Selfies

A collection of macros for quicker development

Another day at work, or on your personal project, and you need to create yet another class, which comes with the user boilerplate:

• The initializer needs to be defined, with n parameters
• Inside that, the usual @param = param, multiplied for how many params you've got there
• Then it's the turn of the attr_reader for those parameters
• Then you are likely to need a class method that does nothing else than initializing the class and calling an instance method of the same name
• more?

This gets boring with the years. So boring that someone might decide to write some macros to reduce the boilerplate.

You add this:

gem 'selfies'

You write this:

class Rectangle
  attr_accessor_init :width, :height, scale: 100
  selfie :area, :perimeter

  def area
    proportion(width * height)
  end

  def perimeter
    proportion((width + height) * 2)
  end

  private

  def proportion(value)
    value.to_f / 100 * scale
  end
end

You get this:

>> Rectangle.area(8, 4)
=> 32.0
>> Rectangle.perimeter(5, 3)
=> 16.0
>> Rectangle.perimeter(5, 3, 50)
=> 8.0

Add this line to your application's Gemfile:

gem 'selfies'

And then execute:

$ bundle

Or install it yourself as:

$ gem install selfies

attr_reader_init: can be used to automatically generate an initialiser for your class

This code:

class Search
  attr_reader_init :term, :page, :limit
end

Is equivalent to:

class Search
  attr_reader :term, :page, :limit

  def initialize(term, page, limit)
    @term = term
    @page = page
    @limit = limit
  end
end

It is possible to specify a default for the last argument only:

This code:

class Search
  attr_reader_init :term, :page, limit: 5
end

Is equivalent to:

class Search
  attr_reader :term, :page, :limit

  def initialize(term, page, limit = 5)
    @term = term
    @page = page
    @limit = limit
  end
end

>> search = Search.new('foo', 1)
>> search.limit
=> 5

You can use any variable name that would make for a valid Ruby variable; Only exception is :args which is used by selfies to define a splat operator:

This code:

class Search
  attr_reader_init :term, :args
end

Is equivalent to:

class Search
  attr_reader :term, :args

  def initialize(term, *args)
    @term = term
    @args = args
  end
end

>> search = Search.new('foo', 2, 10)
>> search.args
=> [2, 10]

attr_accessor_init: same as attr_reader_init, but generates accessors for the given attributes

This code:

class Search
  attr_accessor_init :term, :page, :limit
end

Is equivalent to:

class Search
  attr_accessor :term, :page, :limit

  def initialize(term, page, limit)
    @term = term
    @page = page
    @limit = limit
  end
end

selfie: can be used to automatically create a class method that reference to the instance method of the same class

This code:

class Search
  attr_reader :term, :page, :limit

  def initialize(term, page, limit)
    @term = term
    @page = page
    @limit = limit
  end

  def self.execute!(term, page, limit)
    new(term, page, limit).execute!
  end

  def self.next(term, page, limit)
    new(term, page, limit).next
  end

  def execute!
    # does something
  end

  def next
    # does something else
  end
end

Can be written as:

class Search
  attr_reader_init :term, :page, :limit

  def execute!
    # does something
  end
  selfie :execute!

  def next
    # does something else
  end
  selfie :next
end

If preferred, more methods can be 'selfied' in one liner:

class Search
  ...
  selfie :execute!, :next

  def execute!
    # does something
  end

  def next
    # does something else
  end
end

attr_reader_init and attr_accessor_init:

• Improve message when raising ArgumentError;

selfie:

• Find a suitable syntax that would allow to 'selfie' an instance method that has arguments;

command line:

• Write a command that can initialize a whole class, from creating the file to stub the initial setup;

more?:

• If you also often write repetitive boilerplate, and would like some code to get smaller, drop me a line and we might be able to add more macros.

Ruby version:

>= 2.5

Fork the project, clone the repository and bundle:

>> git clone https://{your_fork}/selfies
>> cd selfies
>> bundle

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.

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

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