Always the only instance

Singleton.coffee

do(w=window,d=document) ->
  
  # log output
  log = ->
    if (typeof console isnt 'undefined')
      console.log.apply(console, arguments);

  ## implements
  class Singleton
    constructor: ( name ) ->
      @name = name
      
    hello: ->
      
      log name

  ## end class Singleton

  instance = null
  w.Singleton = (name) ->
    if ( instance )
      instance
    else
      instance = new Singleton(name)