item = TerminalAtom>;
 
 pub enum TerminalEditorResult {
     Continue,
-    Exit,
+    Exit
 }
 
 pub trait TerminalEditor {
@@ -33,48 +36,26 @@ pub trait TerminalEditor {
 //<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
 
 use {
-    r3vi::{
+    crate::{
-        view::{OuterViewPort},
+        vec::VecBuffer,
-        buffer::vec::*,
+        core::{ViewPort, OuterViewPort}
     },
-    cgmath::Point2,
+    cgmath::Point2
 };
 
 pub fn make_label(s: &str) -> OuterViewPort<dyn TerminalView> {
-    let label = VecBuffer::with_data(s.chars().collect());
+    let label_port = ViewPort::new();
+    let mut label = VecBuffer::with_data(s.chars().collect(), label_port.inner());
 
-    let v = label.get_port()
+    let v = label_port.outer()
         .to_sequence()
         .map(|c| TerminalAtom::from(c))
         .to_index()
         .map_key(
             |idx| Point2::new(*idx as i16, 0),
-            |pt| if pt.y == 0 { Some(pt.x as usize) } else { None },
+            |pt| if pt.y == 0 { Some(pt.x as usize) } else { None }
         );
 
     v
 }
 
-pub trait TerminalProjections {
-    fn with_style(&self, style: TerminalStyle) -> OuterViewPort<dyn TerminalView>;
-    fn with_fg_color(&self, col: (u8, u8, u8)) -> OuterViewPort<dyn TerminalView>;
-    fn with_bg_color(&self, col: (u8, u8, u8)) -> OuterViewPort<dyn TerminalView>;
-}
-
-impl TerminalProjections for OuterViewPort<dyn TerminalView> {
-    fn with_style(&self, style: TerminalStyle) -> OuterViewPort<dyn TerminalView> {
-        self.map_item(
-            move |_idx, a|
-            a.add_style_front(style)
-        )
-    }
-
-    fn with_fg_color(&self, col: (u8, u8, u8)) -> OuterViewPort<dyn TerminalView> {
-        self.with_style(TerminalStyle::fg_color(col))
-    }
-
-    fn with_bg_color(&self, col: (u8, u8, u8)) -> OuterViewPort<dyn TerminalView> {
-        self.with_style(TerminalStyle::bg_color(col))
-    }
-}
-

nested/src/terminal/style.rs

@@ -1,4 +1,4 @@
-use serde::{Deserialize, Serialize};
+use serde::{Serialize, Deserialize};
 
 #[derive(Default, Copy, Clone, PartialEq, Serialize, Deserialize, Debug)]
 pub struct TerminalStyle {
@@ -6,7 +6,7 @@ pub struct TerminalStyle {
     pub bg_color: Option<(u8, u8, u8)>,
     pub bold: Option<bool>,
     pub italic: Option<bool>,
-    pub underline: Option<bool>,
+    pub underline: Option<bool>
 }
 
 impl TerminalStyle {
@@ -85,3 +85,4 @@ impl std::fmt::Display for TerminalStyle {
         Ok(())
     }
 }
+

nested/src/terminal/terminal.rs

@@ -1,33 +1,44 @@
 use {
-    r3vi::{
+    std::{
-        view::{
+        sync::Arc,
-            channel::{queue_channel, set_channel, ChannelReceiver, ChannelSender},
+        io::{Write, stdout, stdin},
-            Observer, OuterViewPort,
+        collections::HashSet
-            grid::*,
+    },
-            index::*,
+    std::sync::RwLock,
-        }
+    async_std::{
+        stream::StreamExt,
+        task
     },
-    super::{TerminalStyle, TerminalView},
-    async_std::{stream::StreamExt, task},
-    cgmath::{Point2, Vector2},
     signal_hook,
     signal_hook_async_std::Signals,
-    std::sync::RwLock,
+    cgmath::{Vector2, Point2},
-    std::{
-        collections::HashSet,
-        io::{stdin, stdout, Write},
-        sync::Arc,
-    },
     termion::{
-        input::{MouseTerminal, TermRead},
         raw::IntoRawMode,
+        input::{TermRead, MouseTerminal}
+    },
+    crate::{
+        core::{
+            OuterViewPort,
+            Observer,
+            channel::{
+                ChannelReceiver,
+                ChannelSender,
+                queue_channel,
+                set_channel
+            }
+        },
+        index::{IndexArea},
+        grid::{GridWindowIterator}
+    },
+    super::{
+        TerminalStyle,
+        TerminalView
     },
 };
 
-#[derive(PartialEq, Eq, Clone)]
 pub enum TerminalEvent {
     Resize(Vector2<i16>),
-    Input(termion::event::Event),
+    Input(termion::event::Event)
 }
 
 pub struct Terminal {
@@ -35,22 +46,24 @@ pub struct Terminal {
     _observer: Arc<RwLock<TermOutObserver>>,
 
     events: ChannelReceiver<Vec<TerminalEvent>>,
-    _signal_handle: signal_hook_async_std::Handle,
+    _signal_handle: signal_hook_async_std::Handle
 }
 
 impl Terminal {
-    pub fn new(port: OuterViewPort<dyn TerminalView>) -> Self {
+    pub fn new(
+        port: OuterViewPort<dyn TerminalView>
+    ) -> Self {
         let (dirty_pos_tx, dirty_pos_rx) = set_channel();
 
         let writer = Arc::new(TermOutWriter {
             out: RwLock::new(MouseTerminal::from(stdout().into_raw_mode().unwrap())),
             dirty_pos_rx,
-            view: port.get_view_arc(),
+            view: port.get_view_arc()
         });
 
         let observer = Arc::new(RwLock::new(TermOutObserver {
             dirty_pos_tx,
-            writer: writer.clone(),
+            writer: writer.clone()
         }));
 
         port.add_observer(observer.clone());
@@ -69,7 +82,7 @@ impl Terminal {
         event_tx.send(TerminalEvent::Resize(Vector2::new(w as i16, h as i16)));
 
         // and again on SIGWINCH
-        let signals = Signals::new(&[signal_hook::consts::signal::SIGWINCH]).unwrap();
+        let signals = Signals::new(&[ signal_hook::consts::signal::SIGWINCH ]).unwrap();
         let handle = signals.handle();
 
         task::spawn(async move {
@@ -77,9 +90,9 @@ impl Terminal {
             while let Some(signal) = signals.next().await {
                 match signal {
                     signal_hook::consts::signal::SIGWINCH => {
-                        let (w, h) = termion::terminal_size().unwrap();
+                        let (w,h) = termion::terminal_size().unwrap();
                         event_tx.send(TerminalEvent::Resize(Vector2::new(w as i16, h as i16)));
-                    }
+                    },
                     _ => unreachable!(),
                 }
             }
@@ -89,7 +102,7 @@ impl Terminal {
             writer,
             _observer: observer,
             events: event_rx,
-            _signal_handle: handle,
+            _signal_handle: handle
         }
     }
 
@@ -104,18 +117,16 @@ impl Terminal {
 
 struct TermOutObserver {
     dirty_pos_tx: ChannelSender<HashSet<Point2<i16>>>,
-    writer: Arc<TermOutWriter>,
+    writer: Arc<TermOutWriter>
 }
 
 impl TermOutObserver {
     fn send_area(&mut self, area: IndexArea<Point2<i16>>) {
         match area {
-            IndexArea::Empty => {}
+            IndexArea::Empty => {},
             IndexArea::Full => {
                 let (w, h) = termion::terminal_size().unwrap();
-                for pos in
+                for pos in GridWindowIterator::from(Point2::new(0, 0) .. Point2::new(w as i16, h as i16)) {
-                    GridWindowIterator::from(Point2::new(0, 0)..Point2::new(w as i16, h as i16))
-                {
                     self.dirty_pos_tx.send(pos);
                 }
             }
@@ -149,7 +160,7 @@ impl Observer<dyn TerminalView> for TermOutObserver {
 pub struct TermOutWriter {
     out: RwLock<MouseTerminal<termion::raw::RawTerminal<std::io::Stdout>>>,
     dirty_pos_rx: ChannelReceiver<HashSet<Point2<i16>>>,
-    view: Arc<RwLock<Option<Arc<dyn TerminalView>>>>,
+    view: Arc<RwLock<Option<Arc<dyn TerminalView>>>>
 }
 
 impl TermOutWriter {
@@ -162,27 +173,22 @@ impl TermOutWriter {
 impl TermOutWriter {
     pub async fn show(&self) -> std::io::Result<()> {
         // init
-        write!(
+        write!(self.out.write().unwrap(), "{}{}{}",
-            self.out.write().unwrap(),
-            "{}{}{}",
                termion::cursor::Hide,
                termion::cursor::Goto(1, 1),
-            termion::style::Reset
+               termion::style::Reset)?;
-        )?;
 
         let mut cur_pos = Point2::<i16>::new(0, 0);
         let mut cur_style = TerminalStyle::default();
 
         // draw atoms until view port is destroyed
         while let Some(dirty_pos) = self.dirty_pos_rx.recv().await {
-            let (w, _h) = termion::terminal_size().unwrap();
+            let (w, h) = termion::terminal_size().unwrap();
 
             if let Some(view) = self.view.read().unwrap().as_ref() {
                 let mut out = self.out.write().unwrap();
 
-                let d = dirty_pos
+                let d = dirty_pos.into_iter().filter(|p| p.x >= 0 && p.y >= 0 && p.x < w as i16 && p.y < w as i16);//.collect::<Vec<_>>();
-                    .into_iter()
-                    .filter(|p| p.x >= 0 && p.y >= 0 && p.x < w as i16 && p.y < w as i16); //.collect::<Vec<_>>();
                 /*
                 d.sort_by(|a,b| {
                     if a.y < b.y {
@@ -193,20 +199,15 @@ impl TermOutWriter {
                         std::cmp::Ordering::Greater
                     }
                 });
-                                                                                           */
+*/
                 for pos in d {
                     if pos != cur_pos {
-                        write!(
+                        write!(out, "{}", termion::cursor::Goto(pos.x as u16 + 1, pos.y as u16 + 1))?;
-                            out,
-                            "{}",
-                            termion::cursor::Goto(pos.x as u16 + 1, pos.y as u16 + 1)
-                        )?;
                     }
 
                     if let Some(atom) = view.get(&pos) {
                         if cur_style != atom.style {
                             cur_style = atom.style;
-                            write!(out, "{}", termion::style::Reset)?;
                             write!(out, "{}", atom.style)?;
                         }
 
