this succinct listing gives you an overview and basic facts about their
status.
-So far I've merely tried to find and list the experimental features and infer
+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.
=head2 Current experiments
=over 8
-=item fork() emulation
+=item C<our> can now have an experimental optional attribute C<unique>
-Introduced in Perl 5.6.1
+Introduced in Perl 5.8.0
-See also L<perlfork>
+Deprecated in Perl 5.10.0
-=item Weak references
+The ticket for this feature is
+L<[perl #119313]|https://rt.perl.org/rt3/Ticket/Display.html?id=119313>.
-Introduced in Perl 5.6.0
+=item Smart match (C<~~>)
-=item Internal file glob
+Introduced in Perl 5.10.0
-Introduced in Perl 5.6.0
+Modified in Perl 5.10.1, 5.12.0
-Accepted in XXX
+Using this feature triggers warnings in the category
+C<experimental::smartmatch>.
-=item 64-bit support
+The ticket for this feature is
+L<[perl #119317]|https://rt.perl.org/rt3/Ticket/Display.html?id=119317>.
-Introduced in Perl 5.005
+=item Lexical C<$_>
-Accepted in XXX
+Introduced in Perl 5.10.0
-=item die accepts a reference
+Using this feature triggers warnings in the category
+C<experimental::lexical_topic>.
-Introduced in Perl 5.005
+The ticket for this feature is
+L<[perl #119315]|https://rt.perl.org/rt3/Ticket/Display.html?id=119315>.
-Accepted in Perl XXX
+=item Pluggable keywords
-=item Unicode support
+The ticket for this feature is
+L<[perl #119455]|https://rt.perl.org/rt3/Ticket/Display.html?id=119455>.
-Introduced in Perl 5.6.0
+See L<perlapi/PL_keyword_plugin> for the mechanism.
-Accepted in Perl 5.8.0 XXX
+Introduced in: Perl 5.11.2
-=item -Dusemultiplicity -Dusethreads
+=item Array and hash container functions accept references
-Introduced in Perl 5.6.0
+Introduced in Perl 5.14.0
-=item Long Doubles Still Don't Work In Solaris
+The ticket for this feature is
+L<[perl #119437]|https://rt.perl.org/rt3/Ticket/Display.html?id=119437>.
-Introduced in Perl 5.7.0
+=item Lexical subroutines
-=item GetOpt::Long Options can now take multiple values at once (experimental)
+Introduced in: Perl 5.18
-C<Getopt::Long> upgraded to version 2.35
+See also: L<perlsub/Lexical Subroutines>
-Removed in Perl 5.8.8
+Using this feature triggers warnings in the category
+C<experimental::lexical_subs>.
-=item 5.005-style threading
+The ticket for this feature is
+L<[perl #120085]|https://rt.perl.org/rt3/Ticket/Display.html?id=120085>.
-Introduced in Perl 5.005
+=item Regular Expression Set Operations
-Removed in Perl 5.10 XXX
+Introduced in: Perl 5.18
-=item Test::Harness::Straps
+The ticket for this feature is
+L<[perl #119451]|https://rt.perl.org/rt3/Ticket/Display.html?id=119451>.
-Removed in Perl 5.10.1
+See also: L<perlrecharclass/Extended Bracketed Character Classes>
-=item perlcc
+Using this feature triggers warnings in the category
+C<experimental::regex_sets>.
-Introduced in Perl 5.005
+=item C<\s> in regexp matches vertical tab
-Removed in Perl 5.9.0
+Introduced in Perl 5.18
-See also L<perlcompile>
+=item Subroutine signatures
-=item C<our> can now have an experimental optional attribute C<unique>
+Introduced in Perl 5.20.0
-Introduced in Perl 5.8.0
+Using this feature triggers warnings in the category
+C<experimental::signatures>.
-Deprecated in Perl 5.10.0
+The ticket for this feature is
+L<[perl #121481]|https://rt.perl.org/Ticket/Display.html?id=121481>.
-=item Assertions
+=item Postfix dereference syntax
-The C<-A> command line switch
+Introduced in Perl 5.20.0
-Introduced in Perl 5.9.0
+Using this feature triggers warnings in the category
+C<experimental::postderef>.
-Removed in Perl 5.9.5
+The ticket for this feature is
+L<[perl #120162]|https://rt.perl.org:443/rt3/Ticket/Display.html?id=120162>.
-=item Linux abstract Unix domain sockets
+=item Aliasing via reference
-Introduced in Perl 5.9.2
+Introduced in Perl 5.22.0
-See also L<Socket>
-
-=item L<Pod::HTML2Pod|Pod::HTML2Pod>
+Using this feature triggers warnings in the category
+C<experimental::refaliasing>.
-=item L<Pod::PXML|Pod::PXML>
+The ticket for this feature is
+L<[perl #122947]|https://rt.perl.org/rt3/Ticket/Display.html?id=122947>.
