On Mon, Oct 15, 2007 at 01:27:26PM -0700, Michael Barto wrote:
> As both Java and Javascript both have a 'true' and 'false' or Boolean
> data type, is there any interest in evolution of Perl to have a true
> Boolean. Or what is the preferred method to do this in Perl.
The place to discuss this is the perl5-****ters mailing list, not an
obscure platform-specific mailing list.
And the answer is no. Because we already have a real Boolean. We have
boolean *context*. An operator like ?: forces its first operand to be
evaluated in boolean context:
$value ? 'true' : 'false'
That first operand can, of course, be a complex expression, the end
result of which is evaluated in boolean context:
cheezburger->{$cutecat}->() ? print "LOL!" : print "OH NOES!"
We also don't have int or float or a numeric type (the internals do, but
Perl the language doesn't) - we have numeric context. Consider this:
$ perl -e 'print "foo\n" if "2abc" == "2def"'
The == operator forces both its operands to be evaulated in numeric
context before comparing them. As numbers, 2abc and 2def are both just
plain ol' 2, so the == returns true and we print. If we change it to
this:
$ perl -e 'print "foo\n" if "2abc" eq "2def"'
then the eq operator evaluates its operands in string context, where
2abc and 2def most definitely aren't the same.
> The "C" programmers want me to use "0"'s and "1"'s.
Seems reasonable. Those do evaluate to false and true in perl. Perl's
comparison operators return 1 for true and the empty string for false.
In numeric context that's the same as returning 1 and 0 because:
'' == 0
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David Cantrell | Hero of the Information Age
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