module-management-0.11: Language/Haskell/Modules/Split.hs
{-# LANGUAGE ScopedTypeVariables, TupleSections #-}
{-# OPTIONS_GHC -Wall #-}
module Language.Haskell.Modules.Split
( DeclName(..)
, splitModule
, splitModuleDecls
) where
import Control.Exception (throw)
import Control.Monad (when)
import Control.Monad.Trans (liftIO)
import Data.Char (isAlpha, isAlphaNum, toUpper)
import Data.Default (Default(def))
import Data.Foldable as Foldable (fold)
import Data.List as List (filter, intercalate, map, nub)
import Data.Map as Map (delete, elems, empty, filter, insert, insertWith, lookup, Map, mapWithKey)
import Data.Maybe (fromMaybe, mapMaybe)
import Data.Monoid ((<>), mempty)
import Data.Sequence ((<|), (|>))
import Data.Set as Set (delete, difference, empty, filter, fold, insert, intersection, map, member, null, Set, singleton, toList, union, unions)
import Data.Set.Extra as Set (gFind, mapM)
import Language.Haskell.Exts (fromParseResult, ParseResult(ParseOk, ParseFailed))
import qualified Language.Haskell.Exts.Annotated as A (Decl, ImportDecl(..), ImportSpecList(..), Module(Module), ModuleHead(ModuleHead), Name)
import Language.Haskell.Exts.Annotated.Simplify (sImportDecl, sImportSpec, sModuleName, sName)
import Language.Haskell.Exts.Pretty (defaultMode, prettyPrint, prettyPrintWithMode)
import Language.Haskell.Exts.SrcLoc (SrcSpanInfo(..))
import qualified Language.Haskell.Exts.Syntax as S (ExportSpec, ImportDecl(..), ModuleName(..), Name(..))
import Language.Haskell.Modules.Fold (echo, echo2, foldDecls, foldExports, foldHeader, foldImports, foldModule, ignore, ignore2, ModuleInfo)
import Language.Haskell.Modules.Imports (cleanImports)
import Language.Haskell.Modules.Internal (doResult, modulePath, ModuleResult(..), MonadClean(getParams), Params(moduVerse, testMode), parseFileWithComments)
import Language.Haskell.Modules.Util.QIO (qLnPutStr, quietly)
import Language.Haskell.Modules.Util.Symbols (exports, imports, symbols)
import Prelude hiding (writeFile)
import System.FilePath ((<.>))
data DeclName
= Exported S.Name -- Maybe because...?
| Internal S.Name
| ReExported S.Name
| Instance
deriving (Eq, Ord, Show)
isReExported :: DeclName -> Bool
isReExported (ReExported _) = True
isReExported _ = False
parseModule :: MonadClean m => S.ModuleName -> m ModuleInfo
parseModule name =
do path <- modulePath name
text <- liftIO $ readFile path
(parsed, comments) <- parseFileWithComments path >>= return . fromParseResult
return (parsed, text, comments)
-- | Do splitModuleBy with a custom symbol to module mapping
splitModule :: MonadClean m => (DeclName -> S.ModuleName) -> S.ModuleName -> m ()
splitModule symbolToModule old = parseModule old >>= splitModuleBy symbolToModule old
-- | Do splitModuleBy with the default symbol to module mapping (was splitModule)
splitModuleDecls :: MonadClean m => S.ModuleName -> m ()
splitModuleDecls old = parseModule old >>= \ m -> splitModuleBy (defaultSymbolToModule old) old m
-- | Split each of a module's declarations into a new module. Update
-- the imports of all the modules in the moduVerse to reflect the split.
-- For example, if you have a module like
--
-- @
-- module Start (a, b, (.+.)) where
-- import
-- a = 1 + a
-- b = 2
-- c = 3
-- c' = 4
-- (.+.) = b + c
-- @
--
-- After running @splitModule@ the @Start@ module will be gone. The
-- @a@ and @b@ symbols will be in new modules named @Start.A@ and
-- @Start.B@. Because they were not exported by @Start@, the @c@ and
-- @c'@ symbols will both be in a new module named @Start.Internal.C@.
-- And the @.+.@ symbol will be in a module named
-- @Start.OtherSymbols@. Note that this module needs to import new
-- @Start.A@ and @Start.Internal.C@ modules.
