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From: dg@lakart.UUCP (David Goodenough)
Newsgroups: comp.lang.c
Subject: Re: ambiguous ?
Message-ID: <733@lakart.UUCP>
Date: 27 Oct 89 16:43:36 GMT
References: <1989Oct25.090802.19444@gdt.bath.ac.uk>
Organization: Lakart Corporation, Newton, MA
Lines: 23

exspes@gdr.bath.ac.uk (P E Smee) sez:
> .....  Algol may have this right,
> they offer two sets of logical operators:  AND and OR which do not short
> circuit; and ANDTHEN and ORELSE which do.  This gives the programmer total
> control, and might be worth considering for some future version of C or
> a C offspring.  Both are useful, and making either from the other in a
> language which only supports one is fiddly at best.

However, those of us that know De Morgan's laws can get by very neatly
with ! & | and a couple of preprocessor macros for non-short circuiting
operators.

#define and(x, y) (!((!(x)) | (!(y))))
#define or(x, y)  (!((!(x)) & (!(y))))

This does rather assume that your optimizer is up to the job, but then
that's a whole other thread. Also, as someone once said "Never sacrifice
clarity for efficiency" (gets +6 ring of fire resistance ready :-) )
-- 
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