Type inference for functions works YAAAY

diff --git a/AST.dcl b/AST.dcl
index 4f65b0e..0bfe1ba 100644 (file)
--- a/AST.dcl
+++ b/AST.dcl
@@ -42,6 +42,9 @@ from StdOverloaded import class toString, class ==, class zero, class <
 instance toString Pos
 instance toString Type
 instance toString AST
+instance toString FieldSelector
+instance toString Op2
+instance toString Expr
 
 instance zero Pos
 instance == Op1

diff --git a/AST.icl b/AST.icl
index 68def61..ae4934f 100644 (file)
--- a/AST.icl
+++ b/AST.icl
@@ -73,6 +73,8 @@ instance print FieldSelector where
        print FieldTl = print "tl"
        print FieldSnd = print "snd"
        print FieldFst = print "fst"
+instance toString FieldSelector  where
+    toString fs = concat $ print fs
 
 instance print VarDef where
        print (VarDef i fs) = printersperse "." [i:printersperse "" fs]
@@ -105,6 +107,8 @@ instance print Expr where
        print (FunExpr _ id as fs) = printFunCall id as ++ printSelectors fs
        print (EmptyListExpr _) = ["[]"]
        print (TupleExpr _ (e1, e2)) = ["(":print e1] ++ [",":print e2] ++ [")"]
+instance toString Expr where
+    toString e = concat $ print e
 
 printSelectors :: [FieldSelector] -> [String]
 printSelectors x = case x of [] = [""]; _ = [".":printersperse "." x]

diff --git a/examples/varEx.spl b/examples/varEx.spl
index 95c9a13..5fc6340 100644 (file)
--- a/examples/varEx.spl
+++ b/examples/varEx.spl
@@ -1,38 +1,50 @@
-Int a = 1 + 1;
-var b = True;
-var c = 2 + 2;
-
-var d = True;
-var e = 4;
-//Int f = 4 + True;
-
-var g = True == True;
-var h = 1 != 3;
-//var i = True == 1;
-
-var j = 1 < 3;
-//var k = True < 3;
-
-var l = 1:2:[];
-
-var m = 4;
-var n = m + 2;
-//var q = v + 2;
-//var z = !v;
-
-var pim = 'a' == 'b';
-//var pim = 'a' + 'b';
-//var pim = ('a':[]) == ('b':[]);
-//var o = v + 2;
-//var p = !v;
-
-var q = facR(3);
-
-facR(n) :: Int -> Int {
-    if (True) {
-        return 3;
+//Int a = 1 + 1;
+b(a, c) { if (c) {
+        return a+4;
     } else {
-        return 4;
-    }
-    return 5;
+        return 0;
+    } 
 }
+d() { return (b(1,True)); }
+e() { return e(); }
+f() { return e(); }
+id(x) {return x;}
+y() { return id(5); }
+z() { return id(True); }
+//var c = 2 + 2;//
+
+//var d = True;
+//var e = 4;
+////Int f = 4 + True;//
+
+//var g = True == True;
+//var h = 1 != 3;
+////var i = True == 1;//
+
+//var j = 1 < 3;
+////var k = True < 3;//
+
+//var l = 1:2:[];//
+
+//var m = 4;
+//var n = m + 2;
+////var q = v + 2;
+////var z = !v;//
+
+//var pim = 'a' == 'b';
+////var pim = 'a' + 'b';
+////var pim = ('a':[]) == ('b':[]);
+////var o = v + 2;
+////var p = !v;//
+
+//var q = facR(3);//
+
+//facR(n) :: Int -> Int {
+//    if (True) {
+//        return 3;
+//    } else {
+//        return 4;
+//    }
+//    return 5;
+//}
+main() {return 0;}
\ No newline at end of file

diff --git a/sem.dcl b/sem.dcl
index 2656624..2b13436 100644 (file)
--- a/sem.dcl
+++ b/sem.dcl
@@ -13,4 +13,4 @@ from StdOverloaded import class toString
 instance toString SemError
 instance toString Gamma
 
-sem :: AST -> Either [SemError] Constraints
+sem :: AST -> Either [SemError] AST

diff --git a/sem.icl b/sem.icl
index 24943fe..791ae69 100644 (file)
--- a/sem.icl
+++ b/sem.icl
@@ -29,6 +29,7 @@ import AST
 
 :: Scheme = Forall [TVar] Type
 :: Gamma :== 'Map'.Map String Scheme //map from Variables! to types
+:: Typing a :== StateT (Gamma, [TVar]) (Either SemError) a
 :: Substitution :== 'Map'.Map TVar Type
 :: Constraints :== [(Type, Type)]
 :: SemError
@@ -48,12 +49,14 @@ instance zero Gamma where
 variableStream :: [TVar]
 variableStream = map toString [1..]
 
