[xmonad] Why isn't mappend for Query flipped?

Adam Vogt vogt.adam at gmail.com
Tue Jun 9 21:19:04 EDT 2009

* On Tuesday, June 09 2009, Brent Yorgey wrote:

>I propose to change the Monoid instance for Query so that 
>    mappend = liftM2 (flip mappend)
>Of course, this has the undesirable side effect of breaking any
>configs where the order actually matters.  But it would certainly make
>more sense moving forward, IMO.

I saw this too when writing XMonad.Hooks.InsertPosition in contrib.

It would be nicer to reflect the change in the type:

  type ManageHook = Query (Dual (Endo WindowSet))

But unfortunately, this requires some simple changes to contrib:
s/Endo/(Dual . Endo)/ should do. Some configs may break too.


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