bug#21551: Fix Mac OS X key bindings bug

[Alan Third]

On Sun, Feb 11, 2018 at 05:57:32PM +0000, Philipp Stephani wrote:
> Anders Lindgren <andlind@gmail.com> schrieb am Sa., 2. Jan. 2016 um
> 09:08 Uhr:
> 
> > I found a case where the code in question is needed, which none of the
> > suggested patches handle correctly.
> >
> > Steps to repeat:
> >
> >     (setq ns-alternate-modifier nil)
> >
> >     Press left CMD-ALT-9
> >
> >     An unmodified Emacs replies "s-]" is not bound. (This assumes a
> > Swedish keyboard layout, other layouts would yield a different character,
> > but the principle is the same).
> >
> >     With either of the two patches, Emacs respond with "s-9" is not bound,
> > which isn't correct.
> >
> 
> In the current master this is now interpreted as M-s-9, which is at least
> somewhat reasonable.

For me it’s s-9, not M-s-9.

> > Unfortunately, I don't know how to distinguish between the cases where we
> > need to strip away modifiers (C-s-a) and when we shouldn't, so I'm leaving
> > this open for now.
> >
> 
> It seems like in the macOS input model, we can't: either we strip away all
> modifiers, or none.

It appears you can using some Carbon stuff. Half‐assed proof of
concept patch attached.

(It’s broken the arrow keys, and I don’t know why...)
-- 
Alan Third

poc.patch
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