Speeding up Selecta in Vim

2015-02-16

I like using Selecta as a fuzzy file opener in Vim. It doesn’t do any caching, so I never have to remember to flush the cache after generating a migration in Rails.

The downside is that if you work on a larger project, it can get kinda pokey. Selecta’s Vim functionality relies on find to populate the file list. If we tell find to ignore directories, it gets a lot faster. Here’s how many files the default find command returns.

><((°> find . -type f | wc -l
   13213

That’s a lot! Let’s see if we can cut it down. I’m using a pretty typical Rails project as an example.

><((°> ls
Gemfile           README.md         coverage          spec
Gemfile.lock      Rakefile          db                tmp
Guardfile         app               lib               vendor
Procfile          bin               log
Procfile.dev      config            public
Procfile.jobs.dev config.ru         script

Logfiles are handy, but I never open them in Vim. If I need to see something, I’ll tail it in the terminal. I also don’t care about tmp. We’ll exclude hidden directories too, just for good measure. Let’s cut those out of the find command.

><((°>
find . \( -path ./log -o -path ./tmp -o -path './.*' \) -prune -o -type f -print | wc -l
    2348

Woah! We just excluded 10,865 files! That oughta speed things up a bit. But first I’ll slow down and explain the command.

-o stands for OR. It breaks the find arguments into two major parts:
- \( -path ./log -o -path ./tmp -o -path './.*' \) -prune
- -type f -print
\( ... \) is a group. We’re using it to OR several -path arguments together.
If one of the paths in the group matched, -prune kicks in and find ignores that path.
Otherwise, the file name is printed.

Now we just have to put it in our config. Here’s what the old Vim mapping looked like:

nnoremap <leader>f :call SelectaCommand("find * -type f", "", ":e")<cr>

Here’s the new one:

let find_cmd = "find . \( -path ./log -o -path ./tmp -o -path './.*' \) "
           \ . "-prune -o -type f -print"
nnoremap <leader>t :call SelectaCommand(find_cmd, "", ":e")<cr>

This is also an example of how to set a variable and concatinate a string in VimL.

Now, this isn’t totally optimal. I’d like to set up some directories that Selecta should ignore on a per-project basis. But it’ll do for now.

Also, Vim isn’t the only place that Selecta is useful! You can use it any place that you can pipe input into a command. This post has a bunch of other nifty examples.