-sem :: AST -> Either [SemError] Constraints
+sem :: AST -> Either [SemError] AST
+//sem a = pure a
 sem (AST fd) = case foldM (const $ hasNoDups fd) () fd 
-               >>| foldM (const isNiceMain) () fd
-               >>| hasMain fd of
+                       >>| foldM (const isNiceMain) () fd
+                       >>| hasMain fd
+                    >>| evalStateT (type fd) (zero, variableStream) of
        Left e = Left [e]
-    _ = Right []
+    Right fds = Right (AST fds)
        //_ = case execRWST (constraints fd) zero variableStream of
        //      Left e = Left [e]
        //      Right (a, b) = Right b
@@ -144,12 +147,12 @@ occurs :: TVar a -> Bool | Typeable a
 occurs tvar a = elem tvar (ftv a)
 
 unify :: Type Type -> Either SemError Substitution
-unify t1=:(IdType tv) t2 = unify t2 t1
 unify t1 t2=:(IdType tv)    | t1 == (IdType tv) = Right zero
                             | occurs tv t1 = Left $ InfiniteTypeError zero t1
                             | otherwise = Right $ 'Map'.singleton tv t1
+unify t1=:(IdType tv) t2 = unify t2 t1
 unify (ta1->>ta2) (tb1->>tb2) = unify ta1 tb1 >>= \s1->
-                                unify tb1 tb2 >>= \s2->
+                                unify ta2 tb2 >>= \s2->
                                 Right $ compose s1 s2
 unify (TupleType (ta1,ta2)) (TupleType (tb1,tb2)) = unify ta1 tb1 >>= \s1->
                                                     unify ta2 tb2 >>= \s2->
@@ -161,8 +164,6 @@ unify t1 t2 | t1 == t2  = Right zero
 //// ------------------------
 //// Algorithm M, Inference and Solving
 //// ------------------------
-//The typing monad
-:: Typing a :== StateT (Gamma, [TVar]) (Either SemError) a
 gamma :: Typing Gamma
 gamma = gets fst
 putGamma :: Gamma -> Typing ()
@@ -221,6 +222,7 @@ instance infer Expr where
         pure ((compose s3 $ compose s2 s1), subst s3 tv)
 
     Op1Expr _ op e1 =
+        abort "infereing op1" >>|
         infer e1 >>= \(s1, t1) -> 
         fresh >>= \tv ->
         let given = t1 ->> tv in 
@@ -228,9 +230,10 @@ instance infer Expr where
         lift (unify expected given) >>= \s2 ->
         pure (compose s2 s1, subst s2 tv)
 
-    EmptyListExpr _ = (\tv->(zero,tv)) <$> fresh
+    EmptyListExpr _ = abort "infereing []" >>| (\tv->(zero,tv)) <$> fresh
 
     TupleExpr _ (e1, e2) = 
+        abort "infereing (,)" >>|
         infer e1 >>= \(s1, t1) -> 
         infer e2 >>= \(s2, t2) ->
         pure (compose s2 s1, TupleType (t1,t2))
@@ -239,6 +242,7 @@ instance infer Expr where
         lookup f >>= \expected ->
         let accST = (\(s,ts) e->infer e >>= \(s_,et)->pure (compose s_ s,ts++[et])) in
         foldM accST (zero,[]) args >>= \(s1, argTs)->
+        //abort (concat (["argsTs: "] ++ (map toString argTs))) >>|
         fresh >>= \tv->
         let given = foldr (->>) tv argTs in
         lift (unify expected given) >>= \s2->
@@ -307,7 +311,9 @@ instance infer [a] | infer a where
     infer []        = pure (zero, VoidType)
     infer [stmt:ss] = 
         infer stmt >>= \(s1, t1) ->
+        applySubst s1 >>|
         infer ss >>= \(s2, t2) ->
+        applySubst s2 >>|
         case t1 of
             VoidType = pure (compose s2 s1, t2)
             _ = case t2 of
@@ -333,34 +339,68 @@ instance type VarDecl where
 
