Emacs Find of the Day: Repeating Commands

One thing that I love about Emacs is that even after 20 years, I’m finding new (old, in actuality) functionality that makes my life better.

Today’s example is repeat-complex-command, which is normally bound to ctrl-x ESC ESC, as noted on the emacs wiki. The problem in my world is that I’m also using CUA mode, from the ergoemacs library, which redefines ctrl-x to do cuts (as in cut, copy, paste).

Normally that doesn’t cause an issue, since if you don’t have a region marked, then ctrl-x is apparently ignored by ergoemacs and is delegated to the default behavior, in which case ctrl-x ESC ESC brings up the previous command in the echo area, ready to be edited.

However, what has arisen as a nuisance in my experience is when I’ve done a search and replace in one region, then want to do a similar but not identical search and replace in a different region, such as renaming variables in two methods.

Normally I’d mark the first method, run search and replace (query-replace or query-replace-regexp), then go to the second method and mark it. At that point I’d like to bring up the previous search-and-replace and modify the command, but when I hit ctrl-x, the currently-marked region (the second method in this example) is cut, per behavior from ergoemacs.

The fix is to map a different key, in my case alt-j alt-j (the mnemonic being that the keys repeat) mapped to repeat-complex-command, per this snippet from my .emacs file(s):

(define-key global-map (kbd "M-j") jep:keymap)
(define-key global-map (kbd "C-j") jep:keymap)

;; CUA settings muck up ctrl-x, so use an alternative, alt-j alt-j:
(define-key jep:keymap (kbd "M-j") 'repeat-complex-command)

Yes, I map both alt-j and ctrl-j as equivalent keys that define my keymap, making it simpler when I have shortcuts that are prefixed with alt- and ctrl-. So alt-j alt-j flows better, as does ctrl-j ctrl-l (which inserts logging statements, if you’re wondering).

All of this is available at my github repository.

But wait — there’s more: the second nugget of the day is that after running repeat-complex-command, the echo area will display the previous command, of course. But then running alt-p will bring up the command prior to that, and alt-p the command prior to that one, etc. On the other hand, and in the opposite direction, alt-n moves forward through the list of commands.

I hope this helps, and I plan to post more about Emacs and what I find therein.

Emacs and colors being reset

I ran into this today, and couldn’t find a quick answer online.

I was updating yasnippet to the current release, and there was an error on startup about dropdown-list.el not be able to be found. That resulted in Emacs aborting the startup process before it reached the settings in my .emacs file that define the color settings.

So Emacs initialized with the default colors (dark on light), whereas my custom settings are light on dark. When I then exited Emacs, it saved the .emacs.desktop file, which I’d thought was just the list of files. However, it also contains the color settings, so after I’d worked around the yasnippet issue, and started Emacs again, it used the default color settings (from the loaded ~/.emacs.desktop file) instead of mine in .emacs.

The fix was to remove the line that begins with “(setq desktop-saved-frameset”, exit Emacs and start it again, in which case the color settings will be loaded from ~/.emacs instead. The next time Emacs is exited (or just desktop-save is run), then the color line in ~/.emacs.desktop will be updated.

This is probably quite an edge case, but I thought perhaps others might run into this issue. I hope this helps.

How much is (was) a Coke worth?

There is the classic experiment done with young children, making them choose between eating one marshmallow now, or having two if they wait 15 minutes.

A conversation last night reminded me of that.

In our conversation, I mentioned owning $3000 worth of Coca-Cola stock when I was 18, having inherited it from a relative. I recall selling the stock shortly after getting it, but I cannot recall what I spent the money on.

So we did a bit of calculation, and determined that if I’d held onto that stock from 1984 until present, it would now be worth over $240,000.

To see the concept of financial delayed gratification quantified, as above, is instructive and humbling.