diff options
Diffstat (limited to 'XMonad/Util/ExtensibleState.hs')
| -rw-r--r-- | XMonad/Util/ExtensibleState.hs | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/XMonad/Util/ExtensibleState.hs b/XMonad/Util/ExtensibleState.hs index 0ac05d6..331dd4b 100644 --- a/XMonad/Util/ExtensibleState.hs +++ b/XMonad/Util/ExtensibleState.hs @@ -1,3 +1,4 @@ +{-# LANGUAGE PatternGuards #-} ----------------------------------------------------------------------------- -- | -- Module : XMonad.Util.ExtensibleState @@ -26,6 +27,7 @@ import Data.Typeable (typeOf,Typeable,cast) import qualified Data.Map as M import XMonad.Core import qualified Control.Monad.State as State +import Data.Maybe (fromMaybe) -- --------------------------------------------------------------------- -- $usage @@ -96,13 +98,10 @@ get = getState' undefined -- `trick' to avoid needing -XScopedTypeVariables case v of Just (Right (StateExtension val)) -> return $ toValue val Just (Right (PersistentExtension val)) -> return $ toValue val - Just (Left str) -> case extensionType (undefined `asTypeOf` k) of - PersistentExtension x -> do - let val = maybe initialValue id $ - cast =<< safeRead str `asTypeOf` (Just x) - put (val `asTypeOf` k) - return val - _ -> return $ initialValue + Just (Left str) | PersistentExtension x <- extensionType k -> do + let val = fromMaybe initialValue $ cast =<< safeRead str `asTypeOf` Just x + put (val `asTypeOf` k) + return val _ -> return $ initialValue safeRead str = case reads str of [(x,"")] -> Just x |