[xmonad] darcs patch: hide existential Layout (mostly) from user API.

[Spencer Janssen]

On Saturday 10 November 2007 18:34:21 David Roundy wrote:
> Hi all,
>
> This allows us to eliminate the wart of requiring a Layout wrapper around
> our layoutHook.  Besides being ugly, this wrapper hampers the composability
> of layouts:  we can't simply write something like:
>
> myconfig = defaultConfig { layoutHook = Layout $ Mirror $ layoutHook
> defaultConfig }
>
> because there's no Read instance for Layout Window, so Mirror (Layout
> Window) has no Read instance.  Obviously, we could get rid of this with an
> unLayout higher-order function, but I see no reason to expose our users to
> this at all.
>
> David
>
> Sat Nov 10 16:30:55 PST 2007  David Roundy <droundy at darcs.net>
>   * hide existential Layout (mostly) from user API.

Applied.