@@ -1,486 +0,0 @@
1−-----------------------------------------------------------------------------
3−-- Module : PureScript.TypeChecker.Types
4−-- Copyright : (c) Phil Freeman 2013
7−-- Maintainer : Phil Freeman <paf31@cantab.net>
8−-- Stability : experimental
13−-----------------------------------------------------------------------------
15−module PureScript.TypeChecker.Types (
23−import Data.Data (Data(..))
24−import Data.Generics (everywhere, everywhereM, everything, mkT, mkM, mkQ, extM, extQ)
26−import PureScript.Values
27−import PureScript.Types
28−import PureScript.Kinds
29−import PureScript.TypeChecker.Monad
30−import PureScript.TypeChecker.Kinds
31−import PureScript.TypeChecker.Synonyms
33−import Control.Monad.State
34−import Control.Monad.Error
36−import Control.Applicative
37−import Control.Arrow (Kleisli(..), (***), (&&&))
38−import qualified Control.Category as C
40−import qualified Data.Map as M
43− = TypeConstraint Int Type
44− | RowConstraint Int Row deriving Show
46−newtype TypeSolution = TypeSolution { runTypeSolution :: (Int -> Type, Int -> Row) }
48−emptyTypeSolution :: TypeSolution
49−emptyTypeSolution = TypeSolution (TUnknown, RUnknown)
51−typeOf :: String -> Value -> Check PolyType
54− (cs, n) <- typeConstraints (M.singleton name me) val
55− solution <- solveTypeConstraints ((TypeConstraint me (TUnknown n)) : cs) emptyTypeSolution
56− return $ varIfUnknown $ fst (runTypeSolution solution) n
58−varIfUnknown :: Type -> PolyType
61− (ty', m) = flip runState M.empty $ everywhereM (flip extM g $ mkM f) ty
62− -- TODO : check no nested unknowns
64− PolyType (sort $ nub $ M.elems m) ty'
66− f :: Type -> State (M.Map Int String) Type
71− let name = "t" ++ show (M.size m)
72− put $ M.insert n name m
73− return $ TypeVar name
74− Just name -> return $ TypeVar name
76− g :: Row -> State (M.Map Int String) Row
81− let name = "r" ++ show (M.size m)
82− put $ M.insert n name m
84− Just name -> return $ RowVar name
87−replaceVarsWithUnknowns :: [String] -> Type -> Check Type
88−replaceVarsWithUnknowns idents = flip evalStateT M.empty . everywhereM (flip extM f $ mkM g)
90− f :: Type -> StateT (M.Map String Int) Check Type
91− f (TypeVar var) | var `elem` idents = do
94− case M.lookup var m of
96− put (M.insert var n m)
98− Just u -> return $ TUnknown u
100− g :: Row -> StateT (M.Map String Int) Check Row
101− g (RowVar var) | var `elem` idents = do
104− case M.lookup var m of
106− put (M.insert var n m)
108− Just u -> return $ RUnknown u
111−replaceType :: (Data d) => Int -> Type -> d -> d
112−replaceType n t = everywhere (mkT go)
114− go (TUnknown m) | m == n = t
117−replaceRow :: (Data d) => Int -> Row -> d -> d
118−replaceRow n r = everywhere (mkT go)
120− go (RUnknown m) | m == n = r
123−typeOccursCheck :: Int -> Type -> Check ()
124−typeOccursCheck u (TUnknown _) = return ()
125−typeOccursCheck u t = when (occursCheck u t) $ throwError $ "Occurs check failed: " ++ show u ++ " = " ++ show t
127−rowOccursCheck :: Int -> Row -> Check ()
128−rowOccursCheck u (RUnknown _) = return ()
129−rowOccursCheck u r = when (occursCheck u r) $ throwError $ "Occurs check failed: " ++ show u ++ " = " ++ show r
131−occursCheck :: (Data d) => Int -> d -> Bool
132−occursCheck u = everything (||) $ flip extQ g $ mkQ False f
