git.iko.soy/rowtype-yoga/purescript-native
on 6e46a60 help sign in
rowtype-yoga/purescript-native/src/Language/PureScript/TypeChecker.hs
248 lines 12 kB history raw
1-----------------------------------------------------------------------------
2--
3-- Module : Language.PureScript.TypeChecker
4-- Copyright : (c) Phil Freeman 2013
5-- License : MIT
6--
7-- Maintainer : Phil Freeman <paf31@cantab.net>
8-- Stability : experimental
9-- Portability :
10--
11-- |
12-- The top-level type checker, which checks all declarations in a module.
13--
14-----------------------------------------------------------------------------
16{-# LANGUAGE FlexibleInstances #-}
18module Language.PureScript.TypeChecker (
19 module T,
20 typeCheckAll
21) where
23import Language.PureScript.TypeChecker.Monad as T
24import Language.PureScript.TypeChecker.Kinds as T
25import Language.PureScript.TypeChecker.Types as T
26import Language.PureScript.TypeChecker.Synonyms as T
28import Data.Maybe
29import qualified Data.Map as M
30import Control.Monad.State
31import Control.Monad.Error
32import Data.Either (rights, lefts)
34import Language.PureScript.Types
35import Language.PureScript.Names
36import Language.PureScript.Values
37import Language.PureScript.Kinds
38import Language.PureScript.Declarations
39import Language.PureScript.Sugar.TypeClasses
41addDataType :: ModuleName -> ProperName -> [String] -> [(ProperName, Maybe Type)] -> Kind -> Check ()
42addDataType moduleName name args dctors ctorKind = do
43 env <- getEnv
44 putEnv $ env { types = M.insert (moduleName, name) (ctorKind, Data) (types env) }
45 forM_ dctors $ \(dctor, maybeTy) ->
46 rethrow (("Error in data constructor " ++ show dctor ++ ":\n") ++) $
47 addDataConstructor moduleName name args dctor maybeTy
49addDataConstructor :: ModuleName -> ProperName -> [String] -> ProperName -> Maybe Type -> Check ()
50addDataConstructor moduleName name args dctor maybeTy = do
51 env <- getEnv
52 dataConstructorIsNotDefined moduleName dctor
53 when (runModuleName moduleName == dctor) $ throwError "A data constructor may not have the same name as its enclosing module."
54 let retTy = foldl TypeApp (TypeConstructor (Qualified (Just moduleName) name)) (map TypeVar args)
55 let dctorTy = maybe retTy (flip function retTy) maybeTy
56 let polyType = mkForAll args dctorTy
57 putEnv $ env { dataConstructors = M.insert (moduleName, dctor) (qualifyAllUnqualifiedNames moduleName env polyType, DataConstructor) (dataConstructors env) }
59addTypeSynonym :: ModuleName -> ProperName -> [String] -> Type -> Kind -> Check ()
60addTypeSynonym moduleName name args ty kind = do
61 env <- getEnv
62 putEnv $ env { types = M.insert (moduleName, name) (kind, TypeSynonym) (types env)
63 , typeSynonyms = M.insert (moduleName, name) (args, qualifyAllUnqualifiedNames moduleName env ty) (typeSynonyms env) }
65typeIsNotDefined :: ModuleName -> ProperName -> Check ()
66typeIsNotDefined moduleName name = do
67 env <- getEnv
68 guardWith (show name ++ " is already defined") $
69 not $ M.member (moduleName, name) (types env)
71dataConstructorIsNotDefined :: ModuleName -> ProperName -> Check ()
72dataConstructorIsNotDefined moduleName dctor = do
73 env <- getEnv
74 guardWith (show dctor ++ " is already defined") $
75 not $ M.member (moduleName, dctor) (dataConstructors env)
77valueIsNotDefined :: ModuleName -> Ident -> Check ()
78valueIsNotDefined moduleName name = do
79 env <- getEnv
80 case M.lookup (moduleName, name) (names env) of
81 Just _ -> throwError $ show name ++ " is already defined"
82 Nothing -> return ()
84addValue :: ModuleName -> Ident -> Type -> Check ()
85addValue moduleName name ty = do
86 env <- getEnv
87 putEnv (env { names = M.insert (moduleName, name) (qualifyAllUnqualifiedNames moduleName env ty, Value) (names env) })
89addTypeClassDictionaries :: [TypeClassDictionaryInScope] -> Check ()
90addTypeClassDictionaries entries = do
91 modify $ \st -> st { checkEnv = (checkEnv st) { typeClassDictionaries = entries ++ (typeClassDictionaries . checkEnv $ st) } }
93-- |
94-- Type check all declarations in a module
95--