@@ -231,3 +232,4 @@ impl TermOutWriter {
         std::io::Result::Ok(())
     }
 }
+

nested/src/terminal/widgets/mod.rs

@@ -1,3 +0,0 @@
-
-pub mod ascii_box;
-

nested/src/terminal/widgets/plot.rs

@@ -1,94 +0,0 @@
-use {
-    cgmath::Point2,
-    nested::{
-        core::{InnerViewPort, Observer, ObserverBroadcast, OuterViewPort, View},
-        sequence::{SequenceView},
-        index::{IndexArea, IndexView},
-        projection::ProjectionHelper,
-        terminal::{TerminalAtom, TerminalView},
-    },
-    std::sync::{Arc, RwLock},
-};
-
-pub struct Plot {
-    limit: usize,
-    data: Arc<dyn SequenceView<Item = usize>>,
-    cast: Arc<RwLock<ObserverBroadcast<dyn TerminalView>>>,
-    proj_helper: ProjectionHelper<(), Self>,
-}
-
-impl View for Plot {
-    type Msg = IndexArea<Point2<i16>>;
-}
-
-impl IndexView<Point2<i16>> for Plot {
-    type Item = TerminalAtom;
-
-    fn get(&self, pt: &Point2<i16>) -> Option<TerminalAtom> {
-        if pt.y >= 0 {
-            if let Some(cur_val) = self.data.get(&(pt.x as usize)) {
-                if cur_val <= self.limit {
-                    if pt.y == (self.limit - cur_val) as i16 {
-                        return Some(TerminalAtom::from(if cur_val < 4 {
-                            'o'
-                        } else if cur_val < 8 {
-                            'O'
-                        } else {
-                            '*'
-                        }));
-                    }
-                }
-                if pt.x > 0 {
-                    if let Some(prev_val) = self.data.get(&((pt.x - 1) as usize)) {
-                        if (pt.y > (self.limit - prev_val) as i16
-                            && pt.y < (self.limit - cur_val) as i16)
-                            || (pt.y < (self.limit - prev_val) as i16
-                                && pt.y > (self.limit - cur_val) as i16)
-                        {
-                            return Some(TerminalAtom::from('.'));
-                        }
-                    }
-                }
-            }
-        }
-        None
-    }
-
-    fn area(&self) -> IndexArea<Point2<i16>> {
-        IndexArea::Range(
-            Point2::new(0, 0)..=Point2::new(self.data.len().unwrap_or(0) as i16, self.limit as i16),
-        )
-    }
-}
-
-impl Plot {
-    pub fn new(
-        data_port: OuterViewPort<dyn SequenceView<Item = usize>>,
-        out_port: InnerViewPort<dyn TerminalView>,
-    ) -> Arc<RwLock<Self>> {
-        let mut proj_helper = ProjectionHelper::new(out_port.0.update_hooks.clone());
-        let proj = Arc::new(RwLock::new(Plot {
-            data: proj_helper.new_sequence_arg((), data_port, |s: &mut Self, idx| {
-                let val = s.data.get(idx).unwrap_or(0);
-
-                if val > s.limit {
-                    s.limit = val;
-                    s.cast.notify(&s.area());
-                } else {
-                    s.cast.notify(&IndexArea::Range(
-                        Point2::new(*idx as i16, 0)..=Point2::new(*idx as i16, s.limit as i16),
-                    ));
-                }
-            }),
-
-            limit: 0,
-            cast: out_port.get_broadcast(),
-            proj_helper,
-        }));
-
-        proj.write().unwrap().proj_helper.set_proj(&proj);
-        out_port.set_view(Some(proj.clone()));
-
-        proj
-    }
-}

nested/src/tree/addr.rs

@@ -1,9 +0,0 @@
-
-pub struct TreeAddr(pub Vec<usize>);
-
-impl From<Vec<usize>> for TreeAddr {
-    fn from(v: Vec<usize>) -> TreeAddr {
-        TreeAddr(v)
-    }
-}
-

nested/src/tree/cursor.rs

@@ -1,45 +0,0 @@
-use {
-    crate::editors::list::ListCursorMode
-};
-
-//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
-
-#[derive(Clone, Eq, PartialEq, Debug)]
-pub struct TreeCursor {
-    pub leaf_mode: ListCursorMode,
-    pub tree_addr: Vec<isize>
-}
-
-impl TreeCursor {
-    pub fn home() -> Self {
-        TreeCursor {
-            leaf_mode: ListCursorMode::Insert,
-            tree_addr: vec![0],
-        }
-    }
-
-    pub fn none() -> Self {
-        TreeCursor {
-            leaf_mode: ListCursorMode::Select,
-            tree_addr: vec![],
-        }
-    }
-
-    pub fn get_subcursor(&self, depth: usize) -> TreeCursor {
-        TreeCursor {
-            leaf_mode: self.leaf_mode,
-            tree_addr: if depth < self.tree_addr.len() {
-                self.tree_addr[ depth.. ].iter().cloned().collect()
-            } else {
-                vec![]
-            }
-        }
-    }
-}
-
-impl Default for TreeCursor {
-    fn default() -> Self {
-        TreeCursor::none()
-    }
-}
-

nested/src/tree/mod.rs

@@ -1,14 +0,0 @@
-pub mod addr;
-pub mod cursor;
-pub mod nav;
-pub mod node;
-pub mod treetype;
-
-pub use {
-    addr::TreeAddr,
-    cursor::TreeCursor,
-    nav::{TreeNav, TreeNavResult, TreeHeightOp},
-    treetype::{TreeType},
-    node::NestedNode
-};
-

nested/src/tree/nav.rs

@@ -1,184 +0,0 @@
-use {
-    r3vi::{
-        view::{
-            OuterViewPort,
-            singleton::*,
-            sequence::*,
-        },
-        buffer::{
-            singleton::SingletonBuffer,
-            vec::VecBuffer
-        },
-        projection::{
-            decorate_sequence::*,
-        }
-    },
-    crate::{
-        editors::list::ListCursorMode,
-        tree::TreeCursor,
-        terminal::{TerminalView, TerminalProjections, make_label}
-    },
-    cgmath::Vector2,
-};
-
-#[derive(Clone, Copy, Eq, PartialEq, Debug)]
-pub enum TreeNavResult { Continue, Exit }
-
-#[derive(Clone, Copy, Eq, PartialEq, Debug)]
-pub enum TreeHeightOp { P, Q, Max }
-
-pub trait TreeNav {
-    /* CORE
-    */
-    fn get_cursor(&self) -> TreeCursor {
-        TreeCursor::default()
-    }
-
-    fn get_addr_view(&self) -> OuterViewPort<dyn SequenceView<Item = isize>> {
-        VecBuffer::<isize>::new().get_port().to_sequence()
-    }
-
-    fn get_mode_view(&self) -> OuterViewPort<dyn SingletonView<Item = ListCursorMode>> {
-        SingletonBuffer::new(ListCursorMode::Select).get_port()
-    }
-
-    fn get_cursor_warp(&self) -> TreeCursor {
-        TreeCursor::default()
-    }
-
-    fn get_height(&self, _op: &TreeHeightOp) -> usize {
-        0
-    }
-
-    fn goby(&mut self, _direction: Vector2<isize>) -> TreeNavResult {
-        TreeNavResult::Exit
-    }
-
-    fn goto(&mut self, _new_cursor: TreeCursor) -> TreeNavResult {
-        TreeNavResult::Exit
-    }
-
-    /* HULL
-    */
-    fn set_addr(&mut self, addr: isize) -> TreeNavResult {
-        let mut c = self.get_cursor();
-        c.tree_addr[0] = addr;
-        self.goto(c)
-    }
-
-    fn set_leaf_mode(&mut self, new_leaf_mode: ListCursorMode) -> TreeNavResult {
-        let mut c = self.get_cursor();
-        c.leaf_mode = new_leaf_mode;
-        self.goto(c)
-    }
-
-    fn get_leaf_mode(&mut self) -> ListCursorMode {
-        self.get_cursor().leaf_mode
-    }
-
-    fn toggle_leaf_mode(&mut self) -> TreeNavResult {
-        let old_mode = self.get_leaf_mode();
-        self.set_leaf_mode(
-            match old_mode {
-                ListCursorMode::Insert => ListCursorMode::Select,
-                ListCursorMode::Select => ListCursorMode::Insert
-            }
-        );
-        TreeNavResult::Continue
-    }
-
-    fn up(&mut self) -> TreeNavResult {
-        self.goby(Vector2::new(0, -1))
-    }
-
-    fn dn(&mut self) -> TreeNavResult {
-        self.goby(Vector2::new(0, 1))
-    }
-
-    fn pxev(&mut self) -> TreeNavResult {
-        self.goby(Vector2::new(-1, 0))
-    }
-
-    fn nexd(&mut self) -> TreeNavResult {
-        self.goby(Vector2::new(1, 0))
-    }
-
-    // TODO
-    fn qpxev(&mut self) -> TreeNavResult {
-        let mut c = self.get_cursor();
-        match c.tree_addr.len() {
-            0 => {
-                self.goto(TreeCursor::home())
-            },
-            depth => {
-                if c.tree_addr[depth-1] != 0 {
-                    c.tree_addr[depth-1] = 0;
-                } else {
-                    self.pxev();
-                    c = self.get_cursor();
-                    let d = c.tree_addr.len();
-                    if d > 0 {
-                        c.tree_addr[d-1] = 0;
-                    }
-                }
-
-                self.goto(c)
-            }
-        }
-    }
-
-    fn qnexd(&mut self) -> TreeNavResult {
-        let mut c = self.get_cursor_warp();
-        match c.tree_addr.len() {
-            0 => {
-                TreeNavResult::Exit
-            },
-            depth => {
-                if c.tree_addr[depth-1] != -1 {
-                    c.tree_addr[depth-1] = -1;
-                } else {
-                    self.nexd();
-                    c = self.get_cursor();
-                    let d = c.tree_addr.len();
-                    if d > 0 {
-                        c.tree_addr[d-1] = -1;
-                    }
-                }
-
-                self.goto(c)
-            }
-        }
-    }
-
-    fn get_cursor_widget(&self) -> OuterViewPort<dyn TerminalView> {
-        VecBuffer::with_data(
-            vec![
-                make_label("@").with_fg_color((150, 80,230)),
-                self.get_addr_view()
-                    .map(|i|
-                        make_label(&format!("{}", i)).with_fg_color((0, 100, 20)))
-                    .separate(make_label(".").with_fg_color((150, 80,230)))
-                    .to_grid_horizontal()
-                    .flatten(),
-                make_label(":").with_fg_color((150, 80,230)),
-                self.get_mode_view()
-                    .map(|mode| {
-                        make_label(
-                            match mode {
-                                ListCursorMode::Insert => "INSERT",
-                                ListCursorMode::Select => "SELECT"
-                            })
-                            .with_fg_color((200, 200, 20))
-                    })
-                    .to_grid()
-                    .flatten(),
-                make_label(":").with_fg_color((150, 80,230))
-            ]
-        ).get_port()
-            .to_sequence()
-            .to_grid_horizontal()
-            .flatten()
-    }
-}
-
-

