     }
 
   set_custom: (custom) ->
-    custom_level.set custom
+    _custom_level.set custom
 
   url:           url
   pretty_source: pretty_source

move_action = (world, args) ->
  [sprite, program, old_index, new_index] = normalize_action_args args

  level_sprite  = custom_level.get().sprites[sprite.index]
  level_program = level_sprite.actions[program]
  action        = level_program[old_index]


  object

get_level_copy = ->
  $.extend true, {}, _custom_level.get()

update_level = (change) ->
  level = get_level_copy()
  change level
  _custom_level.set level

index_of_conditional = (list, condition) ->
  index = -1
