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Re: %nil once again


From: Daniel Kraft
Subject: Re: %nil once again
Date: Fri, 31 Jul 2009 07:05:42 +0200
User-agent: Thunderbird 2.0.0.0 (X11/20070425)

Neil Jerram wrote:
Andy Wingo <address@hidden> writes:

Other things needed would be for instance terminating rest-arguments
by %nil rather than '() and the like.

Why is that needed?  I.e. Why is it important for a rest argument to
be terminated with %nil instead of with () ?

Well, I don't think it is "important" at all, but it would be needed for "complete elisp" semantics, just because it is a list and lists should be terminated by %nil in elisp. Someone might try to check for the end-of-list with (eq tail nil) instead of (null tail) and it should still work.

BTW, for an empty rest argument the elisp documentation explicitly states it "should" be nil (well, but that's obviously so because nil is the empty list).

Daniel

--
Done:  Arc-Bar-Cav-Ran-Rog-Sam-Tou-Val-Wiz
To go: Hea-Kni-Mon-Pri




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