Irreal

The other day I wrote that I was considering installing dumb-jump and giving it a try. I did that and have been using it since I watched Mike Zamansky’s video on Projectile and Dumb-jump. It really is the sweet spot for me. I never liked TAG files and their associated machinery but dumb-jump doesn’t require any of that: it just works.

Recently, AT&T graciously released the source code for Research Unix v.8, v.9, and v.10. That’s a boon for us Unix aficionados who like to read code. I downloaded v.10 and started browsing. This is the first time I’ve had access to the source code for a modern AT&T Unix so I’m not familiar with the files layout. Fortunately, dumb-jump is just what I needed. All the kernel source files are in the sys directory so I put an empty .dumbjump file in sys and now when I’m looking at a function and it calls some other function in a different file, I can jump directly to it and then return.

I added two additional keybindings to the ones recommended in the README. For those who are interested, here is my configuration:

(use-package dumb-jump
  :ensure t
  :bind (("M-g o" . dumb-jump-go-other-window)
         ("M-g j" . dumb-jump-go)
         ("M-g b" . dumb-jump-back)
         ("M-g q" . dumb-jump-quick-look)
         ("M-g x" . dumb-jump-go-prefer-external)
         ("M-g z" . dumb-jump-go-prefer-external-other-window))
  :config (setq dumb-jump-selector 'ivy))

You really want a binding to return to your jumping off place so I added that. I also added a binding for dumb-jump-quick-look, which gives you a short popup of the definition and some context.

The Unix kernel isn’t the largest project by any means but it is good sized. Nevertheless, dumb-jump found and moved to the target file almost instantaneously. I really like this package a lot.

I’m a big advocate of reading code. A lot of what I know about programming, Unix, and Emacs, I learned from reading code. Chen Bin has a parallel if slightly different take on reading code. He says that mastering Emacs is easy if you read the code. He likes to treat packages as a collection of APIs whose source code he can read and use for his own purposes.

As an example, he considers Samuel Barreto’s excellent post on refactoring with counsel-ag that I wrote about earlier. Chen spent a few minutes looking at how counsel built the wgrep buffer and then leveraged that to do some additional processing before calling wgrep. It’s worth taking a look at what he did. You probably won’t need his code but it perfectly illustrates his point: if you read the Emacs code it’s very easy to extend it to solve your particular problem.

Matus Goljer—Fuco1 of Smartparen fame—blogged a nice bit of Elisp that adds imenu functionality to dired. At first, that doesn’t seem to make sense since an imenu menu would simply have the same information as the dired listing itself. What actually happens is that imenu gives you a list of the subdirectories inserted into the dired listing. You can then jump directly to that subdirectory from imenu

If you think that might be useful, take a look at Fuco1’s post for the details.

Daniel Gopar over at Emacs.el has another of his Emacs chats up. This time he talks to Charles Lowell from Frontside Software. What’s interesting about Frontside is that they have a company-wide, shared Emacs configuration. All the developers use the same configuration, which the company maintains.

My first reaction was one of horror. All developers have preferences—this compiler or that PDF reader—but mostly they’re just that: preferences. If your company doesn’t use your favorite C compiler, you grumble a bit but get on with things. Not so with editors. Every first class developer that I know cares passionately about their editor and wouldn’t dream of using something else. With Emacs, you pretty much build your own editor so you get the same reaction if you have to use a different configuration. Most of us know how painful it can be to use someone else’s Emacs. That’s because their configuration is different from yours. I would, therefore, be very leery of coming into a shop that had a company standard editor.

Still, Lowell makes a reasonable case for their practice and it’s not quite as draconian as I’m making it seem. Nevertheless, having to unlearn my Emacs muscle memory would be extraordinarily painful for me. I’ve seen cogent cases made for insisting on everyone using the same versions of packages and editor—especially in shops doing research and running experiments—but it’s much harder, I think, to make the case for having standardized key sequences. Of course, everyone’s mileage varies and the folks at Frontside seem to like the system so it appears to be working for them.

One interesting aspect of Frontside’s practice is that they package their configuration as an Emacs package. That means that the developers update their configuration the way they would any package and it brings in the changes and updates their other packages automatically. If you’re going to insist on a standard configuration, that’s a very nice way of doing it. It’ quick and easy and no one has an excuse for not staying up to date.

Take a look at the video and see what you think. The running time is 43 minutes, 45 seconds so plan accordingly.

Chanyoung is a Swiper user and asks a question I’ve sometimes wondered about: when using swiper, how do you choose the second or subsequent match on a line? If you follow the above link, you will see that abo-abo himself provides the answer.

What you do is call swiper-avy (bound to Ctrl+’) to see tags for every visible match. Then you simply choose the correct tag in the usual Avy way. I’ve known about (and even used) swiper-avy for some time but I always thought of it as a way of choosing the correct line in the minibuffer. That usually brings you to the match you want but not (necessarily) when there is more than one match on the line you want.

It turns out—although I somehow never noticed it—that the visible matches in the searched buffer are also tagged so you can simply choose the tag you want and jump right to the desired match. I know I’ve said it before, but if you aren’t using swiper and counsel you owe it to yourself to give them a try. I’m always learning something new that they can do and they’ve made my navigation a lot more efficient.