Note to future self: This is how scoping works in coffeescript.

CoffeeScript-scope.coffee

class Foo
  @_cattr =
    "a": "apple"
    "b": "banana"
    "c": "cherry"
    "d": "dragonfruit"

  @classCattrGet: ->
    @_cattr

  @classCattrSet: (k, v) ->
    @_cattr[k] = v

  constructor: (@attr) ->
    @attr ?=
      "a": "armadillo"
      "b": "baboon"
      "c": "capybara"
      "d": "dingo"

  instanceCattrGet: ->
    @constructor._cattr

  instanceCattrSet: (k, v) ->
    @constructor._cattr[k] = v

  instanceAttrGet: ->
    @attr

  instanceAttrSet: (k, v) ->
    @attr[k] = v

window.Foo = Foo