--
-- If we had imported and then re-exported a symbol in Start it would
-- go into a module named @Start.ReExported@. Any instance declarations
-- would go into @Start.Instances@.
splitModuleBy :: MonadClean m => (DeclName -> S.ModuleName) -> S.ModuleName -> ModuleInfo -> m ()
splitModuleBy symbolToModule old m =
do univ <- moduVerseCheck
m <- parseModule old
changes <- doSplit symbolToModule univ m >>= return . collisionCheck univ
setMapM_ doResult changes -- Write the new modules
setMapM_ doClean changes -- Clean the new modules after all edits are finished
where
moduVerseCheck = getParams >>= return . fromMaybe (error "moduVerse not set, use modifyModuVerse") . moduVerse
collisionCheck univ s =
if not (Set.null illegal)
then error ("One or more module to be created by splitModule already exists: " ++ show (Set.toList illegal))
else s
where
illegal = Set.intersection univ (created s)
created :: Set ModuleResult -> Set S.ModuleName
created = setMapMaybe (\ x -> case x of Created m _ -> Just m; _ -> Nothing)
-- Make sure this isn't trying to clobber a module that exists (other than 'old'.)
doClean :: MonadClean m => ModuleResult -> m ()
doClean (Created m _) = doClean' m
doClean (Modified m _) = doClean' m
doClean (Removed _) = return ()
doClean (Unchanged _) = return ()
doClean' m =
do flag <- getParams >>= return . not . testMode
when flag (modulePath m >>= cleanImports >> return ())
-- This returns a set of maybe because there may be instance
-- declarations, in which case we want an Instances module to
-- appear in newModuleNames below.
declared :: ModuleInfo -> Set (Maybe S.Name)
declared m = foldDecls (\ d _pref _s _suff r -> Set.union (symbols d) r) ignore2 m Set.empty
exported :: ModuleInfo -> Set (Maybe S.Name)
exported m =
case hasExportList m of
False -> declared m
True -> union (foldExports ignore2 (\ e _pref _s _suff r -> Set.union (symbols e) r) ignore2 m Set.empty)
-- Any instances declared are exported regardless of the export list
(if member Nothing (declared m) then singleton Nothing else Set.empty)
where
hasExportList :: ModuleInfo -> Bool
hasExportList m@(A.Module _ Nothing _ _ _, _, _) = False
hasExportList m@(A.Module _ (Just (A.ModuleHead _ _ _ Nothing)) _ _ _, _, _) = False
hasExportList _ = True
newModuleNames :: (DeclName -> S.ModuleName) -> S.ModuleName -> ModuleInfo -> Set S.ModuleName
newModuleNames symbolToModule old m =
Set.map (symbolToModule . declName' m) (union (declared m) (exported m))
declName' :: ModuleInfo -> Maybe S.Name -> DeclName
declName' m =
declName (reExported m) (internal m)
where
declName :: (S.Name -> Bool) -> (S.Name -> Bool) -> Maybe S.Name -> DeclName
declName reExported internal name =
case name of
Nothing -> Instance
Just name' ->
if reExported name'
then ReExported name'
else if internal name'
then Internal name'
else Exported name'
internal :: ModuleInfo -> S.Name -> Bool
internal m name = member (Just name) (difference (declared m) (exported m))
reExported :: ModuleInfo -> S.Name -> Bool
reExported m name = member (Just name) (difference (exported m) (declared m))
-- | Create the set of module results implied by the split -
-- creations, removals, and modifications. This includes the changes
-- to the imports in modules that imported the original module.
doSplit :: MonadClean m => (DeclName -> S.ModuleName) -> Set S.ModuleName -> ModuleInfo -> m (Set ModuleResult)
doSplit _ _ (A.Module _ _ _ _ [], _, _) = return Set.empty -- No declarations - nothing to split
doSplit _ _ (A.Module _ _ _ _ [_], _, _) = return Set.empty -- One declaration - nothing to split (but maybe we should anyway?)
