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Re: exporting standard-class
- To: Bruce Esrig <email@example.com>
- Subject: Re: exporting standard-class
- From: Gregor.pa@Xerox.COM
- Date: Thu, 25 Aug 88 11:35 PDT
- Cc: commonloops.pa@Xerox.COM
- Fcc: BD:>Gregor>mail>outgoing-mail-3.text.newest
- In-reply-to: <8808191800.AA16009@oravax.UUCP>
- Line-fold: no
Date: Fri, 19 Aug 88 14:00:10 EDT
From: firstname.lastname@example.org (Bruce Esrig)
In a previous query, we asked whether there were any problems
porting pcl to Lucid; we reported that when we make an instance,
we get a message stating that there is no matching method for
the generic function initialize-instance. We now know that
the cause of the problem was that we had created a class with
an undefined metaclass.
The following definition illustrates our problem.
(in-package 'my-package :use '(lisp pcl system))
(defclass topmost_class (standard-class) ())
In this definition, standard-class refers to the internal symbol
of my-package. Should the classes standard-class and above be
exported by the pcl package ? If they were, this problem would not occur.
Alternatively, should there be a way to get warning messages when
forward definitions of class names occur ?
I future versions of PCL, there will be two changes, each of which will
provide you some help with this problem.
1) symbols like standard-class will be exported from the PCL package.
2) attempting to make an instance of a class which has forward
referenced supers will signal an error.