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find my slot
- To: Jon L White <firstname.lastname@example.org>
- Subject: find my slot
- From: Moon@stony-brook.scrc.symbolics.com
- Date: Thu, 29 Nov 1990 18:51:00 PST
- Cc: email@example.com, mop@arisia.Xerox.COM
- Illegal-object: Syntax error in From: address found on alpha.xerox.com: From: David A.Moon <Moon@STONY-BROOK.SCRC.Symbolics.COM> ^ ^-illegal period in phrase \-phrases containing '.' must be quoted
- In-reply-to: <9011292258.AA01506@caligula>
Date: Thu, 29 Nov 1990 17:58 EST
From: Jon L White <firstname.lastname@example.org>
re: Date: Tue, 27 Nov 1990 12:06 EST
Of the 5 major CLOS metaobject types (classes, generic functions,
methods, method combinations, and slot definitions), three have
retrieval functions (FIND-CLASS, FIND-METHOD, FIND-METHOD-COMBINATION),
and one doesn't need one (generic functions). What happened to
It isn't necessary, because CLASS-DIRECT-SLOTS and CLASS-SLOTS are
specified to return lists, therefore the existing FIND function can be
used (with :KEY #'SLOT-DEFINITION-NAME).
If Harley's question is only about introspective capabilities, then
we don't need FIND-METHOD either -- because of the documentation for
GENERIC-FUNCTION-METHODS, METHOD-QUALIFIERS, and METHOD-SPECIALIZERS.
It's true that FIND-METHOD doesn't do anything you can't do yourself given
those other facilities. It also doesn't do anything that's useful, as far
as I can see, if all you have is the standard part of CLOS (chapter 2).
I imagine FIND-METHOD exists because the translation into FIND is quite
complicated. I notice that FIND-METHOD is generic, so maybe it exists
so users can define other methods for it. However, I can't imagine what
one could accomplish, other than perhaps a minor speedup, by writing
specialized methods for FIND-METHOD.
However, FIND-CLASS and FIND-METHOD are "Chapter 2" facilities. Would
you now propose to remove FIND-METHOD? or would the uniformity of
interface resulting from the addition of FIND-SLOT-DEFINITION be
better than trying to retrench into a minimal kernal language?
I'm not proposing anything. I will comment that attempting such
uniformity of interface in CLOS is pretty much a lost cause; CLOS
just shows too well that it is the work of many hands.
The absence of FIND-SLOT-DEFINITION is one of the few things about the
most recent draft of the metaobject protocol I have (July 30, 1990)
that doesn't bother me one little bit.