X-Git-Url: https://git.martlubbers.net/?a=blobdiff_plain;f=sem.icl;h=791ae69a46b3601530d02822edf315404df53a67;hb=51921a9587d60b6411610845f56d62ebd73f80cb;hp=272ef5a38d0f0a5d3cef5652ad84f16d990f5a40;hpb=1f01e39fb2383aa2c63234d0750c0459fe3de752;p=cc1516.git diff --git a/sem.icl b/sem.icl index 272ef5a..791ae69 100644 --- a/sem.icl +++ b/sem.icl @@ -29,6 +29,7 @@ import AST :: 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 @@ -48,12 +49,14 @@ instance zero Gamma where variableStream :: [TVar] variableStream = map toString [1..] -sem :: AST -> Either [SemError] Constraints +sem :: AST -> Either [SemError] AST +//sem a = pure a sem (AST fd) = case foldM (const $ hasNoDups fd) () fd - >>| foldM (const isNiceMain) () fd - >>| hasMain fd of + >>| foldM (const isNiceMain) () fd + >>| hasMain fd + >>| evalStateT (type fd) (zero, variableStream) of Left e = Left [e] - _ = Right [] + Right fds = Right (AST fds) //_ = case execRWST (constraints fd) zero variableStream of // Left e = Left [e] // Right (a, b) = Right b @@ -144,12 +147,12 @@ occurs :: TVar a -> Bool | Typeable a occurs tvar a = elem tvar (ftv a) unify :: Type Type -> Either SemError Substitution -unify t1=:(IdType tv) t2 = unify t2 t1 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 tb1 tb2 >>= \s2-> + unify ta2 tb2 >>= \s2-> Right $ compose s1 s2 unify (TupleType (ta1,ta2)) (TupleType (tb1,tb2)) = unify ta1 tb1 >>= \s1-> unify ta2 tb2 >>= \s2-> @@ -161,8 +164,6 @@ unify t1 t2 | t1 == t2 = Right zero //// ------------------------ //// Algorithm M, Inference and Solving //// ------------------------ -//The typing monad -:: Typing a :== StateT (Gamma, [TVar]) (Either SemError) a gamma :: Typing Gamma gamma = gets fst putGamma :: Gamma -> Typing () @@ -221,6 +222,7 @@ instance infer Expr where pure ((compose s3 $ compose s2 s1), subst s3 tv) Op1Expr _ op e1 = + abort "infereing op1" >>| infer e1 >>= \(s1, t1) -> fresh >>= \tv -> let given = t1 ->> tv in @@ -228,9 +230,10 @@ instance infer Expr where lift (unify expected given) >>= \s2 -> pure (compose s2 s1, subst s2 tv) - EmptyListExpr _ = (\tv->(zero,tv)) <$> fresh + EmptyListExpr _ = abort "infereing []" >>| (\tv->(zero,tv)) <$> fresh TupleExpr _ (e1, e2) = + abort "infereing (,)" >>| infer e1 >>= \(s1, t1) -> infer e2 >>= \(s2, t2) -> pure (compose s2 s1, TupleType (t1,t2)) @@ -239,6 +242,7 @@ instance infer Expr where 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)-> + //abort (concat (["argsTs: "] ++ (map toString argTs))) >>| fresh >>= \tv-> let given = foldr (->>) tv argTs in lift (unify expected given) >>= \s2-> @@ -281,14 +285,14 @@ instance infer Stmt where infer el >>= \(s4, elt)-> applySubst s4 >>| lift (unify tht elt) >>= \s5-> - pure (compose s5 $ compose s4 $ compose s3 $ compose s1 s2, subst s5 tht) + 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 s1 s2, subst s3 wht) + pure (compose s3 $ compose s2 s1, subst s3 wht) AssStmt (VarDef k fs) e = infer e >>= \(s1, et)-> @@ -301,32 +305,112 @@ instance infer Stmt where ReturnStmt Nothing = pure (zero, VoidType) ReturnStmt (Just e) = infer e - +//The type of a list of statements is either an encountered +//return, or VoidType instance infer [a] | infer a where - infer _ = undef - -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) + 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 a + +instance type VarDecl where + type (VarDecl p expected k e) = + infer e >>= \(s, given) -> + applySubst s >>| + case expected of + Nothing = pure zero + Just expected_ = lift (unify expected_ given) + >>| + generalize given >>= \t -> + changeGamma (extend k t) >>| + pure (VarDecl p (Just given) k e) + +instance type FunDecl where + type (FunDecl p f args expected vds stmts) = + introduce f >>| + mapM introduce args >>= \argTs-> + type vds >>= \tVds-> + infer stmts >>= \(s1, result)-> + let given = foldr (->>) result argTs in + applySubst s1 >>| + (case expected of + Nothing = pure zero + Just expected_ = lift (unify expected_ given)) + >>= \s2 -> + let ftype = subst (compose s2 s1) given in + generalize ftype >>= \t-> + changeGamma (extend f t) >>| + pure (FunDecl p f args (Just ftype) tVds stmts) + +instance toString (Maybe a) | toString a where + toString Nothing = "Nothing" + toString (Just e) = concat ["Just ", toString e] + +instance type [a] | type a where + type dcls = mapM type dcls + +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 ": map ((+++) "\n") x] +++ toString 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] +instance toString Substitution where + toString subs = + concat [concat [k, ": ", toString t, "\n"]\\(k, t)<-'Map'.toList subs] + instance toString SemError where toString (SanityError p e) = concat [toString p, "SemError: SanityError: ", e] - toString se = "SemError: " + 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 (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 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) + //// ------------------------ //// First step: Inference //// ------------------------//