[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
- To: Fahlman@CMU-CS-C.ARPA, Robert.Frederking@CMU-CS-CAD.ARPA
- Subject: Painful retraction
- From: "Bernard S. Greenberg" <BSG@SCRC-QUABBIN.ARPA>
- Date: Thu, 23 Aug 84 15:04 EDT
- Cc: alan@MIT-MC.ARPA, common-lisp@SU-AI.ARPA, guy.steele@CMU-CS-A.ARPA
- In-reply-to: <FAHLMAN.12041780645.BABYL@CMU-CS-C.ARPA>
Date: Thu, 23 Aug 1984 13:56 EDT
From: "Scott E. Fahlman" <Fahlman@CMU-CS-C.ARPA>
I don't think it would violate the standard for a particular
implementation to return nil in this case -- this sort of extension in a
situation that would otherwise be an error is generally allowed -- but I
would strongly advocate that no implementor do this without a very good
reason. Users of his system will come to depend on this trick,
sacrificing portability without realizing it.
I don't see any justification for such an extension. Extend CDR to take
the successor of a number... how is that different? NIL is clearly not
defined to be "a member of all data types" or similar. I think the
proposed extension violates the spirit of Lisp.
What do you (Scott) think are similar situations "that would otherwise
be an error" that are really parallel?