- RU.PERL ----------------------------------------------------------- RU.PERL -
Msg : #2536 [500]
От : Nick Kostirya 2:5020/400 11 февраля 04, 10:01
Кому : Yury Kopyl 14 февраля 04, 22:51
Тема : Re: C-style Logical Defined-Or
-------------------------------------------------------------------------------
From: "Nick Kostirya"
>
> NK>>> Привет.
> NK>>> А что "C-style Logical Defined-Or" убрали?
>
> NK>>> В http://search.cpan.org/~nwclark/perl-5.8.3/pod/perlop.pod не
> NK>>> могу найти.
>
>
> NK> http://search.cpan.org/~nwclark/perl-5.8.3/pod/perlop.pod#C-style_
> NK> Logical_Or
>
> NK> Что то не вижу там оператора //
>
>
http://search.cpan.org/~nwclark/perl-5.8.3/pod/perlop.pod#Assignment_Operato
> rs
Hашел!
Это в http://search.cpan.org/src/HVDS/perl-5.9.0/pod/perlop.pod
Вот цитата
=head2 C-style Logical Defined-Or
Although it has no direct equivalent in C, Perl's C operator is related
to its C-style or. In fact, it's exactly the same as C<||>, except that it
tests the left hand side's definedness instead of its truth. Thus, C<$a //
$b>
is similar to C (except that it returns the value of
C<$a>
rather than the value of C) and is exactly equivalent to
C. This is very useful for providing default values
for variables. If you actually want to test if at least one of C<$a> and
C<$b> is defined, use C.
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