Rufo

Ruby formatter

Installation

Add this line to your application's Gemfile:

gem 'rufo'

And then execute:

$ bundle

Or install it yourself as:

$ gem install rufo

Usage

Format files or directories

$ rufo file names or dir names

Format STDIN

$ cat file.rb | rufo

Check that no formatting changes are produced

$ rufo --check file names or dir names

This will print one line for each file that isn't correctly formatted according to rufo, and will exit with exit code 1.

Editor support

• Sublime Text: sublime-rufo

Configuration

Rufo follows most (if not all) of the conventions found in this Ruby style guide. It does a bit more than that, and it can also be configured a bit.

To configure it, place a .rufo file in your project. When formatting a file or a directory via the rufo program, a .rufo file will try to be found in that directory or parent directories.

The .rufo file is a Ruby file that is evaluated in the context of the formatter. These are the available configurations:

# Whether to align successive comments (default: true)
align_comments      true

# Whether to align successive assignments (default: true)
align_assignments   true

# Whether to align successive hash keys (default: true)
align_hash_keys     true

# The indent size (default: 2)
indent_size         2

As time passes there might be more configurations available. Please open an issue if you need something else to be configurable.

Status

The formatter is able to format rails and other projects, so at this point it's pretty mature. There might still be some bugs. Don't hesitate to open an issue if you find something is not working well. In any case, if the formatter chokes on some valid input you will get an error prompting you to submit a bug report here :-)

How it works

Rufo is a real formatter, not a simple find and replace one. It works by employing a Ruby parser and a Ruby lexer. The parser is used for the shape of the program. The program is traversed and the lexer is used to sync this structure to tokens. This is why comments can be handled well, because they are provided by the lexer (comments are not returned by a parser).

To parse and lex, Ripper is used.

As a reference, this was implemented in a similar fashion to Crystal's formatter.

And as a side note, rufo has no dependencies. It only depends on rspec for tests, but that's it. That means it loads very fast (no need to read many Ruby files), and because Ripper is mostly written in C (uses Ruby's lexer and parser) it formats files pretty fast too.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/asterite/rufo.

License

The gem is available as open source under the terms of the MIT License.