wip sugar

README.md

@@ -5,8 +5,6 @@ Rust Implementation of Ladder-Types (parsing, unification, rewriting, etc)
 
 ## Ladder Types
 
-### Motivation
-
 In order to implement complex datastructures and algorithms, usually
 many layers of abstraction are built ontop of each other.
 Consequently higher-level data types are encoded into lower-level data
@@ -59,48 +57,6 @@ this:
 1696093021:1696093039:1528324679:1539892301:1638141920:1688010253
 ```
 
-### Syntax
-
-In their core form, type-terms can be one of the following:
-- (**Atomic Type**)        |   `SomeTypeName`
-- (**Literal Integer**)    |   `0` | `1` | `2` | ...
-- (**Literal Character**)  |   `'a'` | `'b'` | `'c'` | ...
-- (**Literal String**)     |   `"abc"`
-- (**Parameter Application**) | `<T1 T2>` given `T1` and `T2` are type-terms
-- (**Ladder**)                | `T1 ~ T2` given `T1` and `T2` are type-terms
-
-Ontop of that, the following syntax-sugar is defined:
-
-#### Complex Types
-- `[ T ]` <===> `<Seq T>`
-- `{ a:A b:B }` <===> `<Struct <"a" A> <"b" B>>`
-- `a:A | b:B` <===> `<Enum <"a" A> <"b" B>>`
-
-#### Function Types
-- `A -> B` <===> `<Fn A B>`
-
-#### Reference Types
-- `*A`  <===> `<Ptr A>`
-- `&A`  <===> `<ConstRef A>`
-- `&!A` <===> `<MutRef A>`
-
-
-### Equivalences
-
-#### Currying
-`<<A B> C>` <===> `<A B C>`
-
-#### Ladder-Normal-Form
-exhaustively apply `<A B~C>` ===> `<A B>~<A C>`
-
-e.g. `[<Digit 10>]~[Char]~[Ascii]` is in **LNF**
-
-#### Parameter-Normal-Form
-exhaustively apply `<A B>~<A C>` ===> `<A B~C>`
-
-e.g. `[<Digit 10>~Char~Ascii]` is in **PNF**
-
-
 ## How to use this crate
 
 ```rust
@@ -117,19 +73,6 @@ fn main() {
 }
 ```
 
-## Roadmap
-
-- [x] (Un-)Parsing
-- [x] (De-)Currying
-- [x] Unification
-- [x] Ladder-Normal-Form
-- [x] Parameter-Normal-Form
-- [ ] (De)-Sugaring
-  - [ ] Seq
-  - [ ] Enum
-  - [ ] Struct
-  - [ ] References
-  - [ ] Function
 
 ## License
 [GPLv3](COPYING)

src/dict.rs

@@ -1,8 +1,11 @@
-use crate::bimap::Bimap;
+use crate::{
+    bimap::Bimap,
+    sugar::SUGARID_LIMIT
+};
 
 //<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>\\
 
-#[derive(Eq, PartialEq, Hash, Clone, Debug)]
+#[derive(Eq, PartialEq, Hash, Clone, Copy, Debug)]
 pub enum TypeID {
     Fun(u64),
     Var(u64)
@@ -20,11 +23,19 @@ pub struct TypeDict {
 
 impl TypeDict {
     pub fn new() -> Self {
-        TypeDict {
+        let mut dict = TypeDict {
             typenames: Bimap::new(),
             type_lit_counter: 0,
             type_var_counter: 0,
-        }
+        };
+
+        dict.add_typename("Seq".into());
+        dict.add_typename("Enum".into());
+        dict.add_typename("Struct".into());
+
+        assert_eq!( dict.type_lit_counter, SUGARID_LIMIT );
+
+        dict
     }
 
     pub fn add_varname(&mut self, tn: String) -> TypeID {

src/lexer.rs

@@ -6,9 +6,9 @@ pub enum LadderTypeToken {
     Symbol( String ),
     Char( char ),
     Num( i64 ),
-    Open,
+    Open, OpenSeq, OpenStruct,
-    Close,
+    Close, CloseSeq, CloseStruct,
-    Ladder,
+    Ladder, Enum
 }
 
 #[derive(PartialEq, Eq, Clone, Debug)]
@@ -75,6 +75,11 @@ where It: Iterator<Item = char>
                     match c {
                         '<' => { self.chars.next(); return Some(Ok(LadderTypeToken::Open)); },
                         '>' => { self.chars.next(); return Some(Ok(LadderTypeToken::Close)); },
+                        '[' => { self.chars.next(); return Some(Ok(LadderTypeToken::OpenSeq)); },
+                        ']' => { self.chars.next(); return Some(Ok(LadderTypeToken::CloseSeq)); },
+                        '{' => { self.chars.next(); return Some(Ok(LadderTypeToken::OpenStruct)); },
+                        '}' => { self.chars.next(); return Some(Ok(LadderTypeToken::CloseStruct)); },
+                        '|' => { self.chars.next(); return Some(Ok(LadderTypeToken::Enum)); },
                         '~' => { self.chars.next(); return Some(Ok(LadderTypeToken::Ladder)); },
