ruby - extend module inside another module

Question

I'm trying to define a couple of modules to easily add in some instance and class methods to other classes, here's what I'm doing:

module Foo   module Bar     def speak       puts "hey there"     end   end   module Baz     extend Foo::Bar      def welcome       puts "welcome, this is an instance method"     end   end end  class Talker   include Foo::Baz end  Talker.new.welcome Talker.speak 

The output of this is:

welcome, this is an instance method undefined method 'speak' for Talker.class (NoMethodError) 

I was expecting Talker to have the 'speak' method since it includes Foo::Baz which itself extends Foo::Bar.

What am I missing?

Answer 1

You can try this:

module Baz   extend Foo::Bar    def self.included(base)     base.send :extend, Foo::Bar   end    def welcome     puts "welcome, this is an instance method"   end end 

This will auto-extend all classes in wich Baz is included.

PS:

extend Foo::Bar in module Baz was in original snippet, this code do not influence on method def self.included(base).

Answer 2

try this:

class Talker    extend Foo::Baz end 

since you want to call Talker.speak as a class method and not as an instance method (like Talker.new.speak) you have to include the Foo:Baz in a way that the class will take the methods itself.

One possibility is to use 'extend' (as above) the other is modifying it's eigenclass:

class Talker   class << self     include Foo::Baz   end end