On Fri, 9 Jun 2000, Alain wrote:
> >Yet for old-fashioned programmers, this is generally clear. It was said
> >that some programming language (I forgot which) allows `and then' and
> >`or else' as an attempt to make things more clear.
The language is Ada.
However, there is a difference in behavior between "and" and "and then".
With "and then", the right-hand operand is not computed at run-time
if the left-hand operand is known to be false, since the result must
be false. With "and", this is not the case.
Similarly, "or else" does not examine its right-hand operand if the
left-hand operand is known to be true.
C/C++/Java/Perl programmers know this under the names of "&" vs "&&"
and "|" vs. "||" operators.
-- John Cowan cowan@ccil.org "You need a change: try Canada" "You need a change: try China" --fortune cookies opened by a couple that I know
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