From: Thomas Wieczorek <wieczo.yo@...>
Date: 2008-01-23T20:02:12+09:00
Subject: Re: singleton definition differences

On Jan 23, 2008 11:30 AM, Keynan Pratt <keynan@howe.textdrive.com> wrote:
> Not to hijack the thread but does singleton not refer to a pattern
> method that instantiates and returns an object reference and for future
> calls returns the reference of the object which has been cached in
> memory to prevent instantiation of duplicate instances
>

There are singleton methods in Ruby. They have nothing in common with
the Singleton pattern as you described it. You can define singleton
methods for objects, e.g. in irb
irb(main):001:0> foo = "Hello World"
=> "Hello World"
irb(main):002:0> class << foo
irb(main):003:1> def shuffle
irb(main):004:2> split(//).sort { rand }.join ''
irb(main):005:2> end
irb(main):006:1> end
=> nil
irb(main):007:0> foo.shuffle
=> "d HWloorlle"

As you can see, you can modify the methods of single objects instead
modifying the whole class.