lazyproperty.coffee

lazyproperty = (obj, name, func, enumerable) ->
  Object.defineProperty obj, name,
    configurable: true
    enumerable: not not enumerable
    get: ->
      value = func.call(this)
      Object.defineProperty(this, name,
        {value, enumerable: !!enumerable, writable: true})
      value
    set: (value) ->
      Object.defineProperty(this, name,
        {value, enumerable: !!enumerable, writable: true})