When I need to distinguish between the three, I generally go with

  if (!defined($bSomething)) {
    ...
  } elsif ($bSomething) {
    ...
  } else {
    ...
  }

[download]

and sometimes

  my $x = defined($bSomething)
    ? $bSomething : $DEFAULT_VALUE;
  if ($x) {
    ...
  } else {
    ...
  }

[download]

The verbosity doesn't really bother me; it works with older versions of Perl; and it's easy to read.

Best, beth

In reply to Re: An idiom for selecting true, false, or undef. by ELISHEVA
in thread An idiom for selecting true, false, or undef. by kyle

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