semantics of AND and OR with zero or one argument.

• From: Jim Davis <jdavis@parc.xerox.com>
• Date: Mon, 20 Apr 1998 15:37:37 PDT
• To: www-webdav-dasl@w3.org
• Message-Id: <3.0.3.32.19980420153737.00941100@mailback.parc.xerox.com>

At 02:11 PM 4/20/98 PDT, Saveen Reddy (Exchange) wrote:
>Alan, 
>	As you point out the original 00 syntax was incorrect. That was an
>error corrected in the 01 version. The correction in 01 probably needs
>further work as well -- it defines AND and OR as accepting exactly
>two-arguments instead of any list of 2 or more. If there are no objections
>I'll go ahead and update the document to use the syntax you provided below.

Actually, there are perfectly clear semantics for AND and OR of one or even
zero operators.   AND with no arguments is trivially TRUE, and OR is FALSE. 

These are the definitions that fall out of defining AND as evaluating each
argument in turn, until FALSE (or should I say NIL) is obtained (yielding
FALSE) or end of list, which returns TRUE.  (Likewise, mutatis mutandis,
for OR.)  Lisp uses these semantics.

Why not support these semantics?

Received on Monday, 20 April 1998 18:38:00 UTC