                         '\'' => { self.chars.next(); state = LexerState::Char(None); },
                         c => {

src/lib.rs

@@ -6,8 +6,8 @@ pub mod lexer;
 pub mod parser;
 pub mod unparser;
 pub mod curry;
+pub mod sugar;
 pub mod lnf;
-pub mod pnf;
 pub mod subtype;
 pub mod unification;
 

src/parser.rs

@@ -3,6 +3,7 @@ use {
     crate::{
         dict::*,
         term::*,
+        sugar::*,
         lexer::*
     }
 };
@@ -21,7 +22,7 @@ pub enum ParseError {
 //<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>\\
 
 impl TypeDict {
-    pub fn parse(&mut self, s: &str) -> Result<TypeTerm, ParseError> {
+    pub fn parse(&mut self, s: &str) -> Result<SugaredTypeTerm, ParseError> {
         let mut tokens = LadderTypeLexer::from(s.chars()).peekable();
 
         match self.parse_ladder(&mut tokens) {
@@ -36,7 +37,7 @@ impl TypeDict {
         }
     }
 
-    fn parse_app<It>(&mut self, tokens: &mut Peekable<LadderTypeLexer<It>>) -> Result<TypeTerm, ParseError>
+    fn parse_app<It>(&mut self, tokens: &mut Peekable<LadderTypeLexer<It>>) -> Result<SugaredTypeTerm, ParseError>
     where It: Iterator<Item = char>
     {
         let mut args = Vec::new();
@@ -44,7 +45,11 @@ impl TypeDict {
             match tok {
                 Ok(LadderTypeToken::Close) => {
                     tokens.next();
-                    return Ok(TypeTerm::App(args));
+                    return Ok(SugaredTypeTerm::App(args));
+                }
+                Ok(LadderTypeToken::CloseSeq) |
+                Ok(LadderTypeToken::CloseStruct) => {
+                    return Err(ParseError::UnexpectedToken)
                 }
                 _ => {
                     match self.parse_ladder(tokens) {
@@ -57,29 +62,59 @@ impl TypeDict {
         Err(ParseError::UnexpectedEnd)
     }
 
-    fn parse_rung<It>(&mut self, tokens: &mut Peekable<LadderTypeLexer<It>>) -> Result<TypeTerm, ParseError>
+    fn parse_seq<It>(&mut self, tokens: &mut Peekable<LadderTypeLexer<It>>) -> Result<SugaredTypeTerm, ParseError>
+    where It: Iterator<Item = char>
+    {
+        let mut pattern = Vec::new();
+        while let Some(tok) = tokens.peek() {
+            match tok {
+                Ok(LadderTypeToken::CloseSeq) => {
+                    tokens.next();
+                    return Ok(SugaredTypeTerm::Seq(pattern));
+                }
+                Ok(LadderTypeToken::Close) |
+                Ok(LadderTypeToken::CloseStruct) => {
+                    return Err(ParseError::UnexpectedToken)
+                }
+                _ => {
+                    match self.parse_ladder(tokens) {
+                        Ok(a) => { pattern.push(a); }
+                        Err(err) => { return Err(err); }
+                    }
+                }
+            }
+        }
+        Err(ParseError::UnexpectedEnd)
+    }
+
+    fn parse_rung<It>(&mut self, tokens: &mut Peekable<LadderTypeLexer<It>>) -> Result<SugaredTypeTerm, ParseError>
     where It: Iterator<Item = char>
     {
         match tokens.next() {
             Some(Ok(LadderTypeToken::Open)) => self.parse_app(tokens),
+            Some(Ok(LadderTypeToken::OpenSeq)) => self.parse_app(tokens),
+            Some(Ok(LadderTypeToken::OpenStruct)) => self.parse_app(tokens),
+            Some(Ok(LadderTypeToken::Enum)) => self.parse_app(tokens),
             Some(Ok(LadderTypeToken::Close)) => Err(ParseError::UnexpectedClose),
+            Some(Ok(LadderTypeToken::CloseStruct)) => Err(ParseError::UnexpectedToken),
+            Some(Ok(LadderTypeToken::CloseSeq)) => Err(ParseError::UnexpectedToken),
             Some(Ok(LadderTypeToken::Ladder)) => Err(ParseError::UnexpectedLadder),
             Some(Ok(LadderTypeToken::Symbol(s))) =>
-                Ok(TypeTerm::TypeID(
+                Ok(SugaredTypeTerm::TypeID(
                     if let Some(tyid) = self.get_typeid(&s) {
                         tyid
                     } else {
                         self.add_typename(s)
