Ever asked yourself one of these questions?

• Where is the foo method defined in my code?
• Where is the foo method defined in the Rails source?

Then you spend a couple of minutes either grepping your source tree or looking on GitHub and then going back to your editor.

This weekend I went through VIM for Rails developers. There’s a lot that’s out of date, but there’s also some timeless stuff in there too. One thing I saw in there was the use of ctags which is a way of indexing code to help you find out where methods are defined.

Install the ctags package with brew/yum/apt/whatever. Then generate the tags with

ctags -R –exclude=.git –exclude=log *

You may want to add tags to your ~/.gitignore because you don’t want to check this file in.

Also add set tags=./tags; to your .vimrc which tells vim to look for the tags in the current directory. If you have it in a parent directory, use set tags=./tags;/ which tells vim to work backward until it’s found.

Then, put your cursor on a method and type control-] and you’ll jump to the definition. control-T or control-O will take you back to your code. control-W control-] opens it up in a horizontal split. Stack Overflow has some mappings you can use to reduce the number of keystrokes or use vertical splits.

If you use bundler and have it put the gems in your vendor directory, ctags will index those too. So you can look up Rails (or any gem) methods.