NAME

Data::WeakMap - WeakMap that behaves like a hash, and doesn't leak memory

NOTE

This module is currently buggy and should not be used by anyone, as it produces wrong outputs.

SYNOPSIS

            

              
              
use Data::WeakMap;
my $map = Data::WeakMap->new;
# or
my \%map = Data::WeakMap->new;
# Treat it just like a hash, but the keys must be perl references (of any kind)
# For more see here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap
my \%map = Data::WeakMap->new;
my $user = bless {name => 'Peter', age => 32}, 'MyWebSite::User';
$map{$user} = int rand 100;
print $map{$user}; # a number between 0 and 99
my @users = ({name => 'Peter', age => 32}, {name => 'Mary', age => 29}, ...); # 100 users
@map{@users} = @profiles; # map the users to 100 profiles
$map{$users[ $i ]} == $profiles[ $i ];
# you can do any hash operation on %map, except for 'each %map'.
my @keys = keys %map; # as usual...
my $num_keys = keys %map;
foreach my $value (values %map) { ... }
delete $map{ $users[0] };
exists $map{ $users[0] };
# etc
# Here's the 'Weak' part of WeakMaps:
my $regex = qr/123/;
%map = ($regex, 5);
scalar(keys %map); # 1
{
    my $regex2 = qr/234/;
    $map{$regex2} = 10;
    scalar(keys %map); # 2
}
scalar(keys %map); # is now back to 1 (because WeakMap's keys, which are references, are only weak references)
            
          

DESCRIPTION

Data::WeakMap is a Perl implementation of WeakMaps that doesn't leak memory

(For more see here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap)

CAVEATS

Don't do this, ever: each(%map).

Also see the "NOTE" section on why it should not be used.

SEE ALSO

Hash::Util::FieldHash - Core module, probably faster and without bugs, but you can't get a list of what's inside a fieldhash.

LICENSE

Copyright (C) Alexander Karelas.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

AUTHOR

Alexander Karelas <karjala@cpan.org>