handle application as list

src/PostProcess.hs

@@ -30,10 +30,11 @@ runProcess = (fst <$>) .: runStateT
 postprocess :: [H.Def] -> Process [TL]
 postprocess defs = addDef <~> defs >> defToTL <~> defs
 
+-- just adds types for processing type signatures
 addDef :: H.Def -> Process ()
 addDef = \case
-  H.VarDef _ i t _ -> lift . addEnv i =<< typeSigToPolyT t -- the type checker will check this matches the exp
   H.TypeDef _ t _  -> insertType =<< fst <$> typeSigToIdParams t
+  H.VarDef _ i t _ -> pure ()
 
 -- add type before typesig to id params
 defToTL :: H.Def -> Process TL
@@ -92,12 +93,7 @@ expToExp :: H.Exp -> Process Exp
 expToExp = \case
   H.ExpLet p as e  -> Let p <$> assignTo2pl <~> as <*> expToExp e
   H.ExpAbs p is e  -> Abs p is <$> expToExp e
-  H.ExpApp p e1 (e2:es)  -> do
+  H.ExpApp p e es  -> App p <$> expToExp e <*> expToExp <~> es
-    e1' <- expToExp e1
-    e2' <- expToExp e2
-    es' <- traverse expToExp es
-    pure (foldl (App p) (App p e1' e2') es')
-  H.ExpApp p e []  -> throwError Oop
   H.ExpVar p i     -> pure (Var p i)
 
 declTo2pl :: H.Decl -> Process (Id, MonoT)

src/TC.hs

@@ -149,6 +149,9 @@ constructs _ _          = False
 
 infer :: Exp -> Check (Subst, MonoT)
 infer = setPos >=> \case
+
+    Var _ i   -> (emptySubst,) <$> lookupType i
+
     Let _ [] e            -> infer e
     Let p ((i,e1):ies) e2 -> do
       (s1, t1) <- infer e1
@@ -165,13 +168,31 @@ infer = setPos >=> \case
       (s, t) <- infer (Abs p is e)
       pure (s, apply s tv `TArr` t)
 
-  App   p e1 e2 -> localEnv' $ do
+    App _ e es -> go e (reverse es)
-    tv <- fresh
+      where
+        go :: Exp -> [Exp] -> Check (Subst, MonoT)
+        go _ [] = throwError Oop
+        go e1 [e2] = localEnv' $ do
+
             (s1, t1) <- infer e1
             applyEnv s1
-    (s2, t2) <- infer e2
-    s3       <- unify (apply s2 t1) (TArr t2 tv)
-    return (s3 <&> s2 <&> s1, apply s3 tv)
-  App   _ _ _ -> throwError Oop
 
-  Var   _ i   -> (emptySubst,) <$> lookupType i
+            (s2, t2) <- infer e2
+
+            tv <- fresh
+
+            s3 <- unify (apply s2 t1) (t2 `TArr` tv)
+            pure (s3 <&> s2 <&> s1, apply s3 tv)
+
+        go e1 (e2:es) = localEnv' $ do
+
+            (s1, t1) <- go e1 es
+            applyEnv s1
+
+            (s2, t2) <- infer e2
+
+            tv <- fresh
+
+            s3 <- unify (apply s2 t1) (t2 `TArr` tv)
+
+            pure (s3 <&> s2 <&> s1, apply s3 tv)

src/Type.hs

@@ -41,7 +41,7 @@ type Exp = Exp' Pos
 data Exp' a
   = Let a [(Id,Exp)] Exp
   | Abs a [Id] Exp
-  | App a Exp Exp
+  | App a Exp [Exp]
   | Var a Id
   deriving Show
 

tst

@@ -0,0 +1 @@
+λf g x y z w. f w (g x y z)