NAME

       Data::Swap - Swap type and contents of variables

SYNOPSIS

           use Data::Swap;

           my $p = [];
           my $q = {};
           print "$p $q\n";            # ARRAY(0x965cc) HASH(0x966b0)
           swap $p, $q;                # swap referenced variables
           print "$p $q\n";            # HASH(0x965cc) ARRAY(0x966b0)

           my $x = {};
           my $y = $x;                 # $x and $y reference same var
           swap $x, [1, 2, 3];         # swap referenced var with an array
           print "@$y\n";              # 1 2 3

           use Data::Swap 'deref';

           my @refs = (\$x, \@y);
           $_++ for deref @refs;       # dereference a list of references

           # Note that I omitted \%z from the @refs because $_++ would fail
           # on a key, but deref does work on hash-refs too of course.

DESCRIPTION

       This module allows you to swap the contents of two referenced variables, even if they have
       different types.

       The main application is to change the base type of an object after it has been created,
       for example for dynamic loading of data structures:

           swap $self, bless $replacement, $newclass;

       This module additionally contain the function "deref" which acts like a generic list-
       dereferencing operator.

FUNCTIONS

   swap REF1, REF2
       Swaps the contents (and if necessary, type) of two referenced variables.

   deref LIST
       Dereferences a list of scalar refs, array refs and hash refs.  Mainly exists because you
       can't use "map" for this application, as it makes copies of the dereferenced values.

KNOWN ISSUES

       You can't "swap" an overloaded object with a non-overloaded one, unless you use Perl 5.10
       or later.

       Also, don't use "swap" to change the type of a directly accessible variable -- like "swap
       \$x, \@y".  That's just asking for segfaults.  Unfortunately there is no good way for me
       to detect and prevent this.

AUTHOR

       Matthijs van Duin <xmath@cpan.org>

       Copyright (C) 2003, 2004, 2007, 2008  Matthijs van Duin.  This program is free software;
       you can redistribute it and/or modify it under the same terms as Perl itself.