134− f (TUnknown u') | u' == u = True
136− g (RUnknown u') | u' == u = True
139−typeConstraints :: M.Map String Int -> Value -> Check ([TypeConstraint], Int)
140−typeConstraints _ (NumericLiteral _) = do
142− return ([TypeConstraint me Number], me)
143−typeConstraints _ (StringLiteral _) = do
145− return ([TypeConstraint me String], me)
146−typeConstraints _ (BooleanLiteral _) = do
148− return ([TypeConstraint me Boolean], me)
149−typeConstraints m (ArrayLiteral vals) = do
150− all <- mapM (typeConstraints m) vals
151− let (cs, ns) = (concat . map fst &&& map snd) all
153− return (cs ++ map (TypeConstraint me . Array . TUnknown) ns, me)
154−typeConstraints m (Unary op val) = do
155− (cs, n1) <- typeConstraints m val
157− return (cs ++ unaryOperatorConstraints op n1 me, me)
158−typeConstraints m (Binary op left right) = do
159− (cs1, n1) <- typeConstraints m left
160− (cs2, n2) <- typeConstraints m right
162− return (cs1 ++ cs2 ++ binaryOperatorConstraints op n1 n2 me, me)
163−typeConstraints m (ObjectLiteral ps) = do
164− all <- mapM (typeConstraints m . snd) ps
165− let (cs, ns) = (concat . map fst &&& map snd) all
167− let tys = zipWith (\(name, _) u -> (name, TUnknown u)) ps ns
168− return ((TypeConstraint me (Object (typesToRow tys))) : cs, me)
170− typesToRow [] = REmpty
171− typesToRow ((name, ty):tys) = RCons name ty (typesToRow tys)
172−typeConstraints m (Indexer index val) = do
173− (cs1, n1) <- typeConstraints m index
174− (cs2, n2) <- typeConstraints m val
176− return ((TypeConstraint n1 Number) : (TypeConstraint n2 (Array (TUnknown me))) : cs1 ++ cs2, me)
177−typeConstraints m (Accessor prop val) = do
178− (cs, n1) <- typeConstraints m val
181− return ((TypeConstraint n1 (Object (RCons prop (TUnknown me) (RUnknown rest)))) : cs, me)
182−typeConstraints m (Abs args ret) = do
183− ns <- replicateM (length args) fresh
184− let m' = m `M.union` M.fromList (zipWith (,) args ns)
185− (cs, n') <- typeConstraints m' ret
187− return ((TypeConstraint me (Function (map TUnknown ns) (TUnknown n'))) : cs, me)
188−typeConstraints m (App f xs) = do
189− (cs1, n1) <- typeConstraints m f
190− all <- mapM (typeConstraints m) xs
191− let (cs2, ns) = (concat . map fst &&& map snd) all
193− return ((TypeConstraint n1 (Function (map TUnknown ns) (TUnknown me))) : cs1 ++ cs2, me)
194−typeConstraints m (Var var) =
195− case M.lookup var m of
198− case M.lookup var (names env) of
199− Nothing -> throwError $ var ++ " is undefined"
200− Just (PolyType idents ty, _) -> do
202− replaced <- replaceVarsWithUnknowns idents ty
203− return ([TypeConstraint me replaced], me)
206− return ([TypeConstraint u (TUnknown me)], me)
207−typeConstraints m (Block ss) = do
209− (cs, allCodePathsReturn, _) <- typeConstraintsForBlock m M.empty ret ss
210− guardWith "Block is missing a return statement" allCodePathsReturn
212−typeConstraints m (Constructor c) = do
214− case M.lookup c (dataConstructors env) of
215− Nothing -> throwError $ "Constructor " ++ c ++ " is undefined"
216− Just (PolyType idents ty) -> do
218− replaced <- replaceVarsWithUnknowns idents ty
219− return ([TypeConstraint me replaced], me)
220−typeConstraints m (Case val binders) = do
221− (cs1, n1) <- typeConstraints m val
