从类中调用包含模块的方法

Question

I have a use case where I have class A which includes module B .

class A
  include B

  def do_one_thing
    # override module's method. do something different instead
  end

  def do_another_thing
    # Call `do_one_thing` from here,
    # but call the module's method, not the one I overrode above.
  end
end

module B
  included do
    def do_one_thing
      # ...
    end
  end

  # some other methods
end

As shown above, I'm calling do_one_thing from do_another_thing . My problem is that I need to call the module's method (ie the super method). Is this possible in Rails?

Answer 1

To property use the included method, you'll need your B module to extend ActiveSupport::Concern but that won't give you the behaviour you want.

If I were you I'd abandon that pattern and use simple native Ruby module patterns:

module B    
  def do_one_thing
    puts 'in module'
    # ...
  end

  # some other methods
end

class A
  include B

  def do_one_thing  
    super  
    puts 'in class'
    # override module's method. do something different instead
  end

  def do_another_thing
    do_one_thing
    # Call `do_one_thing` from here,
    # but call the module's method, not the one I overrode above.
  end
end

A.new.do_one_thing

The above code will correctly use the module inheritance you are looking for.

Read more about Ruby module inheritance here

Answer 2

You can 'save' included method before override

module B
  extend ActiveSupport::Concern

  included do
    def do_one_thing
      puts 'do_one_thing'
    end
  end
end

class A
  include B

  alias_method :old_do_one_thing, :do_one_thing
  def do_one_thing
    puts "I'd rather do this"
  end

  def do_another_thing
    old_do_one_thing
  end
end

a= A.new
a.do_one_thing
a.do_another_thing