X-Git-Url: https://git.martlubbers.net/?a=blobdiff_plain;f=sem.icl;h=0c5b55273cb8d7fb05f1fe73dc1fa069409ff49c;hb=978dc486bf8c83cf9cad0925e3128574639656e0;hp=a58b2e111e9573947e14227c3dc0df3f7e24b45b;hpb=6a0c1e5bca43fc312e609676de91f5fe4b637c8f;p=cc1516.git diff --git a/sem.icl b/sem.icl index a58b2e1..0c5b552 100644 --- a/sem.icl +++ b/sem.icl @@ -1,313 +1,423 @@ implementation module sem import qualified Data.Map as Map + from Data.Func import $ -import Data.Maybe -import Data.Void -import Data.Either -import Data.Functor -import Control.Applicative +from StdFunc import o, flip, const, id + import Control.Monad -import Control.Monad.State -import Control.Monad.Identity -import Math.Random import Control.Monad.Trans -import StdMisc -from StdFunc import id, const, o +import Control.Monad.State +import Data.Either +import Data.Maybe +import Data.Monoid +import Data.List +import Data.Functor +import Data.Tuple + import StdString import StdTuple import StdList -import StdBool +import StdMisc +import StdEnum import GenEq from Text import class Text(concat), instance Text String import AST -:: 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 >>= \vd1 -> - mapM semFunDecl fd >>= \fd1 -> - mapM semVarDecl vd1 >>= \vd2 -> - mapM semFunDecl fd1 >>= \fd2 -> - mapM semVarDecl vd2 >>= \vd3 -> - mapM semFunDecl fd2 >>= \fd3 -> - mapM semVarDecl vd3 >>= \vd4 -> - mapM semFunDecl fd3 >>= \fd4 -> //Dit is puur om te proberen - pure (vd4, fd4) - -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-> - inferReturnType stmts >>= \returntype`-> - unify returntype` tres >>= \returntype-> - case mt of - Nothing = reconstructType args tres - >>= \ftype`->recoverType ftype` - >>= \ftype->restoreGamma gamma - >>| putIdent f ftype >>| pure ( - FunDecl p f args (Just ftype) newvds newstmts) - Just t = restoreGamma gamma >>| updateFunType t returntype - >>= \tt-> pure (FunDecl p f args (Just tt) newvds newstmts) - -recoverType :: Type -> Env Type -recoverType (IdType ident) = gets (\(st, r)->'Map'.get ident st) - >>= \mt->case mt of - Nothing = pure (IdType ident) - Just t = pure t -recoverType (t1 ->> t2) = recoverType t1 >>= \t1`->recoverType t2 - >>= \t2`->pure (t1` ->> t2`) -recoverType t = pure t - -updateFunType :: Type Type -> Env Type -updateFunType (t1 ->> t2) t3 = updateFunType t2 t3 >>= \t2`->pure $ t1 ->> t2` -updateFunType t1 t2 = unify t1 t2 - -inferReturnType :: [Stmt] -> Env Type -inferReturnType [] = pure VoidType -inferReturnType [ReturnStmt (Just t):rest] = typeExpr t - >>= \tx->inferReturnType rest >>= \ty->unify tx ty -inferReturnType [ReturnStmt _:rest] = - inferReturnType rest >>= \tx-> unify VoidType tx -inferReturnType [_:rest] = inferReturnType rest - -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 $ - ArgumentMisMatchError zero "Not enough arguments" -matchFunctions _ (VoidType ->> _) = liftT $ Left $ - ArgumentMisMatchError zero "Void can't be a non return type" -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 $ - ArgumentMisMatchError zero "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 [IdType "":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=:(IdType id) e = typeExpr e >>= \tex->unify t tex - >>= \type->putIdent id type >>| pure type - 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 VoidType VoidType = pure VoidType - unify VoidType t = pure t - unify t VoidType = pure t - 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 +:: Typing a :== StateT (Gamma, [TVar]) (Either SemError) a +:: Substitution :== 'Map'.Map TVar Type +:: Constraints :== [(Type, Type)] +:: 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..] + +defaultGamma :: Gamma //includes all default functions +defaultGamma = extend "print" (Forall ["a"] ((IdType "a") ->> VoidType)) + $ extend "isEmpty" (Forall ["a"] ((ListType (IdType "a")) ->> BoolType)) + $ extend "read" (Forall [] CharType) + zero + +sem :: AST -> Either [SemError] AST +sem (AST fd) = case foldM (const $ hasNoDups fd) () fd + >>| foldM (const isNiceMain) () fd + >>| hasMain fd + >>| evalStateT (type fd) (defaultGamma, variableStream) of + Left e = Left [e] + Right (_,fds) = Right (AST fds) +where + 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 () + +class Typeable a where + ftv :: a -> [TVar] + subst :: Substitution a -> a + +instance Typeable Scheme where + ftv (Forall bound t) = difference (ftv t) bound + subst s (Forall bound t) = Forall bound $ subst s_ t + where s_ = 'Map'.filterWithKey (\k _ -> not (elem k bound)) s + +instance Typeable [a] | Typeable a where + ftv types = foldr (\t ts-> ftv t ++ ts) [] types + subst s ts = map (\t->subst s t) ts + +instance Typeable Type where + ftv (TupleType (t1, t2)) = ftv t1 ++ ftv t2 + ftv (ListType t) = ftv t + ftv (IdType tvar) = [tvar] + ftv (t1 ->> t2) = ftv t1 ++ ftv t2 + ftv _ = [] + subst s (TupleType (t1, t2))= TupleType (subst s t1, subst s t2) + subst s (ListType t1) = ListType (subst s t1) + subst s (t1 ->> t2) = (subst s t1) ->> (subst s t2) + subst s t1=:(IdType tvar) = 'Map'.findWithDefault t1 tvar s + subst s t = t + +instance Typeable Gamma where + ftv gamma = concatMap id $ map ftv ('Map'.elems gamma) + subst s gamma = Mapmap (subst s) gamma + +extend :: String Scheme Gamma -> Gamma +extend k t g = 'Map'.put k t g + +//// ------------------------ +//// algorithm U, Unification +//// ------------------------ +instance zero Substitution where zero = 'Map'.newMap + +compose :: Substitution Substitution -> Substitution +compose s1 s2 = 'Map'.union (Mapmap (subst s1) s2) s1 +//Note: just like function compositon compose does snd first + +occurs :: TVar a -> Bool | Typeable a +occurs tvar a = elem tvar (ftv a) + +unify :: Type Type -> Either SemError Substitution +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 ta2 tb2 >>= \s2-> + Right $ compose s1 s2 +unify (TupleType (ta1,ta2)) (TupleType (tb1,tb2)) = unify ta1 tb1 >>= \s1-> + unify ta2 tb2 >>= \s2-> + Right $ compose s1 s2 +unify (ListType t1) (ListType t2) = unify t1 t2 +unify t1 t2 | t1 == t2 = Right zero + | otherwise = Left $ UnifyError zero t1 t2 + +//// ------------------------ +//// Algorithm M, Inference and Solving +//// ------------------------ +gamma :: Typing Gamma +gamma = gets fst +putGamma :: Gamma -> Typing () +putGamma g = modify (appFst $ const g) >>| pure () +changeGamma :: (Gamma -> Gamma) -> Typing Gamma +changeGamma f = modify (appFst f) >>| gamma +withGamma :: (Gamma -> a) -> Typing a +withGamma f = f <$> gamma +fresh :: Typing Type +fresh = gets snd >>= \vars-> + modify (appSnd $ const $ tail vars) >>| + pure (IdType (head vars)) + +lift :: (Either SemError a) -> Typing a +lift (Left e) = liftT $ Left e +lift (Right v) = pure v + +//instantiate maps a schemes type variables to variables with fresh names +//and drops the quantification: i.e. forall a,b.a->[b] becomes c->[d] +instantiate :: Scheme -> Typing Type +instantiate (Forall bound t) = + mapM (const fresh) bound >>= \newVars-> + let s = 'Map'.fromList (zip (bound,newVars)) in + pure (subst s t) + +//generalize quentifies all free type variables in a type which are not +//in the gamma +generalize :: Type -> Typing Scheme +generalize t = gamma >>= \g-> pure $ Forall (difference (ftv t) (ftv g)) t + +lookup :: String -> Typing Type +lookup k = gamma >>= \g-> case 'Map'.member k g of + False = liftT (Left $ UndeclaredVariableError zero k) + True = instantiate $ 'Map'.find k g + +//The inference class +//When tying it all together we will treat the program is a big +//let x=e1 in let y=e2 in .... +class infer a :: a -> Typing (Substitution, Type) + +////---- Inference for Expressions ---- + +instance infer Expr where + infer e = case e of + VarExpr _ (VarDef k fs) = lookup k >>= \t -> + foldM foldFieldSelectors t fs >>= \finalT -> + pure (zero, finalT) + + Op2Expr _ e1 op e2 = + infer e1 >>= \(s1, t1) -> + infer e2 >>= \(s2, t2) -> + fresh >>= \tv -> + let given = t1 ->> t2 ->> tv in + op2Type op >>= \expected -> + lift (unify expected given) >>= \s3 -> + pure ((compose s3 $ compose s2 s1), subst s3 tv) + + Op1Expr _ op e1 = + infer e1 >>= \(s1, t1) -> + fresh >>= \tv -> + let given = t1 ->> tv in + op1Type op >>= \expected -> + lift (unify expected given) >>= \s2 -> + pure (compose s2 s1, subst s2 tv) + + EmptyListExpr _ = (\tv->(zero,tv)) <$> fresh + + TupleExpr _ (e1, e2) = + infer e1 >>= \(s1, t1) -> + infer e2 >>= \(s2, t2) -> + pure (compose s2 s1, TupleType (t1,t2)) + + FunExpr _ f args fs = //todo: fieldselectors + 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)-> + fresh >>= \tv-> + let given = foldr (->>) tv argTs in + lift (unify expected given) >>= \s2-> + let fReturnType = subst s2 tv in + foldM foldFieldSelectors fReturnType fs >>= \returnType -> + pure (compose s2 s1, returnType) + + IntExpr _ _ = pure $ (zero, IntType) + BoolExpr _ _ = pure $ (zero, BoolType) + CharExpr _ _ = pure $ (zero, CharType) + +foldFieldSelectors :: Type FieldSelector -> Typing Type +foldFieldSelectors (ListType t) (FieldHd) = pure t +foldFieldSelectors t=:(ListType _) (FieldTl) = pure t +foldFieldSelectors (TupleType (t1, _)) (FieldFst) = pure t1 +foldFieldSelectors (TupleType (_, t2)) (FieldSnd) = pure t2 +foldFieldSelectors t fs = liftT $ Left $ FieldSelectorError zero t fs + +op2Type :: Op2 -> Typing Type +op2Type op +| elem op [BiPlus, BiMinus, BiTimes, BiDivide, BiMod] + = pure (IntType ->> IntType ->> IntType) +| elem op [BiEquals, BiUnEqual] + = fresh >>= \t1-> fresh >>= \t2-> pure (t1 ->> t2 ->> BoolType) +| elem op [BiLesser, BiGreater, BiLesserEq, BiGreaterEq] + = pure (IntType ->> IntType ->> BoolType) +| elem op [BiAnd, BiOr] + = pure (BoolType ->> BoolType ->> BoolType) +| op == BiCons + = fresh >>= \t1-> pure (t1 ->> ListType t1 ->> ListType t1) + +op1Type :: Op1 -> Typing Type +op1Type UnNegation = pure $ (BoolType ->> BoolType) +op1Type UnMinus = pure $ (IntType ->> IntType) + +////----- Inference for Statements ----- +applySubst :: Substitution -> Typing Gamma +applySubst s = changeGamma (subst s) + +instance infer Stmt where + infer s = case s of + IfStmt e th el = + infer e >>= \(s1, et)-> + lift (unify et BoolType) >>= \s2 -> + applySubst (compose s2 s1) >>| + infer th >>= \(s3, tht)-> + applySubst s3 >>| + infer el >>= \(s4, elt)-> + applySubst s4 >>| + lift (unify tht elt) >>= \s5-> + pure (compose s5 $ compose s4 $ compose s3 $ compose s2 s1, subst s5 tht) + + WhileStmt e wh = + infer e >>= \(s1, et)-> + lift (unify et BoolType) >>= \s2 -> + applySubst (compose s2 s1) >>| + infer wh >>= \(s3, wht)-> + pure (compose s3 $ compose s2 s1, subst s3 wht) + + AssStmt (VarDef k fs) e = + lookup k >>= \expected -> + infer e >>= \(s1, given)-> + foldM reverseFs given (reverse fs) >>= \varType-> + lift (unify expected varType) >>= \s2-> + let s = compose s2 s1 in + applySubst s >>| + changeGamma (extend k (Forall [] (subst s varType))) >>| + pure (s, VoidType) + + FunStmt f es _ = pure (zero, VoidType) + + ReturnStmt Nothing = pure (zero, VoidType) + ReturnStmt (Just e) = infer e + +reverseFs :: Type FieldSelector -> Typing Type +reverseFs t FieldHd = pure $ ListType t +reverseFs t FieldTl = pure $ ListType t +reverseFs t FieldFst = fresh >>= \tv -> pure $ TupleType (t, tv) +reverseFs t FieldSnd = fresh >>= \tv -> pure $ TupleType (tv, t) + +//The type of a list of statements is either an encountered +//return, or VoidType +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 + VoidType = pure (compose s2 s1, t1) + _ = lift (unify t1 t2) >>= \s3 -> + pure (compose s3 $ compose s2 s1, t1) + +//the type class inferes the type of an AST element (VarDecl or FunDecl) +//and adds it to the AST element +class type a :: a -> Typing (Substitution, a) + +instance type VarDecl where + type (VarDecl p expected k e) = + infer e >>= \(s1, given) -> + applySubst s1 >>| + case expected of + Nothing = pure zero + Just expected_ = lift (unify expected_ given) + >>= \s2-> + applySubst s2 >>| + let vtype = subst (compose s2 s1) given in + generalize vtype >>= \t -> + changeGamma (extend k t) >>| + pure (compose s2 s1, VarDecl p (Just vtype) k e) + +instance type FunDecl where + type (FunDecl p f args expected vds stmts) = + gamma >>= \outerScope-> //functions are infered in their own scopde + introduce f >>| + mapM introduce args >>= \argTs-> + type vds >>= \(s1, tVds)-> + applySubst s1 >>| + infer stmts >>= \(s2, result)-> + applySubst s1 >>| + let argTs_ = map (subst $ compose s2 s1) argTs in + //abort (concat $ intersperse "\n" $ map toString argTs_) >>| + let given = foldr (->>) result argTs_ in + (case expected of + Nothing = pure zero + Just expected_ = lift (unify expected_ given)) + >>= \s3 -> + let ftype = subst (compose s3 $ compose s2 s1) given in + generalize ftype >>= \t-> + putGamma outerScope >>| + changeGamma (extend f t) >>| + pure (compose s3 $ compose s2 s1, FunDecl p f args (Just ftype) tVds stmts) + +instance type [a] | type a where + type [] = pure (zero, []) + type [v:vs] = + type v >>= \(s1, v_)-> + applySubst s1 >>| + type vs >>= \(s2, vs_)-> + applySubst (compose s2 s1) >>| + pure (compose s2 s1, [v_:vs_]) + +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 ": intersperse "," x] +++ concat [". ", toString t]; instance toString Gamma where - toString (mp, _) = concat - [concat [k, ": ", toString v, "\n"]\\(k, v) <- 'Map'.toList mp] - -getRandomStream :: Int -> [String] -getRandomStream i = genIdents $ filter (isAlpha o toChar) (genRandInt i) - where - genIdents r = let (ic, r2) = splitAt 5 r in [toString ic: genIdents r2] - -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 - Nothing = modify (\(st, r)->('Map'.put i t st, r)) - Just t2 = unify t t2 >>= \t3-> modify (\(st, r)->('Map'.put i t3 st, r)) - -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 + 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 (ParseError p e) = concat [toString p, - "SemError: ParseError: ", e] - 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 (OperatorError p o t) = concat [ - toString p, - "SemError: No ", toString o, " for type ", + toString (SanityError p e) = concat [toString p, + "SemError: SanityError: ", e] + 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 (UndeclaredVariableError p ident) = concat [ - toString p, "SemError: identifier: ", ident, " undefined."] - toString (ArgumentMisMatchError p s) = concat [toString p, - "SemError: Argument mismatch: ", s] - toString (Error e) = "SemError: " +++ e - -saveGamma :: Env Gamma -saveGamma = get - -restoreGamma :: Gamma -> Env Void -restoreGamma (oldstate, _) = gets snd >>= \newr->put (oldstate, newr) - -derive gEq Type -instance == Type where - (==) (IdType _) (IdType _) = True - (==) o1 o2 = gEq{|*|} o1 o2 + 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 toString (Maybe a) | toString a where + toString Nothing = "Nothing" + toString (Just e) = concat ["Just ", toString e] + +instance MonadTrans (StateT (Gamma, [TVar])) where + liftT m = StateT \s-> m >>= \a-> return (a, s) + +Mapmap :: (a->b) ('Map'.Map k a) -> ('Map'.Map k b) +Mapmap _ 'Map'.Tip = 'Map'.Tip +Mapmap f ('Map'.Bin sz k v ml mr) = 'Map'.Bin sz k (f v) + (Mapmap f ml) + (Mapmap f mr)