With Referential, you can convert your ruby methods into curried procs for use in composition, or as arguments to other methods, while still being able to call them directly!

Add this line to your application's Gemfile:

gem 'referential'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install referential

Just extend your class with the Referential module and use the ref keyword:

class Operations
  extend Referential

  ref def add_two(x)
    x + 2
  end

  ref def square(x)
    x ** 2
  end
end

This lets you use these methods as procs in a functional manner (by composing them, passing them as an argument to .map, etc).

Instead of writing:

class Operations
  ...

  def square_and_add_two(x)
    add_two(square(x))
  end
  
  def added_squares(list)
    list.map { |x| add_two(square(x)) }
  end

You can use the composition operator:

class Operations
  ...

  def square_and_add_two(x)
    x.then(&square >> add_two)
    # Or the other way around:
    # (&add_two << square).call(x)
  end
  
  def added_squares(list)
    list.map(&square >> add_two)
  end
end

Operations.new.square_and_add_two(2)
# => 6

Operations.new.added_squares([1, 2, 3])
# => [3, 6, 11]

The original method behaviour is preserved - you can always call square(x) directly.

Class methods can also be turned into procs by using the cref keyword:

module Foo
  extend Referential

  module_function
  cref def square(x)
    x ** 2
  end
end

[1, 2, 3].map(&Foo.square)
#=> [1, 4, 9]

Methods with several arguments, if turned into procs, can be called directly by passing the required number of arguments. If called with fewer arguments than required, a curried proc is returned instead!:

class Operations
  extend Referential

  cref def self.multiply_by(x, y)
    x * y
  end
end

[1, 2, 3].map(&Operations.multiply_by(10))
#=> 10, 20, 30

After checking out the repo, run bundle install to install dependencies. Then, run rspec spec to run the tests.

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.

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

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

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