Irreal

Mike Zamansky is back with another video in his Using Emacs Series. This time he discusses Emacs bookmarks and the Burly package. You can set a bookmark for any file that you need often and use the bookmark-jump function to bring that file up quickly and easily. Burly does the same sort of thing but for window/buffer configurations. Take a look at Zamansky’s video to see it in action.

Bookmarks are one of those things that seem like a no-brainer yet many—or perhaps most—of us don’t make as much use of them as we should. That changed for me several years ago when I stole a bunch of ideas from abo-abo. First off was to install bookmarks+, which among other things lets me bookmark websites so I can go to them right from Emacs. This, along with abo-abo’s headlong package allow me to map the bookmarks to one or two letter sequences. Wrapping all this into a window configuration hydra allows me to enter Hyper+w m t to bring up my tax file or Hyper+w m b to open my blog in Safari. I wrote about all of that here.

Finally, it’s worth mentioning that any files you have in ~/.agenda-files will be loaded automatically when Emacs starts so I usually visit those by typing in the first letter or two of the file name and letting council-find-file load it for me. It’s just as quick and easy as using a bookmark and I don’t have to add it to my bookmarks file.

Emacs has a lot of ways of quickly loading files and happily none of them require the use of a mouse. Take a look at Zamansky’s video for one of them. The video is 17 minutes, 32 seconds so plan accordingly.

Correl Roush has a very nice post that beautifully illustrates the idea of writing code to write code. It’s a tremendously powerful idea because it lets you leverage some other program or programming language to do a task that requires specialized knowledge to code or is otherwise too hard to do directly. Examples that I’ve used are writing code to generate troff source as an intermediate to producing typeset output and code to generate graphviz source as an intermediate to generating a graph.

Roush gives us a nice example of generating graphviz (dot) source code to produce a nice looking graph. The particular problem she’s addressing is building a tool that you can point at a git repository and have it produce a nice graph of the commits. That seems unreasonably hard if you approach the problem ab initio but is very tractable if you leverage git and graphviz to do the hard work. Git can produce a topologically sorted list of commits and graphviz can do all the drawing of the graphs. All Roush has to do is add some glue code.

Roush decided to work in elisp and builds up her application step by step. She starts by showing the dot input she wants to produce and then writes the code to produce it. By iterating through more complicated graphs until she gets the final result, she shows to build the application iteratively, a programming method that I especially like.

I also like the way Roush uses data abstraction. Her list-based implementation may or may not scale to huge git repositories but her use of data abstraction makes it almost trivial to move to a more efficient implementation if required.

One of the things that’s harder than it should be in Emacs is embedded shells. You can type Meta+x shell and sort of have a shell. Except it doesn’t work very well. There are other options but it can be really confusing for the n00b or even a semi-experienced user not familiar with invoking shells from Emacs.

Derek Taylor has a video that explains and compares Emacs shells. He—rightly in my opinion—rejects the shell and ansi-term command as basically unusable for non-trivial commands. Until fairly recently there wasn’t a good solution if you wanted a traditional shell.

As Taylor says, that has recently been remedied by the introduction of vterm. It requires the relatively new module system but solves most of the problems for those who want to have a “normal” Unix shell. It solves all the problems with shell and ansi-term and lets you run a full-function shell from within Emacs.

But that’s not all, of course. There’s also eshell. It’s both less and more than a Unix shell. Some things don’t work as well but eshell has capabilities well beyond those of traditional shells. Taylor demonstrates some—but not all—of those capabilities. There are others that he doesn’t demonstrate.

The video is 17 minutes, 20 seconds long—a bit shorter if you skip the shoutouts at the end—so you’ll have to schedule some time. If you’ve been confused by Emacs shells, take a look at Taylor’s video. It’s a good summary.