                     }
                 )),
-            Some(Ok(LadderTypeToken::Char(c))) => Ok(TypeTerm::Char(c)),
+            Some(Ok(LadderTypeToken::Char(c))) => Ok(SugaredTypeTerm::Char(c)),
-            Some(Ok(LadderTypeToken::Num(n))) => Ok(TypeTerm::Num(n)),
+            Some(Ok(LadderTypeToken::Num(n))) => Ok(SugaredTypeTerm::Num(n)),
             Some(Err(err)) => Err(ParseError::LexError(err)),
             None => Err(ParseError::UnexpectedEnd)
         }
     }
 
-    fn parse_ladder<It>(&mut self, tokens: &mut Peekable<LadderTypeLexer<It>>) -> Result<TypeTerm, ParseError>
+    fn parse_ladder<It>(&mut self, tokens: &mut Peekable<LadderTypeLexer<It>>) -> Result<SugaredTypeTerm, ParseError>
     where It: Iterator<Item = char>
     {
         let mut rungs = Vec::new();
@@ -115,7 +150,7 @@ impl TypeDict {
         match rungs.len() {
             0 => Err(ParseError::UnexpectedEnd),
             1 => Ok(rungs[0].clone()),
-            _ => Ok(TypeTerm::Ladder(rungs)),
+            _ => Ok(SugaredTypeTerm::Ladder(rungs)),
         }
     }
 }

src/pnf.rs

@@ -1,113 +0,0 @@
-use crate::term::TypeTerm;
-
-//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>\\
-
-impl TypeTerm {
-    /// transmute type into Parameter-Normal-Form (PNF)
-    ///
-    /// Example:
-    /// ```ignore
-    /// <Seq <Digit 10>>~<Seq Char>
-    /// ⇒ <Seq <Digit 10>~Char>
-    /// ```
-    pub fn param_normalize(self) -> Self {
-        match self {
-            TypeTerm::Ladder(mut rungs) => {
-                if rungs.len() > 0 {
-                    // normalize all rungs separately
-                    for r in rungs.iter_mut() {
-                        *r = r.clone().param_normalize();
-                    }
-
-                    // take top-rung
-                    match rungs.remove(0) {
-                        TypeTerm::App(params_top) => {
-                            let mut params_ladders = Vec::new();
-                            let mut tail : Vec<TypeTerm> = Vec::new();
-
-                            // append all other rungs to ladders inside
-                            // the application
-                            for p in params_top {
-                                params_ladders.push(vec![ p ]);
-                            }
-
-                            for r in rungs {
-                                match r {
-                                    TypeTerm::App(mut params_rung) => {
-                                        if params_rung.len() > 0 {
-                                            let mut first_param = params_rung.remove(0); 
-
-                                            if first_param == params_ladders[0][0] {
-                                               for (l, p) in params_ladders.iter_mut().skip(1).zip(params_rung) {
-                                                   l.push(p.param_normalize());
-                                               }
-                                            } else {
-                                               params_rung.insert(0, first_param);
-                                               tail.push(TypeTerm::App(params_rung));
-                                            }
-                                        }
-                                    }
-
-                                    TypeTerm::Ladder(mut rs) => {
-                                        for r in rs {
-                                            tail.push(r.param_normalize());
-                                        }
-                                    }
-
-                                    atomic => {
-                                        tail.push(atomic);
-                                    }
-                                }
-                            }
-
-                            let head = TypeTerm::App(
-                                params_ladders.into_iter()
-                                    .map(
-                                        |mut l| {
