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Making (CLASS-OF <class>) be EQ to <class>
- To: Moon@STONY-BROOK.SCRC.Symbolics.COM
- Subject: Making (CLASS-OF <class>) be EQ to <class>
- From: Jon L White <firstname.lastname@example.org>
- Date: Thu, 27 Sep 90 17:52:27 PDT
- Cc: email@example.com
- In-reply-to: David A. Moon's message of Thu, 27 Sep 1990 20:04-0400 <19900928000454.7.MOON@KENNETH-WILLIAMS.SCRC.Symbolics.COM>
re: 1. When CHANGE-CLASS is applied to a class object, shouldn't it also
call MAKE-INSTANCES-OBSOLETE on it? [PCL mail from some time ago
Perhaps. Doesn't it also need to check metaclass compatibility?
Hmmmmm, now that you mention it . . . I guess checking VALIDATE-SUPERCLASS
on the class-prototypes is ok?
2. If there are methods defined on function FOO at classes respectively
<C1, C2 ...>, then how can one temporary override the effective
method at that point, and cause it to defer to the next most
This is just CALL-NEXT-METHOD, so you must mean something that I didn't
I don't think CALL-NEXT-METHOD does exactly that. For example,
CALL-NEXT-METHOD from within a single :AROUND method defined at the
point <C1, C2 ...> will invoke (probably) the primary method defined
at <C1, C2 ...>, rather than, say, the "effective" method defined for
point <C1, T ...>.
I may have misunderstood the semantics of SEND-AS, but that what I expected
it to mean -- "Treat this argument, for purposes of message/generic-function
dispatch, as if it's type were explicity FOOBAR rather than it's real type."
Now, I fully agree with you that replaceing Method Combination by simply
SEND-AS/LEXPR-SEND-AS is a loss; but an ocasional "exceptional" use of this
flavorized kludge might not be so bad.
As my first note mentioned, one is very tempted to use :AROUND methods and
CALL-NEXT-METHOD; but as Gregor indicated, CLOS just isn't one of "those"
kinds of language that make explicit delegation like this easy.
re: [redefinition prohibitions for various CLOS constructs ...]
Maybe another issue covered this, or maybe it's a hole in the language
waiting to be filled by the metaobject protocol.
Probably the latter. By now, it's become a crater.
-- JonL --