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- To: CommonLoops.pa@Xerox.COM
- Subject: subtypep questions
- From: firstname.lastname@example.org (Brad Miller - EMD)
- Date: Thu, 22 Jun 89 9:18:42 CDT
- Redistributed: CommonLoops.pa
I am sure that this question has come up here before, but I have looked
back through the archives and I cannot find the answer. I am trying to
teach myself about CLOS and therefore have been going through Keene's
book and trying the examples. However the first one I try doesn't seem
to be working out. The following is a section of a recent transcript
from Allegro CL 1.2.1 on my Mac II.
? (defclass lock () ((name :initarg :name :reader lock-name)))
#<Standard-Class lock 2638932>
? (defclass null-lock (lock) ())
#<Standard-Class null-lock 2673068>
? (defclass simple-lock (lock)
((owner :initform nil :accessor lock-owner)))
#<Standard-Class simple-lock 2521500>
? (subtypep 'simple-lock 'lock)
*** QUESTION NUMBER 1, why does this not return t t as I would expect?
? (setq *null-lock*
(make-instance 'null-lock :name "Null lock"))
? (setq *simple-lock*
(make-instance 'simple-lock :name "Simple lock"))
? (type-of *null-lock*)
*** QUESTION NUMBER 2, What is this iwmc-class, and what has happened to
my null-lock class?
? (typep *simple-lock* 'simple-lock)
*** COMMENT NUMBER 1, Well at least something worked as I expected.
Any comments or advice to point this wayward programmer in the right direction
would be sincerely appreciated. Thanks in advance.