NAME

Tie::Scalar::Sticky - Block assignments to scalars

SYNOPSIS

use strict;
use Tie::Scalar::Sticky;

tie my $sticky, 'Tie::Scalar::Sticky';

$sticky = 42;
$sticky = '';       # still 42
$sticky = undef;    # still 42
$sticky = 0;        # now it's zero

tie my $sticky, 'Tie::Scalar::Sticky' => qw/ foo bar /;

$sticky = 42;
$sticky = 'foo';    # still 42
$sticky = 'bar';    # still 42
$sticky = 0;        # now it's zero

DESCRIPTION

Scalars tie'ed to this module will 'reject' any assignments of undef or the empty string or any of the extra arugments provided to tie(). It simply removes the need for you to validate assignments, such as:

$var = $val if defined $val && $val ne '';

Actually, that is the exact code used in this module. So, why do this? Because i recently had to loop through a list where some items were undefined and the previously defined value should be used instead. In a nutshell:

tie my $sticky, 'Tie::Scalar::Sticky' => 9, 'string';
for (3,undef,'string',2,'',1,9,0) {
   $sticky = $_;
   print $sticky, ' ';
}

Should print: 3 3 2 2 1 0

AUTHOR

Jeffrey Hayes Anderson <captvanhalen@yahoo.com>

CREDITS

Dan [broquaint] Brook for allowing T::S::S to ignore more than undef and the empty string. (Half of this code has been provided by him. ;))

Perl Monks for the education.

Jeffrey Hayes Anderson <captvanhalen@yahoo.com>

COPYRIGHT

Copyright (c) 2003 Jeffrey Hayes Anderson.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.