Parse lambdas

elliottt · Jan 28, 2018 · bcd607e · bcd607e
1 parent 105c3b6
commit bcd607e
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Showing 3 changed files with 25 additions and 1 deletion.
diff --git a/src/Dang/Syntax/AST.hs b/src/Dang/Syntax/AST.hs
@@ -75,6 +75,7 @@ data ModStruct syn = ModStruct { msMeta  :: MetaOf syn
 data Decl syn = DBind    (MetaOf syn) (Bind syn)
               | DSig     (MetaOf syn) (Sig syn)
               | DData    (MetaOf syn) (Data syn)
+              | DSyn     (MetaOf syn) (Syn syn)
               | DModBind (MetaOf syn) (IdentOf syn) (ModExpr syn)
               | DModType (MetaOf syn) (IdentOf syn) (ModType syn)
                 deriving (Generic)
@@ -91,6 +92,13 @@ data Sig syn = Sig { sigMeta   :: MetaOf syn
                    , sigSchema :: SchemaOf syn
                    } deriving (Generic)
 
+-- | A type synonym.
+data Syn syn = Syn { synMeta   :: MetaOf syn
+                   , synName   :: IdentOf syn
+                   , synParams :: [IdentOf syn]
+                   , synType   :: TypeOf syn
+                   } deriving (Generic)
+
 data ModType syn = MTVar     (MetaOf syn) (IdentOf syn)
                  | MTSig     (MetaOf syn) (ModSig syn)
                  | MTFunctor (MetaOf syn) (IdentOf syn) (ModType syn) (ModType syn)
@@ -193,6 +201,7 @@ deriving instance Cxt Show syn => Show (Expr      syn)
 deriving instance Cxt Show syn => Show (LetDecl   syn)
 deriving instance Cxt Show syn => Show (Literal   syn)
 deriving instance Cxt Show syn => Show (Data      syn)
+deriving instance Cxt Show syn => Show (Syn       syn)
 deriving instance Cxt Show syn => Show (Constr    syn)
 
 -- front-end specific types and schemas
@@ -219,6 +228,9 @@ instance HasRange (Bind Parsed) where
 instance HasRange (Data Parsed) where
   range Data { .. } = dMeta
 
+instance HasRange (Syn Parsed) where
+  range Syn { .. } = synMeta
+
 instance HasRange (Constr Parsed) where
   range Constr { .. } = cMeta
 

diff --git a/src/Dang/Syntax/Lexer.x b/src/Dang/Syntax/Lexer.x
@@ -70,7 +70,7 @@ $white+ ;
 "."      { keyword Kdot    }
 ","      { keyword Kcomma  }
 "_"      { keyword Kwild   }
-"\\"     { keyword Klambda }
+"\"      { keyword Klambda }
 
 -- numbers
 $number+ { emits (TNum 10 . read . T.unpack) }

diff --git a/src/Dang/Syntax/Parser.y b/src/Dang/Syntax/Parser.y
@@ -64,6 +64,7 @@ import           Text.Layout.OffSides (Layout(..),layout,wrapToken)
   'case'   { Keyword Kcase    $$ }
   'of'     { Keyword Kof      $$ }
 
+  '\\'     { Keyword Klambda  $$ }
   '->'     { Keyword Krarrow  $$ }
 
   '_'      { Keyword Kwild    $$ }
@@ -113,6 +114,7 @@ decl :: { [Decl Parsed] }
   : signature     { [ DSig (range sig) sig | sig <- $1 ] }
   | bind          { [DBind (range $1) $1] }
   | data_decl     { [DData (range $1) $1] }
+  | type_synonym  { [DSyn  (range $1) $1] }
   | mod_bind      { [$1] }
   | mod_type_bind { [$1] }
 
@@ -247,6 +249,9 @@ expr :: { Expr Parsed }
   : list1(aexpr)
     { mkEApp $1 }
 
+  | '\\' list1(arg_pat) '->' expr
+    { undefined }
+
   | 'let' layout(let_decl) 'in' expr
     { ELet ($1 <-> $4) (concat $2) $4 }
 
@@ -294,6 +299,13 @@ data_constr :: { Constr Parsed }
              , cName = $1
              , cParams = $2 } }
 
+type_synonym :: { Syn Parsed }
+  : 'type' con list(ident) '=' type
+    { Syn { synMeta = $1 <-> $5
+          , synName = $2
+          , synParams = $3
+          , synType   = $5 } }
+
 
 -- Names -----------------------------------------------------------------------