96-- At this point, many declarations will have been desugared, but it is still necessary to
97--
98-- * Kind-check all types and add them to the @Environment@
99--
100-- * Type-check all values and add them to the @Environment@
101--
102-- * Bring type class instances into scope
103--
104-- * Process module imports
105--
106typeCheckAll :: ModuleName -> [Declaration] -> Check [Declaration]
107typeCheckAll _ [] = return []
108typeCheckAll moduleName (d@(DataDeclaration name args dctors) : rest) = do
109 rethrow (("Error in type constructor " ++ show name ++ ":\n") ++) $ do
110 typeIsNotDefined moduleName name
111 ctorKind <- kindsOf moduleName name args (mapMaybe snd dctors)
112 addDataType moduleName name args dctors ctorKind
113 ds <- typeCheckAll moduleName rest
114 return $ d : ds
115typeCheckAll moduleName (d@(DataBindingGroupDeclaration tys) : rest) = do
116 rethrow ("Error in data binding group:\n" ++) $ do
117 let syns = mapMaybe toTypeSynonym tys
118 let dataDecls = mapMaybe toDataDecl tys
119 (syn_ks, data_ks) <- kindsOfAll moduleName syns (map (\(name, args, dctors) -> (name, args, mapMaybe snd dctors)) dataDecls)
120 forM_ (zip dataDecls data_ks) $ \((name, args, dctors), ctorKind) -> do
121 typeIsNotDefined moduleName name
122 addDataType moduleName name args dctors ctorKind
123 forM_ (zip syns syn_ks) $ \((name, args, ty), kind) -> do
124 typeIsNotDefined moduleName name
125 addTypeSynonym moduleName name args ty kind
126 ds <- typeCheckAll moduleName rest
127 return $ d : ds
128 where
129 toTypeSynonym (TypeSynonymDeclaration nm args ty) = Just (nm, args, ty)
130 toTypeSynonym _ = Nothing
131 toDataDecl (DataDeclaration nm args dctors) = Just (nm, args, dctors)
132 toDataDecl _ = Nothing
133typeCheckAll moduleName (d@(TypeSynonymDeclaration name args ty) : rest) = do
134 rethrow (("Error in type synonym " ++ show name ++ ":\n") ++) $ do
135 typeIsNotDefined moduleName name
136 kind <- kindsOf moduleName name args [ty]
137 addTypeSynonym moduleName name args ty kind
138 ds <- typeCheckAll moduleName rest
139 return $ d : ds
140typeCheckAll _ (TypeDeclaration _ _ : _) = error "Type declarations should have been removed"
141typeCheckAll moduleName (ValueDeclaration name [] Nothing val : rest) = do
142 d <- rethrow (("Error in declaration " ++ show name ++ ":\n") ++) $ do
143 valueIsNotDefined moduleName name
144 [(_, (val', ty))] <- typesOf moduleName [(name, val)]
145 addValue moduleName name ty
146 return $ ValueDeclaration name [] Nothing val'
147 ds <- typeCheckAll moduleName rest
148 return $ d : ds
149typeCheckAll _ (ValueDeclaration _ _ _ _ : _) = error "Binders were not desugared"
150typeCheckAll moduleName (BindingGroupDeclaration vals : rest) = do
151 d <- rethrow (("Error in binding group " ++ show (map fst vals) ++ ":\n") ++) $ do
152 forM_ (map fst vals) $ \name ->
153 valueIsNotDefined moduleName name
154 tys <- typesOf moduleName vals
155 vals' <- forM (zip (map fst vals) (map snd tys)) $ \(name, (val, ty)) -> do
156 addValue moduleName name ty
157 return (name, val)
158 return $ BindingGroupDeclaration vals'
159 ds <- typeCheckAll moduleName rest
160 return $ d : ds
161typeCheckAll moduleName (d@(ExternDataDeclaration name kind) : rest) = do
162 env <- getEnv
163 guardWith (show name ++ " is already defined") $ not $ M.member (moduleName, name) (types env)
164 putEnv $ env { types = M.insert (moduleName, name) (kind, TypeSynonym) (types env) }
165 ds <- typeCheckAll moduleName rest
166 return $ d : ds
167typeCheckAll moduleName (d@(ExternDeclaration importTy name _ ty) : rest) = do
168 rethrow (("Error in foreign import declaration " ++ show name ++ ":\n") ++) $ do
169 env <- getEnv
170 kind <- kindOf moduleName ty
171 guardWith "Expected kind *" $ kind == Star
172 case M.lookup (moduleName, name) (names env) of
173 Just _ -> throwError $ show name ++ " is already defined"
174 Nothing -> putEnv (env { names = M.insert (moduleName, name) (qualifyAllUnqualifiedNames moduleName env ty, Extern importTy) (names env) })
175 ds <- typeCheckAll moduleName rest
176 return $ d : ds
