What is/was CLOS and does it still "exist"?

[Bruce M. Axtens]

Dear comp.lang.clos

What was CLOS? Or is it still a case of "what is CLOS"?

Are there still interpreters/compilers for it, and if so, where?

Kind regards,
Bruce. M. Axtens.

[Simon Leinen]

Bruce M Axtens writes:
> Dear comp.lang.clos
> What was CLOS? Or is it still a case of "what is CLOS"?

Common Lisp Object System. This is a set of object-oriented extensions
that were added to Common Lisp during the ANSI standardization effort
(X3J13).

So it used to be an extension to (early/pre-) Common Lisp, now it's part
of it. Since it's no longer considered as separate, the name "CLOS" is
used less and less.

> Are there still interpreters/compilers for it, and if so, where?

CLOS is (or should be) included in all Common Lisp implementations. At
least they should all have the elementary operations like DEFCLASS,
DEFMETHOD, DEFGENERIC, and so on.

There is a further level of CLOS that allows the object system itself to
be extended through definition of new "metaclasses", and to be inspected
(I think this is called introspection or reflection). This part of CLOS
is called the MOP or Meta-Object Protocol. It was mostly left out of
Common Lisp (wasn't ready when CL was done), so that part is much less
standardized, and it's a little hard to write portable code. I'm
certain someone made a library that provides portable access to those
parts of the MOP that have been widely implemented.
--
Simon.

[Bruce M. Axtens]

Simon Leinen wrote:
> Common Lisp Object System. This is a set of object-oriented extensions
> that were added to Common Lisp during the ANSI standardization effort
> (X3J13).

Simon, that's very helpful and fills the gap in my understanding. Thanks
very much.

Kind regards,
Bruce.

[Pascal J. Bourguignon]

Simon Leinen <simon....@switch.ch> writes:

There is CLOSER-MOP trying to provide a portability layer for MOP.

--
__Pascal Bourguignon__ http://www.informatimago.com/