[Xmonad] Issue 78 in xmonad: Extension state
dons at galois.com
Wed Oct 31 14:02:24 EDT 2007
> Issue 78: Extension state
> Comment #1 by daveroundy:
> Note, we could also make other hooks use the same mechanism as
> Layouts. The Layout mechanism is similar in effect to a writer monad,
> but with a special-case for when the state doesn't change, so we won't
> have to redraw the windows if a message doesn't change the layout.
> This approach seems to work well for Layouts, but I suppose isn't
> needed for other hooks (as we don't care whether or not they've
> changed). It also make it pretty easy to write buggy layout
> combinators, since it's all too easy to ignore that return value.
> I wonder if perhaps a custom monad would be helpful for Layouts? And
> whether perhaps we could use a similar approach for hooks? i.e. if we
> put hooks into a monad that allows them to return a modified hook,
> wouldn't that be enough?
If we moved to a monadic model for private state, I would imaging
we'd move the layouts over to that as well.
More information about the Xmonad