diff --git a/src/dict.rs b/src/dict.rs
index 419d599..a28573c 100644
--- a/src/dict.rs
+++ b/src/dict.rs
@@ -1,4 +1,7 @@
-use crate::bimap::Bimap;
+use crate::{
+    bimap::Bimap,
+    sugar::SUGARID_LIMIT
+};
 
 //<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>\\
 
@@ -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 {
diff --git a/src/lexer.rs b/src/lexer.rs
index 8c56a0d..62b8efe 100644
--- a/src/lexer.rs
+++ b/src/lexer.rs
@@ -6,9 +6,9 @@ pub enum LadderTypeToken {
     Symbol( String ),
     Char( char ),
     Num( i64 ),
-    Open,
-    Close,
-    Ladder,
+    Open, OpenSeq, OpenStruct,
+    Close, CloseSeq, CloseStruct,
+    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 => {
diff --git a/src/lib.rs b/src/lib.rs
index e073b0b..a23069f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -7,6 +7,7 @@ pub mod parser;
 pub mod unparser;
 pub mod sugar;
 pub mod curry;
+pub mod sugar;
 pub mod lnf;
 pub mod subtype;
 pub mod unification;
diff --git a/src/parser.rs b/src/parser.rs
index 85ff9b4..87ed5c1 100644
--- a/src/parser.rs
+++ b/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::Num(n))) => Ok(TypeTerm::Num(n)),
+            Some(Ok(LadderTypeToken::Char(c))) => Ok(SugaredTypeTerm::Char(c)),
+            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)),
         }
     }
 }
diff --git a/src/sugar.rs b/src/sugar.rs
deleted file mode 100644
index 4d13f78..0000000
--- a/src/sugar.rs
+++ /dev/null
@@ -1,95 +0,0 @@
-use {
-    crate::{TypeTerm, TypeID}
-};
-
-pub enum SugaredTypeTerm {
-    TypeID(TypeID),
-    Num(i64),
-    Char(char),
-    Univ(Box< SugaredTypeTerm >),
-    Spec(Vec< SugaredTypeTerm >),
-    Func(Vec< SugaredTypeTerm >),
-    Morph(Vec< SugaredTypeTerm >),
-    Ladder(Vec< SugaredTypeTerm >),
-    Struct(Vec< SugaredTypeTerm >),
-    Enum(Vec< SugaredTypeTerm >),
-    Seq(Vec< SugaredTypeTerm >)
-}
-
-impl TypeTerm {
-    pub fn sugar(self: TypeTerm, dict: &mut crate::TypeDict) -> SugaredTypeTerm {
-        match self {
-            TypeTerm::TypeID(id) => SugaredTypeTerm::TypeID(id),
-            TypeTerm::Num(n) => SugaredTypeTerm::Num(n),
-            TypeTerm::Char(c) => SugaredTypeTerm::Char(c),
-            TypeTerm::App(args) => if let Some(first) = args.first() {
-                if first == &dict.parse("Func").unwrap() {
-                    SugaredTypeTerm::Func( args[1..].into_iter().map(|t| t.clone().sugar(dict)).collect() )
-                }
-                else if first == &dict.parse("Morph").unwrap() {
-                    SugaredTypeTerm::Morph( args[1..].into_iter().map(|t| t.clone().sugar(dict)).collect() )
-                }
-                else if first == &dict.parse("Struct").unwrap() {
-                    SugaredTypeTerm::Struct( args[1..].into_iter().map(|t| t.clone().sugar(dict)).collect() )
-                }
-                else if first == &dict.parse("Enum").unwrap() {
-                    SugaredTypeTerm::Enum( args[1..].into_iter().map(|t| t.clone().sugar(dict)).collect() )
-                }
-                else if first == &dict.parse("Seq").unwrap() {
-                    SugaredTypeTerm::Seq( args[1..].into_iter().map(|t| t.clone().sugar(dict)).collect() )
-                }
-                else if first == &dict.parse("Spec").unwrap() {
-                    SugaredTypeTerm::Spec( args[1..].into_iter().map(|t| t.clone().sugar(dict)).collect() )
-                }
-                else if first == &dict.parse("Univ").unwrap() {
-                    SugaredTypeTerm::Univ(Box::new(
-                        SugaredTypeTerm::Spec(
-                            args[1..].into_iter().map(|t| t.clone().sugar(dict)).collect()
-                        )
-                    ))
-                }
-                else {
-                    SugaredTypeTerm::Spec(args.into_iter().map(|t| t.sugar(dict)).collect())
-                }
-            } else {
-                SugaredTypeTerm::Spec(args.into_iter().map(|t| t.sugar(dict)).collect())
-            },
-            TypeTerm::Ladder(rungs) =>            
-               SugaredTypeTerm::Ladder(rungs.into_iter().map(|t| t.sugar(dict)).collect())
-        }
-    }
-}
-
-impl SugaredTypeTerm {
-    pub fn desugar(self, dict: &mut crate::TypeDict) -> TypeTerm {
-        match self {
-            SugaredTypeTerm::TypeID(id) => TypeTerm::TypeID(id),
-            SugaredTypeTerm::Num(n) => TypeTerm::Num(n),
-            SugaredTypeTerm::Char(c) => TypeTerm::Char(c),
-            SugaredTypeTerm::Univ(t) => t.desugar(dict),
-            SugaredTypeTerm::Spec(ts) => TypeTerm::App(ts.into_iter().map(|t| t.desugar(dict)).collect()),
