module Language.PureScript.TypeChecker (
module T,
typeCheckAll
) where
import Language.PureScript.TypeChecker.Monad as T
import Language.PureScript.TypeChecker.Kinds as T
import Language.PureScript.TypeChecker.Types as T
import Language.PureScript.TypeChecker.Synonyms as T
import Data.Maybe
import qualified Data.Map as M
import Control.Monad.State
import Control.Monad.Error
import Data.Either (rights, lefts)
import Language.PureScript.Types
import Language.PureScript.Names
import Language.PureScript.Kinds
import Language.PureScript.Declarations
addDataType :: ModuleName -> ProperName -> [String] -> [(ProperName, Maybe Type)] -> Kind -> Check ()
addDataType moduleName name args dctors ctorKind = do
env <- getEnv
putEnv $ env { types = M.insert (moduleName, name) (ctorKind, Data) (types env) }
forM_ dctors $ \(dctor, maybeTy) ->
rethrow (("Error in data constructor " ++ show name ++ ":\n") ++) $
addDataConstructor moduleName name args dctor maybeTy
addDataConstructor :: ModuleName -> ProperName -> [String] -> ProperName -> Maybe Type -> Check ()
addDataConstructor moduleName name args dctor maybeTy = do
env <- getEnv
dataConstructorIsNotDefined moduleName dctor
let retTy = foldl TypeApp (TypeConstructor (Qualified (Just moduleName) name)) (map TypeVar args)
let dctorTy = maybe retTy (\ty -> Function [ty] retTy) maybeTy
let polyType = mkForAll args dctorTy
putEnv $ env { dataConstructors = M.insert (moduleName, dctor) polyType (dataConstructors env) }
addTypeSynonym :: ModuleName -> ProperName -> [String] -> Type -> Kind -> Check ()
addTypeSynonym moduleName name args ty kind = do
env <- getEnv
putEnv $ env { types = M.insert (moduleName, name) (kind, TypeSynonym) (types env)
, typeSynonyms = M.insert (moduleName, name) (args, ty) (typeSynonyms env) }
typeIsNotDefined :: ModuleName -> ProperName -> Check ()
typeIsNotDefined moduleName name = do
env <- getEnv
guardWith (show name ++ " is already defined") $
not $ M.member (moduleName, name) (types env)
dataConstructorIsNotDefined :: ModuleName -> ProperName -> Check ()
dataConstructorIsNotDefined moduleName dctor = do
env <- getEnv
guardWith (show dctor ++ " is already defined") $
not $ M.member (moduleName, dctor) (dataConstructors env)
valueIsNotDefined :: ModuleName -> Ident -> Check ()
valueIsNotDefined moduleName name = do
env <- getEnv
case M.lookup (moduleName, name) (names env) of
Just _ -> throwError $ show name ++ " is already defined"
Nothing -> return ()
addValue :: ModuleName -> Ident -> Type -> Check ()
addValue moduleName name ty = do
env <- getEnv
putEnv (env { names = M.insert (moduleName, name) (ty, Value) (names env) })
typeCheckAll :: ModuleName -> [Declaration] -> Check ()
typeCheckAll _ [] = return ()
typeCheckAll moduleName (DataDeclaration name args dctors : rest) = do
rethrow (("Error in type constructor " ++ show name ++ ":\n") ++) $ do
typeIsNotDefined moduleName name
ctorKind <- kindsOf moduleName name args (mapMaybe snd dctors)
addDataType moduleName name args dctors ctorKind
typeCheckAll moduleName rest
typeCheckAll moduleName (DataBindingGroupDeclaration tys : rest) = do
rethrow (("Error in data binding group " ++ show (map (\(name, _, _) -> name) tys) ++ ":\n") ++) $ do
forM_ tys $ \(name, _, _) ->
typeIsNotDefined moduleName name
ks <- kindsOfAll moduleName (map (\(name, args, dctors) -> (name, args, mapMaybe snd dctors)) tys)
forM (zip tys ks) $ \((name, args, dctors), ctorKind) ->
addDataType moduleName name args dctors ctorKind
typeCheckAll moduleName rest
typeCheckAll moduleName (TypeSynonymDeclaration name args ty : rest) = do
rethrow (("Error in type synonym " ++ show name ++ ":\n") ++) $ do
typeIsNotDefined moduleName name
kind <- kindsOf moduleName name args [ty]
addTypeSynonym moduleName name args ty kind
typeCheckAll moduleName rest
typeCheckAll _ (TypeDeclaration _ _ : _) = error "Type declarations should have been removed"
typeCheckAll moduleName (ValueDeclaration name [] Nothing val : rest) = do
rethrow (("Error in declaration " ++ show name ++ ":\n") ++) $ do
valueIsNotDefined moduleName name
[ty] <- typesOf moduleName [(name, val)]
addValue moduleName name ty
typeCheckAll moduleName rest
typeCheckAll _ (ValueDeclaration _ _ _ _ : _) = error "Binders were not desugared"
typeCheckAll moduleName (BindingGroupDeclaration vals : rest) = do
rethrow (("Error in binding group " ++ show (map fst vals) ++ ":\n") ++) $ do
forM_ (map fst vals) $ \name ->
valueIsNotDefined moduleName name
tys <- typesOf moduleName vals
forM (zip (map fst vals) tys) $ \(name, ty) ->
addValue moduleName name ty
typeCheckAll moduleName rest
typeCheckAll moduleName (ExternDataDeclaration name kind : rest) = do
env <- getEnv
guardWith (show name ++ " is already defined") $ not $ M.member (moduleName, name) (types env)
putEnv $ env { types = M.insert (moduleName, name) (kind, TypeSynonym) (types env) }
typeCheckAll moduleName rest
typeCheckAll moduleName (ExternMemberDeclaration member name ty : rest) = do
rethrow (("Error in foreign import member declaration " ++ show name ++ ":\n") ++) $ do
env <- getEnv
kind <- kindOf moduleName ty
guardWith "Expected kind *" $ kind == Star
case M.lookup (moduleName, name) (names env) of
Just _ -> throwError $ show name ++ " is already defined"
Nothing -> case ty of
_ | isSingleArgumentFunction ty -> do
putEnv (env { names = M.insert (moduleName, name) (ty, Extern) (names env)
, members = M.insert (moduleName, name) member (members env) })
| otherwise -> throwError "Foreign member declarations must have function types, with an single argument."
