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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

our can now have an experimental optional attribute unique

Introduced in Perl 5.8.0

Deprecated in Perl 5.10.0

Smart match (~~)

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.

Lexical $_

Introduced in Perl 5.10.0

Using this feature triggers warnings in the category experimental::lexical_topic.

Pluggable keywords

See "PL_keyword_plugin" in perlapi for the mechanism.

Introduced in: Perl 5.11.2

Array and hash container functions accept references

Introduced in Perl 5.14.0

Lexical subroutines

Introduced in: Perl 5.18

See also: "Lexical Subroutines" in perlsub

Using this feature triggers warnings in the category experimental::lexical_subs.

Regular Expression Set Operations

Introduced in: Perl 5.18

See also: "Extended Bracketed Character Classes" in perlrecharclass

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

\s in regexp matches vertical tab

Introduced in Perl 5.18

The <:win32> IO pseudolayer

See also perlrun

lex_start API

Introduced in Perl 5.13.7

internal API for %^H

Introduced in Perl 5.13.7

See also cophh_ in perlapi.

alloccopstash

Introduced in Perl 5.18.0

av_create_and_push
av_create_and_unshift_one
av_create_and_unshift_one
cop_store_label

Introduced in Perl 5.16.0

PL_keyword_plugin
gv_fetchmethod_*_flags

Introduced in Perl 5.16.0

hv_iternext_flags
lex_bufutf8
lex_discard_to
lex_grow_linestr
lex_next_chunk
lex_peek_unichar
lex_read_space
lex_read_to
lex_read_unichar
lex_stuff_pv
lex_stuff_pvn
lex_stuff_pvs
lex_stuff_sv
lex_unstuff
op_scope
op_lvalue
parse_fullstmt
parse_stmtseq
PL_parser->bufend
PL_parser->bufptr
PL_parser->linestart
PL_parser->linestr
Perl_signbit
pad_findmy
sv_utf8_decode
sv_utf8_downgrade
bytes_from_utf8
bytes_to_utf8
utf8_to_bytes
There is an installhtml target in the Makefile.
Unicode in Perl on EBCDIC

See also: "Special Backtracking Control Verbs" in perlre

Code expressions, conditional expressions, and independent expressions in regexes
gv_try_downgrade

See also perlintern

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

die accepts a reference

Introduced in Perl 5.005

DB module

Introduced in Perl 5.6.0

See also perldebug, perldebtut

Weak references

Introduced in Perl 5.6.0

Internal file glob

Introduced in Perl 5.6.0

fork() emulation

Introduced in Perl 5.6.1

See also perlfork

-Dusemultiplicity -Duseithreads

Introduced in Perl 5.6.0

Accepted in Perl 5.8.0

Support for long doubles

Introduced in Perl 5.6.0

Accepted in Perl 5.8.1

The \N regex character class

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

Linux abstract Unix domain sockets

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

Lvalue subroutines

Introduced in Perl 5.6.0

Accepted in Perl 5.20.0

See also perlsub

Backtracking control verbs

(*ACCEPT)

Introduced in: Perl 5.10

Accepted in Perl 5.20.0

The <:pop> IO pseudolayer

See also perlrun

Accepted in Perl 5.20.0

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

perlcc

Introduced in Perl 5.005

Moved from Perl 5.9.0 to CPAN

The pseudo-hash data type

Introduced in Perl 5.6.0

Removed in Perl 5.9.0

GetOpt::Long Options can now take multiple values at once (experimental)

Getopt::Long upgraded to version 2.35

Removed in Perl 5.8.8

Assertions

The -A command line switch

Introduced in Perl 5.9.0

Removed in Perl 5.9.5

Test::Harness::Straps

Moved from Perl 5.10.1 to CPAN

legacy

The experimental legacy pragma was swallowed by the feature pragma.

Introduced in: 5.11.2

Removed in: 5.11.3

AUTHORS

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

Sébastien 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.