/usr/share/perl5/Tie/Cycle.pm is in libtie-cycle-perl 1.21-1.
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 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 | package Tie::Cycle;
use strict;
our $VERSION = '1.21';
use Carp qw(carp);
use constant CURSOR_COL => 0;
use constant COUNT_COL => 1;
use constant ITEM_COL => 2;
sub TIESCALAR {
my( $class, $list_ref ) = @_;
my $self = bless [], $class;
unless( $self->STORE( $list_ref ) ) {
carp "The argument to Tie::Cycle must be an array reference";
return;
}
return $self;
}
sub FETCH {
my( $self ) = @_;
my $index = $self->[CURSOR_COL]++;
$self->[CURSOR_COL] %= $self->_count;
return $self->_item( $index );
}
sub STORE {
my( $self, $list_ref ) = @_;
return unless ref $list_ref eq ref [];
my @shallow_copy = map { $_ } @$list_ref;
$self->[CURSOR_COL] = 0;
$self->[COUNT_COL] = scalar @shallow_copy;
$self->[ITEM_COL] = \@shallow_copy;
}
sub reset { $_[0]->[CURSOR_COL] = 0 }
sub previous {
my( $self ) = @_;
my $index = $self->_cursor - 1;
$self->[CURSOR_COL] %= $self->_count;
return $self->_item( $index );
}
sub next {
my( $self ) = @_;
my $index = $self->_cursor + 1;
$self->[CURSOR_COL] %= $self->_count;
return $self->_item( $index );
}
sub _cursor { $_[0]->[CURSOR_COL] }
sub _count { $_[0]->[COUNT_COL] }
sub _item {
my( $self, $index ) = @_;
$index = defined $index ? $index : $self->_cursor;
$self->[ITEM_COL][ $index ]
}
"Tie::Cycle";
__END__
=encoding utf8
=head1 NAME
Tie::Cycle - Cycle through a list of values via a scalar.
=head1 SYNOPSIS
use v5.10.1;
use Tie::Cycle;
tie my $cycle, 'Tie::Cycle', [ qw( FFFFFF 000000 FFFF00 ) ];
say $cycle; # FFFFFF
say $cycle; # 000000
say $cycle; # FFFF00
say $cycle; # FFFFFF back to the beginning
(tied $cycle)->reset; # back to the beginning
=head1 DESCRIPTION
You use C<Tie::Cycle> to go through a list over and over again.
Once you get to the end of the list, you go back to the beginning.
You don't have to worry about any of this since the magic of
tie does that for you.
The tie takes an array reference as its third argument. The tie
should succeed unless the argument is not an array reference.
Previous versions required you to use an array that had more
than one element (what's the pointing of looping otherwise?),
but I've removed that restriction since the number of elements
you want to use may change depending on the situation.
During the tie, this module makes a shallow copy of the array
reference. If the array reference contains references, and those
references are changed after the tie, the elements of the cycle
will change as well. See the included F<test.pl> script for an
example of this effect.
=head1 OBJECT METHODS
You can call methods on the underlying object (which you access
with C<tied()> ).
=over 4
=item reset
Roll the iterator back to the starting position. The next access
will give the first element in the list.
=item previous
Give the previous element. This does not affect the current position.
=item next
Give the next element. This does not affect the current position.
You can peek at the next element if you like.
=back
=head1 SOURCE AVAILABILITY
This module is on Github:
https://github.com/briandfoy/tie-cycle
=head1 AUTHOR
brian d foy, C<< <bdfoy@cpan.org> >>
=head1 COPYRIGHT AND LICENSE
Copyright 2000-2013, brian d foy, All rights reserved
This software is available under the same terms as perl.
=cut
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