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From: Hyman Rosen <hyrosen@mail.com>
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Newsgroups: comp.lang.ada
Subject: Re: and then... (a curiosity)
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Date: Fri, 05 Sep 2008 11:14:59 -0400
Xref: g2news1.google.com comp.lang.ada:1948
Date: 2008-09-05T11:14:59-04:00
List-Id: <comp.lang.ada>

Robert A Duff wrote:
> I'm just trying to explore the consequences of this seemingly-simple
> language design choice.  It doesn't seem so simple to me.

There are two kinds of "and" - the one that's involved in
control flow, and should therefore be short-circuited, and
the one that combines booleans, which is just an arithmetic
function like addition and should therefore not be short-
circuited.

Both C and Ada have this, C through "&&" and "&" and Ada
through "and then" and "and". Given the nature of code,
the control flow variant appears far more often than the
arithmetic one, so I guess some people are disturbed by
the fact that the most common variant is wordier. As a
long-time reader of this newsgroup, I know the mantra that
"Ada is designed for readers, not writers. Shorter is not
necessarily better." :-)

By the way, C++ made the design mistake of allowing && and
|| to be overloaded, whereupon they lose their short-circuit
behavior and become normal evaluate-both-operands functions.
Just awful.