- toString (OperatorError p o t) = concat [
- toString p,
- "SemError: No ", toString o, " for type ",
- toString t]
- toString (UndeclaredVariableError p ident) = concat [
- toString p, "SemError: identifier: ", ident, " undefined."]
-
-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 semFunDecl fd >>= \fds ->
- mapM semVarDecl vd >>= \vds ->
- pure (vds, fds)
-
-semFunDecl :: FunDecl -> Env FunDecl
-semFunDecl fd=:(FunDecl p f _ mt vds stmts) = case mt of
- Nothing = let t = IdType f in putIdent f t >>| pure fd
- Just t = putIdent f t >>| pure fd
-
-semVarDecl :: VarDecl -> Env VarDecl
-semVarDecl (VarDecl pos type ident ex) = unify type ex
- >>= \t-> putIdent ident t >>| (pure $ VarDecl pos t ident ex)
-
-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)
-
-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)) = 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
-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
-
-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 //whoop whoop, functions can return functions
-unifyApp (tf1 ->> tf2) [t1:ts] = unify tf1 t1 >>| unifyApp tf2 ts
-unifyApp t1 t2 = liftT $ Left $ UnifyError zero t1 (IdType "[expressions, FIXME]")
-
-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
- unify (IdType i) e = undef
- //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
-
-replace :: String Type -> Env Void
-replace ident type = get >>= \(st, fr)->put ('Map'.fromList $
- map (itupdate ident type) ('Map'.toList st), fr)
- where
- itupdate :: String Type (String, Type) -> (String, Type)
- itupdate ident newtype ov=:(key, IdType type) = if (ident == type)
- (key, newtype) ov
- itupdate ident newtype (key, TupleType (t1, t2))
- # (_, t1) = itupdate ident newtype (key, t1)
- # (_, t2) = itupdate ident newtype (key, t2)
- = (key, TupleType (t1, t2))
- itupdate ident newtype (key, ListType t1)
- # (_, t1) = itupdate ident newtype (key, t1)
- = (key, ListType t1)
- itupdate _ _ k = k
-
-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