.. proc

Format

..(Args)

Returns

The return value of the parent proc.

Args

The arguments to pass to the parent proc. This defaults to the arguments to the current proc.

If object O is derived from object P, P is called the parent of O. If a proc (or verb) is defined in both O and P, O can call P’s version by using ..().

mob
  P
    verb/history()
      world << "P"
 
    O
      history()
        world << "O"
        ..()          // call P.history()

Here O is derived from P. When P calls “history”, his name is displayed. When O calls “history”, his name is displayed, followed by the name of his parent, P.

If O overrides the same proc more than once, ..() will search for the previous version and use that. For instance, you could have two O.history() procs; the second overrides the first, but the original could still be called via ..(). The original in turn could call ..() to reach P.history(). Overriding the same proc more than once in the same type should be avoided wherever possible, because it incurs extra overhead, it makes the code harder to read, and it isn’t always clear which one gets called first. (Usually, the only time you’ll want this to happen is when using libraries.)

..() can also be used for predefined procs.

mob/Move()            // override proc
  world << "moving..."
  return ..()         // call default

This proc will print “moving…” whenever the mob moves.

See also