Using bindings instead of alias_method_chain.

bindings.rb

require 'rubygems'
require 'activesupport'

# Let's say there's some Widget class.
class Widget
  def sproing
    [:original]
  end
end

# We can use alias_method_chain to wrap that behavior...
class Widget
  def sproing_with_amc
    sproing_without_amc + [:amc]
  end
  alias_method_chain :sproing, :amc
end

# ...or we can use a binding.
class Widget
  original_sproing = Widget.instance_method(:sproing)
  define_method(:sproing) do
    original_sproing.bind(self).call + [:binding]
  end
end

# Note that original_sproing is a local variable.  Its scope
# ends with the end of that class declaration.  The reference
# to it here would raise a NameError.
# 
# class Widget
#   puts original_sproing
# end


require 'spec'

describe Widget, "#sproing" do
  it "calls the original implementation" do
    Widget.new.sproing.should include(:original)
  end
  
  it "calls the alias_method_chain implementation" do
    Widget.new.sproing.should include(:amc)
  end
  
  it "calls the binding implementation" do
    Widget.new.sproing.should include(:binding)
  end
end