- 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".
The ticket for this experiment is [perl #13173]
<https://github.com/Perl/perl5/issues/13173>.
- Pluggable keywords
- Introduced in Perl 5.11.2
See "PL_keyword_plugin" in perlapi for the
mechanism.
The ticket for this experiment is [perl #13199]
<https://github.com/Perl/perl5/issues/13199>.
- Regular Expression Set Operations
- Introduced in Perl 5.18
Using this feature triggers warnings in the category
"experimental::regex_sets".
The ticket for this experiment is [perl #13197]
<https://github.com/Perl/perl5/issues/13197>.
See also: "Extended Bracketed Character Classes" in
perlrecharclass
- Subroutine signatures
- Introduced in Perl 5.20.0
Using this feature triggers warnings in the category
"experimental::signatures".
The ticket for this experiment is [perl #13681]
<https://github.com/Perl/perl5/issues/13681>.
- Aliasing via reference
- Introduced in Perl 5.22.0
Using this feature triggers warnings in the category
"experimental::refaliasing".
The ticket for this experiment is [perl #14150]
<https://github.com/Perl/perl5/issues/14150>.
See also: "Assigning to References" in perlref
- The "const" attribute
- Introduced in Perl 5.22.0
Using this feature triggers warnings in the category
"experimental::const_attr".
The ticket for this experiment is [perl #14428]
<https://github.com/Perl/perl5/issues/14428>.
See also: "Constant Functions" in perlsub
- use re 'strict';
- Introduced in Perl 5.22.0
Using this feature triggers warnings in the category
"experimental::re_strict".
The ticket for this experiment is [perl #18755]
<https://github.com/Perl/perl5/issues/18755>
See "'strict' mode" in re
- The <:win32> IO pseudolayer
- Using this feature triggers warnings in the category
"experimental::win32_perlio".
The ticket for this experiment is [perl #13198]
<https://github.com/Perl/perl5/issues/13198>.
See also "PERLIO" in perlrun
- Declaring a reference to a variable
- Introduced in Perl 5.26.0
Using this feature triggers warnings in the category
"experimental::declared_refs".
The ticket for this experiment is [perl #15458]
<https://github.com/Perl/perl5/issues/15458>.
See also: "Declaring a Reference to a Variable" in
perlref
- There is an "installhtml" target in the Makefile.
- The ticket for this experiment 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".
The ticket for this experiment is [perl #18756]
<https://github.com/Perl/perl5/issues/18756>.
See also: "(*positive_lookbehind:pattern)" in
perlre and "(*negative_lookbehind:pattern)" in
perlre
- Unicode private use character hooks
- Introduced in Perl 5.30.0.
This feature is part of an interface intended for internal and
experimental use by the perl5 developers. You are unlikely to encounter
it in the wild.
Using this feature triggers warnings in the category
"experimental::private_use".
The ticket for this experiment is [perl #18758]
<https://github.com/Perl/perl5/issues/18758>.
- Unicode property wildcards
- Introduced in Perl 5.30.0.
This feature allows regular expression matching against
Unicode character properties to be expressed more concisely.
Using this feature triggers warnings in the category
"experimental::uniprop_wildcards".
The ticket for this experiment is [perl #18759]
<https://github.com/Perl/perl5/issues/18759>.
- isa infix operator
- Introduced in Perl 5.32.0.
Using this feature triggers warnings in the category
"experimental::isa".
The ticket for this experiment is [perl #18754]
<https://github.com/Perl/perl5/issues/18754>
- try/catch control structure
- Introduced in Perl 5.34.0.
Using this feature triggers warnings in the category
"experimental::try".
The ticket for this experiment is [perl #18760]
<https://github.com/Perl/perl5/issues/18760>