 instance type FunDecl where
     type (FunDecl p f args expected vds stmts) = 
+        introduce f >>|
+        mapM introduce args >>= \argTs->
         type vds >>= \tVds->
-        infer stmts >>= \(s, given)->
-        applySubst s >>|
+        infer stmts >>= \(s1, result)->
+        let given = foldr (->>) result argTs in 
+        applySubst s1 >>|
         (case expected of
             Nothing = pure zero
             Just expected_ = lift (unify expected_ given))
-        >>|
-        generalize given >>= \t->
+        >>= \s2 ->
+        let ftype = subst (compose s2 s1) given in
+        generalize ftype >>= \t->
         changeGamma (extend f t) >>| 
-        pure (FunDecl p f args (Just given) tVds stmts)
+        pure (FunDecl p f args (Just ftype) tVds stmts)
+
+instance toString (Maybe a) | toString a where
+    toString Nothing = "Nothing"
+    toString (Just e) = concat ["Just ", toString e]
 
 instance type [a] | type a where
     type dcls = mapM type dcls
 
-
+introduce :: String -> Typing Type
+introduce k = 
+    fresh >>= \tv ->
+    changeGamma (extend k (Forall [] tv)) >>|
+    pure tv
 
 instance toString Scheme where
     toString (Forall x t) = 
-        concat ["Forall ": map ((+++) "\n") x] +++ toString t
+        concat ["Forall ": intersperse "," x] +++ concat [". ", toString t];
 
 instance toString Gamma where
     toString mp = 
         concat [concat [k, ": ", toString v, "\n"]\\(k, v)<-'Map'.toList mp]
 
+instance toString Substitution where
+    toString subs = 
+        concat [concat [k, ": ", toString t, "\n"]\\(k, t)<-'Map'.toList subs]
+
 instance toString SemError where
     toString (SanityError p e) = concat [toString p, 
         "SemError: SanityError: ", e]
-    toString se = "SemError: "
+    toString (ParseError p s) = concat [toString p, 
+        "ParseError: ", s]
+    toString (UnifyError p t1 t2) = concat [toString p, 
+        "Can not unify types, expected|given:\n", toString t1,
+        "\n", toString t2]
+    toString (InfiniteTypeError p t) = concat [toString p, 
+        "Infinite type: ", toString t]
+    toString (FieldSelectorError p t fs) = concat [toString p,
+        "Can not run fieldselector '", toString fs, "' on type: ",
+        toString t]
+    toString (OperatorError p op t) = concat [toString p,
+        "Operator error, operator '", toString op, "' can not be",
+        "used on type: ", toString t]
+    toString (UndeclaredVariableError p k) = concat [toString p,
+        "Undeclared identifier: ", k]
+    toString (ArgumentMisMatchError p str) = concat [toString p,
+        "Argument mismatch: ", str]
+    toString (Error e) = concat ["Unknown error during semantical",
+        "analysis: ", e]
 
 instance MonadTrans (StateT (Gamma, [TVar])) where
     liftT m = StateT \s-> m >>= \a-> return (a, s)

diff --git a/spl.icl b/spl.icl
index 8004933..cf3d5f3 100644 (file)
--- a/spl.icl
+++ b/spl.icl
@@ -69,9 +69,9 @@ Start w
                                stdin <<<  "//PARSER\n" <<< toString parseOut <<< "//PARSER\n")
                        = case sem parseOut of
                                (Left e) = snd $ fclose (stdin <<< join "\n" (map toString e)) w
-                               (Right constraints)
+                               (Right ast)
                                # stdin = if (not args.sem) stdin (stdin
-                                       <<< "//SEM G\n" <<< printConstraints constraints <<< "//SEMA\n")
+                                       <<< "//SEM G\n" <<< toString ast <<< "//SEMA\n")
                                = snd $ fclose (stdin <<< "\n") w
                where
                        printConstraints :: Constraints -> String