-from parse import :: ParserOutput, :: Error
-
-:: Gamma :== ('Map'.Map String Type, [String])
-:: Env a :== StateT Gamma (Either SemError) a
-//StateT (Gamma -> Either SemError (a, Gamma))
-
-//we need to redefine this even though it is in Control.Monad.State
-instance MonadTrans (StateT Gamma) where
- liftT m = StateT \s-> m >>= \a-> return (a, s)
-
-get = gets id
-
-sem :: AST -> SemOutput
-sem (AST vd fd) = case runStateT m ('Map'.newMap, getRandomStream 1) of
- Left e = Left [e]
- Right ((vds, fds), gamma) = Right ((AST vds fds), gamma)
-where
- m :: Env ([VarDecl], [FunDecl])
- m = mapM semVarDecl vd >>= \vds ->
- mapM semFunDecl fd >>= \fds1 ->
- mapM semFunDecl fds1 >>= \fds2 ->
- pure (vds, fds2)
-
-semFunDecl :: FunDecl -> Env FunDecl
-semFunDecl fd=:(FunDecl p f args mt vds stmts) =
- (case mt of
- Nothing = genType args >>= \infft->putIdent f infft >>| pure infft
- Just t = putIdent f t >>| pure t) >>= \ft ->
- saveGamma >>= \gamma ->
- matchFunctions args ft >>= \tres->
- mapM semVarDecl vds >>= \newvds->
- mapM (checkStmt tres) stmts >>= \newstmts->
- pure IntType >>= \returntype->
- case mt of
- Nothing = reconstructType args returntype
- >>= \ftype->restoreGamma gamma
- >>| putIdent f ftype >>| pure (
- FunDecl p f args (Just ftype) newvds newstmts)
- Just t = restoreGamma gamma
- >>| pure (FunDecl p f args mt newvds newstmts)
-
-reconstructType :: [String] Type -> Env Type
-reconstructType [] t = pure t
-reconstructType [x:xs] t = gets (\(st, r)->'Map'.get x st)
- >>= \mtype->case mtype of
- Nothing = liftT $ Left $ Error "Not used ????"
- Just type = reconstructType xs t >>= \resttype->pure (type ->> resttype)
-
-genType :: [String] -> Env Type
-genType [] = freshIdent >>= \fi->pure $ IdType fi
-genType [x:xs] = liftM2 (->>) (freshIdent >>= \fi->pure $ IdType fi)
- (genType xs)
-
-matchFunctions :: [String] Type -> Env Type
-matchFunctions [] (_ ->> _) = liftT $ Left $ Error "Not enough arguments"
-matchFunctions _ (VoidType ->> _) = liftT $ Left $ Error "Cannot have a void type in the middle of the function definition"
-matchFunctions [x:xs] (t1 ->> t2) =
- modify (\(st, r)->('Map'.put x t1 st, r)) >>| matchFunctions xs t2
-matchFunctions [] t = pure t
-matchFunctions _ t = liftT $ Left $ Error "Too much argumnts"
-
-semVarDecl :: VarDecl -> Env VarDecl
-semVarDecl (VarDecl pos type ident ex) = unify type ex
- >>= \t-> putIdent ident t >>| (pure $ VarDecl pos t ident ex)
-
-checkStmt ::Type Stmt -> Env Stmt
-checkStmt t (IfStmt c st se) = unify BoolType c >>| mapM (checkStmt t) st
- >>= \st1-> mapM (checkStmt t) se >>= \se1-> pure (IfStmt c st1 se1)
-checkStmt t w=:(WhileStmt c et) = unify BoolType c >>| mapM (checkStmt t) et
- >>= \et1-> pure w
-checkStmt t a=:(AssStmt (VarDef ident fs) e) = gets (\(st, r)->'Map'.get ident st)
- >>= \mt->case mt of
- Nothing = liftT $ Left $ UndeclaredVariableError zero ident
- Just t = unify t fs >>= \t1 -> unify t1 e >>| pure a
-checkStmt t r=:(FunStmt (FunCall f es)) = typeFun f es >>| pure r
-checkStmt VoidType r=:(ReturnStmt Nothing) = pure r
