Irreal

As many Mac OS X/Emacs users know, OS X has many of the Emacs key bindings defined for the entire system. Thus, bindings like 【Ctrl+f】, 【Ctrl+b】, 【Ctrl+a】, 【Ctrl+e】, 【Ctrl+k】, 【Ctrl+y】, 【Ctrl+p】, 【Ctrl+n】, and a few others work across the whole system.

Less well known is that the Cocoa Text System is customizable and you can add other Emacs bindings to make a comfortable and familiar environment whether you’re in Emacs, Mail, Safari, or whatever. Even better is that Jacob Rus has already compiled the necessary bindings for you so all you need do is download the file and install it in the proper place on your system.

The full explanation is available here but the TL;DR is:

1. Download the bindings file.
2. Rename the file to DefaultKeyBinding.dict.
3. Stash the file into the ~/Library/KeyBindings folder.

There’s lot of information at the site, though, so it’s well worth a look. It has bindings with 【Esc】 rather than 【⌥ Opt】 as the 【Meta】 key, BBEdit key bindings for any heretics reading this, and many other tidbits as well. But if you just want Emacs key bindings where 【⌥ Opt】 is the 【Meta】 key, then just follow the 3 steps above.

As I’ve written before, I came to Emacs after years as a Vi/Vim user. One of the things I was used to doing in Vim was to go to line N in a file by typing :N in command mode. I learned Emacs mostly by referring to the Emacs Reference Card that’s included with the distribution and, unfortunately, the reference card does not mention any way of jumping to a particular line. Over time I evolved some dopey way of doing it, probably 【Meta+< Ctrl+N Ctrl+n】 or something equally horrible.

Eventually, I discovered the answer hidden away in the Edit→Go To menu. The official way is 【Meta+g g】 to bring up the Go To Line: prompt in the minibuffer but 【Meta+g Meta+g】 also works and is easier to type. Mac OS X users can use 【⌘ Cmd+l】 if they prefer.

None of this is earth shattering and perhaps I’m the only Emacs user who didn’t know it but I am writing it down in case someone else out there is also wondering how to do it.

Emacs’ regular expressions are notoriously tricky. They aren’t Perl Regular Expression compatible and the escaping rules are not always what you’d expect if you’re used to Unix regular expressions. Most of us, therefore, have experienced wasted time and frustration trying to get a complicated regular expression right. Fortunately, Emacs provides a tool to help ease the way: re-builder.

re-builder provides interactive feedback on your regular expression as you build it. Any matches for a partial or complete regular expression are shown in the current buffer. If you have subexpressions, they are highlighted in a different color so you can see if you’re getting what you expected (non-color displays are handled too). If the regular expression is invalid (at any point) re-builder will tell you and you can query the error with 【Ctrl+c Ctrl+u】 to find out why re-builder is complaining.

When you’re satisfied with the regular expression, you can copy it to the kill ring with 【Ctrl+c Ctrl+w】 and then quit re-builder with 【Ctrl+c Ctrl+q】.

Although re-builder attaches itself to the buffer that is current when you call it, you can change the target buffer with 【Ctrl+c Ctrl+b】 and the desired buffer name.

Summary

Xah Lee has added another page to his excellent series on Emacs Lisp. This time it’s about printing in Emacs Lisp. Most of us who have written any elisp are familiar with the message function, which prints a message to the “*Messages*” buffer and echoes it to the minibuffer.

Often times, we want to write messages to some other buffer—the two posts on Xah’s Challenge are examples. The basic mechanism for doing that is to use with-output-to-temp-buffer in conjunction with the print, prin1, or princ functions. Head over to Lee’s post for all the details if you don’t already know them. It’s a nice summary of the various printing commands.

There are several excellent blogs that cover using Emacs (emacs-fu, Got Emacs?, Mastering Emacs, Xah’s Emacs Tutorial, and many others) but Lee’s Emacs Lisp Tutorial is the only one I know that regularly covers Emacs Lisp and how to use it to solve editing problems. Emacs Lisp is pretty much like other Lisps so anyone using Common Lisp or Scheme will be comfortable with most of it but the problem is that Emacs Lisp has tons of functions that are specific to the Emacs editing environment and none of those will be familiar to someone coming from another Lisp. That’s where Lee’s Emacs Lisp Tutorial is essential. He gives you real working examples and you see those commands in action.

Bozhidar Batsov over at (think) recently loaded the current development version of Emacs 24 and gives us a peek at its features. The post is a very nice look at what’s coming in the next version of Emacs and well worth a look by all Emacs fans. His writeup is fairly comprehensive—at least for the features he covers—so I won’t try to summarize it here; you should go read it yourself.

Batsov doesn’t say whether he is using it for day-to-day work or just playing around with it. I remember using the Emacs 23 development version long before it was officially released and never had any problems. It would be nice to know if Emacs 24 is at that state yet. I’m very happy with Emacs 23 so I don’t feel the need to jump into the new version before it’s completely baked but some of you may be waiting for one of those new features and feel differently. Be sure to let us know if you do adapt it for day-to-day use and how it works out.

Update: Asked and answered. Batsov comments that he has been using Emacs 24 for day-to-day work for about a month and that it’s rock solid. Anyone who can’t wait for those new features should give it a try.