nested/src/tree/node.rs

@@ -1,343 +0,0 @@
-use {
-    std::{sync::{Arc, RwLock}, any::Any},
-    cgmath::{Vector2, Point2},
-    r3vi::{
-        view::{View, ViewPort, OuterViewPort, AnyOuterViewPort, singleton::*, sequence::*},
-        buffer::{singleton::*}
-    },
-    laddertypes::{TypeTerm},
-    crate::{
-        type_system::{ReprTree, Context},
-        terminal::{TerminalView, TerminalEvent, TerminalEditor, TerminalEditorResult, TerminalAtom},
-        diagnostics::{Diagnostics, Message},
-        tree::{TreeNav, TreeCursor, TreeNavResult, TreeHeightOp},
-        editors::list::{ListCursorMode},
-        commander::ObjCommander,
-    }
-};
-
-/* TODO: refactoring proposal
-
-struct NestedNodeDisplay {
-    /// display view
-    pub view: Option< OuterViewPort<dyn TerminalView> >,
-
-    /// diagnostics
-    pub diag: Option< OuterViewPort<dyn SequenceView<Item = Message>> >,
-
-    /// depth
-    pub depth: SingletonBuffer< usize >,    
-}
-
-struct NestedNodeEdit {
-    /// abstract editor
-    pub editor: SingletonBuffer<
-                    Option< Arc<dyn Any + Send + Sync> >
-    >,
-
-    pub spillbuf: VecBuffer< NestedNode >,
-
-    /// commander & navigation
-    pub cmd: SingletonBuffer<
-                 Option< Arc<RwLock<dyn ObjCommander + Send + Sync>> >
-             >,
-    pub close_char: SingletonBuffer< Option< char > >,
-
-    // could be replaced by cmd when TreeNav -CmdObjects are used
-    pub tree_nav: SingletonBuffer<
-                      Option< Arc<RwLock<dyn TreeNav + Send + Sync>> >
-                  >,    
-}
-
-pub struct NewNestedNode {
-    /// context
-    pub ctx: Arc<RwLock<Context>>,
-
-    /// abstract data view
-    pub data: Arc<RwLock<ReprTree>>,
-
-    /// viewports for terminal display
-    pub disp: NestedNodeDisplay,
-
-    /// editor & commander objects
-    pub edit: NestedNodeEdit
-}
-
-*/
-
-#[derive(Clone)]
-pub struct NestedNode {    
-    /// context
-    pub ctx: Arc<RwLock<Context>>,
-
-    /// abstract data view
-    pub data: Arc<RwLock<ReprTree>>,
-
-    /// display view
-    pub view: Option< OuterViewPort<dyn TerminalView> >,
-
-    /// diagnostics
-    pub diag: Option< OuterViewPort<dyn SequenceView<Item = Message>> >,
-
-    /// depth
-    pub depth: OuterViewPort< dyn SingletonView<Item = usize> >,
-
-    /// abstract editor
-    pub editor: SingletonBuffer<
-                    Option< Arc<dyn Any + Send + Sync> >
-                >,
-
-    pub spillbuf: Arc<RwLock<Vec<Arc<RwLock<NestedNode>>>>>,
-
-    /// commander & navigation
-    pub cmd: SingletonBuffer<
-                 Option< Arc<RwLock<dyn ObjCommander + Send + Sync>> >
-             >,
-    pub close_char: SingletonBuffer<
-                        Option< char >
-                    >,
-    pub tree_nav: SingletonBuffer<
-                      Option< Arc<RwLock<dyn TreeNav + Send + Sync>> >
-                  >,
-}
-
-impl NestedNode {
-    pub fn new(ctx: Arc<RwLock<Context>>, data: Arc<RwLock<ReprTree>>, depth: OuterViewPort<dyn SingletonView<Item = usize>>) -> Self {
-        NestedNode {
-            ctx,
-            data,
-            view: None,
-            diag: None,
-            depth,
-            editor: SingletonBuffer::new(None),
-            spillbuf: Arc::new(RwLock::new(Vec::new())),
-            cmd: SingletonBuffer::new(None),
-            close_char: SingletonBuffer::new(None),
-            tree_nav: SingletonBuffer::new(None)
-        }
-    }
-
-    /* TODO: move into separate file/module
-    */
-    pub fn from_char(ctx: Arc<RwLock<Context>>, c: char) -> NestedNode {
-        let buf = r3vi::buffer::singleton::SingletonBuffer::<char>::new(c);
-
-        NestedNode::new(
-            ctx.clone(),
-            ReprTree::new_leaf(
-                Context::parse(&ctx, "Char"),
-                buf.get_port().into()
-            ),
-            SingletonBuffer::new(0).get_port()
-        )
-            .set_view(buf.get_port()
-                      .map(|c| TerminalAtom::from(c))
-                      .to_index()
-                      .map_key(
-                          |_x| {
-                              Point2::new(0, 0)
-                          },
-                          |p| {
-                              if *p == Point2::new(0,0) { Some(()) } else { None }
-                          })
-            )
-            .set_editor(Arc::new(RwLock::new(buf)))
-    }
-
-    
-    //\\//\\
-
-    pub fn morph(self, ty: TypeTerm) -> NestedNode {
-        Context::morph_node(self, ty)
-    }
-
-    pub fn get_type(&self) -> TypeTerm {
-        self.data.read().unwrap().get_type().clone()
-    }
-
-    //\\//\\
-    
-    pub fn set_editor(mut self, editor: Arc<dyn Any + Send + Sync>) -> Self {
-        self.editor.set(Some(editor));
-        self
-    }
-
-    pub fn set_view(mut self, view: OuterViewPort<dyn TerminalView>) -> Self {
-        self.view = Some(view);
-        self
-    }
-
-    pub fn set_cmd(mut self, cmd: Arc<RwLock<dyn ObjCommander + Send + Sync>>) -> Self {
-        self.cmd.set(Some(cmd));
-        self
-    }
-
-    pub fn set_nav(mut self, nav: Arc<RwLock<dyn TreeNav + Send + Sync>>) -> Self {
-        self.tree_nav.set(Some(nav));
-        self
-    }
-
-    pub fn set_diag(mut self, diag: OuterViewPort<dyn SequenceView<Item = Message>>) -> Self {
-        self.diag = Some(diag);
-        self
-    }
-
-    //\\//\\
-
-    pub fn get_diag(&self) -> OuterViewPort<dyn SequenceView<Item = Message>> {
-        self.diag.clone().unwrap_or(ViewPort::new().into_outer())
-    }
-
-    pub fn get_view(&self) -> OuterViewPort<dyn TerminalView> {
-        self.view.clone().unwrap_or(ViewPort::new().into_outer())
-    }
-    
-    pub fn get_data_port<'a, V: View + ?Sized + 'static>(&'a self, type_str: impl Iterator<Item = &'a str>) -> Option<OuterViewPort<V>>
-    where V::Msg: Clone {
-        let ctx = self.ctx.clone();
-        let type_ladder = type_str.map(|s| Context::parse(&ctx, s));
-
-        let repr_tree = ReprTree::descend_ladder(&self.data, type_ladder)?;
-        repr_tree.clone().read().unwrap()
-            .get_port::<V>().clone()
-    }
-
-    pub fn get_data_view<'a, V: View + ?Sized + 'static>(&'a self, type_str: impl Iterator<Item = &'a str>) -> Option<Arc<V>>
-    where V::Msg: Clone {
-        self.get_data_port::<V>(type_str)?.get_view()
-    }
-
-    /* TODO
-    pub fn get_seq_view<'a, T: Clone>(&self, type_str: impl Iterator<Item = &'a str>) -> Option<OuterViewPort<dyn SingletonView<Item = T>>> {
-        self.get_data_view::<dyn SequenceView<Item = NestedNode>>(type_str)
-            .unwrap()
-            .map({
-                move |node| {
-                    node.get_data_view::<dyn SingletonView<Item = T>>().get()
-                }
-            })
-    }
-     */
-    
-    pub fn get_edit<T: Send + Sync + 'static>(&self) -> Option<Arc<RwLock<T>>> {
-        if let Some(edit) = self.editor.get() {
-            if let Ok(edit) = edit.downcast::<RwLock<T>>() {
-                Some(edit)
-            } else {
-                None
-            }
-        } else {
-            None
-        }
-    }
-}
-
-/*
-impl TreeType for NestedNode {
-    fn get_type(&self, addr: &TreeAddr) -> TypeLadder {
-        if let Some(editor) = self.editor {
-            editor.read().unwrap().get_type(addr)
-        } else {
-            vec![]
-        }
-    }
-}
- */
-
-/* TODO: remove that at some point
-*/
-impl TerminalEditor for NestedNode {
-    fn get_term_view(&self) -> OuterViewPort<dyn TerminalView> {
-        self.get_view()
-    }
-
-    fn handle_terminal_event(&mut self, event: &TerminalEvent) -> TerminalEditorResult {
-        let buf = SingletonBuffer::new(event.clone());
-
-        if let Some(cmd) = self.cmd.get() {
-            cmd.write().unwrap().send_cmd_obj(
-                ReprTree::new_leaf(
-                    self.ctx.read().unwrap().type_term_from_str("TerminalEvent").unwrap(),
-                    AnyOuterViewPort::from(buf.get_port())
-                ));
-        }
-
-        TerminalEditorResult::Continue
-    }
-}
-
-impl TreeNav for NestedNode {
-    fn get_cursor(&self) -> TreeCursor {
-        if let Some(tn) = self.tree_nav.get() {
-            tn.read().unwrap().get_cursor()
-        } else {
-            TreeCursor::default()
-        }
-    }
-
-    fn get_addr_view(&self) -> OuterViewPort<dyn SequenceView<Item = isize>> {
-        if let Some(tn) = self.tree_nav.get() {
-            tn.read().unwrap().get_addr_view()
-        } else {
-            OuterViewPort::default()
-        }
-    }
-
-    fn get_mode_view(&self) -> OuterViewPort<dyn SingletonView<Item = ListCursorMode>> {
-        if let Some(tn) = self.tree_nav.get() {
-            tn.read().unwrap().get_mode_view()
-        } else {
-            OuterViewPort::default()
-        }        
-    }
-
-    fn get_cursor_warp(&self) -> TreeCursor {
-        if let Some(tn) = self.tree_nav.get() {
-            tn.read().unwrap().get_cursor_warp()
-        } else {
-            TreeCursor::default()
-        }
-    }
-
-    fn get_height(&self, op: &TreeHeightOp) -> usize {
-        if let Some(tn) = self.tree_nav.get() {
-            tn.read().unwrap().get_height( op )
-        } else {
-            0
-        }
-    }
-
-    fn goby(&mut self, direction: Vector2<isize>) -> TreeNavResult {
-        if let Some(tn) = self.tree_nav.get() {
-            tn.write().unwrap().goby(direction)
-        } else {
-            TreeNavResult::Exit
-        }
-    }
-
-    fn goto(&mut self, new_cursor: TreeCursor) -> TreeNavResult {
-        if let Some(tn) = self.tree_nav.get() {
-            tn.write().unwrap().goto(new_cursor)
-        } else {
-            TreeNavResult::Exit
-        }
-    }
-}
-
-impl ObjCommander for NestedNode {
-    fn send_cmd_obj(&mut self, cmd_obj: Arc<RwLock<ReprTree>>) -> TreeNavResult {
-        if let Some(cmd) = self.cmd.get() {
-            // todo: filter out tree-nav cmds and send them to tree_nav
-            cmd.write().unwrap().send_cmd_obj(cmd_obj)
-        } else {
-            TreeNavResult::Exit
-        }
-    }
-}
-
-impl Diagnostics for NestedNode {
-    fn get_msg_port(&self) -> OuterViewPort<dyn SequenceView<Item = Message>> {
-        self.get_diag()
-    }
-}
-

