Re: [xmonad] XMonad.Config.Prime, a monadic config syntax

On Mon, Oct 1, 2012 at 2:31 PM, Brent Yorgey wrote:

Just looking at the Haddocks, I like it very much!

Thanks! On Mon, Oct 01, 2012 at 02:40:57PM -0400, Brandon Allbery wrote:

On Mon, Oct 1, 2012 at 2:31 PM, Brent Yorgey wrote:

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Can you say a bit more about exactly why TH is required? I get that fclabels depends on it, but why do you have to turn on the TemplateHaskell flag in your xmonad config? (I haven't actually looked at the code.)

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+-- > $(modifyLayout [| smartBorders |])

This strikes me as somewhat unfortunate, but it's possible that we can't do better given that layouts are rather ugly type-wise currently.

Yeah, the problem is that the XConfig is parameterized on the layout type, and the State monad can't vary the type of its state. So I wrap the layoutHook in the Layout existential and mess with it that way. You don't _need_ TH. You could write this in your config: layoutHook =. (\(Layout l) -> Layout (l ||| simpleTabbed)) The TH is just to hide that nastiness so you can write: $(addLayout [| simpleTabbed |]) instead. (Unfortunately, due to Haskell magic I don't understand, I can't just write an 'fmap' for existentials. Though I just discovered the exists package. Maybe it has the magic I desire...) I've long considered layout persistence via Show/Read to be a hack (seems like we could represent layouts with a single type), but changing that would be a much bigger thing. :) fclabels, OTOH, is no big thing. I'm not really using the TemplateHaskell part of it (just a smidge), and the rest I could just reimplement.