65 lines
2.2 KiB
Haskell
65 lines
2.2 KiB
Haskell
module Language.Haskell.GhcMod.Utils where
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import MonadUtils (MonadIO, liftIO)
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import Control.Exception
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import Control.Monad.Error (MonadError(..), Error(..))
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import System.Directory (getCurrentDirectory, setCurrentDirectory)
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import System.Process (readProcessWithExitCode)
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import System.Exit (ExitCode(..))
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import System.IO (hPutStrLn, stderr)
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import System.IO.Error (tryIOError)
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-- dropWhileEnd is not provided prior to base 4.5.0.0.
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dropWhileEnd :: (a -> Bool) -> [a] -> [a]
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dropWhileEnd p = foldr (\x xs -> if p x && null xs then [] else x : xs) []
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extractParens :: String -> String
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extractParens str = extractParens' str 0
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where
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extractParens' :: String -> Int -> String
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extractParens' [] _ = []
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extractParens' (s:ss) level
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| s `elem` "([{" = s : extractParens' ss (level+1)
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| level == 0 = extractParens' ss 0
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| s `elem` "}])" && level == 1 = [s]
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| s `elem` "}])" = s : extractParens' ss (level-1)
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| otherwise = s : extractParens' ss level
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readProcess' :: (MonadIO m, Error e, MonadError e m)
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=> String
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-> [String]
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-> m String
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readProcess' cmd opts = do
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(rv,output,err) <- liftIO $ readProcessWithExitCode cmd opts ""
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case rv of
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ExitFailure val -> do
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liftIO $ hPutStrLn stderr err
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throwError $ strMsg $
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cmd ++ " " ++ unwords opts ++ " (exit " ++ show val ++ ")"
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ExitSuccess ->
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return output
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withDirectory_ :: FilePath -> IO a -> IO a
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withDirectory_ dir action =
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bracket getCurrentDirectory setCurrentDirectory
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(\_ -> setCurrentDirectory dir >> action)
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rethrowError :: MonadError e m => (e -> e) -> m a -> m a
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rethrowError f action = action `catchError` \e -> throwError $ f e
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tryFix :: MonadError e m => m a -> (e -> m ()) -> m a
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tryFix action fix = do
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action `catchError` \e -> fix e >> action
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-- | 'IOException's thrown in the computation passed to this function will be
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-- converted to 'MonadError' failures using 'throwError'.
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liftIOExceptions :: (MonadIO m, Error e, MonadError e m) => IO a -> m a
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liftIOExceptions action = do
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res <- liftIO $ tryIOError action
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case res of
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Right a -> return a
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Left e -> case show e of
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"" -> throwError $ noMsg
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msg -> throwError $ strMsg msg
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