-                                            l.dedup();
-                                            match l.len() {
-                                                0 => TypeTerm::unit(),
-                                                1 => l.remove(0),
-                                                _ => TypeTerm::Ladder(l).param_normalize()
-                                            }
-                                        }
-                                    )
-                                    .collect()
-                            );
-
-                            if tail.len() > 0 {
-                                tail.insert(0, head);
-                                TypeTerm::Ladder(tail)
-                            } else {
-                                head
-                            }
-                        }
-
-                        TypeTerm::Ladder(mut r) => {
-                            r.append(&mut rungs);
-                            TypeTerm::Ladder(r)
-                        }
-
-                        atomic => {
-                            rungs.insert(0, atomic);
-                            TypeTerm::Ladder(rungs)
-                        }
-                    }
-                } else {
-                    TypeTerm::unit()
-                }
-            }
-
-            TypeTerm::App(params) => {
-                TypeTerm::App(
-                    params.into_iter()
-                        .map(|p| p.param_normalize())
-                        .collect())
-            }
-
-            atomic => atomic
-        }
-    }
-}
-
-//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>\\

src/sugar.rs

@@ -0,0 +1,134 @@
+use crate::{
+    TypeTerm,
+    TypeID
+};
+
+pub const SEQ_SUGARID : TypeID = TypeID::Fun(0);
+pub const ENUM_SUGARID : TypeID = TypeID::Fun(1);
+pub const STRUCT_SUGARID : TypeID = TypeID::Fun(2);
+pub const SUGARID_LIMIT : u64 = 3;
+
+#[derive(Clone)]
+pub enum SugaredTypeTerm { 
+    /* Atomic Terms */
+
+    // Base types from dictionary
+    TypeID(TypeID),
+
+    // Literals
+    Num(i64),
+    Char(char),
+
+    
+
+    /* Complex Terms */
+
+    // Type Parameters
+    // avoid currying to save space & indirection
+    App(Vec< SugaredTypeTerm >),
+
+    // Type Ladders
+    Ladder(Vec< SugaredTypeTerm >),
+
+
+    /* Sugar Terms */
+    Seq( Vec<SugaredTypeTerm> ),
+    Enum( Vec<SugaredTypeTerm> ),
+    Struct( Vec<SugaredTypeTerm> )
+}
+
+
+#[derive(Clone)]
+struct TypeAssignment {
+    id: Option<String>,
+    ty: TypeTerm,
+}
+
+#[derive(Clone)]
+struct LayoutSugar {
+    Seq( Vec<TypeAssignment> ),
+    Enum( Vec<TypeAssignment> ),
+    Struct( Vec<TypeAssignment> )
+}
+
+
+
+impl SugaredTypeTerm {
+    pub fn desugar(self) -> TypeTerm {
+        match self {
+            SugaredTypeTerm::TypeID(id) => TypeTerm::TypeID(id),
+            SugaredTypeTerm::Num(n) => TypeTerm::Num(n),
+            SugaredTypeTerm::Char(c) => TypeTerm::Char(c),
+            SugaredTypeTerm::App(params) => TypeTerm::App(params.into_iter().map(|p| p.desugar()).collect()),
+            SugaredTypeTerm::Ladder(rungs) => TypeTerm::Ladder(rungs.into_iter().map(|p| p.desugar()).collect()),
+            SugaredTypeTerm::Seq(pattern) => {
+                let mut params : Vec<TypeTerm> = pattern.into_iter().map(|p| p.desugar()).collect();
+                params.insert(0, TypeTerm::TypeID(SEQ_SUGARID));
+                TypeTerm::App(params)
+            }
+            SugaredTypeTerm::Enum(options) => {
+                let mut params : Vec<TypeTerm> = options.into_iter().map(|o| o.desugar()).collect();
+                params.insert(0, TypeTerm::TypeID(ENUM_SUGARID));
+                TypeTerm::App(params)
+            }
+            SugaredTypeTerm::Struct(members) => {
+                let mut params : Vec<TypeTerm> = members.into_iter().map(|m| m.desugar()).collect();
+                params.insert(0, TypeTerm::TypeID(STRUCT_SUGARID));
