xmonad grid browser

gridbrowse.hs

-- grid browser
-- excerpt from xmonad.hs

gridBrowse cwd' = do
    refresh
    cwd   <- liftIO $ canonicalizePath cwd'
    isdir <- liftIO $ doesDirectoryExist cwd
    if isdir
        then do
            ls <- liftIO $ getDirectoryContents cwd >>= markdirs
            let ls' = if cwd == "/" then togs ls else ("../",cwd ++ "/.."):togs ls
            gridselect (buildDefaultGSConfig colorizer) ls' >>= flip whenJust gridBrowse
        else do
            perms <- liftIO $ getPermissions cwd
            spawn $ if executable perms then cwd
                else "/usr/bin/xdg-open \"" ++ cwd ++ "\""
    where
        togs = map (\l -> (l,cwd' ++ "/" ++ l)) . filter (not . isPrefixOf ".")
        markdirs = mapM $ \l -> do
            isdir <- doesDirectoryExist (cwd' ++ "/" ++ l)
            return $ l ++ if isdir then "/" else ""
        colorizer s b = do
            c <- stringColorizer s b
            return $ if last s == '/' then (fst c, "black") else c