/usr/share/perl5/DBM/Deep/Null.pm is in libdbm-deep-perl 2.0011-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 | package DBM::Deep::Null;
use 5.008_004;
use strict;
use warnings FATAL => 'all';
=head1 NAME
DBM::Deep::Null - NULL object
=head1 PURPOSE
This is an internal-use-only object for L<DBM::Deep>. It acts as a NULL object
in the same vein as MARCEL's L<Class::Null>. I couldn't use L<Class::Null>
because DBM::Deep needed an object that always evaluated as undef, not an
implementation of the Null Class pattern.
=head1 OVERVIEW
It is used to represent null sectors in DBM::Deep.
=cut
use overload
'bool' => sub { undef },
'""' => sub { undef },
'0+' => sub { 0 },
('cmp' =>
'<=>' => sub {
return 0 if !defined $_[1] || !length $_[1];
return $_[2] ? 1 : -1;
}
)[0,2,1,2], # same sub for both ops
'%{}' => sub {
require Carp;
Carp::croak("Can't use a stale reference as a HASH");
},
'@{}' => sub {
require Carp;
Carp::croak("Can't use a stale reference as an ARRAY");
},
fallback => 1,
nomethod => 'AUTOLOAD';
sub AUTOLOAD { return; }
1;
__END__
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