Question

I’m new to Ruby and was reading this post comparing a mixin to a C# interface. What is unclear to me is whether or not a method from the mixin can be redefined in the class which implements it.

For example, if I put include myMixin — which has a method toJSON — in a class MyClass, can I redefine toJSON in MyClass, or am I stuck with the behavior defined in myMixin?

For anyone with further interest, is that blog post a good source of information? Is it reasonable to compare a Ruby mixin to a C# interface?

Answer 1

methods defined in a class will always override methods mixed into that class through a module in Ruby

For example:

module Bang
   def bar
      "lol"
   end
end

class Foo
   include Bang
   def bar
      42
   end
end

Foo.new.bar
 => 42 

Regardless of when the module is included, the method bar defined on the class will be called first. This is because of how ruby looks up methods – it searches the class itself before it searches any modules included into the class.

http://anders.janmyr.com/2009/06/ruby-method-lookup.html

http://blog.rubybestpractices.com/posts/gregory/031-issue-2-method-lookup.html