nested/src/tree/treetype.rs

@@ -1,14 +0,0 @@
-
-use {
-    laddertypes::{TypeTerm, TypeID},
-    crate::{
-        tree::{TreeAddr}
-    }
-};
-
-pub trait TreeType {
-    fn get_type(&self, addr: &TreeAddr) -> Vec<TypeTerm> {
-        vec![]
-    }
-}
-

nested/src/tree_nav.rs

@@ -0,0 +1,71 @@
+
+use crate::list::ListCursorMode;
+
+#[derive(Clone, Copy, Eq, PartialEq)]
+pub enum TreeNavResult {
+    Continue,
+    Exit
+}
+/*
+impl From<TreeNavResult> for TerminalEditorResult {
+    fn from(v: TreeNavResult) -> TerminalEditorResult {
+        match v {
+            TreeNavResult::Continue => TerminalEditorResult::Continue,
+            TreeNavResult::Exit => TerminalEditorResult::Exit
+        }
+    }
+}
+*/
+#[derive(Clone, Eq, PartialEq)]
+pub struct TreeCursor {
+    pub leaf_mode: ListCursorMode,
+    pub tree_addr: Vec<usize>
+}
+
+impl Default for TreeCursor {
+    fn default() -> Self {
+        TreeCursor {
+            leaf_mode: ListCursorMode::Select,
+            tree_addr: vec![]
+        }
+    }
+}
+
+pub trait TreeNav {
+    fn up(&mut self) -> TreeNavResult {
+        TreeNavResult::Exit
+    }
+
+    fn dn(&mut self) -> TreeNavResult {
+        TreeNavResult::Exit
+    }
+
+    fn pxev(&mut self) -> TreeNavResult {
+        TreeNavResult::Exit
+    }
+
+    fn nexd(&mut self) -> TreeNavResult {
+        TreeNavResult::Exit
+    }
+
+    fn goto_home(&mut self) -> TreeNavResult {
+        TreeNavResult::Exit        
+    }
+
+    fn goto_end(&mut self) -> TreeNavResult {
+        TreeNavResult::Exit        
+    }
+
+    fn goto(&mut self, new_cursor: TreeCursor)  -> TreeNavResult {
+        TreeNavResult::Exit
+    }
+
+    fn get_cursor(&self) -> TreeCursor {
+        TreeCursor::default()
+    }
+}
+
+use crate::terminal::{TerminalView, TerminalEditor};
+
+pub trait TerminalTreeEditor = TerminalEditor + TreeNav;
+

