Rebind module method example

1_rebinding_module_method.rb

# run me with ruby >= 2.0

module A
  def x(arg)
    "hi #{arg}"
  end
end

module B
  def x(arg)
    "cooool #{arg}"
  end 
end

class Awesome
  attr_accessor :woodoo

  def be_awesome(name)
    woodoo.bind(self).call(name)
  end 
end

a = Awesome.new

a.woodoo = A.instance_method(:x)
result = a.be_awesome("tomas")
puts result

a.woodoo = B.instance_method(:x)
result = a.be_awesome("tomas")
puts result

# If you run this with Ruby >= 2.0
# You should see this on your screen:
#
# hi tomas
# cooool tomas
#

2_rebinding_class_instance_method.rb

# you cannot bind class instance methods
# unless they are from the same ancestory chain:
#
class A
  def x(arg)
    "hi #{arg}"
  end 
end

class Awesome < A 
  attr_accessor :woodoo

  def be_awesome(name)
    woodoo.bind(self).call(name)
  end 

  def x(arg)
    "hi #{arg}"
  end 
end

a = Awesome.new
a.woodoo = A.instance_method(:x)
a.be_awesome("tomas")

# => "hi tomas"

more info

• http://www.rubytapas.com/episodes episode 091 (All Hail Avdi Grimm !!! )
• http://stackoverflow.com/questions/4470108/when-monkey-patching-a-method-can-you-call-the-overridden-method-from-the-new-i
• https://github.com/equivalent/scrapbook2/blob/master/ruby.md#rebinding-methods