ghc-mod/Language/Haskell/GhcMod/Utils.hs
2014-09-18 10:45:14 +02:00

66 lines
2.1 KiB
Haskell

{-# LANGUAGE CPP #-}
module Language.Haskell.GhcMod.Utils where
import Language.Haskell.GhcMod.Error
import MonadUtils (MonadIO, liftIO)
import System.Directory (getCurrentDirectory, setCurrentDirectory)
import System.Exit (ExitCode(..))
import System.Process (readProcessWithExitCode)
#ifndef SPEC
import System.Environment
#endif
-- dropWhileEnd is not provided prior to base 4.5.0.0.
dropWhileEnd :: (a -> Bool) -> [a] -> [a]
dropWhileEnd p = foldr (\x xs -> if p x && null xs then [] else x : xs) []
extractParens :: String -> String
extractParens str = extractParens' str 0
where
extractParens' :: String -> Int -> String
extractParens' [] _ = []
extractParens' (s:ss) level
| s `elem` "([{" = s : extractParens' ss (level+1)
| level == 0 = extractParens' ss 0
| s `elem` "}])" && level == 1 = [s]
| s `elem` "}])" = s : extractParens' ss (level-1)
| otherwise = s : extractParens' ss level
readProcess' :: (MonadIO m, MonadError GhcModError m)
=> String
-> [String]
-> m String
readProcess' cmd opts = do
(rv,output,err) <- liftIO (readProcessWithExitCode cmd opts "")
`modifyError'` GMEProcess ([cmd] ++ opts)
case rv of
ExitFailure val -> do
throwError $ GMEProcess ([cmd] ++ opts) $ strMsg $
cmd ++ " " ++ unwords opts ++ " (exit " ++ show val ++ ")"
++ "\n" ++ err
ExitSuccess ->
return output
withDirectory_ :: (MonadIO m, ExceptionMonad m) => FilePath -> m a -> m a
withDirectory_ dir action =
gbracket (liftIO getCurrentDirectory) (liftIO . setCurrentDirectory)
(\_ -> liftIO (setCurrentDirectory dir) >> action)
-- | Returns the path to the currently running ghc-mod executable. With ghc<7.6
-- this is a guess but >=7.6 uses 'getExecutablePath'.
ghcModExecutable :: IO FilePath
#ifndef SPEC
ghcModExecutable = getExecutable'
where
getExecutable' :: IO FilePath
# if __GLASGOW_HASKELL__ >= 706
getExecutable' = getExecutablePath
# else
getExecutable' = getProgName
# endif
#else
ghcModExecutable = return "dist/build/ghc-mod/ghc-mod"
#endif