Comment 2 for bug 458164

Releated discussion over here:

  http://<email address hidden>/msg00158.html

Searching over the online version of AMOP

  http://www.lisp.org/mop/concepts.html
  http://www.lisp.org/mop/dictionary.html

the only references to CLASS-PROTOTYPE that specify anything are

"Generic Function class-prototype class

Returns a prototype instance of class. Whether the instance is initialized is not specified. The results are undefined if a portable program modifies the binding of any slot of prototype instance.

This generic function signals an error if class has not been finalized."

and a table that says "No behavior is specified for this method beyond that specified for the generic function." in reference to CLASS-PROTOTYPE on standard-class, funcallable-standard-class, forward-referenced-class, and built-in-class.

So...

I don't see anywhere the requirement for the "prototype instance" to be a direct instance. As a matter of fact, I don't see "prototype instance" specified anywhere. It is blatantly underspecified.

I do think that restricting it to direct instances and signalling an error if we cannot provide one is sensible, so that users can rely on

  (bar (class-prototype 'foo))

dispatching on the method specialized on FOO instead of some of its subclasses -- but don't see how this is directly supported by AMOP: it's just the way we decide to interpret the term "prototype instance".

  status confirmed
  importance medium
  tags pcl