gistfile1.rb

require 'rubygems'
require 'mixology'

module Callback
 def before_filter filter, filtered_method
   Callback.method_factory(filter, filtered_method)
 end

 # Needed defin_method here so it's called in module's context
 def self.method_factory(filter, filtered_method)
   define_method(filtered_method) do
     send filter
     super
   end
 end
end

class Coffee
 def spoon_required
   puts "get a spoon to steer sugar || creme"
 end

 def cost
   puts "3"
 end

 def taste
   puts "African Arabica"
 end
end

coffee = Coffee.new
coffee.mixin Callback
coffee.before_filter :spoon_required, :cost
coffee.cost
coffee.cost