Add "fun" syntax.

1 files changed, 19 insertions, 9 deletions

diff --git a/parser.sml b/parser.sml
index e4c7359..c1432f2 100644
--- a/parser.sml
+++ b/parser.sml
@@ -458,15 +458,25 @@ struct
       const (Syntax.ECase (e, arms)))))
   <|> orelseExpr) st
   and dec : Syntax.dec parser = fn st =>
-    (reserved "val" >>
-    bind (true <$ reserved "rec" <|> const false) (fn isRec =>
-    bind pat (fn p =>
-    reserved "=" >>
-    bind expr (fn e =>
-    const
-      (if isRec
-      then Syntax.DValRec (p, e)
-      else Syntax.DVal (p, e)))))) st
+      ((reserved "val" >>
+      bind (true <$ reserved "rec" <|> const false) (fn isRec =>
+      bind pat (fn p =>
+      reserved "=" >>
+      bind expr (fn e =>
+      const
+        (if isRec
+        then Syntax.DValRec (p, e)
+        else Syntax.DVal (p, e))))))
+  <|> (reserved "fun" >>
+      bind identifier (fn name =>
+      bind (many1 atpat) (fn args =>
+      reserved "=" >>
+      bind expr (fn body =>
+      const
+        (Syntax.DValRec
+          ( Syntax.PVar name
+          , foldr Syntax.ELambda body args
+          ))))))) st
 
   val program : Syntax.expr parser = (fn decs => Syntax.ELet (decs, Syntax.EInt 0)) <$> many dec
   fun parse (f : string) : (string, Syntax.expr) Result.either = runParser program f