in reply to undef == 0?

I suppose you prefer something like SQL's tri-state logic. Frankly, I find (NULL = NULL) being NULL much more confusing than (undef == 0) being true!

-sam

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Re^2: undef == 0?
by stu42j (Sexton) on Oct 24, 2007 at 17:42 UTC
    Yeah, I was thinking somewhere along the lines of how SQL treats NULLs. Although I suppose that instinctively, I would expect undef == 0 to be false but undef == undef to be true. Not that it would be right in any way.
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Re^2: undef == 0?
by snopal (Pilgrim) on Oct 24, 2007 at 18:29 UTC

    Tristate... you said the magic word! 

    my $test = return_from_function();

if (not defined $test) {
  # do this if evaluates to undefined
} elsif (!$test) {
  # do this if evaluates to zero equivalent
} elsif ($test) {
  # do this if evaluates to non-zero equivalent
}

    [download]

    If you really wanted, you could throw in a $test eq '' in there too, but I've found that to be gratuitous code abuse.

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