Extending a Ruby parent class' method with a different-named method

Question

I have a class Parent and a class Child (which is a ~~child~~ subclass of Parent).

Parent has a method called aaaa.
Child has a method called bbbb.

This is what I want to achieve:

I want bbbb to be an extension of aaaa. If I call aaaa on a Child object, it will run what aaaa would normally do, plus whatever else in bbbb.
Calling bbbb will do the same as above (runs what aaaa would normally do and then do whatever else is in bbbb).

This is what I ended up doing:

class Parent

  def aaaa
    print "A"
  end

end

class Child < Parent

  alias_method :original_aaaa,:aaaa
  def bbbb
    original_aaaa
    print "B"
  end
  alias_method :aaaa,:bbbb

end

c = Child.new
c.aaaa # => AB
c.bbbb # => AB

It works. I guess. But it felt really hackish. Plus, a disadvantage of this is that if I wanted to extend aaaa with the same name either before or after defining bbbb, things get a bit strange.

Is there a simpler way to achieve this?

I could see reasons for doing this. This question has some thoughts about how to handle this: http://stackoverflow.com/questions/2564391/how-do-i-call-a-super-class-method — timpone, Oct 08 '13 at 02:22
You seem to be using the term "extend" in a misleading way. This term is reserved to mean something different than what you probably mean. You should use a different term. — sawa, Oct 08 '13 at 02:51
Maybe something like "enhancement", "addition", etc. I am not sure. It is up to you. — sawa, Oct 08 '13 at 03:08

score 5 · Accepted Answer · answered Oct 08 '13 at 02:53

5

class Parent
  def aaaa
    print "A"
  end
end

class Child < Parent
  def aaaa
    super
    print "B"
  end
  alias bbbb :aaaa
end

answered Oct 08 '13 at 02:53

sawa

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This seemed the obvious answer as soon as I read the question, But the sophistication of how the OP asked the question led me to believe that `super` was not a sufficient strategy for a solution. I will look forward to their response to your answer. – New Alexandria Oct 08 '13 at 03:06
1

@NewAlexandria: Nah, I'm just dumb :) – Saturn Oct 08 '13 at 03:07
1

Dumb enough to ask the question very well. – New Alexandria Oct 08 '13 at 03:08

score 0 · Answer 2 · answered Sep 30 '21 at 19:51

Thanks above answer @sawa Below my use case I like to share: super is work by order!

   class Parent
      def aaaa
        print "A"
      end
    end
    
    class Child < Parent
      def aaaa
        super
        print "B"
      end
      alias bbbb :aaaa
    end
    
    Class Grand < Child
      def aaaa
        print "C"
        super
      end
    end
    => :aaa
    
    g = Grand.new
    g.aaaa #=> CAB

Extending a Ruby parent class' method with a different-named method

2 Answers2