module EzAttributes

Easily define initializers with keyword args. It supports required and optional args.

@example

class User
  extend EzAttributes

  # Here name and age are required, and email has a default value, so it is optional.
  attributes :name, :age, email: 'guest@user.com'
end

User.new(name: 'Matheus', age: 22)
=> #<User:0x000055bac152f130 @name="Matheus", @age=22, @email="guest@user.com">

Constants

EXCEPTIONS: Attributes that won't have a getter to prevent conflicts with default methods
VERSION: Gem version

Public Instance Methods

attribute(name) click to toggle source

Defines a single keyword argument for a class initializer

# File lib/ez_attributes.rb, line 43
def attribute(name)
  attributes(name)
end

attributes(*args, **args_with_default) click to toggle source

Defines multiple keyword arguments for a class initializer

# File lib/ez_attributes.rb, line 24
  def attributes(*args, **args_with_default)
    required_args = args.map { |name| "#{name}:" }
    optional_args = args_with_default.map { |name, _| "#{name}: __args_with_default[:#{name}]" }
    init_args = (required_args + optional_args).join(', ')

    define_method('__args_with_default', -> { Marshal.load(Marshal.dump(args_with_default)) })
    private :__args_with_default

    all_args = args + args_with_default.keys
    attr_reader(*(all_args - EXCEPTIONS))

    class_eval <<~RUBY, __FILE__, __LINE__ + 1
      def initialize(#{init_args})
        #{all_args.map { |name| "@#{name} = binding.local_variable_get(:#{name})" }.join('; ')}
      end
    RUBY
  end