+                TypeTerm::App(params)
+            }
+        }
+    }
+
+    // normalize any unsugared parts into sugared form
+    pub fn sugar(self) -> SugaredTypeTerm {
+        // todo: optimize
+        self.desugar().sugar()
+    }
+}
+
+impl TypeTerm {
+    pub fn sugar(self) -> SugaredTypeTerm {
+        match self {
+            TypeTerm::TypeID(id) => SugaredTypeTerm::TypeID(id),
+            TypeTerm::Num(n) => SugaredTypeTerm::Num(n),
+            TypeTerm::Char(c) => SugaredTypeTerm::Char(c),
+            TypeTerm::App(mut params) => {
+                if params.len() > 0 {
+                    let prim = params.remove(0);
+                    match prim {
+                        TypeTerm::TypeID( SEQ_SUGARID ) =>
+                            SugaredTypeTerm::Seq(
+                                params
+                                    .into_iter()
+                                    .map(|p| p.sugar())
+                                    .collect()
+                            ),
+
+                        TypeTerm::TypeID( ENUM_SUGARID ) =>
+                            SugaredTypeTerm::Enum(
+                                params
+                                    .into_iter()
+                                    .map(|p| p.sugar())
+                                    .collect()
+                            ),
+                        TypeTerm::TypeID( STRUCT_SUGARID ) =>
+                            SugaredTypeTerm::Struct(
+                                params
+                                    .into_iter()
+                                    .map(|p| p.sugar())
+                                    .collect()
+                            ),
+                        other => SugaredTypeTerm::App(
+                            params.into_iter().map(|p| p.sugar()).collect()
+                        )
+                    }
+                } else {
+                    SugaredTypeTerm::App(vec![])
+                }
+            },
+            TypeTerm::Ladder(rungs) => {
+                SugaredTypeTerm::Ladder(rungs.into_iter().map(|r| r.sugar()).collect())
+            }
+        }
+    }
+}

src/test/mod.rs

@@ -2,8 +2,8 @@
 pub mod lexer;
 pub mod parser;
 pub mod curry;
+pub mod sugar;
 pub mod lnf;
-pub mod pnf;
 pub mod subtype;
 pub mod substitution;
 pub mod unification;

src/test/parser.rs

@@ -1,6 +1,6 @@
 
 use {
-    crate::{term::*, dict::*, parser::*}
+    crate::{term::*, dict::*, parser::*, sugar::SUGARID_LIMIT}
 };
 
 //<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>\\
@@ -17,7 +17,7 @@ fn test_parser_id() {
     );
 
     assert_eq!(
-        Ok(TypeTerm::TypeID(TypeID::Fun(0))),
+        Ok(TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0))),
         dict.parse("A")
     );
 }
@@ -43,16 +43,16 @@ fn test_parser_app() {
     assert_eq!(
         TypeDict::new().parse("<A B>"),
         Ok(TypeTerm::App(vec![
-            TypeTerm::TypeID(TypeID::Fun(0)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
-            TypeTerm::TypeID(TypeID::Fun(1)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+1)),
         ]))
     );
     assert_eq!(
         TypeDict::new().parse("<A B C>"),
         Ok(TypeTerm::App(vec![
-            TypeTerm::TypeID(TypeID::Fun(0)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
-            TypeTerm::TypeID(TypeID::Fun(1)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+1)),
-            TypeTerm::TypeID(TypeID::Fun(2)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+2)),
         ]))
     );
 }
@@ -78,16 +78,16 @@ fn test_parser_ladder() {
     assert_eq!(
         TypeDict::new().parse("A~B"),
         Ok(TypeTerm::Ladder(vec![
-            TypeTerm::TypeID(TypeID::Fun(0)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
-            TypeTerm::TypeID(TypeID::Fun(1)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+1)),
         ]))
     );
     assert_eq!(
