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Re: Issue EQUALP-GENERIC
- To: Kim A. Barrett <IIM@ECLA.USC.EDU>
- Subject: Re: Issue EQUALP-GENERIC
- From: Gregor.pa@Xerox.COM
- Date: Wed, 1 Mar 89 19:50 PST
- Cc: cl-cleanup@SAIL.STANFORD.EDU, JonL@LUCID.COM
- Fcc: BD:>Gregor>mail>outgoing-mail-5.text.newest
- In-reply-to: <12474360416.19.IIM@ECLA.USC.EDU>
- Line-fold: no
Date: Tue, 28 Feb 89 13:48:20 PST
From: Kim A. Barrett <IIM@ECLA.USC.EDU>
Thanks for developing this proposal. Those other ones of us who
mentioned we would think about it have been too swamped.
This message comments on only one small part of your proposal. I may
comment on other parts later.
An error is signaled on an attempt to add a method on any built-in class.
Adding a method on a class after ALLOCATE-INSTANCE has been called on the
class has undefined consequences.
These two points confuse me. I think the first is just covered by one
of the principles outlined in chapter 3. Specifically, the results are
undefined if you define a method on a specified generic function with
specified classes as the specializers. This is really just the obvious
extension of the function redefinition issue. I don't think it is worth
defining a new class of generic function which signals this error.
The second seems well intentioned but unreasonable. For one thing, some
implementations may call allocate-instance before defclass returns. For
another, it seems too painful to suggest that in order to define such a
method you have to boot your lisp first. If this is really the only way
the rest of the proposal can hold together, I think we need to reconsider