223− cs2 <- typeConstraintsForBinders m n1 ret binders
224− return (cs1 ++ cs2, ret)
225−typeConstraints m (TypedValue val poly@(PolyType idents ty)) = do
227− guardWith ("Expected type of kind *, was " ++ show kind) $ kind == Star
228− desugared <- replaceAllTypeSynonyms ty
229− (cs, n1) <- typeConstraints m val
230− return (TypeConstraint n1 desugared : cs, n1)
232−replaceAllTypeSynonyms :: Type -> Check Type
233−replaceAllTypeSynonyms ty = do
235− go (M.toList $ typeSynonyms env) ty
237− go [] ty = return ty
238− go ((name, (args, repl)):rest) ty = do
239− ty' <- either throwError return (substituteTypeSynonym name args repl ty)
242−unaryOperatorConstraints :: UnaryOperator -> Int -> Int -> [TypeConstraint]
243−unaryOperatorConstraints Negate val result = [TypeConstraint val Number, TypeConstraint result Number]
244−unaryOperatorConstraints Not val result = [TypeConstraint val Boolean, TypeConstraint result Boolean]
245−unaryOperatorConstraints BitwiseNot val result = [TypeConstraint val Number, TypeConstraint result Number]
247−binaryOperatorConstraints :: BinaryOperator -> Int -> Int -> Int -> [TypeConstraint]
248−binaryOperatorConstraints Add = symBinOpConstraints Number
249−binaryOperatorConstraints Subtract = symBinOpConstraints Number
250−binaryOperatorConstraints Multiply = symBinOpConstraints Number
251−binaryOperatorConstraints Divide = symBinOpConstraints Number
252−binaryOperatorConstraints Modulus = symBinOpConstraints Number
253−binaryOperatorConstraints LessThan = asymBinOpConstraints Number Boolean
254−binaryOperatorConstraints LessThanOrEqualTo = asymBinOpConstraints Number Boolean
255−binaryOperatorConstraints GreaterThan = asymBinOpConstraints Number Boolean
256−binaryOperatorConstraints GreaterThanOrEqualTo = asymBinOpConstraints Number Boolean
257−binaryOperatorConstraints BitwiseAnd = symBinOpConstraints Number
258−binaryOperatorConstraints BitwiseOr = symBinOpConstraints Number
259−binaryOperatorConstraints BitwiseXor = symBinOpConstraints Number
260−binaryOperatorConstraints ShiftLeft = symBinOpConstraints Number
261−binaryOperatorConstraints ShiftRight = symBinOpConstraints Number
262−binaryOperatorConstraints ZeroFillShiftRight = symBinOpConstraints Number
263−binaryOperatorConstraints EqualTo = equalityBinOpConstraints
264−binaryOperatorConstraints NotEqualTo = equalityBinOpConstraints
265−binaryOperatorConstraints And = symBinOpConstraints Boolean
266−binaryOperatorConstraints Or = symBinOpConstraints Boolean
267−binaryOperatorConstraints Concat = symBinOpConstraints String
269−equalityBinOpConstraints :: Int -> Int -> Int -> [TypeConstraint]
270−equalityBinOpConstraints left right result = [TypeConstraint left (TUnknown right), TypeConstraint result Boolean]
272−symBinOpConstraints :: Type -> Int -> Int -> Int -> [TypeConstraint]
273−symBinOpConstraints ty left right result = asymBinOpConstraints ty ty left right result
275−asymBinOpConstraints :: Type -> Type -> Int -> Int -> Int -> [TypeConstraint]
276−asymBinOpConstraints ty res left right result = [TypeConstraint left ty, TypeConstraint right ty, TypeConstraint result res]
278−typeConstraintsForBinder :: Int -> Binder -> Check ([TypeConstraint], M.Map String Int)
279−typeConstraintsForBinder val (StringBinder _) = constantBinder val String
