Crazyton

tldr:

Shorter way to write Singletons

# instead of

Luke.instance.name

# you can call

Luke.name

Sometimes I wanted to create something richer than a module with module_function, but without the def self. syntax of class methods.

I therefore created Crazyton. Under the hood it uses method_missing with Singleton to provide its functionality, which is sort of crazy, hence the name.

One of the advantages of using classes over modules is that you can use inheritance.

Since Crazyton uses a Singleton under the hood, you can manage state on the class without having to resort to class variables:

Add this line to your application's Gemfile:

gem 'crazyton'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install crazyton

Create a class and include the Crazyton module in order for its instance methods to be exposed as class methods:

class Dog
    include Crazyton

    def bark
        puts 'woof'
    end
end

Dog.bark
=> woof

With great power comes great responsibility or at least the need for understanding.

Crazyton uses method_missing to delegate methods from the class to the Singleton instance, this means that if a class method already exists with the same name, the class method will be called not the instance method:

class Dog
    include Crazyton

    def bark
        puts "Woof"
    end

    def self.bark
        puts "Peep"
    end
end

Dog.bark
=> Peep

Furthermore, the self in the delegated methods is not the same self as in the normal class methods since there is an underlying Singleton instance that we delegate to:

class Dog
    include Crazyton

    def pet
        @pets ||= 0
        @pets += 1
    end

    def how_many_pets
      puts @pets
    end

    def self.class_pets
        puts @pets || 0
    end
end

Dog.pet
Dog.pet
Dog.how_many_pets
=> 2
Dog.class_pets
=> 0

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.

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

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