Meta-programming in coffescript

gistfile1.coffee

class Entity
  applyEvent: (event, args) ->
    @[Entity._handler event] args...
  @_handler: (name) -> "on_#{name}"

  @event: (name, handler) ->
     @::[name] = ->
        @applyEvent name, arguments
     @::[Entity._handler name] = handler

# --------

class Foo extends Entity
  constructor: (@me = 10) ->

  @event 'hello', (subject) ->
    alert "hello, #{subject} #{@me}"

f = new Foo
f.hello 'world'