nested/src/type_system/context.rs

@@ -1,433 +0,0 @@
-use {
-    r3vi::{view::{OuterViewPort, singleton::*}, buffer::{singleton::*}},
-    laddertypes::{TypeDict, TypeTerm, TypeID},
-    crate::{
-        type_system::{ReprTree},
-        tree::NestedNode
-    },
-    std::{
-        collections::HashMap,
-        sync::{Arc, RwLock},
-    }
-};
-
-//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
-
-#[derive(Clone, Copy, Hash, PartialEq, Eq)]
-pub enum MorphismMode {
-    /// Isomorphism
-    /// e.g. `( PositionalInteger 10 BigEndian ) <~> ( PositionalInteger 16 LittleEndian )`
-    Iso,
-
-    /// Monomorphism, i.e. injective functions,
-    /// upcast-view, downcast-control, semantic gain
-    /// e.g. `( Sequence ( Digit 16 ) ) ~> ( PositionalInteger 16 LittleEndian )`
-    Mono,
-
-    /// Epimorphsim, i.e. surjective functions,
-    /// upcast-control, downcast-view, possible loss of entropy
-    /// e.g. `( Ascii ) ~> ( Digit 16 )`
-    Epi,
-
-    /// Any other function
-    Any,
-}
-
-#[derive(Clone, Hash, PartialEq, Eq, Debug)]
-pub struct MorphismType {
-//    pub mode: MorphismMode,
-    pub src_type: Option<TypeTerm>,
-    pub dst_type: TypeTerm,
-}
-
-#[derive(Clone, Hash, Eq, PartialEq)]
-pub struct MorphismTypePattern {
-    pub src_tyid: Option<TypeID>,
-    pub dst_tyid: TypeID
-}
-
-impl MorphismType {
-    pub fn to_str(&self, ctx: &Context) -> String {
-        format!("{:?} -> {:?}",
-                if let Some(t) = self.src_type.as_ref() {
-                    ctx.type_term_to_str(t)
-                } else {
-                    "None".into()
-                },
-                ctx.type_term_to_str(&self.dst_type))
-    }
-}
-
-impl MorphismTypePattern {
-    pub fn to_str(&self, ctx: &Context) -> String {
-        format!("{:?} -> {:?}",
-                if let Some(t) = self.src_tyid.as_ref() {
-                    ctx.type_term_to_str(&TypeTerm::TypeID(t.clone()))
-                } else {
-                    "None".into()
-                },
-                ctx.type_term_to_str(&TypeTerm::TypeID(self.dst_tyid.clone())))
-    }
-}
-
-impl From<MorphismType> for MorphismTypePattern {    
-    fn from(value: MorphismType) -> MorphismTypePattern {
-        fn strip( x: &TypeTerm ) -> TypeID {
-            match x {
-                TypeTerm::TypeID(id) => id.clone(),
-                TypeTerm::App(args) => strip(&args[0]),
-                TypeTerm::Ladder(args) => strip(&args[0]),
-                    _ => unreachable!()
-            }
-        }
-
-        MorphismTypePattern {
-            src_tyid: value.src_type.map(|x| strip(&x)),
-            dst_tyid: strip(&value.dst_type)
-        }
-    }
-}
-
-//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
-
-#[derive(Clone)]
-pub struct Context {
-    /// assigns a name to every type
-    pub type_dict: Arc<RwLock<TypeDict>>,
-
-    /// named vertices of the graph
-    nodes: HashMap< String, NestedNode >,
-
-    /// todo: beautify
-    /// types that can be edited as lists
-    pub list_types: Vec< TypeID >,
-    pub meta_chars: Vec< char >,
-
-    /// graph constructors
-    /// TODO: move into separate struct MorphismMap or something
-    morphisms: HashMap<
-                   MorphismTypePattern,
-                   Arc<
-                           dyn Fn( NestedNode, TypeTerm ) -> Option<NestedNode>
-                           + Send + Sync
-                   >
-               >,
-
-    /// recursion
-    parent: Option<Arc<RwLock<Context>>>,
-}
-
-impl Default for Context {
-    fn default() -> Context {
-        let mut ctx = Context::new();
-
-        ctx.add_list_typename("Sequence");
-        ctx.add_synonym("Seq", "Sequence");
-        ctx.add_list_typename("SepSeq");
-        ctx.add_typename("NestedNode");
-        ctx.add_typename("TerminalEvent");
-        
-        crate::editors::list::init_ctx( &mut ctx );
-        crate::editors::char::init_ctx( &mut ctx );
-        crate::editors::integer::init_ctx( &mut ctx );
-        crate::editors::typeterm::init_ctx( &mut ctx );
-
-        ctx
-    }
-}
-
-impl Context {
-    pub fn with_parent(parent: Option<Arc<RwLock<Context>>>) -> Self {
-        Context {
-            type_dict: match parent.as_ref() {
-                Some(p) => p.read().unwrap().type_dict.clone(),
-                None => Arc::new(RwLock::new(TypeDict::new()))
-            },
-            morphisms: HashMap::new(),
-            nodes: HashMap::new(),
-            list_types: match parent.as_ref() {
-                Some(p) => p.read().unwrap().list_types.clone(),
-                None => Vec::new()
-            },
-            meta_chars: match parent.as_ref() {
-                Some(p) => p.read().unwrap().meta_chars.clone(),
-                None => Vec::new()
-            },
-            parent,
-        }
-    }
-
-    pub fn new() -> Self {
-        Context::with_parent(None)
-    }
-
-    pub fn depth(&self) -> usize {
-        if let Some(parent) = self.parent.as_ref() {
-            parent.read().unwrap().depth() + 1
-        } else {
-            0
-        }
-    }
-
-    pub fn parse(ctx: &Arc<RwLock<Self>>, s: &str) -> TypeTerm {
-        ctx.read().unwrap().type_term_from_str(s).expect("could not parse type term")
-    }
-
-    pub fn add_typename(&mut self, tn: &str) -> TypeID {
-        self.type_dict.write().unwrap().add_typename(tn.to_string())
-    }
-
-    pub fn add_varname(&mut self, vn: &str) -> TypeID {
-        self.type_dict.write().unwrap().add_varname(vn.to_string())
-    }
-
-    pub fn add_synonym(&mut self, new: &str, old: &str) {
-        self.type_dict.write().unwrap().add_synonym(new.to_string(), old.to_string());
-    }
-
-    pub fn add_list_typename(&mut self, tn: &str) {
-        let tid = self.add_typename(tn);
-        self.list_types.push( tid );
-    }
-
-    pub fn is_list_type(&self, t: &TypeTerm) -> bool {
-        match t {
-            TypeTerm::TypeID(id) => {
-                self.list_types.contains(id)
-            }
-            TypeTerm::Ladder(args) |
-            TypeTerm::App(args) => {
-                if args.len() > 0 {
-                    if self.is_list_type(&args[0]) {
-                        true
-                    } else {
-                        false
-                    }
-                } else {
-                    false
-                }
-            }
-            _ => false
-        }
-    }
-
-    pub fn get_typeid(&self, tn: &str) -> Option<TypeID> {
-        self.type_dict.read().unwrap().get_typeid(&tn.into())
-    }
-
-    pub fn get_fun_typeid(&self, tn: &str) -> Option<u64> {
-        match self.get_typeid(tn) {
-            Some(TypeID::Fun(x)) => Some(x),
-            _ => None
-        }
-    }
-
-    pub fn get_typename(&self, tid: &TypeID) -> Option<String> {
-        self.type_dict.read().unwrap().get_typename(tid)
-    }
-
-    pub fn get_var_typeid(&self, tn: &str) -> Option<u64> {
-        match self.get_typeid(tn) {
-            Some(TypeID::Var(x)) => Some(x),
-            _ => None
-        }
-    }
-
-    pub fn type_term_from_str(&self, tn: &str) -> Result<TypeTerm, laddertypes::parser::ParseError> {
-        self.type_dict.write().unwrap().parse(&tn)
-    }
-
-    pub fn type_term_to_str(&self, t: &TypeTerm) -> String {
-        self.type_dict.read().unwrap().unparse(&t)
-    }
-
-    pub fn add_node_ctor(&mut self, tn: &str, mk_editor: Arc<dyn Fn(Arc<RwLock<Self>>, TypeTerm, OuterViewPort<dyn SingletonView<Item = usize>>) -> Option<NestedNode> + Send + Sync>) {
-        let dict = self.type_dict.clone();
-        let mut dict = dict.write().unwrap();
-
-        let tyid =
-            if let Some(tyid) = dict.get_typeid(&tn.into()) {
-                tyid
-            } else {
-                dict.add_typename(tn.into())
-            };
-
-        let morphism_pattern = MorphismTypePattern {
-            src_tyid: None,
-            dst_tyid: tyid
-        };
-
-        drop(dict);
-
-        self.add_morphism(morphism_pattern, Arc::new(move |node, dst_type| {
-            mk_editor(node.ctx.clone(), dst_type, node.depth)
-        }));
-    }
-
-    pub fn add_morphism(
-        &mut self,
-        morph_type_pattern: MorphismTypePattern,
-        morph_fn: Arc<
-                     dyn Fn( NestedNode, TypeTerm ) -> Option<NestedNode>
-                     + Send + Sync
-                  >
-    ) {
-        self.morphisms.insert(morph_type_pattern, morph_fn);
-    }
-
-    pub fn get_morphism(&self, ty: MorphismType) -> Option<Arc<dyn Fn(NestedNode, TypeTerm) -> Option<NestedNode> + Send + Sync>> {
-        let pattern = MorphismTypePattern::from(ty.clone());
-
-        if let Some(morphism) = self.morphisms.get( &pattern ) {
-            Some(morphism.clone())
-        } else {
-            self.parent.as_ref()?
-                .read().unwrap()
-                .get_morphism(ty)
-        }
-    }
-
-    pub fn make_node(ctx: &Arc<RwLock<Self>>, type_term: TypeTerm, depth: OuterViewPort<dyn SingletonView<Item = usize>>) -> Option<NestedNode> {
-        let mk_node = ctx.read().unwrap().get_morphism(MorphismType {
-            src_type: None,
-            dst_type: type_term.clone()
-        }).expect(&format!("morphism {}", ctx.read().unwrap().type_term_to_str(&type_term)));
-
-        /* create new context per node ?? too heavy.. whats the reason? TODO */
-
-        let new_ctx = Arc::new(RwLock::new(Context::with_parent(Some(ctx.clone()))));
-
-        mk_node(
-            NestedNode::new(new_ctx, ReprTree::new_arc(type_term.clone()), depth),
-            type_term
-        )
-    }
-
-    pub fn morph_node(mut node: NestedNode, dst_type: TypeTerm) -> NestedNode {
-        let src_type = node.data.read().unwrap().get_type().clone();
-        let pattern = MorphismType { src_type: Some(src_type), dst_type: dst_type.clone() };
-
-        /* it is not univesally true to always use ascend.
-         */
-        node.data =
-            ReprTree::ascend(
-                &node.data,
-                dst_type.clone()
-            );
-
-        let m = node.ctx.read().unwrap().get_morphism(pattern.clone());
-        if let Some(transform) = m {
-            if let Some(new_node) = transform(node.clone(), dst_type) {
-                new_node
-            } else {
-                node.clone()
-            }
-        } else {
-            eprintln!("could not find morphism {}", pattern.to_str(&node.ctx.read().unwrap()));
-            node
-        }
-    }
-
-    /// adds an object without any representations
-    pub fn add_obj(ctx: Arc<RwLock<Context>>, name: String, typename: &str) {
-        let type_tag = ctx.read().unwrap()
-            .type_dict.write().unwrap()
-            .parse(typename).unwrap();
-
-        if let Some(node) = Context::make_node(&ctx, type_tag, SingletonBuffer::new(0).get_port()) {
-            ctx.write().unwrap().nodes.insert(name, node);
-        }
-    }
-
-    pub fn get_obj(&self, name: &String) -> Option<NestedNode> {
-        if let Some(obj) = self.nodes.get(name) {
-            Some(obj.clone())
-        } else if let Some(parent) = self.parent.as_ref() {
-            parent.read().unwrap().get_obj(name)
-        } else {
-            None
-        }
-    }
-
-/*
-    pub fn get_obj_port<'a, V: View + ?Sized + 'static>(
-        &self,
-        name: &str,
-        type_ladder: impl Iterator<Item = &'a str>,
-    ) -> Option<OuterViewPort<V>>
-    where
-        V::Msg: Clone,
-    {
-        self.get_obj(&name.into())?
-            .downcast_ladder(type_ladder.map(|tn| self.type_dict.type_term_from_str(tn).unwrap()))?
-            .get_port()
-    }
-
-    pub fn insert_repr<'a>(
-        &mut self,
-        name: &str,
-        type_ladder: impl Iterator<Item = &'a str>,
-        port: AnyOuterViewPort,
-    ) {
-        self.get_obj(&name.to_string())
-            .unwrap()
-            .repr
-            .write()
-            .unwrap()
-            .insert_leaf(
-                type_ladder.map(|tn| self.type_dict.type_term_from_str(tn).unwrap()),
-                port,
-            );
-    }
-
-    pub fn epi_cast(&mut self, name: &str, typename: &str) {
-        let dst_type = self.type_dict.type_term_from_str(typename).unwrap();
-        let old_obj = self.objects.get(&name.to_string()).unwrap().clone();
-        let new_obj = if let Some(ctor) = self.morphism_constructors.get(&MorphismType {
-            mode: MorphismMode::Epi,
-            src_type: old_obj.type_tag.clone(),
-            dst_type: dst_type.clone(),
-        }) {
-            ctor(old_obj.clone())
-        } else {
-            Arc::new(RwLock::new(ReprTree::new(dst_type)))
-        };
-
-        new_obj
-            .repr
-            .write()
-            .unwrap()
-            .insert_branch(old_obj.type_tag, old_obj.repr);
-
-        self.objects.insert(name.to_string(), new_obj);
-    }
-
-    pub fn mono_view<'a, V: View + ?Sized + 'static>(
-        &mut self,
-        name: &str,
-        type_ladder: impl Iterator<Item = &'a str>,
-    ) -> Option<OuterViewPort<V>>
-    where
-        V::Msg: Clone,
-    {
-        if let Some(p) = self.get_obj_port(name, type_ladder) {
-            Some(p)
-        } else {
-            // todo : add repr with morphism constructor (if one exists)
-            /*
-            if let Some(ctor) = self.morphism_constructors.get(
-                &MorphismType {
-                    mode: MorphismMode::Mono,
-                    src_type: old_obj.type_tag.clone(),
-                    dst_type:
-                }
-            )
-            */
-            None
-        }
-}
-    */
-}
-
-//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
-

nested/src/type_system/mod.rs

@@ -1,8 +0,0 @@
-pub mod context;
-pub mod repr_tree;
-
-pub use {
-    context::{Context, MorphismMode, MorphismType, MorphismTypePattern},
-    repr_tree::ReprTree
-};
-