         TypeDict::new().parse("A~B~C"),
         Ok(TypeTerm::Ladder(vec![
-            TypeTerm::TypeID(TypeID::Fun(0)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
-            TypeTerm::TypeID(TypeID::Fun(1)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+1)),
-            TypeTerm::TypeID(TypeID::Fun(2)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+2)),
         ]))
     );
 }
@@ -98,12 +98,12 @@ fn test_parser_ladder_outside() {
         TypeDict::new().parse("<A B>~C"),
         Ok(TypeTerm::Ladder(vec![
             TypeTerm::App(vec![
-                TypeTerm::TypeID(TypeID::Fun(0)),
+                TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
-                TypeTerm::TypeID(TypeID::Fun(1)),
+                TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+1)),
             ]),
-            TypeTerm::TypeID(TypeID::Fun(2)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+2)),
         ]))
-    );    
+    );
 }
 
 #[test]
@@ -111,10 +111,10 @@ fn test_parser_ladder_inside() {
     assert_eq!(
         TypeDict::new().parse("<A B~C>"),
         Ok(TypeTerm::App(vec![
-            TypeTerm::TypeID(TypeID::Fun(0)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
             TypeTerm::Ladder(vec![
-                TypeTerm::TypeID(TypeID::Fun(1)),
+                TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+1)),
-                TypeTerm::TypeID(TypeID::Fun(2)),
+                TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+2)),
             ])
         ]))
     );    
@@ -125,12 +125,12 @@ fn test_parser_ladder_between() {
     assert_eq!(
         TypeDict::new().parse("<A B~<C D>>"),
         Ok(TypeTerm::App(vec![
-            TypeTerm::TypeID(TypeID::Fun(0)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
             TypeTerm::Ladder(vec![
-                TypeTerm::TypeID(TypeID::Fun(1)),
+                TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+1)),
                 TypeTerm::App(vec![
-                    TypeTerm::TypeID(TypeID::Fun(2)),
+                    TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+2)),
-                    TypeTerm::TypeID(TypeID::Fun(3)),
+                    TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+3)),
                 ])
             ])
         ]))
@@ -156,48 +156,48 @@ fn test_parser_ladder_large() {
         Ok(
             TypeTerm::Ladder(vec![
                 TypeTerm::App(vec![
-                    TypeTerm::TypeID(TypeID::Fun(0)),
+                    TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
                     TypeTerm::Ladder(vec![
-                        TypeTerm::TypeID(TypeID::Fun(1)),
+                        TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+1)),
                         TypeTerm::App(vec![
-                            TypeTerm::TypeID(TypeID::Fun(2)),
+                            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+2)),
-                            TypeTerm::TypeID(TypeID::Fun(3))
+                            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+3))
                         ]),
                         TypeTerm::App(vec![
-                            TypeTerm::TypeID(TypeID::Fun(4)),
+                            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+4)),
-                            TypeTerm::TypeID(TypeID::Fun(5))
+                            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+5))
                         ]),
-                        TypeTerm::TypeID(TypeID::Fun(6)),
+                        TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+6)),
                         TypeTerm::App(vec![
-                            TypeTerm::TypeID(TypeID::Fun(7)),
+                            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+7)),
                             TypeTerm::Num(10),
-                            TypeTerm::TypeID(TypeID::Fun(8))