280−typeConstraintsForBinder val (NumberBinder _) = constantBinder val Number
281−typeConstraintsForBinder val (BooleanBinder _) = constantBinder val Boolean
282−typeConstraintsForBinder val (VarBinder name) = do
284− return ([TypeConstraint me (TUnknown val)], M.singleton name me)
285−typeConstraintsForBinder val (NullaryBinder ctor) = do
287− case M.lookup ctor (dataConstructors env) of
288− Just (PolyType args ret) -> do
289− ret' <- replaceVarsWithUnknowns args ret
290− return ([TypeConstraint val ret'], M.empty)
291− _ -> throwError $ "Constructor " ++ ctor ++ " is not defined"
292−typeConstraintsForBinder val (UnaryBinder ctor binder) = do
294− case M.lookup ctor (dataConstructors env) of
295− Just (PolyType idents f@(Function [_] _)) -> do
297− (Function [ty] ret) <- replaceVarsWithUnknowns idents f
298− (cs, m1) <- typeConstraintsForBinder obj binder
299− return ((TypeConstraint val ret) : (TypeConstraint obj ty) : cs, m1)
300− Just _ -> throwError $ ctor ++ " is not a unary constructor"
301− _ -> throwError $ "Constructor " ++ ctor ++ " is not defined"
302−typeConstraintsForBinder val (ObjectBinder props) = do
305− (cs, m1) <- typeConstraintsForProperties row (RUnknown rest) props
306− return ((TypeConstraint val (Object (RUnknown row))) : cs, m1)
308− typeConstraintsForProperties :: Int -> Row -> [(String, Binder)] -> Check ([TypeConstraint], M.Map String Int)
309− typeConstraintsForProperties nrow row [] = return ([RowConstraint nrow row], M.empty)
310− typeConstraintsForProperties nrow row ((name, binder):binders) = do
312− (cs1, m1) <- typeConstraintsForBinder propTy binder
313− (cs2, m2) <- typeConstraintsForProperties nrow (RCons name (TUnknown propTy) row) binders
314− return (cs1 ++ cs2, M.union m1 m2)
315−typeConstraintsForBinder val (ArrayBinder binders rest) = do
317− all <- mapM (typeConstraintsForBinder el) binders
318− let (cs1, m1) = (concat . map fst &&& M.unions . map snd) all
319− let arrayConstraint = TypeConstraint val (Array (TUnknown el))
321− Nothing -> return (arrayConstraint : cs1, m1)
323− (cs2, m2) <- typeConstraintsForBinder val binder
324− return (arrayConstraint : cs1 ++ cs2, M.union m1 m2)
326−constantBinder :: Int -> Type -> Check ([TypeConstraint], M.Map String Int)
327−constantBinder val ty = return ([TypeConstraint val ty], M.empty)
329−typeConstraintsForBinders :: M.Map String Int -> Int -> Int -> [(Binder, Value)] -> Check [TypeConstraint]
330−typeConstraintsForBinders _ _ _ [] = return []
331−typeConstraintsForBinders m nval ret ((binder, val):bs) = do
332− (cs1, m1) <- typeConstraintsForBinder nval binder
333− (cs2, n2) <- typeConstraints (M.union m m1) val
334− cs3 <- typeConstraintsForBinders m nval ret bs
335− return ((TypeConstraint n2 (TUnknown ret)) : cs1 ++ cs2 ++ cs3)
337−typeConstraintsForStatement :: M.Map String Int -> M.Map String Int -> Int -> Statement -> Check ([TypeConstraint], Bool, M.Map String Int)
338−typeConstraintsForStatement m mass ret (VariableIntroduction name val) = do
339− case M.lookup name (m `M.union` mass) of
341− (cs1, n1) <- typeConstraints m val
342− return $ (cs1, False, M.insert name n1 mass)
343− Just ty -> throwError $ "Variable with name " ++ name ++ " already exists."
