Mon 04 September 2017 | -- (permalink)

Finally got around to fixing the "Meta" key handling on my laptop so that XQuartz, Terminal, and Emacs would all agree on which key is Meta. A friend asked me to document this.

Emacs

Just works out of the box. Well, if one picks the right box.

I had been running an ancient Carbon Emacs from much too long ago, because it was tightly integrated with some packages I cared about and didn't have time to cut loose from that. Finally made time and moved everything up to Emacs 25, which is what started me into the Meta key swamp.

Carbon Emacs 22 used the Mac's Command key. Cocoa Emacs 25 uses the Mac's Option key. Overall, Option is a much better choice, because it doesn't interfere with things like task switching or other sort-of-built-in stuff, so this was pretty clearly a good move, but switching back and forth was driving me nuts.

The one catch with upgrading to Cocoa Emacs 25 was that the pre-compiled binary version everybody seems to recommend (https://emacsformacosx.com/) dumped core when I tried it (not immediately, it waited until I used a library which runs subprocesses, but still, clearly unacceptable). Don't know why, don't much care.

Homebrew to the rescue:

brew install -s emacs --with-cocoa --with-gnutls

I'll try the precompiled version again eventually (brew cask makes this easy) but not this week.

Terminal

Getting Terminal to send the Option key as the Meta key turned out to be trivial, wish I'd known about this years ago:

• Open Terminal's Preference menu (Command-,);
• Select Profiles;
• Down near the bottom click Use Option as Meta key.

This Just Works, and means that the Meta key now works properly for ssh connections too.

Well, ignoring locale issues -- on Linux, the Meta key sort of defaults to supporting character composition, but if you're willing to switch to LOCALE=C you get a real 1980s Meta key. On the rare occasions when I need to compose non-ASCII characters, I don't generally do it on the bash command line, so having a working Meta key is more useful to me. YMMV.

XQuartz

This one had me stumped for a while, but the solution turned out to be simple: xmodmap. Which is even automatic, if one uses the right filename, so just place:

! Map MacBookAir "Option" key to mod2, ie, the meta bit.
! This assumes XQuartz "Option sends Alt_L and Alt_R" config box is checked.
!
clear mod1
add mod2 = Alt_L Alt_R

into ~/.XModmap and set the Option sends Alt_L and Alt_R option checkbox in XQuartz's preferences menu.