method_container

method_container.rb

require "method_source"

def method_container_for(target, &blk)
  # create adhoc class under target
  method_container = Class.new

  def method_container.method_added(mname)
    # do whatever you want with methods (e.g. "use the source" )
    p instance_method(mname).source
  end

  method_container.class_eval &blk
  method_container
end

method_container = method_container_for(Fixnum) do
  def foo
    print "hello\n"
  end
end

method_container.new.foo