-checkStmt t r=:(ReturnStmt (Just e)) = unify t e >>| pure r
-
-typeExpr :: Expr -> Env Type
-typeExpr (IntExpr _ _) = pure IntType
-typeExpr (CharExpr _ _) = pure CharType
-typeExpr (BoolExpr _ _) = pure BoolType
-typeExpr (Op1Expr p UnNegation expr) = unify BoolType expr
-typeExpr (Op1Expr p UnMinus expr) = unify IntType expr
-typeExpr (TupleExpr p (e1, e2)) = typeExpr e1
- >>= \t1-> typeExpr e2 >>= \t2-> pure $ TupleType (t1, t2)
-typeExpr (Op2Expr p e1 op e2)
-| isMember op [BiPlus, BiMinus, BiTimes, BiDivide, BiMod] =
- typeOp2 e1 e2 op [IntType] IntType
-| isMember op [BiEquals, BiUnEqual] =
- typeOp2 e1 e2 op [IntType, BoolType, CharType] BoolType
-| isMember op [BiLesser, BiGreater, BiLesserEq, BiGreaterEq] =
- typeOp2 e1 e2 op [IntType, CharType] BoolType
-| isMember op [BiAnd, BiOr] =
- typeOp2 e1 e2 op [BoolType] BoolType
-| op == BiCons = typeExpr e1 >>= \t1-> typeExpr e2
- >>= \t2-> unify (ListType t1) t2
-typeExpr (EmptyListExpr p) = freshIdent >>= \frsh-> let t = IdType frsh in
- putIdent frsh t >>| pure t
-typeExpr (FunExpr p (FunCall f es)) = typeFun f es
-typeExpr (VarExpr p (VarDef ident fs)) = gets (\(st, r)->'Map'.get ident st)
- >>= \mt->case mt of
- Nothing = liftT $ Left $ UndeclaredVariableError p ident
- Just t = unify t fs
-typeOp2 :: Expr Expr Op2 [Type] Type -> Env Type
-typeOp2 e1 e2 op ts ret = typeExpr e1 >>= \t1-> typeExpr e2 >>= \t2->
- unify t1 t2 >>= \t3->if (isMember t3 ts) (pure ret)
- (liftT $ Left $ OperatorError (extrPos e1) op t3)
-
-buildFunctionType :: String [Expr] -> Env Type
-buildFunctionType frsh [] = let t = IdType frsh in putIdent frsh t >>| pure t
-buildFunctionType frsh [e:es] = (->>) <$> typeExpr e <*> buildFunctionType frsh es
-
-unifyApp :: Type [Expr] -> Env Type
-unifyApp t [] = pure t
-unifyApp (tf1 ->> tf2) [t1:ts] = unify tf1 t1 >>| unifyApp tf2 ts
-unifyApp t1 t2 = liftT $ Left $ UnifyError zero t1 (IdType "[expressions, FIXME]")
-
-typeFun :: String [Expr] -> Env Type
-typeFun f es = gets (\(st, r)->'Map'.get f st) >>= \mt-> case mt of
- Nothing = freshIdent >>= \frsh-> buildFunctionType frsh es
- >>= \ft-> putIdent f ft >>| (pure $ IdType frsh)
- Just t = unifyApp t es
-
-resultType :: Type -> Type
-resultType (_ ->> t) = resultType t
-resultType t = t
-
-class unify a :: Type a -> Env Type
-
-instance unify [FieldSelector] where
- unify t [] = pure t
- unify (ListType t) [FieldHd:fs] = unify t fs
- unify t=:(ListType _) [FieldTl:fs] = unify t fs
- unify (TupleType (t, _)) [FieldFst:fs] = unify t fs
- unify (TupleType (_, t)) [FieldSnd:fs] = unify t fs
- unify t [fs:_] = liftT $ Left $ FieldSelectorError zero t fs
-
-instance unify Expr where
- unify (_ ->> _) e = liftT $ Left $ ParseError (extrPos e)
- "Expression cannot be a higher order function. Yet..."
- unify VoidType e = liftT $ Left $ ParseError (extrPos e)
- "Expression cannot be a Void type."
-// unify (IdType _) e = liftT $ Left $ ParseError (extrPos e)
-// "Expression cannot be an polymorf type."
- unify VarType e = typeExpr e
- //we have to cheat to decorate the error, can be done nicer?
