CoffeeScript class decorators

class-decor.coffee

# Just playing around with some ideas...

interface = (names...) -> (klass) -> throw new Error "Missing #{n}" for n in names when not klass::[n]?; klass
extender = (props) -> (klass) -> klass::[k]=v for k,v of props; klass

watchable = interface 'watch', 'unwatch'
writable = interface 'write'
evented = extender
  on: (event, callback) -> do stuff
  trigger: (name, args...) -> do stuff


writable class User
  write: -> write stuff

evented class Post
  # Gets the `on` and `trigger` methods copied to its prototype

writable watchable class Blog
  write: -> write stuff
  watch: -> watch stuff
  # Missing 'unwatch' causes an error

writable evented class Category
  write: -> write stuff
  # Also gets `on` and `trigger` methods