[xmonad] Tabbed.addTabs broken?

[Andrea Rossato]

I also have some more general thoughts your mail generated.

On Tue, Feb 12, 2008 at 06:17:55PM -0500, David Roundy wrote:
> I'm a little unclear here:  what is it that you want tabbed to do? I had to
> make this change (I think) in order to make tabbed work properly when it is
> placed in a subset of the screen.  Your tabbed was trying to draw the tabs
> at the top of the screen regardless, as I recall.  Certainly we must use
> the locations of the windows to determine the locations of the tabs,
> otherwise everythings going to look crazy.

There are cases in which the window's location cannot be used, such as
the case of a floating layout with a tabbed-like decoration. I think
that in such cases we must use the screen rectangle a layout (or a layout
modifier) gets in doLayout/redoLayout.

LayoutModifier has the modifyLayout method for this purpose only:
change the rectangle (or the stack, which is quite uncommon - no one
is doing so right now) and produce the (window,rectangle) list
accordingly.

But probably this is incompatible with what comes next.

> 
> > But, as far as I understand, this is needed for WindowNavigation (I do
> > not understand well its code, and I didn't have time to study it).
> 
> No, this bit is no longer needed for WindowNavigation.  It is, however,
> needed if you want to apply this decoration to a more interesting layout
> than Simplest.  (Which was required by WindowNavigation, prior to the patch
> mentioned below.)  I do think this is a good idea, as it gives us a more
> composable interface (i.e. we could combine layouts *prior* to adding
> decorations, which might have advantages).

Applying decorations after combining layouts is definitely something
*very* good. I'm wondering if this is compatible with the above.
(Probably not?)

(And so, this would answer also my previous mail, probably: a
TabbedLikeDecoration style is *incompatible* with the possibility of
decorating layouts after combining them).

What I'm asking is this: if there is this incompatibility, should we
enforce it in the DecorationStyle class (which would mean, remove the
screen rectangle from the decorate method) or just warn the user that
a given style cannot be used for combined layouts?

Thanks for you kind attention.

Andrea