typeCheckAll moduleName rest
where
isSingleArgumentFunction (Function [_] _) = True
isSingleArgumentFunction (ForAll _ t) = isSingleArgumentFunction t
isSingleArgumentFunction _ = False
typeCheckAll moduleName (ExternDeclaration name ty : rest) = do
rethrow (("Error in foreign import declaration " ++ show name ++ ":\n") ++) $ do
env <- getEnv
kind <- kindOf moduleName ty
guardWith "Expected kind *" $ kind == Star
case M.lookup (moduleName, name) (names env) of
Just _ -> throwError $ show name ++ " is already defined"
Nothing -> putEnv (env { names = M.insert (moduleName, name) (ty, Extern) (names env) })
typeCheckAll moduleName rest
typeCheckAll moduleName (FixityDeclaration _ name : rest) = do
typeCheckAll moduleName rest
env <- getEnv
guardWith ("Fixity declaration with no binding: " ++ name) $ M.member (moduleName, Op name) $ names env
typeCheckAll currentModule (ImportDeclaration moduleName idents : rest) = do
env <- getEnv
rethrow errorMessage $ do
guardWith ("Module " ++ show moduleName ++ " does not exist") $ moduleExists env
case idents of
Nothing -> do
shadowIdents (map snd $ filterModule (names env)) env
shadowTypes (map snd $ filterModule (types env)) env
Just idents' -> do
shadowIdents (lefts idents') env
shadowTypes (rights idents') env
typeCheckAll currentModule rest
where errorMessage = (("Error in import declaration " ++ show moduleName ++ ":\n") ++)
filterModule = filter ((== moduleName) . fst) . M.keys
moduleExists env = not (null (filterModule (names env))) || not (null (filterModule (types env)))
shadowIdents idents' env =
forM_ idents' $ \ident -> do
guardWith (show currentModule ++ "." ++ show ident ++ " is already defined") $ (currentModule, ident) `M.notMember` names env
case (moduleName, ident) `M.lookup` names env of
Just (pt, _) -> modifyEnv (\e -> e { names = M.insert (currentModule, ident) (pt, Alias moduleName ident) (names e) })
Nothing -> throwError (show moduleName ++ "." ++ show ident ++ " is undefined")
shadowTypes pns env =
forM_ pns $ \pn -> do
guardWith (show currentModule ++ "." ++ show pn ++ " is already defined") $ (currentModule, pn) `M.notMember` types env
case (moduleName, pn) `M.lookup` types env of
Nothing -> throwError (show moduleName ++ "." ++ show pn ++ " is undefined")
Just (k, _) -> do
modifyEnv (\e -> e { types = M.insert (currentModule, pn) (k, DataAlias moduleName pn) (types e) })
let keys = map (snd . fst) . filter (\(_, fn) -> fn `constructs` pn) . M.toList . dataConstructors $ env
forM_ keys $ \dctor -> do
guardWith (show currentModule ++ "." ++ show dctor ++ " is already defined") $ (currentModule, dctor) `M.notMember` dataConstructors env
case (moduleName, dctor) `M.lookup` dataConstructors env of
Just ctorTy -> modifyEnv (\e -> e { dataConstructors = M.insert (currentModule, dctor) ctorTy (dataConstructors e) })
Nothing -> throwError (show moduleName ++ "." ++ show dctor ++ " is undefined")
constructs (TypeConstructor (Qualified (Just mn) pn')) pn
= mn == moduleName && pn' == pn
constructs (ForAll _ ty) pn = ty `constructs` pn
constructs (Function _ ty) pn = ty `constructs` pn
constructs (TypeApp ty _) pn = ty `constructs` pn
constructs fn _ = error $ "Invalid arguments to construct" ++ show fn