344−typeConstraintsForStatement m mass ret (Assignment tgt val) = do
345− (cs1, n1) <- typeConstraints m val
346− cs2 <- typeConstraintsForAssignmentTarget m mass n1 tgt
347− return (cs1 ++ cs2, False, mass)
348−typeConstraintsForStatement m mass ret (While val inner) = do
349− (cs1, n1) <- typeConstraints m val
350− (cs2, allCodePathsReturn, _) <- typeConstraintsForBlock m mass ret inner
351− return $ ((TypeConstraint n1 Boolean) : cs1 ++ cs2, allCodePathsReturn, mass)
352−typeConstraintsForStatement m mass ret (IfThenElse val thens Nothing) = do
353− (cs1, n1) <- typeConstraints m val
354− (cs2, allCodePathsReturn, _) <- typeConstraintsForBlock m mass ret thens
355− return $ ((TypeConstraint n1 Boolean) : cs1 ++ cs2, allCodePathsReturn, mass)
356−typeConstraintsForStatement m mass ret (IfThenElse val thens (Just elses)) = do
357− (cs1, n1) <- typeConstraints m val
358− (cs2, allCodePathsReturn1, _) <- typeConstraintsForBlock m mass ret thens
359− (cs3, allCodePathsReturn2, _) <- typeConstraintsForBlock m mass ret elses
360− return $ ((TypeConstraint n1 Boolean) : cs1 ++ cs2 ++ cs3, allCodePathsReturn1 && allCodePathsReturn2, mass)
361−typeConstraintsForStatement m mass ret (For (init, cond, cont) inner) = do
362− (cs1, b1, mass1) <- typeConstraintsForStatement m mass ret init
363− guardWith "Cannot return from inside for" $ not b1
364− (cs2, n1) <- typeConstraints (m `M.union` mass1) cond
365− (cs3, b2, mass2) <- typeConstraintsForStatement (m `M.union` mass1) mass1 ret cont
366− guardWith "Cannot return from inside for" $ not b2
367− (cs4, allCodePathsReturn, _) <- typeConstraintsForBlock (m `M.union` mass2) mass2 ret inner
368− return $ ((TypeConstraint n1 Boolean) : cs1 ++ cs2 ++ cs3 ++ cs4, allCodePathsReturn, mass)
369−typeConstraintsForStatement m mass ret (Return val) = do
370− (cs1, n1) <- typeConstraints (m `M.union` mass) val
371− return ((TypeConstraint n1 (TUnknown ret)) : cs1, True, mass)
373−typeConstraintsForAssignmentTarget :: M.Map String Int -> M.Map String Int -> Int -> AssignmentTarget -> Check [TypeConstraint]
374−typeConstraintsForAssignmentTarget m mass nval (AssignVariable var) =
375− case M.lookup var mass of
376− Nothing -> throwError $ "No local variable with name " ++ var
378− return [TypeConstraint nval (TUnknown ty)]
379−typeConstraintsForAssignmentTarget m mass nval (AssignArrayIndex index tgt) = do
381− (cs1, n1) <- typeConstraints (m `M.union` mass) index
382− cs2 <- typeConstraintsForAssignmentTarget m mass arr tgt
383− return $ (TypeConstraint arr (Array (TUnknown nval))) : (TypeConstraint n1 Number) : cs1 ++ cs2
384−typeConstraintsForAssignmentTarget m mass nval (AssignObjectProperty prop tgt) = do
387− cs <- typeConstraintsForAssignmentTarget m mass obj tgt
388− return $ (TypeConstraint obj (Object (RCons prop (TUnknown nval) $ RUnknown row))) : cs
390−typeConstraintsForBlock :: M.Map String Int -> M.Map String Int -> Int -> [Statement] -> Check ([TypeConstraint], Bool, M.Map String Int)
391−typeConstraintsForBlock _ mass _ [] = return ([], False, mass)
392−typeConstraintsForBlock m mass ret (s:ss) = do
393− (cs1, b1, mass1) <- typeConstraintsForStatement (m `M.union` mass) mass ret s
395− (True, []) -> return (cs1, True, mass1)
396− (True, _) -> throwError "Unreachable code"
398− (cs2, b2, mass2) <- typeConstraintsForBlock m mass1 ret ss
399− return (cs1 ++ cs2, b2, mass2)
401−solveTypeConstraints :: [TypeConstraint] -> TypeSolution -> Check TypeSolution
402−solveTypeConstraints [] s = return s
403−solveTypeConstraints all@(TypeConstraint n t:cs) s = do
405− let s' = let (f, g) = runTypeSolution s
