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Re: Are isomorphic structures EQUAL?
- To: JAR@ai.ai.mit.edu
- Subject: Re: Are isomorphic structures EQUAL?
- From: Bobrow.pa@Xerox.COM (Danny Bobrow)
- Date: Sun, 01 Jun 1986 19:54:00 -0000
- Cc: Moon@SCRC-STONY-BROOK.ARPA, common-lisp@SU-AI.ARPA
- In-reply-to: Jonathan A Rees <JAR@ai.ai.mit.edu>'s message of Thu, 29 May 86 14:23 EDT
- Sender: Bobrow.pa@Xerox.COM
"I would mildly object to having [EQUAL] recursively compare components
because that seems to be a violation of the data abstraction
that structures are supposed to provide."
One of the proposed uses for a multi-methods in CommonLoop was to allow
methods that declared themselves as -inside- both structures, and have
the system ensure that it was called in just such a case. It would seem
that EQUAL and others are good candidates for such methods.
"I would like to change the language so that the the type of
(whose DEFSTRUCT doesn't use :TYPE) is disjoint from other types."
I agree on the utility of providing easy mechanisms to suport
disjointness. Are there implementations out there that do not support