nested/src/type_system/repr_tree.rs

@@ -1,235 +0,0 @@
-use {
-    r3vi::view::{AnyOuterViewPort, OuterViewPort, View},
-    laddertypes::{TypeTerm},
-    crate::{
-        type_system::{Context}
-    },
-    std::{
-        collections::HashMap,
-        sync::{Arc, RwLock},
-    },
-};
-
-//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
-
-#[derive(Clone)]
-pub struct ReprTree {
-    type_tag: TypeTerm,
-    port: Option<AnyOuterViewPort>,
-    branches: HashMap<TypeTerm, Arc<RwLock<ReprTree>>>,
-}
-
-impl std::fmt::Debug for ReprTree {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "type: {:?}", self.type_tag)?;
-
-        for (_k,x) in self.branches.iter() {
-            write!(f, "child: {:?}", x)?;
-        }
-
-        Ok(())
-    }
-}
-
-impl ReprTree {
-    pub fn new(type_tag: impl Into<TypeTerm>) -> Self {
-        ReprTree {
-            type_tag: type_tag.into(),
-            port: None,
-            branches: HashMap::new(),
-        }
-    }
-
-    pub fn new_arc(type_tag: impl Into<TypeTerm>) -> Arc<RwLock<Self>> {
-        Arc::new(RwLock::new(Self::new(type_tag)))
-    }
-
-    pub fn get_type(&self) -> &TypeTerm {
-        &self.type_tag
-    }
-
-    pub fn from_char(ctx: &Arc<RwLock<Context>>, c: char) -> Arc<RwLock<Self>> {
-        let buf = r3vi::buffer::singleton::SingletonBuffer::<char>::new(c);
-        ReprTree::new_leaf(
-            Context::parse(ctx, "Char"),
-            buf.get_port().into()
-        )
-    }
-
-    pub fn new_leaf(type_tag: impl Into<TypeTerm>, port: AnyOuterViewPort) -> Arc<RwLock<Self>> {
-        let mut tree = ReprTree::new(type_tag.into());
-        tree.insert_leaf(vec![].into_iter(), port);
-        Arc::new(RwLock::new(tree))
-    }
-
-    pub fn insert_branch(&mut self, repr: Arc<RwLock<ReprTree>>) {
-        self.branches.insert(repr.clone().read().unwrap().type_tag.clone(), repr.clone());
-    }
-
-    pub fn insert_leaf(
-        &mut self,
-        mut type_ladder: impl Iterator<Item = TypeTerm>,
-        port: AnyOuterViewPort,
-    ) {
-        if let Some(type_term) = type_ladder.next() {
-            if let Some(next_repr) = self.branches.get(&type_term) {
-                next_repr.write().unwrap().insert_leaf(type_ladder, port);
-            } else {
-                let mut next_repr = ReprTree::new(type_term.clone());
-                next_repr.insert_leaf(type_ladder, port);
-                self.insert_branch(Arc::new(RwLock::new(next_repr)));
-            }
-        } else {
-            self.port = Some(port);
-        }
-    }
-
-    //<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
-
-    pub fn get_port<V: View + ?Sized + 'static>(&self) -> Option<OuterViewPort<V>>
-    where
-        V::Msg: Clone,
-    {
-        Some(
-            self.port
-                .clone()?
-                .downcast::<V>()
-                .ok()?
-        )
-    }
-
-    pub fn get_view<V: View + ?Sized + 'static>(&self) -> Option<Arc<V>>
-    where
-        V::Msg: Clone,
-    {
-            self.get_port::<V>()?
-                .get_view()
-    }
-
-    pub fn descend(&self, dst_type: impl Into<TypeTerm>) -> Option<Arc<RwLock<ReprTree>>> {
-        self.branches.get(&dst_type.into()).cloned()
-    }
-
-    pub fn descend_ladder(rt: &Arc<RwLock<Self>>, mut repr_ladder: impl Iterator<Item = TypeTerm>) -> Option<Arc<RwLock<ReprTree>>> {
-        if let Some(first) = repr_ladder.next() {
-            let rt = rt.read().unwrap();
-            repr_ladder.fold(
-                rt.descend(first),
-                |s, t| s?.read().unwrap().descend(t))
-        } else {
-            Some(rt.clone())
-        }
-    }
-
-    pub fn ascend(rt: &Arc<RwLock<Self>>, type_term: impl Into<TypeTerm>) -> Arc<RwLock<ReprTree>> {
-        let mut n = Self::new(type_term);
-        n.insert_branch(rt.clone());
-        Arc::new(RwLock::new(n))
-    }
-
-/*
-    pub fn add_iso_repr(
-        &self,
-        type_ladder: impl Iterator<Item = TypeTerm>,
-        morphism_constructors: &HashMap<MorphismType, Box<dyn Fn(Object) -> Object>>,
-    ) {
-        let mut cur_repr = self.repr.clone();
-
-        for dst_type in type_ladder {
-            if let Some(next_repr) = self.repr.read().unwrap().branches.get(&dst_type) {
-                // go deeper
-                cur_repr = next_repr.clone();
-            } else {
-                // search for morphism constructor and insert new repr
-                let mut obj = None;
-
-                for src_type in cur_repr.read().unwrap().branches.keys() {
-                    if let Some(ctor) = morphism_constructors.get(&MorphismType {
-                        mode: MorphismMode::Iso,
-                        src_type: src_type.clone(),
-                        dst_type: dst_type.clone(),
-                    }) {
-                        let new_obj = ctor(Object {
-                            type_tag: src_type.clone(),
-                            repr: cur_repr
-                                .read()
-                                .unwrap()
-                                .branches
-                                .get(&src_type)
-                                .unwrap()
-                                .clone(),
-                        });
-
-                        assert!(new_obj.type_tag == dst_type);
-
-                        obj = Some(new_obj);
-                        break;
-                    }
-                }
-
-                if let Some(obj) = obj {
-                    cur_repr
-                        .write()
-                        .unwrap()
-                        .insert_branch(obj.type_tag, obj.repr);
-                } else {
-                    panic!("could not find matching isomorphism!");
-                }
-            }
-        }
-    }
-
-    pub fn add_mono_repr<'a>(
-        &self,
-        type_ladder: impl Iterator<Item = TypeTerm>,
-        morphism_constructors: &HashMap<MorphismType, Box<dyn Fn(Object) -> Object>>,
-    ) {
-        let mut cur_type = self.type_tag.clone();
-        let mut cur_repr = self.repr.clone();   
-
-        for dst_type in type_ladder {
-            if let Some(next_repr) = self.repr.read().unwrap().branches.get(&dst_type) {
-                // go deeper
-                cur_type = dst_type;
-                cur_repr = next_repr.clone();
-            } else {
-                if let Some(constructor) = morphism_constructors.get(&MorphismType {
-                    mode: MorphismMode::Mono,
-                    src_type: cur_type.clone(),
-                    dst_type: dst_type.clone(),
-                }) {
-                    let new_obj = constructor(Object {
-                        type_tag: cur_type.clone(),
-                        repr: cur_repr
-                            .read()
-                            .unwrap()
-                            .branches
-                            .get(&cur_type)
-                            .unwrap()
-                            .clone(),
-                    });
-
-                    assert!(new_obj.type_tag == dst_type);
-                    cur_repr
-                        .write()
-                        .unwrap()
-                        .insert_branch(new_obj.type_tag.clone(), new_obj.repr.clone());
-
-                    cur_type = new_obj.type_tag;
-                    cur_repr = new_obj.repr;
-                }
-            }
-        }
-    }
-
-    // replace with higher-level type in which self is a repr branch
-    pub fn epi_cast<'a>(
-        &self,
-        _type_ladder: impl Iterator<Item = TypeTerm>,
-        _morphism_constructors: &HashMap<MorphismType, Box<dyn Fn(Object) -> Object>>,
-    ) {
-        // todo        
-}
-    */
-}
-

nested/src/utils/color.rs

@@ -1,31 +0,0 @@
-use {
-    crate::terminal::TerminalStyle,
-};
-
-pub fn bg_style_from_depth(depth: usize) -> TerminalStyle {
-    match depth {
-        0 => TerminalStyle::bg_color((150,80,230)),
-        1 => TerminalStyle::bg_color((66,66,66)),
-        2 => TerminalStyle::bg_color((44,44,44)),
-        3 => TerminalStyle::bg_color((33,33,33)),
-        4 => TerminalStyle::bg_color((28,28,28)),
-        5 => TerminalStyle::bg_color((21,21,21)),
-        _ => TerminalStyle::default(),
-    }
-}
-
-pub fn fg_style_from_depth(depth: usize) -> TerminalStyle {
-    if depth  == 0 {
-        TerminalStyle::fg_color((200, 200, 200))
-    } else {
-        match depth % 5 {
-            0 => TerminalStyle::fg_color((128, 106, 97)),
-            1 => TerminalStyle::fg_color((100, 120, 232)),
-            2 => TerminalStyle::fg_color((180, 100, 96)),
-            3 => TerminalStyle::fg_color((188, 155, 18)),
-            4 => TerminalStyle::fg_color((135, 182, 134)),
-            _ => TerminalStyle::default()
-        }
-    }
-}
-

nested/src/utils/mod.rs

@@ -1,6 +0,0 @@
-pub mod bimap;
-pub mod modulo;
-pub mod color;
-
-pub use modulo::modulo;
-pub use bimap::Bimap;

nested/src/utils/modulo.rs

@@ -1,10 +0,0 @@
-
-pub fn modulo(a: isize, b: isize) -> isize {
-    if b > 0 {
-        ((a % b) + b) % b
-    } else {
-        0
-    }
-}
-
-

nested/src/vec/buffer.rs

@@ -0,0 +1,134 @@
+use {
+    std::{
+        sync::Arc,
+        ops::{Deref, DerefMut},
+    },
+    std::sync::RwLock,
+    crate::{
+        core::{View, Observer, ObserverBroadcast, InnerViewPort},
+        vec::VecDiff
+    }
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<T> View for Vec<T>
+where T: Clone + Send + Sync + 'static {
+    type Msg = VecDiff<T>;
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+#[derive(Clone)]
+pub struct VecBuffer<T>
+where T: Clone + Send + Sync + 'static
+{
+    data: Arc<RwLock<Vec<T>>>,
+    cast: Arc<RwLock<ObserverBroadcast<RwLock<Vec<T>>>>>
+}
+
+impl<T> VecBuffer<T>
+where T: Clone + Send + Sync + 'static
+{
+    pub fn with_data(
+        data: Vec<T>,
+        port: InnerViewPort<RwLock<Vec<T>>>
+    ) -> Self {
+        let mut b = VecBuffer::new(port);
+        for x in data.into_iter() {
+            b.push(x);
+        }
+
+        b
+    }
+
+    pub fn new(port: InnerViewPort<RwLock<Vec<T>>>) -> Self {
+        let data = Arc::new(RwLock::new(Vec::new()));
+        port.set_view(Some(data.clone()));
+        VecBuffer { data, cast: port.get_broadcast() }
+    }
+
+    pub fn apply_diff(&mut self, diff: VecDiff<T>) {
+        let mut data = self.data.write().unwrap();
+        match &diff {
+            VecDiff::Clear => { data.clear(); },
+            VecDiff::Push(val) => { data.push(val.clone()); },
+            VecDiff::Remove(idx) => { data.remove(*idx); },
+            VecDiff::Insert{ idx, val } => { data.insert(*idx, val.clone()); },
+            VecDiff::Update{ idx, val } => { data[*idx] = val.clone(); }
+        }
+        drop(data);
+
+        self.cast.notify(&diff);
+    }
+
+    pub fn len(&self) -> usize {
+        self.data.read().unwrap().len()
+    }
+
+    pub fn get(&self, idx: usize) -> T {
+        self.data.read().unwrap()[idx].clone()
+    }
+
+    pub fn clear(&mut self) {
+        self.apply_diff(VecDiff::Clear);
+    }
+
+    pub fn push(&mut self, val: T) {
+        self.apply_diff(VecDiff::Push(val));
+    }
+
+    pub fn remove(&mut self, idx: usize) {
+        self.apply_diff(VecDiff::Remove(idx));
+    }
+
+    pub fn insert(&mut self, idx: usize, val: T) {
+        self.apply_diff(VecDiff::Insert{ idx, val });
+    }
+
+    pub fn update(&mut self, idx: usize, val: T) {
+        self.apply_diff(VecDiff::Update{ idx, val });
+    }
+
+    pub fn get_mut(&mut self, idx: usize) -> MutableVecAccess<T> {
+        MutableVecAccess {
+            buf: self.clone(),
+            idx,
+            val: self.get(idx)
+        }
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct MutableVecAccess<T>
+where T: Clone + Send + Sync + 'static {
+    buf: VecBuffer<T>,
+    idx: usize,
+    val: T,
+}
+
+impl<T> Deref for MutableVecAccess<T>
+where T: Clone + Send + Sync + 'static {
+    type Target = T;
+
+    fn deref(&self) -> &T {
+        &self.val
+    }
+}
+
+impl<T> DerefMut for MutableVecAccess<T>
+where T: Clone + Send + Sync + 'static {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.val
+    }
+}
+
+impl<T> Drop for MutableVecAccess<T>
+where T: Clone + Send + Sync + 'static {
+    fn drop(&mut self) {
+        self.buf.update(self.idx, self.val.clone());
+    }
+}
+
+

