Irreal

Tony Aldon wondered how hi-line-mode worked so he looked into it. He was so enchanted with what he found that he decided to share it on reddit. That might not sound too interesting but hi-line-mode depends on two Emacs features, post-command-hook and overlays, that are interesting in their own right. Once you understand them, understanding hi-line-mode is trivial.

The post-command-hook variable, as its name suggests, contains a list of functions to run after every command. Since virtually everything Emacs does—including inserting characters into a buffer—is through a command, the hook gets run every time Emacs does something. In particular, hi-line-mode can be called after every command to update the current line’s highlighting.

The other important aspect of hi-line-mode is the overlay. This is pretty simple and allows you to, among other things, change the text face of a region in the buffer. In the case of hi-line-mode, it changes the background color of the current line to whatever color you’ve chosen.

Once you grok hooks and overlays, it’s easy to understand how hi-line-mode works. Aldon’s post is useful not because it explains how hi-line-mode works but because it explains post-command-hook and overlays. Those are things you can use in your own Elisp code.

Irreal regulars know that I’m a huge fan of Christopher Wellons’ Elfeed. It’s an Emacs-based RSS reader that allows you to manage and read your RSS feeds from within Emacs. If you’re already an Emacs user, there’s no reason not to be using it.

Ramces Red has a post that explains how and why to use elfeed. Ramces covers the installation and configuration of Elfeed. Other than specifying which feeds you want to follow, you can get away with no configuration at all but Elfeed allows extensive customization. There’s also a thorough and flexible tagging mechanism that you can use to sort posts according to interest.

To me, the most useful thing Elfeed brings to RSS is the ability to store the feeds forever. They all go into a database that is searchable by date and content. Even years later, you can search and find an entry and as long as the original post is still online, you can revisit it.

The one thing that his post doesn’t mention is that you can maintain your list of feeds in Org-mode. To do that you need to load elfeed-org. After that, it’s easy to add or delete entries from your feed even if you aren’t an Elisp expert.

I can’t recommend Elfeed enough. Take a look at Ramces’ post to see why.

In response to my post Renaming Tags, Karl Voit pointed me to his recent post on How To Use Tags. He said that his system could solve many of the problems I experience with using tags. It’s a long post with lots of good advice but the heart of it are 8 rules he uses for choosing tags. It’s definitely worth taking a look at those rules if you use tags.

The two rules that would most help me are:

1. Use as few tags as possible
2. By convention, tags are plural

My major problem is #1. Rather than deciding on a specific set of tags, I tend to make them up as I go along. All of my tagging is happening in an Org Mode context so I get a list for the first tag but I’m on my own for any subsequent tags so I can’t see what I’ve used before. Voit’s tagging system is more general and acts at the file level so his tools have a way of handling this problem.

After dealing with grocery/groceries for a while I (sort of) settled on a rule of using the singular form but I didn’t make it a hard rule. A lot of my problems would disappear if I strictly enforced this rule.

Even if I religiously followed Voit’s suggestions, I would still find myself needing to bulk change tags so I’m grateful for Sagar’s post. Still, if you’re a tag user, you can make your life a lot easier by reading and following the advice in Voit’s post.

I’ve been using paredit for 11 or 12 years. I don’t use nearly all its features but I still wouldn’t want to live without it. As I discovered early on, the real secret of paredit is understanding slurp and barf. Without them you can’t edit your file effectively.

Susam Pal has a short post about mnemonics for remembering the shortcuts for paredit’s slurp and barf. Some developers, he says, confuse the shortcuts for snarfing for those for slurping. Pal provides the mnemonics that he used to remember them. I never had that problem. To me, the braces suggest pointing out so Ctrl+} and Ctrl+{ are clearly for barfing.

Actually, I don’t find his mnemonics very helpful but your mileage may vary. His post also gives examples of using slurp and barf so you may find that helpful if you’re not familiar with paredit. One thing for sure, if you’re writing in any of the Lisps, learning paredit is definitely worthwhile.

Arne Babenhauserheide has an interesting post on how he listens to podcasts in Emacs using Elfeed and EMMS. It’s a perfect workflow: the podcast episodes are collected from RSS and listed with Elfeed and those he wants to listen to are queued by simply typing A next to the entry in Elfeed. That queues up the entry in EMMS. Babenhauserheide has a step-by-step guide to the workflow in the post.

There’s a tiny bit of configuration to do but it’s just a few lines. Best of all, everything happens from within Emacs and you can do other work while you’re listening if you like.

I don’t generally listen to podcasts but if I did, I’d certainly try this method out. The nice thing about it is that it’s simple to set up and try out. If you decide you don’t like it, it’s easy to back out the changes. Of course, you’ll want Elfeed regardless because it’s the absolute best RSS reader. I don’t use EMMS because

1. I’m too lazy to set it up
2. I don’t usually listen to music while I’m working so I just depend on iTunes. (See #1.)

If you’re an Emacs user who listens to podcasts, be sure to take a look at Babenhauserheide’s post. The section on Elfeed/EMMS is short and will take less than a minute to read.