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 put a space after a hash brace. Valid values are:
#
# * :dynamic: if there's a space, keep it. If not, don't keep it (default)
# * :always: always put a space after a hash brace
# * :never: never put a space after a hash brace
space_after_hash_brace :dynamic

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

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

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

# Whether to align successive case when (default: true)
align_case_when 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.

Modules

Classes