gistfile1.rb

module Redef
  def foo
    puts "'foo' from module"
  end
end

class A
  define_method("foo") do
    puts "'foo' from define_method"
  end
  include Redef
end

A.new.foo 
# ===> 'foo' from define_method
# why not "'foo' from module" ?

# David's example
class A
  def foo
    puts "'foo' from A"
  end
  include Redef
end
A.new.foo
# ===> 'foo' from A
  

=begin
David A. Black says:

It's a matter of the order of method lookup. In general, an object
looks for a method first in its class, and then in modules mixed into
that class.

------
7stud says:

By the way, you can get the lookup order using the ancestors method:

A.ancestors
# ===> [A, Redef, Object, Kernel]

Does not list singleton class though:

class A
  def initialize
    extend Redef
  end
end

A.ancestors
# ===> [A, Object, Kernel]
=end