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PERLEXPERIMENT(1) Perl Programmers Reference Guide PERLEXPERIMENT(1)

NAME

perlexperiment - A listing of experimental features in Perl

DESCRIPTION

This document lists the current and past experimental features in the perl core. Although all of these are documented with their appropriate topics, this succinct listing gives you an overview and basic facts about their status.

So far we've merely tried to find and list the experimental features and infer their inception, versions, etc. There's a lot of speculation here.

Current experiments

Introduced in Perl 5.10.0

Modified in Perl 5.10.1, 5.12.0

Using this feature triggers warnings in the category "experimental::smartmatch".

The ticket for this feature is [perl #13173] <https://github.com/Perl/perl5/issues/13173>.

The ticket for this feature is [perl #13199] <https://github.com/Perl/perl5/issues/13199>.

See "PL_keyword_plugin" in perlapi for the mechanism.

Introduced in Perl 5.11.2

Introduced in Perl 5.18

The ticket for this feature is [perl #13197] <https://github.com/Perl/perl5/issues/13197>.

See also: "Extended Bracketed Character Classes" in perlrecharclass

Using this feature triggers warnings in the category "experimental::regex_sets".

Introduced in Perl 5.20.0

Using this feature triggers warnings in the category "experimental::signatures".

The ticket for this feature is [perl #13681] <https://github.com/Perl/perl5/issues/13681>.

Introduced in Perl 5.22.0

Using this feature triggers warnings in the category "experimental::refaliasing".

The ticket for this feature is [perl #14150] <https://github.com/Perl/perl5/issues/14150>.

See also: "Assigning to References" in perlref

Introduced in Perl 5.22.0

Using this feature triggers warnings in the category "experimental::const_attr".

The ticket for this feature is [perl #14428] <https://github.com/Perl/perl5/issues/14428>.

See also: "Constant Functions" in perlsub

Introduced in Perl 5.22.0

Using this feature triggers warnings in the category "experimental::re_strict".

See "'strict' mode" in re

The ticket for this feature is [perl #13198] <https://github.com/Perl/perl5/issues/13198>.

See also "PERLIO" in perlrun

Introduced in Perl 5.26.0

Using this feature triggers warnings in the category "experimental::declared_refs".

The ticket for this feature is [perl #15458] <https://github.com/Perl/perl5/issues/15458>.

See also: "Declaring a Reference to a Variable" in perlref

The ticket for this feature is [perl #12726] <https://github.com/Perl/perl5/issues/12726>.
(Limited) Variable-length look-behind
Introduced in Perl 5.30.0. Variability of up to 255 characters is handled.

Using this feature triggers warnings in the category "experimental::vlb".

See also: "(*positive_lookbehind:pattern)" in perlre and "(*negative_lookbehind:pattern)" in perlre

Accepted features

These features were so wildly successful and played so well with others that we decided to remove their experimental status and admit them as full, stable features in the world of Perl, lavishing all the benefits and luxuries thereof. They are also awarded +5 Stability and +3 Charisma.

64-bit support
Introduced in Perl 5.005
Introduced in Perl 5.005
Introduced in Perl 5.6.0

See also perldebug, perldebtut

Introduced in Perl 5.6.0
Introduced in Perl 5.6.0
Introduced in Perl 5.6.1

See also perlfork

Introduced in Perl 5.6.0

Accepted in Perl 5.8.0

Introduced in Perl 5.6.0

Accepted in Perl 5.8.1

The "\N" character class, not to be confused with the named character sequence "\N{NAME}", denotes any non-newline character in a regular expression.

Introduced in Perl 5.12

Exact version of acceptance unclear, but no later than Perl 5.18.

"(?{code})" and "(??{ code })"
Introduced in Perl 5.6.0

Accepted in Perl 5.20.0

See also perlre

Introduced in Perl 5.9.2

Accepted before Perl 5.20.0. The Socket library is now primarily maintained on CPAN, rather than in the perl core.

See also Socket

Introduced in Perl 5.6.0

Accepted in Perl 5.20.0

See also perlsub

"(*ACCEPT)"

Introduced in Perl 5.10

Accepted in Perl 5.20.0

See also "PERLIO" in perlrun

Accepted in Perl 5.20.0

"\s" in regexp matches vertical tab
Accepted in Perl 5.22.0
Introduced in Perl 5.20.0

Accepted in Perl 5.24.0

Introduced in Perl 5.18.0

Accepted in Perl 5.26.0

Introduced in Perl 5.22.0

Accepted in Perl 5.28.0

Introduced in Perl 5.28.0

Accepted in Perl 5.32.0

Introduced in Perl 5.28.0

Accepted in Perl 5.32.0

Removed features

These features are no longer considered experimental and their functionality has disappeared. It's your own fault if you wrote production programs using these features after we explicitly told you not to (see perlpolicy).

5.005-style threading
Introduced in Perl 5.005

Removed in Perl 5.10

Introduced in Perl 5.005

Moved from Perl 5.9.0 to CPAN

Introduced in Perl 5.6.0

Removed in Perl 5.9.0

"Getopt::Long" upgraded to version 2.35

Removed in Perl 5.8.8

The "-A" command line switch

Introduced in Perl 5.9.0

Removed in Perl 5.9.5

Moved from Perl 5.10.1 to CPAN
"legacy"
The experimental "legacy" pragma was swallowed by the "feature" pragma.

Introduced in Perl 5.11.2

Removed in Perl 5.11.3

Using this feature triggered warnings in the category "experimental::lexical_topic".

Introduced in Perl 5.10.0

Removed in Perl 5.24.0

Using this feature triggered warnings in the category "experimental::autoderef".

Superseded by "Postfix dereference syntax".

Introduced in Perl 5.14.0

Removed in Perl 5.24.0

"our" can have an experimental optional attribute "unique"
Introduced in Perl 5.8.0

Deprecated in Perl 5.10.0

Removed in Perl 5.28.0

SEE ALSO

For a complete list of features check feature.

AUTHORS

brian d foy "<brian.d.foy@gmail.com>"

Sebastien Aperghis-Tramoni "<saper@cpan.org>"

COPYRIGHT

Copyright 2010, brian d foy "<brian.d.foy@gmail.com>"

LICENSE

You can use and redistribute this document under the same terms as Perl itself.

2020-12-18 perl v5.32.1