- unify t e = StateT $ \s0 -> let res = runStateT m s0 in case res of
- Left err = Left $ decErr e err
- Right t = Right t //note, t :: (Type, Gamma)
- where m = typeExpr e >>= \tex-> unify t tex
-
-instance unify Type where
- unify IntType IntType = pure IntType
- unify BoolType BoolType = pure BoolType
- unify CharType CharType = pure CharType
- unify (IdType i) t=:(IdType j) = replace i t >>| pure t
- unify t (IdType i) = unify (IdType i) t
- unify (IdType i) t = replace i t >>| pure t
- unify (ListType t1) (ListType t2) = unify t1 t2 >>| (pure $ ListType t1)
- unify (ta1 ->> ta2) (tb1 ->> tb2) = unify ta1 tb1 >>= \ta-> unify ta2 tb2
- >>= \tb-> pure (ta ->> tb)
- unify t1 t2 = liftT $ Left $ UnifyError zero t1 t2
-
-instance zero Pos where
- zero = {line=0,col=0}
-
-decErr :: Expr SemError -> SemError
-decErr e (UnifyError _ t1 t2) = UnifyError (extrPos e) t1 t2
-decErr e (FieldSelectorError _ t fs) = FieldSelectorError (extrPos e) t fs
-decErr e (ParseError _ s) = ParseError (extrPos e) s
-decErr e err = err
-
-dc2 :: Expr (Either SemError a) -> Either SemError a
-dc2 e (Right t) = Right t
-dc2 e (Left err) = Left err
-
-extrPos :: Expr -> Pos
-extrPos (VarExpr p _) = p
-extrPos (Op2Expr p _ _ _) = p
-extrPos (Op1Expr p _ _) = p
-extrPos (IntExpr p _) = p
-extrPos (CharExpr p _) = p
-extrPos (BoolExpr p _) = p
-extrPos (FunExpr p _) = p
-extrPos (EmptyListExpr p) = p
-extrPos (TupleExpr p _) = p
+
+
+:: Scheme = Forall [TVar] Type
+:: Gamma :== 'Map'.Map String Scheme //map from Variables! to types
+:: Substitution :== 'Map'.Map TVar Type
+:: Constraints :== [(Type, Type)]
+:: Infer a :== RWST Gamma Constraints [String] (Either SemError) a
+:: SemError
+ = ParseError Pos String
+ | UnifyError Pos Type Type
+ | InfiniteTypeError Pos Type
+ | FieldSelectorError Pos Type FieldSelector
+ | OperatorError Pos Op2 Type
+ | UndeclaredVariableError Pos String
+ | ArgumentMisMatchError Pos String
+ | SanityError Pos String
+ | Error String
+
+instance zero Gamma where
+ zero = 'Map'.newMap
+
+variableStream :: [TVar]
+variableStream = map toString [1..]
+
+sem :: AST -> Either [SemError] Constraints
+sem (AST fd) = case foldM (const $ hasNoDups fd) () fd
+ >>| foldM (const isNiceMain) () fd
+ >>| hasMain fd of
+ Left e = Left [e]
+ _ = case execRWST (constraints fd) zero variableStream of
+ Left e = Left [e]
+ Right (a, b) = Right b
+where
+ constraints :: [FunDecl] -> Infer ()
+ constraints _ = pure ()
+ //TODO: fix
+ //constraints fds = mapM_ funconstraint fds >>| pure ()
+
+ funconstraint :: FunDecl -> Infer ()
+ funconstraint fd=:(FunDecl _ ident args mt vardecls stmts) = case mt of
+ Nothing = abort "Cannot infer functions yet"
+ Just t = inEnv (ident, (Forall [] t)) (
+ mapM_ vardeclconstraint vardecls >>| pure ())
+
+ vardeclconstraint :: VarDecl -> Infer ()
+ vardeclconstraint _ = pure ()
+ //TODO: fix!
+ //vardeclconstraint (VarDecl p mt ident expr) = infer expr
+ //>>= \it->inEnv (ident, (Forall [] it)) (pure ())
+
+ hasNoDups :: [FunDecl] FunDecl -> Either SemError ()
+ hasNoDups fds (FunDecl p n _ _ _ _)
+ # mbs = map (\(FunDecl p` n` _ _ _ _)->if (n == n`) (Just p`) Nothing) fds
+ = case catMaybes mbs of
+ [] = Left $ SanityError p "HUH THIS SHOULDN'T HAPPEN"
+ [x] = pure ()
+ [_:x] = Left $ SanityError p (concat
+ [n, " multiply defined at ", toString p])
+
+ hasMain :: [FunDecl] -> Either SemError ()
+ hasMain [(FunDecl _ "main" _ _ _ _):fd] = pure ()
+ hasMain [_:fd] = hasMain fd
+ hasMain [] = Left $ SanityError zero "no main function defined"
+
+ isNiceMain :: FunDecl -> Either SemError ()
+ isNiceMain (FunDecl p "main" as mt _ _) = case (as, mt) of
+ ([_:_], _) = Left $ SanityError p "main must have arity 0"
+ ([], t) = (case t of
+ Nothing = pure ()
+ Just VoidType = pure ()
+ _ = Left $ SanityError p "main has to return Void")
+ isNiceMain _ = pure ()
+
+instance toString Scheme where
+ toString (Forall x t) =
+ concat ["Forall ": map ((+++) "\n") x] +++ toString t