:: 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
getRandomStream :: Int -> [String]
getRandomStream i = genIdents $ filter (isAlpha o toChar) (genRandInt i)
where
- genIdents r = let (ic, r) = splitAt 5 r in [toString ic: genIdents r]
+ genIdents r = let (ic, r2) = splitAt 5 r in [toString ic: genIdents r2]
-freshIdent :: Gamma -> (String, Gamma)
-freshIdent (st, [ident:rest]) = case 'Map'.get ident st of
- Nothing = (ident, (st, rest))
- _ = freshIdent (st, rest)
+freshIdent :: Env String
+freshIdent = get >>= \(st, [ident:rest])-> put (st, rest)
+ >>| case 'Map'.get ident st of
+ Nothing = pure ident
+ _ = freshIdent
putIdent :: String Type -> Env Void
putIdent i t = gets (\(st, r)->'Map'.get i st) >>= \mt -> case mt of
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]
+ toString (FieldSelectorError p t fs) = concat [
+ toString p,
+ "SemError: Cannot select ", toString fs, " from type: ",
+ toString t]
+ toString (UndeclaredVariableError p ident) = concat [
+ toString p, "SemError: identifier: ", ident, " undefined."]
sem :: AST -> SemOutput
-sem (AST vd fd) = case evalStateT m ('Map'.newMap, getRandomStream 0) of
+sem (AST vd fd) = case runStateT m ('Map'.newMap, getRandomStream 1) of
Left e = Left [e]
- Right (vds, fds) = Right (AST vds fds)
+ Right ((vds, fds), gamma) = Right ((AST vds fds), gamma)
where
- m :: Env (([VarDecl], [FunDecl]))
+ m :: Env ([VarDecl], [FunDecl])
m = (mapM semVarDecl vd) >>= \vds ->
mapM semFunDecl fd >>= \fds ->
pure (vds, fds)
-
-
-splitEithers :: [Either a b] -> Either [a] [b]
-splitEithers [] = Right []
-splitEithers [Right x:xs] = splitEithers xs >>= \rest->Right [x:rest]
-splitEithers xs = Left $ [x\\(Left x)<-xs]
-
semFunDecl :: FunDecl -> Env FunDecl
-semFunDecl f = pure f
+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
//a
typeExpr (Op2Expr p e1 BiCons e2) = typeExpr e1 >>= \t1-> typeExpr e2
>>= \t2-> unify (ListType t1) t2
-//typeExpr (FunExpr p FunCall) = undef
-typeExpr (EmptyListExpr p) = pure $ ListType IntType //we'll need quantified types
-//typeExpr (VarExpr Pos VarDef) = undef //when checking var-expr, be sure to
- //put the infered type in the context
+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 = let t = IdType f in putIdent f t >>| pure t
+ 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
+
+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 (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 (ListType t1) (ListType t2) = unify t1 t2
+ 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 t1 t2 = liftT $ Left $ UnifyError zero t1 t2
instance zero Pos where
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
extrPos (BoolExpr p _) = p
extrPos (FunExpr p _) = p
extrPos (EmptyListExpr p) = p
-extrPos (TupleExpr p _) = p
\ No newline at end of file
+extrPos (TupleExpr p _) = p
+
+instance toString Gamma where
+ toString (mp, _) = concat
+ [concat [k, ": ", toString v, "\n"]\\(k, v) <- 'Map'.toList mp]
+
+
+// class free a :: a -> Env [a]