177typeCheckAll moduleName (d@(FixityDeclaration _ name) : rest) = do
178 ds <- typeCheckAll moduleName rest
179 env <- getEnv
180 guardWith ("Fixity declaration with no binding: " ++ name) $ M.member (moduleName, Op name) $ names env
181 return $ d : ds
182typeCheckAll currentModule (d@(ImportDeclaration moduleName idents) : rest) = do
183 env <- getEnv
184 rethrow errorMessage $ do
185 guardWith ("Module " ++ show moduleName ++ " does not exist") $ moduleExists env
186 case idents of
187 Nothing -> do
188 shadowIdents (map snd $ filterModule (names env)) env
189 shadowTypes (map snd $ filterModule (types env)) env
190 Just idents' -> do
191 shadowIdents (lefts idents') env
192 shadowTypes (rights idents') env
193 shadowTypeClassInstances env
194 ds <- typeCheckAll currentModule rest
195 return $ d : ds
196 where
197 errorMessage = (("Error in import declaration " ++ show moduleName ++ ":\n") ++)
198 filterModule = filter ((== moduleName) . fst) . M.keys
199 moduleExists env = not (null (filterModule (names env))) || not (null (filterModule (types env)))
200 shadowIdents idents' env =
201 forM_ idents' $ \ident -> do
202 case (moduleName, ident) `M.lookup` names env of
203 Just (_, Alias _ _) -> return ()
204 Just (pt, _) -> do
205 guardWith (show currentModule ++ "." ++ show ident ++ " is already defined") $ (currentModule, ident) `M.notMember` names env
206 modifyEnv (\e -> e { names = M.insert (currentModule, ident) (pt, Alias moduleName ident) (names e) })
207 Nothing -> throwError (show moduleName ++ "." ++ show ident ++ " is undefined")
208 shadowTypes pns env =
209 forM_ pns $ \pn -> do
210 case (moduleName, pn) `M.lookup` types env of
211 Nothing -> throwError (show moduleName ++ "." ++ show pn ++ " is undefined")
212 Just (_, DataAlias _ _) -> return ()
213 Just (k, _) -> do
214 guardWith (show currentModule ++ "." ++ show pn ++ " is already defined") $ (currentModule, pn) `M.notMember` types env
215 modifyEnv (\e -> e { types = M.insert (currentModule, pn) (k, DataAlias moduleName pn) (types e) })
216 let keys = map (snd . fst) . filter (\(_, (fn, _)) -> fn `constructs` pn) . M.toList . dataConstructors $ env
217 forM_ keys $ \dctor -> do
218 case (moduleName, dctor) `M.lookup` dataConstructors env of
219 Just (_, Alias _ _) -> return ()
220 Just (ctorTy, _) -> do
221 guardWith (show currentModule ++ "." ++ show dctor ++ " is already defined") $ (currentModule, dctor) `M.notMember` dataConstructors env
222 modifyEnv (\e -> e { dataConstructors = M.insert (currentModule, dctor) (ctorTy, Alias moduleName (Ident (runProperName dctor))) (dataConstructors e) })
223 Nothing -> throwError (show moduleName ++ "." ++ show dctor ++ " is undefined")
224 shadowTypeClassInstances env = do
225 let instances = filter (\tcd ->
226 let Qualified (Just mn) _ = tcdName tcd in
227 moduleName == mn && tcdType tcd == TCDRegular
228 ) (typeClassDictionaries env)
229 forM_ instances $ \tcd -> do
230 let (Qualified _ ident) = tcdName tcd
231 addTypeClassDictionaries [tcd { tcdName = (Qualified (Just currentModule) ident), tcdType = TCDAlias (tcdName tcd) }]
232 constructs (TypeConstructor (Qualified (Just mn) pn')) pn
233 = mn == moduleName && pn' == pn
234 constructs (ForAll _ ty _) pn = ty `constructs` pn
235 constructs (TypeApp (TypeApp t _) ty) pn | t == tyFunction = ty `constructs` pn
236 constructs (TypeApp ty _) pn = ty `constructs` pn
237 constructs fn _ = error $ "Invalid arguments to constructs: " ++ show fn
238typeCheckAll moduleName (d@(TypeClassDeclaration _ _ _) : rest) = do
239 env <- getEnv
240 ds <- typeCheckAll moduleName rest
241 return $ qualifyAllUnqualifiedNames moduleName env d : ds
242typeCheckAll moduleName (d@(TypeInstanceDeclaration deps className ty _) : rest) = do
243 env <- getEnv
244 dictName <- Check . lift $ mkDictionaryValueName moduleName className ty
245 addTypeClassDictionaries (qualifyAllUnqualifiedNames moduleName env
246 [TypeClassDictionaryInScope (Qualified (Just moduleName) dictName) className ty (Just deps) TCDRegular])
247 ds <- typeCheckAll moduleName rest
248 return $ qualifyAllUnqualifiedNames moduleName env d : ds