406− in TypeSolution (replaceType n t . f, replaceType n t . g)
407− cs' <- fmap concat $ mapM (substituteTypeInConstraint n t) cs
408− solveTypeConstraints cs' s'
409−solveTypeConstraints (RowConstraint n r:cs) s = do
411− let s' = let (f, g) = runTypeSolution s
412− in TypeSolution $ (replaceRow n r . f, replaceRow n r . g)
413− cs' <- fmap concat $ mapM (substituteRowInConstraint n r) cs
414− solveTypeConstraints cs' s'
416−substituteTypeInConstraint :: Int -> Type -> TypeConstraint -> Check [TypeConstraint]
417−substituteTypeInConstraint n s (TypeConstraint m t)
418− | n == m = unifyTypes s t
419− | otherwise = return [TypeConstraint m (replaceType n s t)]
420−substituteTypeInConstraint n s (RowConstraint m r)
421− = return [RowConstraint m (replaceType n s r)]
423−substituteRowInConstraint :: Int -> Row -> TypeConstraint -> Check [TypeConstraint]
424−substituteRowInConstraint n r (TypeConstraint m t)
425− = return [TypeConstraint m (replaceRow n r t)]
426−substituteRowInConstraint n r (RowConstraint m r1)
427− | m == n = unifyRows r r1
428− | otherwise = return [RowConstraint m (replaceRow n r r1)]
430−unifyTypes :: Type -> Type -> Check [TypeConstraint]
431−unifyTypes (TUnknown u1) (TUnknown u2) | u1 == u2 = return []
432−unifyTypes (TUnknown u) t = do
434− return [TypeConstraint u t]
435−unifyTypes t (TUnknown u) = do
437− return [TypeConstraint u t]
438−unifyTypes Number Number = return []
439−unifyTypes String String = return []
440−unifyTypes Boolean Boolean = return []
441−unifyTypes (Array s) (Array t) = unifyTypes s t
442−unifyTypes (Object row1) (Object row2) = unifyRows row1 row2
443−unifyTypes (Function args1 ret1) (Function args2 ret2) = do
444− guardWith "Function applied to incorrect number of args" $ length args1 == length args2
445− cs1 <- fmap concat $ zipWithM unifyTypes args1 args2
446− cs2 <- unifyTypes ret1 ret2
448−unifyTypes (TypeVar v1) (TypeVar v2) | v1 == v2 = return []
449−unifyTypes (TypeConstructor c1) (TypeConstructor c2) | c1 == c2 = return []
450−unifyTypes (TypeVar v1) (TypeVar v2) = return []
451−unifyTypes (TypeApp t1 t2) (TypeApp t3 t4) = do
452− cs1 <- unifyTypes t1 t3
453− cs2 <- unifyTypes t2 t4
455−unifyTypes t1 t2 = throwError $ "Cannot unify " ++ show t1 ++ " with " ++ show t2 ++ "."
457−unifyRows :: Row -> Row -> Check [TypeConstraint]
460− (s1, r1') = toList r1
461− (s2, r2') = toList r2
462− int = [ (t1, t2) | (name, t1) <- s1, (name', t2) <- s2, name == name' ]
463− sd1 = [ (name, t1) | (name, t1) <- s1, not (elem name (map fst s2)) ]
464− sd2 = [ (name, t2) | (name, t2) <- s2, not (elem name (map fst s1)) ]
465− in rethrow (\e -> "Cannot unify " ++ show r1 ++ " with " ++ show r2 ++ ": " ++ e) $ do
466− cs1 <- fmap concat $ mapM (uncurry unifyTypes) int
467− cs2 <- unifyRows' sd1 r1' sd2 r2'
470− unifyRows' :: [(String, Type)] -> Row -> [(String, Type)] -> Row -> Check [TypeConstraint]
471− unifyRows' [] (RUnknown u) sd r = do
473− return [RowConstraint u (fromList (sd, r))]
474− unifyRows' ((name, ty):row) r others (RUnknown u) = do
476− cs <- unifyRows' row r others (RUnknown u')
477− return [ RowConstraint u (RCons name ty (RUnknown u')) ]
478− unifyRows' [] REmpty [] REmpty = return []
479− unifyRows' sd1 r1 sd2 r2 = throwError $ "Cannot unify " ++ show (fromList (sd1, r1)) ++ " with " ++ show (fromList (sd2, r2)) ++ "."
480− toList :: Row -> ([(String, Type)], Row)
481− toList (RCons name ty row) = let (tys, rest) = toList row
482− in ((name, ty):tys, rest)
484− fromList :: ([(String, Type)], Row) -> Row
485− fromList ([], r) = r
486− fromList ((name, t):ts, r) = RCons name t (fromList (ts, r))