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tri-state flags
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From:
Bart Lateur
Date:
December 5, 2001 00:03
Subject:
tri-state flags
Message ID:
9b1r0uonrb1qj51r0hfpdl63b1cslc4d8j@4ax.com
I often use tri-state flags, with possible value true (1), false (0), or
undetermined (undef).
The question is: how do you test for one of the flags, in particular for
0, without warnings?
For true, it's easy:
$flag
For undef, it's not hard:
!defined $flag
But for 0?
Note that "$flag" may well be an expression, so repetition as in the
next, is not good:
defined $flag && !$flag
So, who does better?
--
Bart.
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tri-state flags
by Bart Lateur