doSplit _ _ (A.Module _ Nothing _ _ _, _, _) = throw $ userError $ "splitModule: no explicit header"
doSplit symbolToModule univ m@(A.Module _ (Just (A.ModuleHead _ moduleName _ _)) _ _ _, _, _) =
do qLnPutStr ("Splitting " ++ show moduleName)
updated <- Set.mapM (updateImports m (sModuleName moduleName) symbolToModule) (Set.delete old univ)
let moduleNames = newModuleNames symbolToModule old m
let split = union (Set.map newModule moduleNames)
(if member old moduleNames then Set.empty else singleton (Removed old))
return $ union split updated
where
-- The name of the module to be split
old = sModuleName moduleName
-- Build a map from module name to the list of declarations that
-- will be in that module. All of these declarations used to be
-- in moduleName.
moduleDeclMap :: Map S.ModuleName [(A.Decl SrcSpanInfo, String)]
moduleDeclMap = foldDecls (\ d pref s suff r -> Set.fold (\ sym mp -> insertWith (++) (symbolToModule (declName' m sym)) [(d, pref <> s <> suff)] mp) r (symbols d)) ignore2 m Map.empty
-- Build a new module given its name and the list of
-- declarations it should contain.
newModule :: S.ModuleName -> ModuleResult
newModule name'@(S.ModuleName modName) =
(if member name' univ then Modified else Created) name' $
case Map.lookup name' moduleDeclMap of
Nothing ->
-- Build a module that re-exports a symbol
Foldable.fold (foldHeader echo2 echo (\ _n pref _ suff r -> r |> pref <> modName <> suff) echo m mempty) <>
Foldable.fold (foldExports echo2 ignore ignore2 m mempty) <>
doSeps (Foldable.fold (foldExports ignore2
(\ e pref s suff r -> if setAny isReExported (Set.map (declName' m) (symbols e)) then r |> [(pref, s <> suff)] else r)
(\ s r -> r |> [("", s)]) m mempty)) <>
Foldable.fold (foldImports (\ _i pref s suff r -> r |> pref <> s <> suff) m mempty)
Just modDecls ->
-- Change the module name in the header
Foldable.fold (foldHeader echo2 echo (\ _n pref _ suff r -> r |> pref <> modName <> suff) echo m mempty) <>
-- If the module has an export list use its outline
(let mh = let (A.Module _ x _ _ _, _, _) = m in x
me = maybe Nothing (\ h -> let (A.ModuleHead _ _ _ x) = h in x) mh in
maybe "\n ( " (\ _ -> Foldable.fold $ foldExports (<|) ignore ignore2 m mempty) me <>
intercalate "\n , " (nub (List.map (prettyPrintWithMode defaultMode) (newExports modDecls))) <> "\n" <>
maybe " ) where\n" (\ _ -> Foldable.fold $ foldExports ignore2 ignore (<|) m mempty) me) <>
-- The prefix of the imports section
fromMaybe "" (foldImports (\ _i pref _ _ r -> maybe (Just pref) Just r) m Nothing) <>
unlines (List.map (prettyPrintWithMode defaultMode) (elems (newImports modDecls))) <> "\n" <>
-- Grab the old imports
fromMaybe "" (foldImports (\ _i pref s suff r -> Just (maybe (s <> suff) (\ l -> l <> pref <> s <> suff) r)) m Nothing) <>
-- fromMaybe "" (foldDecls (\ _d pref _ _ r -> maybe (Just pref) Just r) ignore2 m text Nothing) <>
concatMap snd (reverse modDecls)
where
-- Build export specs of the symbols created by each declaration.
newExports :: [(A.Decl SrcSpanInfo, String)] -> [S.ExportSpec]
newExports modDecls = nub (concatMap (exports . fst) modDecls)
newImports :: [(A.Decl SrcSpanInfo, String)] -> Map S.ModuleName S.ImportDecl
newImports modDecls =
mapWithKey toImportDecl (Map.delete name'
(Map.filter (\ pairs ->
let declared = justs (Set.unions (List.map (symbols . fst) pairs)) in
not (Set.null (Set.intersection declared (referenced modDecls)))) moduleDeclMap))
-- In this module, we need to import any module that declares a symbol
-- referenced here.
referenced :: [(A.Decl SrcSpanInfo, String)] -> Set S.Name
referenced modDecls = Set.map sName (gFind modDecls :: Set (A.Name SrcSpanInfo))
-- Re-construct a separated list
doSeps :: [(String, String)] -> String
doSeps [] = ""
doSeps ((_, hd) : tl) = hd <> concatMap (\ (a, b) -> a <> b) tl
-- | Update the imports to reflect the changed module names in symbolToModule.