+                            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+8))
                         ]),
                         TypeTerm::App(vec![
-                            TypeTerm::TypeID(TypeID::Fun(0)),
+                            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
                             TypeTerm::Ladder(vec![
                                 TypeTerm::App(vec![
-                                    TypeTerm::TypeID(TypeID::Fun(9)),
+                                    TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+9)),
                                     TypeTerm::Num(10)
                                 ]),
-                                TypeTerm::TypeID(TypeID::Fun(10))
+                                TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+10))
                             ])
                         ])
                     ])
                 ]),
                 TypeTerm::App(vec![
-                    TypeTerm::TypeID(TypeID::Fun(11)),
+                    TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+11)),
-                    TypeTerm::TypeID(TypeID::Fun(10)),
+                    TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+10)),
                     TypeTerm::Char(':')
                 ]),
                 TypeTerm::App(vec![
-                    TypeTerm::TypeID(TypeID::Fun(0)),
+                    TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
-                    TypeTerm::TypeID(TypeID::Fun(10))
+                    TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+10))
                 ]),
-                TypeTerm::TypeID(TypeID::Fun(12)),
+                TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+12)),
                 TypeTerm::App(vec![
-                    TypeTerm::TypeID(TypeID::Fun(0)),
+                    TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
-                    TypeTerm::TypeID(TypeID::Fun(13))
+                    TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+13))
                 ])
             ])
         )

src/test/pnf.rs

@@ -1,41 +0,0 @@
-use crate::dict::TypeDict;
-
-#[test]
-fn test_param_normalize() {
-    let mut dict = TypeDict::new();
-
-    assert_eq!(
-        dict.parse("A~B~C").expect("parse error"),
-        dict.parse("A~B~C").expect("parse error").param_normalize(),
-    );
-
-    assert_eq!(
-        dict.parse("<A B>~C").expect("parse error"),
-        dict.parse("<A B>~C").expect("parse error").param_normalize(),
-    );
-
-    assert_eq!(
-        dict.parse("<A B~C>").expect("parse error"),
-        dict.parse("<A B>~<A C>").expect("parse error").param_normalize(),
-    );
-
-    assert_eq!(
-        dict.parse("<A B~C D~E>").expect("parse error"),
-        dict.parse("<A B D>~<A C D>~<A C E>").expect("parse errror").param_normalize(),
-    );
-
-    assert_eq!(
-        dict.parse("<Seq <Digit 10>~Char>").expect("parse error"),
-        dict.parse("<Seq <Digit 10>>~<Seq Char>").expect("parse errror").param_normalize(),
-    );
-
-    assert_eq!(
-        dict.parse("<A <B C~D~E> F~G H H>").expect("parse error"),
-        dict.parse("<A <B C> F H H>
-                   ~<A <B D> F H H>
-                   ~<A <B E> F H H>
-                   ~<A <B E> G H H>").expect("parse errror")
-               .param_normalize(),
-    );
-}
-

src/test/sugar.rs

@@ -0,0 +1,10 @@
+
+#[test]
+fn test_sugar() {
+
+    let mut dict = crate::TypeDict::new();
+
+    
+}
+
+

src/test/unification.rs

@@ -13,8 +13,8 @@ fn test_unify(ts1: &str, ts2: &str, expect_unificator: bool) {
     dict.add_varname(String::from("V"));
     dict.add_varname(String::from("W"));
 
-    let mut t1 = dict.parse(ts1).unwrap();
+    let mut t1 = dict.parse(ts1).unwrap().desugar();
-    let mut t2 = dict.parse(ts2).unwrap();
+    let mut t2 = dict.parse(ts2).unwrap().desugar();
     let σ = crate::unify( &t1, &t2 );
 
     if expect_unificator {