Class factory in CoffeeScript

classgen.coffee

gen = (clsname, val) ->
  C = class
  C.prototype[val] = -> "#{clsname} says #{val}"
  C

Cat = gen 'Cat', 'meow'
console.log Cat
c = new Cat
alert c.meow()

Dog = gen 'Dog', 'woff'
d = new Dog
alert d.woff()

The point is that the class name and some of the behaviour is are dynamic parameters, not symbols in the code.