fowlie.rb

[27] (pry) main: 0> class Pig
[27] (pry) main: 0*   def self.fowlie
[27] (pry) main: 0*     puts "fowlie"
[27] (pry) main: 0*   end  
[27] (pry) main: 0*   cm = "fowlie"
[27] (pry) main: 0*   class << self; self; end.class_eval do
[27] (pry) main: 0*     alias_method "original_#{cm}", cm
[27] (pry) main: 0*     def fowlie
[27] (pry) main: 0*       original_fowlie
[27] (pry) main: 0*       puts "decorated fowlie"
[27] (pry) main: 0*     end  
[27] (pry) main: 0*   end  
[27] (pry) main: 0* end  
=> nil
[28] (pry) main: 0> Pig.fowlie
fowlie
decorated fowlie
=> nil
[29] (pry) main: 0>