/ 
List-MoreUtils-0.400_005
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/ List::MoreUtils

NAME

List::MoreUtils - Provide the stuff missing in List::Util

SYNOPSIS

use List::MoreUtils qw(:strict); # use as initially thought
use List::MoreUtils qw(:relax); # use alias changes
use List::MoreUtils qw(:modern); # use compat mode to List::Util

use List::MoreUtils qw(:all); # use all with precedence 'relax', 'strict', 'modern';

use List::MoreUtils any => { impl => 'modern' },
                    all =>  { impl => 'strict' },
                    'none', 'notall', # currently ':all' precedence
                    'firstidx' => { impl => 'strict' },
                    all => { impl => 'modern', as => 'modern_all' };

DESCRIPTION

List::MoreUtils provides some trivial but commonly needed functionality on lists which is not going to go into List::Util.

All of the below functions are implementable in only a couple of lines of Perl code. Using the functions from this module however should give slightly better performance as everything is implemented in C. The pure-Perl implementation of these functions only serves as a fallback in case the C portions of this module couldn't be compiled on this machine.

EXPORTS

Nothing by default. To import all of this module's symbols, do the conventional

use List::MoreUtils ':all';

or

use List::MoreUtils ':default';

It may make more sense though to only import the stuff your program actually needs:

use List::MoreUtils qw{ any firstidx };

IMPLEMENTATIONS

List::MoreUtils supports several implementations of some functions. The available ones are:

strict

This is the original author of List::MoreUtils. His implementations shall be default and will be probably later.

relax

This is a self-volunteered author who accidently broke the API of the original author but it was recognized to late and we currently have modules on CPAN and DarkPAN relying on the broken API. So this is the current default implementation for some time ...

modern

This implementation contains functions adapted by List::Util since it has a new maintainer. Unfortunately the API isn't 100% List::MoreUtils compatible, but since List::MoreUtils provides always a pure Perl implementation, it might be a valueable upgrade path...

all

This is a precedence list of existing implementations. It's qw(relax strict modern).

default

This is a precedence list of existing implementations. It's qw(strict relax modern).

IMPLICIT

List::MoreUtils silently supported just being required in historic versions. Because of the different available implementations and the breakage in 0.28 the provided implementation on require is unpredictable. If one need to rely on a dedicated implementation, choose it by use List::Moreutils qw(:impl).

ENVIRONMENT

When LIST_MOREUTILS_PP is set, the module will always use the pure-Perl implementation and not the XS one. This environment variable is really just there for the test-suite to force testing the Perl implementation, and possibly for reporting of bugs. I don't see any reason to use it in a production environment.

BUGS

There is a problem with a bug in 5.6.x perls. It is a syntax error to write things like:

my @x = apply { s/foo/bar/ } qw{ foo bar baz };

It has to be written as either

my @x = apply { s/foo/bar/ } 'foo', 'bar', 'baz';

or

my @x = apply { s/foo/bar/ } my @dummy = qw/foo bar baz/;

Perl 5.5.x and Perl 5.8.x don't suffer from this limitation.

If you have a functionality that you could imagine being in this module, please drop me a line. This module's policy will be less strict than List::Util's when it comes to additions as it isn't a core module.

When you report bugs, it would be nice if you could additionally give me the output of your program with the environment variable LIST_MOREUTILS_PP set to a true value. That way I know where to look for the problem (in XS, pure-Perl or possibly both).

SUPPORT

Bugs should always be submitted via the CPAN bug tracker.

You can find documentation for this module with the perldoc command.

perldoc List::MoreUtils

You can also look for information at:

Where can I go for help?

If you have a bug report, a patch or a suggestion, please open a new report ticket at CPAN (but please check previous reports first in case your issue has already been addressed).

Report tickets should contain a detailed description of the bug or enhancement request and at least an easily verifiable way of reproducing the issue or fix. Patches are always welcome, too - and it's cheap to send pull-requests on GitHub. Please keep in mind that code changes are more likely accepted when they're bundled with an approving test.

If you think you've found a bug then please read "How to Report Bugs Effectively" by Simon Tatham: http://www.chiark.greenend.org.uk/~sgtatham/bugs.html.

Where can I go for help with a concrete version?

Bugs and feature requests are accepted against the latest version only. To get patches for earlier versions, you need to get an agreement with a developer of your choice - who may or not report the issue and a suggested fix upstream (depends on the license you have chosen).

Business support and maintenance

For business support you can contact Jens via his CPAN email address rehsackATcpan.org. Please keep in mind that business support is neither available for free nor are you eligible to receive any support based on the license distributed with this package.

THANKS

Credits go to a number of people: Steve Purkis for giving me namespace advice and James Keenan and Terrence Branno for their effort of keeping the CPAN tidier by making List::Utils obsolete.

Brian McCauley suggested the inclusion of apply() and provided the pure-Perl implementation for it.

Eric J. Roode asked me to add all functions from his module List::MoreUtil into this one. With minor modifications, the pure-Perl implementations of those are by him.

The bunch of people who almost immediately pointed out the many problems with the glitchy 0.07 release (Slaven Rezic, Ron Savage, CPAN testers).

A particularly nasty memory leak was spotted by Thomas A. Lowery.

Lars Thegler made me aware of problems with older Perl versions.

Anno Siegel de-orphaned each_arrayref().

David Filmer made me aware of a problem in each_arrayref that could ultimately lead to a segfault.

Ricardo Signes suggested the inclusion of part() and provided the Perl-implementation.

Robin Huston kindly fixed a bug in perl's MULTICALL API to make the XS-implementation of part() work.

TODO

A pile of requests from other people is still pending further processing in my mailbox. This includes:

  • List::Util export pass-through

    Allow List::MoreUtils to pass-through the regular List::Util functions to end users only need to use the one module.

  • uniq_by(&@)

    Use code-reference to extract a key based on which the uniqueness is determined. Suggested by Aaron Crane.

  • delete_index

  • random_item

  • random_item_delete_index

  • list_diff_hash

  • list_diff_inboth

  • list_diff_infirst

  • list_diff_insecond

    These were all suggested by Dan Muey.

  • listify

    Always return a flat list when either a simple scalar value was passed or an array-reference. Suggested by Mark Summersault.

SEE ALSO

List::Util

AUTHOR

Jens Rehsack <rehsack AT cpan.org>

Adam Kennedy <adamk@cpan.org>

Tassilo von Parseval <tassilo.von.parseval@rwth-aachen.de>

COPYRIGHT AND LICENSE

Some parts copyright 2011 Aaron Crane.

Copyright 2004 - 2010 by Tassilo von Parseval

Copyright 2013 - 2014 by Jens Rehsack

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.4 or, at your option, any later version of Perl 5 you may have available.