Mixin based coffeescript classes

gistfile1.coffee

class Composable
  @include = (modules...) ->
    @composable_modules ||= []
    for module in modules
      @composable_modules.push module

  apply_mixins: ->
    @__proto__.constructor.composable_modules ||= []
    for module in @__proto__.constructor.composable_modules
      for key, value of module.prototype
        this[key] ||= value
  constructor: ->
    @apply_mixins()

class Mixin
  foo: ->
    alert "foo from mixin"

class Composed extends Composable
  @include Mixin

c = new Composed()
c.foo()