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# perlexperiment

Perl 5 version 18.2 documentation
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# perlexperiment

- NAME
- DESCRIPTION
  - Current experiments
  - Accepted features
  - Removed features
- AUTHORS
- COPYRIGHT
- LICENSE

# 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

- -Dusemultiplicity -Duseithreads

  Introduced in Perl 5.6.0

- Long Doubles Still Don't Work In Solaris

  Introduced in Perl 5.7.0

- `our` can now have an experimental optional attribute `unique`

  Introduced in Perl 5.8.0

  Deprecated in Perl 5.10.0

- Linux abstract Unix domain sockets

  Introduced in Perl 5.9.2

  See also Socket

- Pod::HTML2Pod
- Pod::PXML
- The <:pop> IO pseudolayer

  See also perlrun

- The <:win32> IO pseudolayer

  See also perlrun

- MLDBM

  See also perldsc

- internal functions with M flag

  See also perlguts

- 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
- Lvalue subroutines

  Introduced in Perl 5.6.0

  See also perlsub

- There is an `installhtml` target in the Makefile.
- Unicode in Perl on EBCDIC
- `(?{code})`

  See also perlre

- `(??{ code })`

  See also perlre

- Smart match (`~~` )

  Introduced in Perl 5.10.0

  Modified in Perl 5.10.1, 5.12.0

- Lexical `$_`

  Introduced in Perl 5.10.0

- Backtracking control verbs

  `(*ACCEPT)`

  Introduced in: Perl 5.10

  See also: Special Backtracking Control Verbs in perlre

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

  See also perlintern

- Experimental Support for Sun Studio Compilers for Linux OS

  See also perllinux

- 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

- Regular Expression Set Operations

  Introduced in: Perl 5.18

  See also: Extended Bracketed Character Classes in perlrecharclass

## 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.

- 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

- fork() emulation

  Introduced in Perl 5.6.1

  See also perlfork

- 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

- die accepts a reference

  Introduced in Perl 5.005

- 64-bit support

  Introduced in Perl 5.005

## 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).

- `legacy`

  The experimental `legacy` pragma was swallowed by the `feature` pragma.

  Introduced in: 5.11.2

  Removed in: 5.11.3

- 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

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

  `Getopt::Long` upgraded to version 2.35

  Removed in Perl 5.8.8

- The pseudo-hash data type

  Introduced in Perl 5.6.0

  Removed in Perl 5.9.0

- 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

# 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.

Page index

- NAME
- DESCRIPTION
  - Current experiments
  - Accepted features
  - Removed features
- AUTHORS
- COPYRIGHT
- LICENSE