Permalink
Switch branches/tags
Nothing to show
Find file
Fetching contributors…
Cannot retrieve contributors at this time
88 lines (78 sloc) 2.05 KB
-----------------------------------------------------------------------------
--
-- Module : Config.hs
-- Copyright : (c) Asumu Takikawa 2007
-- License :
--
-- Maintainer :
-- Stability : unstable
-- Portability : not portable, PropLang
--
-- GuiHaskell configuration API
--
-- GuiHaskell stores each configuration value in a
-- separate file inside of a configuration directory
-- (e.g. ~/.guihaskell/config)
--
-----------------------------------------------------------------------------
module Config (
confInit, newConfValueWithDefault
) where
import Control.Monad
import System.Directory
import System.FilePath
import System.IO
import System.IO.Error
import PropLang.Event
import PropLang.Value
--
-- Make sure we can do config stuff
--
confInit :: IO ()
confInit = do
d <- getConfigDir
createDirectoryIfMissing True d
--
-- A value constructor that reads and writes using a
-- set of config files
--
--newConfValue :: (Eq a, Show a, Read a) => String -> Event -> IO (Value a)
--newConfValue = newConfValueWithDefault ""
--
-- Config constructor that takes a default value
--
newConfValueWithDefault
:: (Eq a, Show a, Read a) => a -> String -> Event -> IO (Value a)
newConfValueWithDefault def name ev = do
cf <- confFile
exists <- doesFileExist cf
if exists then do return ()
else do openFile cf WriteMode >>= hClose -- touch
return $ Value (setter) (getter)
where
setter x = do
cf <- confFile
old <- getter
h <- openFile cf WriteMode
hPutStr h $ show x
hClose h
if old /= x then do raise ev
else do return ()
getter = do
cf <- confFile
h <- openFile cf ReadMode
val <- catch (readIO =<< hGetLine h)
(\e -> if isEOFError e
then return def
else ioError e)
hClose h
return val
confFile = do d <- getConfigDir; return $ d </> name
--
-- The directory where config files reside
-- Might need special case for Windows?
--
getConfigDir :: IO FilePath
getConfigDir = do
d <- getHomeDirectory
return $ d </> ".guihaskell" </> "config"