在Ruby 2.0中，如何对特征使用mix方法

Question

module A

end

class D

  mix A

end  

c1 = D.new

Here is my output:

archie@local$ruby mixins-traits.rb 
mixins-traits.rb:4:in `<class:D>': undefined method `mix' for D:Class (NoMethodError)
    from mixins-traits.rb:3:in `<main>'

Answer 1

Traits didn't make it into Ruby 2.0. They are neither mentioned in the Release Notes nor in the NEWS .

Answer 2

I don't know ruby has mix keyword? usually it use include keyword. example: class D include A end .

Answer 3

Yes, you have to add an include, for example:

module A
  def a1
  end
end

class Sample  
  include A    #include method
end

samp = Sample.new