nested/src/vec/mod.rs

@@ -0,0 +1,25 @@
+
+pub mod buffer;
+pub mod vec2seq;
+pub mod vec2json;
+pub mod vec2bin;
+
+pub use {
+    buffer::VecBuffer
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+use {
+    serde::{Serialize, Deserialize}
+};
+
+#[derive(Clone, Serialize, Deserialize)]
+pub enum VecDiff<T> {
+    Clear,
+    Push(T),
+    Remove(usize),
+    Insert{ idx: usize, val: T },
+    Update{ idx: usize, val: T }
+}
+

nested/src/vec/vec2bin.rs

@@ -0,0 +1,67 @@
+use {
+    std::{
+        sync::Arc,
+        io::Write
+    },
+    std::sync::RwLock,
+    serde::Serialize,
+    crate::{
+        core::{Observer, OuterViewPort},
+        vec::VecDiff
+    }
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+/// Serialization Observer for `Vec`
+pub struct VecBinWriter<T, W>
+where T: Clone + Send + Sync + 'static,
+      W: Write + Send + Sync {
+    data: Option<Arc<RwLock<Vec<T>>>>,
+    out: RwLock<W>
+}
+
+
+impl<T> OuterViewPort<RwLock<Vec<T>>>
+where T: Clone + Serialize + Send + Sync + 'static {
+    pub fn serialize_bin<W: Write + Send + Sync + 'static>(&self, out: W) -> Arc<RwLock<VecBinWriter<T, W>>> {
+        let writer = Arc::new(RwLock::new(
+            VecBinWriter {
+                data: None,
+                out: RwLock::new(out),
+            }
+        ));
+        self.add_observer(writer.clone());
+        writer
+    }
+}
+
+impl<T, W> Observer<RwLock<Vec<T>>> for VecBinWriter<T, W>
+where T: Clone + Serialize + Send + Sync + 'static,
+      W: Write + Send + Sync
+{
+    fn reset(&mut self, view: Option<Arc<RwLock<Vec<T>>>>) {
+        self.data = view;
+        let mut out = self.out.write().unwrap();
+
+        out.write(&bincode::serialized_size(&VecDiff::<T>::Clear).unwrap().to_le_bytes()).expect("");
+        out.write(&bincode::serialize(&VecDiff::<T>::Clear).unwrap()).expect("");
+
+        if let Some(data) = self.data.as_ref() {
+            for x in data.read().unwrap().iter() {
+                out.write(&bincode::serialized_size(&VecDiff::Push(x)).unwrap().to_le_bytes()).expect("");
+                out.write(&bincode::serialize(&VecDiff::Push(x)).unwrap()).expect("");
+            }
+        }
+
+        out.flush().expect("");
+    }
+
+    fn notify(&mut self, diff: &VecDiff<T>) {
+        let mut out = self.out.write().unwrap();
+        out.write(&bincode::serialized_size(diff).unwrap().to_le_bytes()).expect("");
+        out.write(&bincode::serialize(diff).unwrap()).expect("");
+        out.flush().expect("");
+    }
+}
+

nested/src/vec/vec2json.rs

@@ -0,0 +1,91 @@
+use {
+    std::{
+        sync::Arc,
+        io::Write
+    },
+    std::sync::RwLock,
+    async_std::{
+        io::{Read, ReadExt},
+        stream::{StreamExt}
+    },
+    serde::{Serialize, de::DeserializeOwned},
+    crate::{
+        core::{Observer, OuterViewPort},
+        vec::{VecDiff, VecBuffer}
+    }
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct VecJsonWriter<T, W>
+where T: Clone + Send + Sync + 'static,
+      W: Write + Send + Sync {
+    data: Option<Arc<RwLock<Vec<T>>>>,
+    out: RwLock<W>
+}
+
+impl<T> OuterViewPort<RwLock<Vec<T>>>
+where T: Clone + Serialize + Send + Sync + 'static {
+    pub fn serialize_json<W: Write + Send + Sync + 'static>(&self, out: W) -> Arc<RwLock<VecJsonWriter<T, W>>> {
+        let writer = Arc::new(RwLock::new(
+            VecJsonWriter {
+                data: None,
+                out: RwLock::new(out),
+            }
+        ));
+        self.add_observer(writer.clone());
+        writer
+    }
+}
+
+impl<T, W> Observer<RwLock<Vec<T>>> for VecJsonWriter<T, W>
+where T: Clone + Serialize + Send + Sync + 'static,
+      W: Write + Send + Sync
+{
+    fn reset(&mut self, view: Option<Arc<RwLock<Vec<T>>>>) {
+        self.data = view;
+
+        self.out.write().unwrap().write(&serde_json::to_string(&VecDiff::<T>::Clear).unwrap().as_bytes()).expect("");
+        self.out.write().unwrap().write(b"\n").expect("");
+
+        if let Some(data) = self.data.as_ref() {
+            for x in data.read().unwrap().iter() {
+                self.out.write().unwrap().write(&serde_json::to_string(&VecDiff::Push(x)).unwrap().as_bytes()).expect("");
+                self.out.write().unwrap().write(b"\n").expect("");
+            }
+        }
+
+        self.out.write().unwrap().flush().expect("");
+    }
+
+    fn notify(&mut self, diff: &VecDiff<T>) {
+        self.out.write().unwrap().write(serde_json::to_string(diff).unwrap().as_bytes()).expect("");
+        self.out.write().unwrap().write(b"\n").expect("");
+        self.out.write().unwrap().flush().expect("");
+    }
+}
+
+impl<T> VecBuffer<T>
+where T: DeserializeOwned + Clone + Send + Sync + 'static
+{
+    pub async fn from_json<R: Read + async_std::io::Read + Unpin>(&mut self, read: R) {
+        let mut bytes = read.bytes();
+        let mut s = String::new();
+        while let Some(Ok(b)) = bytes.next().await {
+            match b {
+                b'\n' => {
+                    if s.len() > 0 {
+                        let diff = serde_json::from_str::<VecDiff<T>>(&s).expect("error parsing json");
+                        self.apply_diff(diff);
+                        s.clear();
+                    }
+                },
+                c => {
+                    s.push(c as char);
+                }
+            }
+        }
+    }
+}
+
+

nested/src/vec/vec2seq.rs

@@ -0,0 +1,116 @@
+use {
+    std::{
+        sync::Arc,
+    },
+    std::sync::RwLock,
+    crate::{
+        core::{View, Observer, ObserverExt, ObserverBroadcast, ViewPort, InnerViewPort, OuterViewPort},
+        sequence::SequenceView,
+        vec::VecDiff
+    }
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+/// Adapter View implementing `Sequence` for `Vec`
+pub struct VecSequence<T>
+where T: Clone + Send + Sync + 'static {
+    cur_len: usize,
+    data: Option<Arc<RwLock<Vec<T>>>>,
+    cast: Arc<RwLock<ObserverBroadcast<dyn SequenceView<Item = T>>>>
+}
+
+
+impl<T> VecSequence<T>
+where T: Clone + Send + Sync + 'static {
+    pub fn new(
+        port: InnerViewPort<dyn SequenceView<Item = T>>
+    ) -> Arc<RwLock<Self>> {
+        let seq = Arc::new(RwLock::new(
+            VecSequence {
+                cur_len: 0,
+                data: None,
+                cast: port.get_broadcast()
+            }
+        ));
+        port.set_view(Some(seq.clone()));
+        seq
+    }
+}
+
+impl<T> Observer<RwLock<Vec<T>>> for VecSequence<T>
+where T: Clone + Send + Sync + 'static {
+    fn reset(&mut self, view: Option<Arc<RwLock<Vec<T>>>>) {
+        let old_len = self.cur_len;
+        self.data = view;
+        let new_len =
+            if let Some(data) = self.data.as_ref() {
+                data.read().unwrap().len()
+            } else {
+                0
+            };
+
+        self.cur_len = new_len;
+        self.cast.notify_each(0 .. std::cmp::max(old_len, new_len));
+    }
+
+    fn notify(&mut self, diff: &VecDiff<T>) {
+        match diff {
+            VecDiff::Clear => {
+                self.cast.notify_each(0 .. self.cur_len);
+                self.cur_len = 0
+            },
+            VecDiff::Push(_) => {
+                self.cast.notify(&self.cur_len);
+                self.cur_len += 1;
+            },
+            VecDiff::Remove(idx) => {
+                self.cast.notify_each(*idx .. self.cur_len);
+                self.cur_len -= 1;
+            },
+            VecDiff::Insert{ idx, val: _ } => {
+                self.cur_len += 1;
+                self.cast.notify_each(*idx .. self.cur_len);
+            },
+            VecDiff::Update{ idx, val: _ } => {
+                self.cast.notify(&idx);
+            }
+        }
+    }
+}
+
+impl<T> View for VecSequence<T>
+where T: Clone + Send + Sync + 'static {
+    type Msg = usize;
+}
+
+impl<T> SequenceView for VecSequence<T>
+where T: Clone + Send + Sync + 'static {
+    type Item = T;
+
+    fn get(&self, idx: &usize) -> Option<T> {
+        self.data.as_ref()?
+            .read().unwrap()
+            .get(*idx).cloned()
+    }
+
+    fn len(&self) -> Option<usize> {
+        Some(self.cur_len)
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<T> OuterViewPort<RwLock<Vec<T>>>
+where T: Clone + Send + Sync + 'static {
+    pub fn to_sequence(&self) -> OuterViewPort<dyn SequenceView<Item = T>> {
+        let port = ViewPort::new();
+        port.add_update_hook(Arc::new(self.0.clone()));
+
+        let vec_seq = VecSequence::new(port.inner());
+        self.add_observer(vec_seq.clone());
+        port.into_outer()
+    }
+}
+
+

rust-toolchain

@@ -1,3 +1,9 @@
-[toolchain]
+# If you see this, run `rustup self update` to get rustup 1.23 or newer.
-channel = "nightly"
 
