rbs-macros

Rubyists💎 love metaprogramming.

rbs-macros bridges between RBS and metaprogramming, by allowing you to define a macro, which is then used to generate RBS definitions based on macro invocations.

Installation

bundle add rbs-macros --group development,test --require false

Or equivalently, add to Gemfile:

group :development, :test do
  gem "rbs-macros", "~> [VERSION]", require: false
end

Then run bundle install.

Usage

[!NOTE] at the time of writing, rbs-macros is still in early development, and the API is subject to change.

Assumes you have already set up rbs_collection.yaml via rbs collection init.

Add to Rakefile:

desc "Generate RBS files using macros"
task :rbs_gen do
  require "rbs_macros"
  require "rbs_macros/macros/forwardable"
  RbsMacros.run do |config|
    lock_path = Pathname("rbs_collection.lock.yaml")
    config.loader.add_collection(
      RBS::Collection::Config::Lockfile.from_lockfile(
        lockfile_path: lock_path,
        data: YAML.load_file(lock_path.to_s)
      )
    )
    config.macros << RbsMacros::Macros::ForwardableMacros.new
    config.macros << RbsMacros::Macros::SingleForwardableMacros.new
  end
end

Then run:

bundle exec rake rbs_gen

Example

Suppose there are the following files:

# lib/array_wrapper.rb
class ArrayWrapper
  extend Forwardable
  def_delegators :@storage, :[], :size
end

# sig/array_wrapper.rbs
class ArrayWrapper[T]
  extend Forwardable
  @storage: Array[T]
end

Then the output will be:

# sig/generated/array_wrapper.rbs
class ArrayWrapper
  def []: (::int index) -> T
        | (::int start, ::int length) -> ::Array[T]?
        | (::Range[::Integer?] range) -> ::Array[T]?

  def size: () -> ::Integer
end

Future plans

  • You will be able to define sharable macros and included them in your gem. For example, the ffi gem may include its own macros to generate RBS files for FFI definitions.
  • Additionally, you will be able to load all the relevant macros based on the gem list in Gemfile.
  • The behavior is currently largely dependent on the order the source files are processed. I will try to stabilize it to some extent in the future.
  • Possible new builtin macros:
    • Improved forwardable macros
    • Struct/Data macros
    • FFI
    • ActiveRecord

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake test 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 the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/wantedly/rbs_macros. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

License

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

Code of Conduct

Everyone interacting in the RbsMacros project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.