Broken monads

[cc1516.git] / sem.icl

diff --git a/sem.icl b/sem.icl
index 9be1948..4a3fbe5 100644 (file)
--- a/sem.icl
+++ b/sem.icl
@@ -20,10 +20,41 @@ import AST
 from parse import :: ParserOutput, :: Error
 
 :: Gamma :== 'Map'.Map String Type
-:: Env a :== (State Gamma (Either SemError a))
+:: Env a = Env (State Gamma (Either SemError a))
+
+instance Functor Env where
+    fmap f m = liftM f m
+
+instance Applicative Env where
+    (<*>) f g   = ap f g
+    pure  a     = Env $ pure $ Right a
+
+instance Alternative Env where
+    empty       = Env $ pure $ Left (Error "Undefined error")
+    (<|>) f g   = f >>= \ef -> g >>= \eg -> Env $ pure $ (ef <|> eg) //case ef of 
+        //Left e  = eg
+        //Right r = Right r
+
+instance Monad Env where
+    bind e f    = e >>= \ee -> Env $ pure $ case ee of
+        (Left e) = Left e
+        (Right r) = f r
 
 get = state $ \s -> (s,s)
 
+instance toString SemError where
+    toString (ParseError p e) = concat [
+        toString p,"SemError: ParseError: ", e]
+    toString (Error e) = "SemError: " +++ e
+    toString (UnifyErrorStub t1 t2) = toString (UnifyError {line=0,col=0} t1 t2)
+    toString (UnifyError p t1 t2) = concat [
+        toString p,
+        "SemError: Cannot unify types. Expected: ",
+        toString t1, ". Given: ", toString t2]
+
+sem :: AST -> SemOutput
+sem x = undef
+/*
 putIdent :: String Type -> Env Void
 putIdent i t = gets ('Map'.get i) >>= \mt -> case mt of
     Nothing = pure <$> modify ('Map'.put i t)
@@ -31,16 +62,6 @@ putIdent i t = gets ('Map'.get i) >>= \mt -> case mt of
         Left e  = pure $ Left e
         Right t3 = pure <$> modify ('Map'.put i t3)
 
-instance toString SemError where
-       toString (ParseError p e) = concat [
-               toString p,"SemError: ParseError: ", e]
-       toString (Error e) = "SemError: " +++ e
-       toString (UnifyErrorStub t1 t2) = toString (UnifyError {line=0,col=0} t1 t2)
-       toString (UnifyError p t1 t2) = concat [
-               toString p,
-               "SemError: Cannot unify types. Expected: ",
-               toString t1, ". Given: ", toString t2]
-
 sem :: AST -> SemOutput
 sem (AST vd fd)
 # (eithervds, gamma) = runState (mapM semVarDecl vd) 'Map'.newMap
@@ -75,11 +96,11 @@ typeExpr (TupleExpr p (e1, e2)) = typeExpr e1
        >>= \ete1->typeExpr e2 >>= \ete2->pure (
                ete1 >>= \te1->ete2 >>= \te2->Right $ TupleType (te1, te2))
 //Int
-typeExpr (Op2Expr p e1 BiPlus e2) = undef
-typeExpr (Op2Expr p e1 BiMinus e2) = undef
-typeExpr (Op2Expr p e1 BiTimes e2) = undef
-typeExpr (Op2Expr p e1 BiDivide e2) = undef
-typeExpr (Op2Expr p e1 BiMod e2) = undef
+typeExpr (Op2Expr p e1 BiPlus e2) = unify IntType e1 >>| unify IntType e2
+typeExpr (Op2Expr p e1 BiMinus e2) = unify IntType e1 >>| unify IntType e2
+typeExpr (Op2Expr p e1 BiTimes e2) = unify IntType e1 >>| unify IntType e2
+typeExpr (Op2Expr p e1 BiDivide e2) = unify IntType e1 >>| unify IntType e2
+typeExpr (Op2Expr p e1 BiMod e2) = unify IntType e1 >>| unify IntType e2
 //bool, char of int
 typeExpr (Op2Expr p e1 BiEquals e2) = undef
 typeExpr (Op2Expr p e1 BiUnEqual e2) = undef
@@ -95,7 +116,8 @@ typeExpr (Op2Expr p e1 BiOr e2) = undef
 typeExpr (Op2Expr p e1 BiCons e2) = undef
 //typeExpr (FunExpr Pos FunCall) = undef
 //typeExpr (EmptyListExpr Pos) = undef
-//typeExpr (VarExpr Pos VarDef) = undef
+//typeExpr (VarExpr Pos VarDef) = undef //when checking var-expr, be sure to put the infered type
+                                        //in the context
 
 class unify a :: Type a -> Env Type
 
@@ -106,6 +128,7 @@ instance unify Expr where
                        "Expression cannot be a Void type."
        unify (IdType _) e = pure $ Left $ ParseError (extrPos e)
                        "Expression cannot be an polymorf type."
+    unify VarType e = typeExpr e
        unify t e = typeExpr e
                >>= \eithertype->case eithertype of
                        Left e = pure $ Left e
@@ -137,3 +160,4 @@ extrPos (BoolExpr p _) = p
 extrPos (FunExpr p _) = p
 extrPos (EmptyListExpr p) = p
 extrPos (TupleExpr p _) = p
+*/
\ No newline at end of file