Irreal

A really powerful Emacs feature for those who know a bit of Elisp in the ability to advise functions. Historically, the defadvice macro allowed the specification of code to run before, after, or around a function call. It’s really handy for modifying the action of a function without changing the function itself or getting into the details of how a function works. I have advice for 7 functions in my init.el, an indication that it’s more useful than you might think.

The defadvice macro has been obsoleted by the newer and more flexible advice-add and add-function macros. You’ll usually want to use advice-add because it works in more situations. The new macros support a finer grained specification of where the advice is to be applied.

Kaushal Modi over at A Scripter’s Notes has an excellent post that explains all the methods of specifying where the advice will operate. These methods are called “advice combinators”. Modi has what are essentially railway diagrams that illustrate the operation of each of the combinators. They’re an easy way of understanding what each of them does. He also has a summary table that describes in words how each of them works.

You should also take a look at the built-in add-function documentation that shows the new function that is created for each of the combinators.

Modi’s post is the best explanation of using advice that I’ve seen. You should definitely take a look at his post to see what’s possible.

Vivek Haldar has an observation about the expected lifetime of Emacs:

Safe to say that at this point #emacs has gone Lindy.https://t.co/HjsfWmE3ug

— Vivek Haldar (@vivekhaldar) June 12, 2022

The Lindy Effect postulates that the longer some (nonperishable) entity has existed, the more likely that it will continue to exist. It’s a bit more technical so follow the link to Wikipedia if you want the details.

Nothing lasts forever, of course, so even the mighty Emacs will eventually fade away but not, if you believe in Lindy’s law, anytime soon. It make sense if you think about it: the fact that Emacs has lasted as long as it has means that it’s meeting the needs of its users and continuing to adapt to new needs so its chances for continued support from its current users and its being embraced by new users is good.

This week there were two excellent posts on highlighting in Emacs. The first was Marcin Borkowski’s post, Highlighting and de-highlighting things. He covers most of highlighting commands but not their default keybindings.

When I first saw Borkowski’s post I thought I’d write about it if only to have a handy guide to the commands. Before I could do that, Mickey Petersen published his post on the same subject matter. That post, Highlighting by Word, Line and Regexp covers a few more commands and includes their bindings. Mickey also explains how to make a set of highlightings persist in a file.

It turns out that even Irreal has plowed this ground but it was so long ago (over a decade) that I’d forgotten all about it. One nice thing about that post is that I provided a table of keybindings at the end but I didn’t cover all the commands. Below is a new table based on Mickey’s list of bindings. The purpose of many of them is obvious from the command name but take a look at Mickey’s post for what all these commands do. If you can remember the Meta+s h part, the commands are pretty mnemonic but, of course, if you use them regularly they’ll get burned into your muscle memory.

As regular readers know, I’m a huge fan of RSS and of using elfeed to read and curate my feeds. If you’re an Emacs user and not using elfeed, you’re really missing out. It’s the absolute best feed reader I’ve ever used.

You may not know it but you can add YouTube channels to your elfeed feeds. If you follow one or more channels on YouTube, elfeed is a nice way of keeping up with them without a lot of fuss. Things just got a lot better.

Karthink has a new package, elfeed-tube, that makes following YouTube channels even better and easier. The package is so versatile that I won’t even try to cover everything it does; you should head over to the elfeed-tube GitHub repository for a long and thorough description of everything it’s capable of.

I found the link to elfeed-tube on reddit. The comments were uniformly positive, saying among other things, that the package “just worked” out of the box. This looks like a really great package for Emacs users who follow YouTube channels.

If you’ve been around Emacs for a while, you probably know that Emacs has you covered if you call find-file (Ctrl+x Ctrl+f) and specify a path with a missing directory. You simply get asked if you want to create the missing directory and give your assent with a simple Return Return.

That’s pretty simple and convenient but Bozhidar Batsov is committed to eliminating as much friction as possible and doesn’t want to have to do anything to create those missing directories. He just wants it to happen. Of course, being Batsov, he made it happen. It turns out to be pretty easy and he gives two solutions for doing it.

Almost every time I get the missing directory error it’s because I mistyped the path. That means that automating the creation of missing directories would almost always be a fail for me. But that’s me. Others, like Batsov, view it as a win. If you fall on Batsov’s side of the question, take a look at his post to see how easy it is to do.

The final, obvious, oft repeated, but mandatory observation is how easy Emacs makes it to fine tune it to each individual user’s workflow.