Irreal

Tony Aldon has a nice follow on to his video on regular expression string replacement. In that first video, he mentioned the visual-regexp package as a way of building a regular expression interactively. At the time, I thought that it as pretty much what you get from the builtin re-builder command but maybe a little easier to use.

In his latest video, Aldon shows how to use re-builder to help build a function that searches with a semi-complicated regular expression and replaces parts of the matched strings. The details of the strings and their replacements don’t matter; they’re just a convenient vehicle to illustrate the process.

One of the really nice things about re-builder is that you can easily change the input method and re-builder will automatically translate the regex back to standard notation when you save it. If you get confused by multiple backslashes and when to use them, this can make working with Emacs regular expressions easier.

Likewise, it’s easy to toggle whether or not the regular expression should ignore case. It’s a simple keystroke; you don’t need to manually change the value of case-fold-search.

Aldon demonstrates all this in his video. The shortcuts he uses—other than the one to start re-builder itself—are the default ones so it’s a good way to learn the package.

The video is just shy of 32 minutes so plan accordingly.

Torstein Johansen has an interesting post on his new Emacs configuration. He’s a long time Emacs user and his old configuration was 20 years old and 1617 lines long. After he refactored his configuration it was down to 368 lines. A lot of the refactoring was simply a matter of removing packages whose functionality had been superseded by core Emacs.

One thing he does in the video is to number each section of the configuration and then add (occur "^;; [0-9]+") at the top. Executing that expression generates a table of contents for the file. That seems like a nice feature but it’s not in his final configuration, which may mean that there’s a problem when Emacs starts.

My own configuration is currently 2461 lines long so I’m sure it could also do with some refactoring. It’s a bit over 15 years old now so there’s bound to be some cruft in there. One comfort that I took away from Johansen’s video is that he keeps almost everything in a single file.

The current conventional practice is to separate discrete functionality into separate files. Johansen finds this hard to navigate and I agree. I get a lot of pushback whenever I say that but it’s still true. It’s nice to know that at least one other person agrees with me.

If you like seeing what other people are doing with their configuration, Johansen’s video is worth watching. The video is 27 minutes, 50 seconds long so you’ll need to schedule some time for it.

Tony Aldon has a short video on a couple of alternate ways to do regex search and replace in Emacs. The straightforward way to do that is to use query-replace-regexp (Ctrl+Meta+%) but you can do the same operation in steps by first doing isearch-forward-regexp (Ctrl+Meta+s) to make sure you’re finding the right search object and then calling query-replace-regexp to specify the replacement. That’s not as wasteful as it seems because it will remember the search string from the isearch-forward-regexp and you need only specify the substitution.

Aldon gives an example of this in operation so you can see exactly how it works. Take a look at the video to see the details.

The second method is essentially the same except that it uses the package visual-regexp to get immediate feedback on what the regular expression will match as you type it. That can be pretty handy if Emacs regular expressions are your second choice for regex work and you don’t use them all the time. Again, take a look at the video to see the package in action.

Most of the time you’re probably better off to just use query-replace-regexp but if you’re unsure of the regex, the two step process can make sense. The first method uses functions that are all built-in so it’s always available. If you want to see what’s going to be matched as you enter the regex, the visual-regexp package may be for you.

The video is only 8 minutes so it should be easy to fit in.

Here’s a blast from the past that I recently came across again. It’s Xah Lee’s post on Why Emacs Keys are Painful. Lee, as most of you probably know, is obsessed with keyboard ergonomics and it is fair, I think, to consider him an expert on the matter. His post considers the question of why—given how painful they can be—Emacs shortcuts are the way they are.

The answer, he says, is pretty simple. First, and probably most important, when Emacs was designed, the implementors were using various Lisp keyboards that mostly had the Ctrl key to the left of the space key and the Meta key to the left of Ctrl. Modern keyboards, of course, have those two keys reversed making Emacs shortcuts less ergonomic.

Secondly, the common shortcuts were chosen to be mnemonic rather than ergonomic. Emacs has so many shortcuts that even with the mnemonic choice they’re hard to remember so it’s not clear it was a bad tradeoff. Except for RSI.

Many Emacs users have developed cases of RSI so bad that they’ve moved to Evil mode for relief. Sometimes this was after years of using the conventional keybindings. I’ve been lucky in that respect. Even though I came from Vi(m), I’ve been using the standard shortcuts for over 15 years without ill effect. But others haven’t been as fortunate so the ergonomics of the bindings is definitely not a trivial complaint.

Of course, in this as in other things, Emacs has you covered. Lee, for example, has his
own set of bindings developed along ergonomic lines. And if reaching for the Ctrl and Meta keys is painful for you, there’s always evil mode.

Like mbork, Vivek Haldar a short list of some changes he likes in Emacs 29. As with mbork’s list, these aren’t the big things, they’re some small changes that he finds particularly helpful or appealing. You can follow the Twitter thread for the details but the TL;DR is

• Changing the font size globally
• Find sibling file
• Rename the visited file
• Variable pitch text
• Pixel scroll precision mode
• Split root window below or to the right
• Eval region or buffer
• Scratch buffer command to switch to or open the scratch buffer
• Highlight undefined commands in shell buffers
• A couple of new mouse events

Merry Christmas to everyone from me and the minions.