[Xmonad] darcs patch: Main.hs: get rid off non-standard patter... (and 4 more)

[David Roundy]

On Wed, Jun 20, 2007 at 07:29:46PM +0200, joachim.fasting at gmail.com wrote:
> [Main.hs: get rid off non-standard pattern guards.
> joachim.fasting at gmail.com**20070618222530
>  Use nested case statements when creating the winset binding.
>  Looks _really_ ugly, compared to the original, and adds 3 loc.
> ] {
> hunk ./Main.hs 53
> -    let winset | ("--resume" : s : _) <- args
> -               , [(x, "")]            <- reads s = x
> -               | otherwise = new [0..fromIntegral workspaces-1] (fromIntegral $ length xinesc)
> +    let defaultWinset = new [0..fromIntegral workspaces-1] (fromIntegral $ length xinesc)
> +        winset = case args of
> +                    ("--resume" : s : _) -> case reads s of
> +                                              [(x, [])] -> x
> +                                              _         -> defaultWinset
> +                    _                    -> defaultWinset

This could be prettier with

let winset = maybe (new [0..fromIntegral workspaces-1] (fromIntegral $ length xinesc)) id $
             do ("--resume" : s : _) <- args
                [(x, "")] <- reads s
                return x

which I think is closer to what the pattern guards desugar to.

> [Remove use of ';' to circumvent layout rules.
> joachim.fasting at gmail.com**20070620165951
>  This adds about 3 loc, but using ';' is cheating anyways.
> ] {
> hunk ./Main.hs 60
> -        safeLayouts = case defaultLayouts of [] -> (full, []); (x:xs) -> (x,xs)
> +        safeLayouts = case defaultLayouts of
> +                        []     -> (full, [])
> +                        (x:xs) -> (x,xs)

It's a question of style preference, but I consider

       safeLayouts = case defaultLayouts of []     -> (full, [])
                                            (x:xs) -> (x,xs)

to be more readable.  In isolation it's equally readable, but it allows me
to see more code on the screen simultaneously.
-- 
David Roundy
Department of Physics
Oregon State University