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From: hohl@diana.informatik.uni-stuttgart.de (Hubertus Hohl)
Newsgroups: comp.lang.clos
Subject: Bug in May Day PCL (REV 4)
Message-ID: <7533@ifi.informatik.uni-stuttgart.de>
Date: 8 Feb 91 07:42:46 GMT
Sender: news@ifistg.uucp
Lines: 37

Slot access in the new Revision 4 PCL [May Day PCL (REV 4)] does not always 
work correctly. Consider the following code fragment (extracted
from a more complex piece of code):
  
   (defclass thing ()
     ((t-1 :initform 999)))

   (defmethod m1 ((maybe-a-thing t))
     (if (typep maybe-a-thing 'thing)
         (slot-value maybe-a-thing 't-1)
         maybe-a-thing))

   (m1 (make-instance 'thing)) => 999

   (m1 'foo)  => 
   Error: No matching method for the generic-function #<Function FIND-SLOT-DEFINITION @ #x47fcbe>,
   when called with arguments (#<Built-In-Class SYMBOL 23723516> T-1).

Of course, I know that method M1 could (and should) be replaced by 
two methods M1 that specialize on THING and T respectively! Anyway, this 
behaviour did not show up in May Day PCL (REV 3). 
Any bug fixes would be appreciated, especially from the people who contributed
to Revision 4!

Thanks in advance.

==============================================================================
Hubertus Hohl                     e-mail: hohl@dia.informatik.uni-stuttgart.de
Institut fuer Informatik
Herdweg 51
D - 7000 Stuttgart 1                               Tel.:  (+49|0) 711 121 1358
==============================================================================
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==============================================================================
Hubertus Hohl                 e-mail: hohl@dia.informatik.uni-stuttgart.dbp.de
Institut fuer Informatik