From: Eero Saynatkari <ruby-ml@...>
Date: 2006-10-27T15:25:40+09:00
Subject: Re: Singleton Methods

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On 2006.10.27 15:15, bparanj@gmail.com wrote:
> What is the purpose of singleton method? Why is singleton method
> defined on individual object instead of a class? TIA

That, precisely, IS the point of a singleton method: being defined
for one object only. It is often useful to be able to define special
behaviour for an individual object. One could imagine several things
but a very good example is one that you have seen before on some
instances of class Class:

  class Foo
    def self.foo=20
      puts 'Yay singletons!'
    end
  end

  # Same as
  Foo =3D Class.new
 =20
  def Foo.foo
    puts 'Yay singletons!'
  end

This is how Ruby implements 'class methods' without having to=20
include any special behaviour. Just objects and singleton methods.

Generally, any object-level customisation. In Ruby, a type is=20
more important than a class.

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