+# NOTE: above comment is for older `rustup` (before TOML support was added),
+# which will treat the first line as the toolchain name, and therefore show it
+# to the user in the error, instead of "error: invalid channel name '[toolchain]'".
+
+[toolchain]
+channel = "nightly-2021-10-26"
+components = ["rust-src", "rustc-dev", "llvm-tools-preview"]

sdf_editor/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "sdf_editor"
+version = "0.1.0"
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+nako = {git= "https://git.exobiont.de/senvas/nako.git"}
+nako_std = {git= "https://git.exobiont.de/senvas/nako.git"}
+nakorender = {git="https://git.exobiont.de/senvas/nako.git", default-features = false}
+nested = { path = "../nested" }
+cgmath = "*"
+termion = "*"
+font-kit = "*"
+
+[dependencies.async-std]
+version = "1.9.0"
+features = ["unstable", "attributes"]

sdf_editor/src/main.rs

@@ -0,0 +1,288 @@
+
+use{
+    std::{
+        sync::{Arc, RwLock, Mutex},
+        collections::HashMap
+    },
+    cgmath::{Point2, Vector2},
+    termion::event::{Event, Key},
+    nested::{
+        core::{
+            View,
+            ViewPort,
+            Observer,
+            ObserverExt,
+            OuterViewPort,
+            port::UpdateTask
+        },
+        singleton::{SingletonBuffer, SingletonView},
+        sequence::{SequenceView},
+        integer::{PosIntEditor},
+        terminal::{Terminal, TerminalAtom, TerminalStyle, TerminalView, TerminalCompositor, TerminalEvent, TerminalEditor},
+        list::{ListEditor},
+        tree_nav::{TreeNav},
+        sdf::SdfTerm
+    },
+    nako::{
+        stream::{SecondaryStream2d, PrimaryStream2d},
+        glam::{Vec2, Vec3, UVec2, IVec2},
+        operations::{
+            planar::primitives2d::Box2d,
+            volumetric::{Color, Union, Round},
+        },
+    },
+    nakorender::{
+        backend::{Backend, LayerId, LayerId2d, LayerInfo},
+        marp::MarpBackend,
+        winit, camera::Camera2d
+    },
+    nako_std::{
+        text::Character
+    },
+    std::{fs::File, io::Read, mem::needs_drop, path::Path},
+    font_kit::font::Font,
+};
+
+// projects a Sequence of ints to a color tuple
+struct ColorCollector {
+    src_view: Option<Arc<dyn SequenceView<Item = u32>>>,
+    color: SingletonBuffer<(u8, u8, u8)>
+}
+
+impl ColorCollector {
+    fn update(&mut self) {
+        if let Some(l) = self.src_view.as_ref() {
+            let r = l.get(&0).unwrap_or(0);
+            let g = l.get(&1).unwrap_or(0);
+            let b = l.get(&2).unwrap_or(0);
+
+            self.color.set((r as u8, g as u8, b as u8));
+        }
+    }
+}
+
+impl Observer<dyn SequenceView<Item = u32>> for ColorCollector {
+    fn reset(&mut self, new_view: Option<Arc<dyn SequenceView<Item = u32>>>) {
+        self.src_view = new_view;
+        self.update();
+    }
+
+    fn notify(&mut self, idx: &usize) {
+        self.update();
+    }
+}
+
+#[async_std::main]
+async fn main() {
+    let term_port = ViewPort::new();
+    let compositor = TerminalCompositor::new(term_port.inner());
+
+    let mut color_editor = ListEditor::new(
+        || {
+            Arc::new(RwLock::new(PosIntEditor::new(16)))
+        },
+        nested::list::ListEditorStyle::HorizontalSexpr
+    );
+
+    color_editor.goto(nested::tree_nav::TreeCursor {
+        leaf_mode: nested::list::ListCursorMode::Insert,
+        tree_addr: vec![ 0 ]
+    });
+
+    let color_port = ViewPort::new();
+    let color_collector = Arc::new(RwLock::new(ColorCollector {
+        src_view: None,
+        color: SingletonBuffer::new((200, 200, 0), color_port.inner())
+    }));
+
+    let col_seq_port = color_editor.get_data_port().map(
+        |sub_editor| sub_editor.read().unwrap().get_value()
+    );
+    color_port.add_update_hook(Arc::new(col_seq_port.0.clone()));
+    col_seq_port.add_observer(
+        color_collector.clone()
+    );
+
+    compositor.write().unwrap().push(color_editor.get_term_view().offset(Vector2::new(0, 0)));
+
+    let event_loop = nakorender::winit::event_loop::EventLoop::new();
+    let window = nakorender::winit::window::Window::new(&event_loop).unwrap();
+    let mut renderer = Arc::new(Mutex::new(nakorender::marp::MarpBackend::new(&window, &event_loop)));
+
+    // terminal view
+    let mut sdf_term = Arc::new(RwLock::new(SdfTerm::new(renderer.clone())));
+    term_port.outer().add_observer(sdf_term.clone());
+
+    // color preview
+    let color_view = color_port.outer().get_view();
+    let color_layer_id = renderer.lock().unwrap().new_layer_2d();
+    renderer.lock().unwrap().update_camera_2d(color_layer_id, Camera2d{
+        extent: Vec2::new(4.0, 4.0),
+        location: Vec2::new(-2.0, -2.0),
+        rotation: 0.0
+    });
+    renderer.lock().unwrap().set_layer_info(color_layer_id.into(), LayerInfo{
+        extent: UVec2::new(600, 600),
+        location: IVec2::new(200,100)
+    });
+
+    event_loop.run(move |event, _target, control_flow|{
+        //Set to polling for now, might be overwritten
+        //TODO: Maybe we want to use "WAIT" for the ui thread? However, the renderer.lock().unwrap()s don't work that hard
+        //if nothing changes. So should be okay for a alpha style programm.
+        *control_flow = winit::event_loop::ControlFlow::Poll;
+
+        //now check if a rerender was requested, or if we worked on all
+        //events on that batch
+        match event{
+            winit::event::Event::WindowEvent{window_id: _, event: winit::event::WindowEvent::Resized(newsize)} => {
+                
+            }
+            winit::event::Event::WindowEvent{window_id: _, event: winit::event::WindowEvent::KeyboardInput{ device_id, input, is_synthetic }} => {
+                if input.state == winit::event::ElementState::Pressed {
+                    if let Some(kc) = input.virtual_keycode {
+                        match kc {
+                            winit::event::VirtualKeyCode::Space |
+                            winit::event::VirtualKeyCode::Return => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Char(' '))));
+                            }
+                            winit::event::VirtualKeyCode::Key0 |
+                            winit::event::VirtualKeyCode::Numpad0 => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Char('0'))));
+                            }
+                            winit::event::VirtualKeyCode::Key1 |
+                            winit::event::VirtualKeyCode::Numpad1 => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Char('1'))));
+                            }
+                            winit::event::VirtualKeyCode::Key2 |
+                            winit::event::VirtualKeyCode::Numpad2 => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Char('2'))));
+                            }
+                            winit::event::VirtualKeyCode::Key3 |
+                            winit::event::VirtualKeyCode::Numpad3 => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Char('3'))));
+                            }
+                            winit::event::VirtualKeyCode::Key4 |
+                            winit::event::VirtualKeyCode::Numpad4 => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Char('4'))));
+                            }
+                            winit::event::VirtualKeyCode::Key5 |
+                            winit::event::VirtualKeyCode::Numpad5 => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Char('5'))));
+                            }
+                            winit::event::VirtualKeyCode::Key6 |
+                            winit::event::VirtualKeyCode::Numpad6 => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Char('6'))));
+                            }
+                            winit::event::VirtualKeyCode::Key7 |
+                            winit::event::VirtualKeyCode::Numpad7 => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Char('7'))));
+                            }
+                            winit::event::VirtualKeyCode::Key8 |
+                            winit::event::VirtualKeyCode::Numpad8 => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Char('8'))));
+                            }
+                            winit::event::VirtualKeyCode::Key9 |
+                            winit::event::VirtualKeyCode::Numpad9 => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Char('9'))));
+                            }
+                            winit::event::VirtualKeyCode::A => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Char('a'))));
+                            }
+                            winit::event::VirtualKeyCode::B => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Char('b'))));
+                            }
+                            winit::event::VirtualKeyCode::C => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Char('c'))));
+                            }
+                            winit::event::VirtualKeyCode::D => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Char('d'))));
+                            }
+                            winit::event::VirtualKeyCode::E => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Char('e'))));
+                            }
+                            winit::event::VirtualKeyCode::F => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Char('f'))));
+                            }
+                            winit::event::VirtualKeyCode::Tab => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Insert)));
+                            }
+                            winit::event::VirtualKeyCode::Delete => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Delete)));
+                            }
+                            winit::event::VirtualKeyCode::Back => {
+                                color_editor.handle_terminal_event(&TerminalEvent::Input(Event::Key(Key::Backspace)));
+                            }
+                            winit::event::VirtualKeyCode::Left => {
+                                color_editor.pxev();
+                            }
+                            winit::event::VirtualKeyCode::Right => {
+                                color_editor.nexd();
+                            }
+                            winit::event::VirtualKeyCode::Up => {
+                                color_editor.up();
+                            }
+                            winit::event::VirtualKeyCode::Down => {
+                                color_editor.dn();
+                                color_editor.goto_home();
+                            }
+                            winit::event::VirtualKeyCode::Home => {
+                                color_editor.goto_home();
+                            }
+                            winit::event::VirtualKeyCode::End => {
+                                color_editor.goto_end();
+                            }
+                            _ => {
+                            }
+                        }
+                    }
+                }
+            }
+            winit::event::Event::MainEventsCleared => {
+                window.request_redraw();
+            }
+            winit::event::Event::RedrawRequested(_) => {
+                color_port.update();
+                term_port.update();
+
+                let c = color_view.get();
+                let color_stream = PrimaryStream2d::new()
+                    .push(
+                        SecondaryStream2d::new(
+                            Union,
+                            Box2d {
+                                extent: Vec2::new(0.5, 0.5)
+                            }
+                        ).push_mod(
+                            Color(
+                                Vec3::new(
+                                    (c.0 as f32 / 255.0).clamp(0.0, 1.0),
+                                    (c.1 as f32 / 255.0).clamp(0.0, 1.0),
+                                    (c.2 as f32 / 255.0).clamp(0.0, 1.0),
+                                )
+                            )
+                        ).push_mod(
+                            Round{radius: 0.2}
+                        ).build()
+                    ).build();
+
+                renderer.lock().unwrap().update_sdf_2d(color_layer_id, color_stream);
+                renderer.lock().unwrap().set_layer_order(
+                    vec![
+                        vec![ color_layer_id.into() ].into_iter(),
+                        sdf_term.read().unwrap().get_order().into_iter()
+                    ]
+                        .into_iter()
+                        .flatten()
+                        .collect::<Vec<_>>()
+                        .as_slice()
+                );
+
+                renderer.lock().unwrap().render(&window);
+            }
+            _ => {},
+        }
+        
+    })
+}
+