A Couple Useful Aliases for EMACS

Yes. I am an Emacs user. (or, as i call it... EMACS... the editor so ossm, you have to write it in all caps!) But there are a few things I don't like about Emacs, and here's the simple solution I found for them.

Problem 1 : Trailing White-Space is Of the Devil

So if you look at the Mozilla bugs I tried to fix, I think they all have a comment from bsmith and ekr saying something like "uh.. trailing white-space." Yes. It is the sad truth, but God's own text editor has issues with leaving trailing white-spaces in code. I don't remember it used to have this problem in the 80's, so obviously this is Apple's fault.

Seriously though... I could have sworn this didn't used to be a problem. Maybe it's just we had worse tools for detecting trailing white-space and I just didn't notice. But it's really noticeable when you try to generate diffs to attach to bug reports. (The Mozilla process is to attach a diff to a bug, get it reviewed and then apply it to a repository somewhere.)

At first, I simply tried to just delete all trailing white-space in the file I was working on, but any given file in the Firefox source base, one in a hundred lines has trailing white-space so I wound up making diffs with bajillions of updates that had nothing to do with the issue at hand. To me, this stinks of bad form.

Yes, I should have created a bug titled "file foo.cpp has a lot of trailing white-space" and applied the change there, but there was about zero chance of the bug getting a positive review without someone saying "hey! why don't we refactor all the code and add these other features while we're removing all this trailing white-space." And honestly, I got tired of saying "don't make me slap you..." to all the people who suggested this.

So rather than debug a bunch of elisp code, I figured I would take inspiration from the hackers of old and just use a sed script to fix the problem. It removes trailing white-space from lines that begin with a plus ('+') character. If you're familiar with diff or patch tools you'll understand why I did this. Here's the alias I added in my .bashrc file:

alias bongo='sed -e '"'"'s/^\+\(.*[^ \t]\)[ \t]*$/\+\1/'"'"''

You can now do things like this if you don't trust your ability to spot trailing white-space in your code:

hg diff | bongo > current.diff

or if you don't trust other people, you can do this:

cat random.diff | bongo | patch -p1

Problem 2 : I Usually Don't Like EMACS in XWindows

But sometimes I do. So I do the following:

alias emacs='emacs -nw'

This tells emacs to launch in the current terminal window.

Hope these suggestions help, or inspire you to hack your own environment. -Cheers!