updateImports :: MonadClean m => ModuleInfo -> S.ModuleName -> (DeclName -> S.ModuleName) -> S.ModuleName -> m ModuleResult
updateImports m old symbolToModule name =
do path <- modulePath name
quietly $ qLnPutStr $ "updateImports " ++ show name
text' <- liftIO $ readFile path
parsed <- parseFileWithComments path
case parsed of
ParseOk (m', comments') ->
let text'' = Foldable.fold (foldModule echo2 echo echo echo echo2 echo echo2
(\ i pref s suff r -> r |> pref <> updateImportDecl s i <> suff)
echo echo2 (m', text', comments') mempty) in
return $ if text' /= text'' then Modified name text'' else Unchanged name
ParseFailed _ _ -> error $ "Parse error in " ++ show name
where
updateImportDecl :: String -> A.ImportDecl SrcSpanInfo -> String
updateImportDecl s i =
if sModuleName (A.importModule i) == old
then intercalate "\n" (List.map prettyPrint (updateImportSpecs i (A.importSpecs i)))
else s
updateImportSpecs :: A.ImportDecl SrcSpanInfo -> Maybe (A.ImportSpecList SrcSpanInfo) -> [S.ImportDecl]
-- No spec list, import all the split modules
updateImportSpecs i Nothing = List.map (\ x -> (sImportDecl i) {S.importModule = x}) (Map.elems moduleMap)
-- If flag is True this is a "hiding" import
updateImportSpecs i (Just (A.ImportSpecList _ flag specs)) =
concatMap (\ spec -> let xs = mapMaybe (\ sym -> Map.lookup (declName' m sym) moduleMap) (toList (symbols spec)) in
List.map (\ x -> (sImportDecl i) {S.importModule = x, S.importSpecs = Just (flag, [sImportSpec spec])}) xs) specs
moduleMap = symbolToModuleMap symbolToModule m
symbolToModuleMap :: (DeclName -> S.ModuleName) -> ModuleInfo -> Map DeclName S.ModuleName
symbolToModuleMap symbolToModule m =
mp'
where
mp' = foldExports ignore2 (\ e _ _ _ r -> Set.fold f r (symbols e)) ignore2 m mp
mp = foldDecls (\ d _ _ _ r -> Set.fold f r (symbols d)) ignore2 m Map.empty
f sym mp'' =
Map.insert
(declName' m sym)
(symbolToModule (declName' m sym))
mp''
-- | What module should this symbol be moved to?
defaultSymbolToModule :: S.ModuleName -> DeclName -> S.ModuleName
defaultSymbolToModule (S.ModuleName parentModuleName) name =
S.ModuleName (parentModuleName <.> case name of
Instance -> "Instances"
ReExported _ -> "ReExported"
Internal x -> "Internal" <.> f x
Exported x -> f x)
where
f (S.Symbol s) = g s
f (S.Ident s) = g s
-- Any symbol that starts with a letter is converted to a module name
-- by capitalizing and keeping the remaining alphaNum characters.
g (c : s) | isAlpha c = toUpper c : List.filter isAlphaNum s
g _ = "OtherSymbols"
-- | Build an import of the symbols created by a declaration.
toImportDecl :: S.ModuleName -> [(A.Decl SrcSpanInfo, String)] -> S.ImportDecl
toImportDecl (S.ModuleName modName) decls =
S.ImportDecl {S.importLoc = def,
S.importModule = S.ModuleName modName,
S.importQualified = False,
S.importSrc = False,
S.importPkg = Nothing,
S.importAs = Nothing,
S.importSpecs = Just (False, nub (concatMap (imports . fst) decls))}
justs :: Ord a => Set (Maybe a) -> Set a
justs = Set.fold (\ mx s -> maybe s (`Set.insert` s) mx) Set.empty
setAny :: Ord a => (a -> Bool) -> Set a -> Bool
setAny f s = not (Set.null (Set.filter f s))
setMapMaybe :: Ord b => (a -> Maybe b) -> Set a -> Set b
setMapMaybe p s = Set.fold f Set.empty s
where f x s' = maybe s' (\ y -> Set.insert y s') (p x)
setMapM_ :: (Monad m, Ord b) => (a -> m b) -> Set a -> m ()
setMapM_ f s = do _ <- Set.mapM f s
return ()