Clone::PP(3) User Contributed Perl Documentation Clone::PP(3)
NAME
Clone::PP - Recursively copy Perl datatypes
SYNOPSIS
use Clone::PP qw(clone);
$item = { 'foo' => 'bar', 'move' => [ 'zig', 'zag' ] };
$copy = clone( $item );
$item = [ 'alpha', 'beta', { 'gamma' => 'vlissides' } ];
$copy = clone( $item );
$item = Foo->new();
$copy = clone( $item );
Or as an object method:
require Clone::PP;
push @Foo::ISA, 'Clone::PP';
$item = Foo->new();
$copy = $item->clone();
DESCRIPTION
This module provides a general-purpose clone function to make deep
copies of Perl data structures. It calls itself recursively to copy
nested hash, array, scalar and reference types, including tied
variables and objects.
The clone() function takes a scalar argument to copy. To duplicate
arrays or hashes, pass them in by reference:
my $copy = clone(\@array); my @copy = @{ clone(\@array) };
my $copy = clone(\%hash); my %copy = %{ clone(\%hash) };
The clone() function also accepts an optional second parameter that can
be used to limit the depth of the copy. If you pass a limit of 0, clone
will return the same value you supplied; for a limit of 1, a shallow
copy is constructed; for a limit of 2, two layers of copying are done,
and so on.
my $shallow_copy = clone( $item, 1 );
To allow objects to intervene in the way they are copied, the clone()
function checks for a couple of optional methods. If an object provides
a method named "clone_self", it is called and the result returned
without further processing. Alternately, if an object provides a method
named "clone_init", it is called on the copied object before it is
returned.
BUGS
Some data types, such as globs, regexes, and code refs, are always
copied shallowly.
References to hash elements are not properly duplicated. (This is why
two tests in t/dclone.t that are marked "todo".) For example, the
following test should succeed but does not:
my $hash = { foo => 1 };
$hash->{bar} = \{ $hash->{foo} };
my $copy = clone( \%hash );
$hash->{foo} = 2;
$copy->{foo} = 2;
ok( $hash->{bar} == $copy->{bar} );
To report bugs via the CPAN web tracking system, go to
"http://rt.cpan.org/NoAuth/Bugs.html?Dist=Clone-PP" or send mail to
"Dist=Clone-PP#rt.cpan.org", replacing "#" with "@".
SEE ALSO
Clone(3) - a baseclass which provides a "clone()" method.
MooseX::Clone(3) - find-grained cloning for Moose objects.
The "dclone()" function in Storable(3).
Data::Clone(3) - polymorphic data cloning (see its documentation for
what that means).
Clone::Any(3) - use whichever of the cloning methods is available.
REPOSITORY
<https://github.com/neilbowers/Clone-PP>
AUTHOR AND CREDITS
Developed by Matthew Simon Cavalletto at Evolution Softworks. More
free Perl software is available at "www.evoscript.org".
COPYRIGHT AND LICENSE
Copyright 2003 Matthew Simon Cavalletto. You may contact the author
directly at "evo@cpan.org" or "simonm@cavalletto.org".
Code initially derived from Ref.pm. Portions Copyright 1994 David Muir
Sharnoff.
Interface based by Clone by Ray Finch with contributions from
chocolateboy. Portions Copyright 2001 Ray Finch. Portions Copyright
2001 chocolateboy.
You may use, modify, and distribute this software under the same terms
as Perl.
perl v5.34.1 2020-10-20 Clone::PP(3)
clone-pp 1.80.0 - Generated Fri Jun 20 07:44:20 CDT 2025