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|
{-# LANGUAGE ForeignFunctionInterface #-}
{-
Bustle.Util: miscellaneous utility functions
Copyright © 2008–2012 Collabora Ltd.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
-}
module Bustle.Util
(
io
, warn
, getCacheDir
-- You probably don't actually want to use this function.
, traceM
, NonEmpty(..)
, mapNonEmpty
, nonEmptyToList
)
where
import Control.Monad.Trans (MonadIO, liftIO)
import Debug.Trace (trace)
import System.IO (hPutStrLn, stderr)
import Foreign.C.String
import System.Directory
import System.FilePath ((</>))
import Bustle.Translation (__)
-- Escape hatch to log a value from a non-IO monadic context.
traceM :: (Show a, Monad m) => a -> m ()
traceM x = trace (show x) $ return ()
-- Log a warning which isn't worth showing to the user, but which might
-- interest someone debugging the application.
warn :: String -> IO ()
warn = hPutStrLn stderr . (__ "Warning: " ++)
-- Shorthand for liftIO.
io :: MonadIO m => IO a -> m a
io = liftIO
foreign import ccall "g_get_user_cache_dir"
g_get_user_cache_dir :: IO CString
getCacheDir :: IO FilePath
getCacheDir = do
dotCache <- peekCString =<< g_get_user_cache_dir
let dir = dotCache </> "bustle"
createDirectoryIfMissing True dir
return dir
-- I don't want to depend on 'semigroups' for this.
data NonEmpty a = a :| [a]
deriving (Show, Eq)
mapNonEmpty :: (a -> b)
-> NonEmpty a
-> NonEmpty b
mapNonEmpty f (x :| xs) = f x :| map f xs
nonEmptyToList :: NonEmpty a -> [a]
nonEmptyToList (x :| xs) = x:xs
|