-            SugaredTypeTerm::Ladder(ts) => TypeTerm::Ladder(ts.into_iter().map(|t|t.desugar(dict)).collect()),
-            SugaredTypeTerm::Func(ts) => TypeTerm::App(
-                std::iter::once( dict.parse("Func").unwrap() ).chain(
-                    ts.into_iter().map(|t| t.desugar(dict))
-                ).collect()),
-            SugaredTypeTerm::Morph(ts) => TypeTerm::App(
-                std::iter::once( dict.parse("Morph").unwrap() ).chain(
-                    ts.into_iter().map(|t| t.desugar(dict))
-                ).collect()),
-            SugaredTypeTerm::Struct(ts) => TypeTerm::App(
-                std::iter::once( dict.parse("Struct").unwrap() ).chain(
-                    ts.into_iter().map(|t| t.desugar(dict))
-                ).collect()),
-            SugaredTypeTerm::Enum(ts) => TypeTerm::App(
-                std::iter::once( dict.parse("Enum").unwrap() ).chain(
-                    ts.into_iter().map(|t| t.desugar(dict))
-                ).collect()),
-            SugaredTypeTerm::Seq(ts) => TypeTerm::App(
-                std::iter::once( dict.parse("Seq").unwrap() ).chain(
-                    ts.into_iter().map(|t| t.desugar(dict))
-                ).collect()),
-        }
-    }
-}
-
diff --git a/src/test/mod.rs b/src/test/mod.rs
index d116412..ea52c7d 100644
--- a/src/test/mod.rs
+++ b/src/test/mod.rs
@@ -2,6 +2,7 @@
 pub mod lexer;
 pub mod parser;
 pub mod curry;
+pub mod sugar;
 pub mod lnf;
 pub mod subtype;
 pub mod substitution;
diff --git a/src/test/parser.rs b/src/test/parser.rs
index 1166229..49deb7c 100644
--- a/src/test/parser.rs
+++ b/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(1)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
+            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(1)),
-            TypeTerm::TypeID(TypeID::Fun(2)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+1)),
+            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(1)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
+            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(1)),
-            TypeTerm::TypeID(TypeID::Fun(2)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
+            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+1)),
+            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(1)),
+                TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
+                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(2)),
+                TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+1)),
+                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(3)),
+                    TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+2)),
+                    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(3))
+                            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+2)),
+                            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+3))
                         ]),
                         TypeTerm::App(vec![
-                            TypeTerm::TypeID(TypeID::Fun(4)),
-                            TypeTerm::TypeID(TypeID::Fun(5))
+                            TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+4)),
+                            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(10)),
+                    TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+11)),
+                    TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+10)),
                     TypeTerm::Char(':')
                 ]),
                 TypeTerm::App(vec![
-                    TypeTerm::TypeID(TypeID::Fun(0)),
-                    TypeTerm::TypeID(TypeID::Fun(10))
+                    TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
+                    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(13))
+                    TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+0)),
+                    TypeTerm::TypeID(TypeID::Fun(SUGARID_LIMIT+13))
                 ])
             ])
         )
diff --git a/src/test/sugar.rs b/src/test/sugar.rs
new file mode 100644
index 0000000..c6a9768
--- /dev/null
+++ b/src/test/sugar.rs
@@ -0,0 +1,10 @@
+
+#[test]
+fn test_sugar() {
+
+    let mut dict = crate::TypeDict::new();
+
+    
+}
+
+
diff --git a/src/test/unification.rs b/src/test/unification.rs
index 34d355d..19c6768 100644
--- a/src/test/unification.rs
+++ b/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 t2 = dict.parse(ts2).unwrap();
+    let mut t1 = dict.parse(ts1).unwrap().desugar();
+    let mut t2 = dict.parse(ts2).unwrap().desugar();
     let σ = crate::unify( &t1, &t2 );
 
     if expect_unificator {