My Favorite Emacs Hacks

January 3, 2009

During the holiday downtime, I decided to spend a little time improving my most some tools, specifically Emacs. While I was experimenting and tuning I realized that I really love Emacs, and I thought I’d share some of my favorite things about it.

:EXTENDED:

Awesome daemon support

Once you start having a bunch of extra modules and customizations, Emacs beings to take a while to boot up. Fortunately we can just fire up an Emacs server inside a running session, and then connect to it via emacsclient.

In Emacs 23 (not yet released, but very usable) the emacsclient can even create new graphical (X or Cocoa) or text frames. This means that with EDITOR set to emacsclient -t it works just like a normal console Emacs would, except that it starts instantly and has access to all my already open buffers.

I used to use Vim at the command line because it loaded much faster than Emacs, but now I can finally drop that habit.

Interactively Do Things

ido brings Quicksilver and Spotlight type search to Emacs. It shows me possible fuzzy completions for what I’m looking for whenever I look for files or want to change buffers. Using ido has really increased my ability to get around in all my projects quickly.

nxml Mode

The nxml mode is an amazing thing. It validates the XML document live and tells you exactly whats wrong. Just like a spell checker from a modern word processor, it underlines the offending characters in red. Moving the cursor over them tells you exactly what’s wrong.

I use it for HTML, XSLT, and any other XML markup I’m working on, and I never have to worry if it’s correct.

Yet Another Snippet

yasnippet bring TextMate style snippets to Emacs. Now, snippets are nothing new for Emacs; we’ve had skeleton mode and similar things for a long time. yasnippet is just a lot easier.

My main use of yasnippet is to insert things like doctypes and other long strings that have some information that I must complete.

dabbrev

dabbrev is on by default in all the Emacs that I’ve run into, and it allows you to dynamically auto-complete anything based on the words it finds in your open buffers. Invoking it multiple times will complete longer and longer parts.

Just like everything with Emacs, it takes a good idea (text completion) and makes it extremely general. It works great on code, blog posts, and anything else I happen to be writing.

Find Tag (M-.)

Shortly after I started working with Monty on the Xiph.org codecs (Ogg, Vorbis, Theora) I noticed that he was using his editor a level far beyond what I was used to. The best thing I saw him do was find-tag which jumps to the function definition of the function name under your cursor. Using that, Monty could surf around the code base at blinding speed.

find-tag uses information in special tag files to implement this. Emacs can also do many other things with tags like project lists and auto-completion.

Flyspell

Flyspell brings word processor style spell checking into Emacs. Just like nxml mode’s validation, Flyspell checks the spelling of words live, and gives visual indications where things have gone wrong.

Flyspell is also well supported in other modes, so that it knows which parts to check and which parts to skip. It’s not perfect, but it is extremely useful.

Theming

A lot of people complain that Emacs is ugly, and the default configuration is certainly not going to win any awards. I will say though that Emacs is extremely well though out from a usability standpoint, and it mostly stays out of the way as much as possible. It is nice to get color syntax highlighting though, and color-theme does just that.

My personal favorite is color-theme-dark-laptop, which is somewhat similar to TextMate’s Twilight theme.

Help In All Forms

Last, but absolutely not least, is the help system. Emacs has the best help system I have ever seen.

First, you can get help in any number of ways:

• Use the interactive tutorial (C-h t)
• Read the manual (C-h r)
• Read various other manuals (usually I’m after the Emacs Lisp manual and tutorial) (C-h i)
• Look up what keys do what in the current buffer (C-h b)
• Look up what some key does by pressing the key (C-h k)
• Look up the name of a function (C-h f)
• Look up the name of a variable (C-h v)
• Look up functions about some topic (C-h a)

Not only can you find all this information easily, but if you have the source code package installed, it will link you directly to the implementation. This means if I am looking up information about a particular Emacs function, within a few key presses I’m staring at the actual function.

Emacs is probably the only system for which I don’t use Google as the first place for answers to my questions. Nearly everything is a few key presses away, even if you have no idea what you are looking for.

Emacs Rocks

I still have tons to learn about Emacs, but it already fits like a glove. Did I mention that it works the same whether I’m on OS X or Linux or in a terminal or the windowing system?

For those of you who also use Emacs, I’d love to hear about your favorite things.