-=item threads
-
-=item The <:pop> IO pseudolayer
-
-See also L<perlrun>
+See also: L<perlref/Assigning to References>
=item The <:win32> IO pseudolayer
-See also L<perlrun>
-
-=item MLDBM
-
-See also L<perldsc>
+The ticket for this feature is
+L<[perl #119453]|https://rt.perl.org/rt3/Ticket/Display.html?id=119453>.
-=item internal functions with M flag
-
-See also L<perlguts>
-
-=item lex_start API
-
-Introduced in Perl 5.13.7
+See also L<perlrun>
-=item internal API for C<%H>
+=item There is an C<installhtml> target in the Makefile.
-Introduced in Perl 5.13.7
+The ticket for this feature is
+L<[perl #116487]|https://rt.perl.org/rt3/Ticket/Display.html?id=116487>.
-See also C<cophh_> in L<perlapi>.
+=item Unicode in Perl on EBCDIC
-=item av_create_and_push
+=back
-=item av_create_and_unshift_one
+=head2 Accepted features
-=item av_create_and_unshift_one
+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.
-=item PL_keyword_plugin
+=over 8
-=item hv_iternext_flags
+=item 64-bit support
-=item lex_bufutf8
+Introduced in Perl 5.005
-=item lex_discard_to
+=item die accepts a reference
-=item lex_grow_linestr
+Introduced in Perl 5.005
-=item lex_next_chunk
+=item DB module
-=item lex_peek_unichar
+Introduced in Perl 5.6.0
-=item lex_read_space
+See also L<perldebug>, L<perldebtut>
-=item lex_read_to
+=item Weak references
-=item lex_read_unichar
+Introduced in Perl 5.6.0
-=item lex_stuff_pv
+=item Internal file glob
-=item lex_stuff_pvn
+Introduced in Perl 5.6.0
-=item lex_stuff_pvs
+=item fork() emulation
-=item lex_stuff_sv
+Introduced in Perl 5.6.1
-=item lex_unstuff
+See also L<perlfork>
-=item parse_fullstmt
+=item -Dusemultiplicity -Duseithreads
-=item parse_stmtseq
+Introduced in Perl 5.6.0
-=item PL_parser-E<gt>bufend
+Accepted in Perl 5.8.0
-=item PL_parser-E<gt>bufptr
+=item Support for long doubles
-=item PL_parser-E<gt>linestart
+Introduced in Perl 5.6.0
-=item PL_parser-E<gt>linestr
+Accepted in Perl 5.8.1
-=item Perl_signbit
+=item The C<\N> regex character class
-=item pad_findmy
+The C<\N> character class, not to be confused with the named character
+sequence C<\N{NAME}>, denotes any non-newline character in a regular
+expression.
-=item sv_utf8_decode
+Introduced in Perl 5.12
-=item sv_utf8_downgrade
+Exact version of acceptance unclear, but no later than Perl 5.18.
-=item bytes_from_utf8
+=item C<(?{code})> and C<(??{ code })>
-=item bytes_to_utf8
+Introduced in Perl 5.6.0
-=item utf8_to_bytes
+Accepted in Perl 5.20.0
-=item DB module
+See also L<perlre>
-Introduced in Perl 5.6.0
+=item Linux abstract Unix domain sockets
-See also L<perldebug>, L<perldebtut>
+Introduced in Perl 5.9.2
-=item The pseudo-hash data type
+Accepted before Perl 5.20.0. The Socket library is now primarily maintained
+on CPAN, rather than in the perl core.
-Introduced in Perl 5.6.0
+See also L<Socket>
=item Lvalue subroutines
Introduced in Perl 5.6.0
-See also L<perlsub>
-
-=item There is an C<installhtml> target in the Makefile.
+Accepted in Perl 5.20.0
-=item Unicode in Perl on EBCDIC
+See also L<perlsub>
-=item C<(?{code})>
+=item Backtracking control verbs
-See also L<perlre>
+C<(*ACCEPT)>
-=item C<(??{ code })>
+Introduced in: Perl 5.10
-See also L<perlre>
+Accepted in Perl 5.20.0
-=item Backtracking control verbs
+=item The <:pop> IO pseudolayer
-C<(*ACCEPT)>
+See also L<perlrun>
-Introduced in: Perl 5.10
+Accepted in Perl 5.20.0
-See also: L<perlre/"Special Backtracking Control Verbs">
+=back
-=item Code expressions, conditional expressions, and independent expressions in regexes
+=head2 Removed features
-=item The C<\N> regex character class
+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 L<perlpolicy>).
-The C<\N> character class, not to be confused with the named character
-sequence C<\N{NAME}>, denotes any non-newline character in a regular
-expression.
+=over 8
-Introduced in: Perl 5.12
+=item 5.005-style threading
-See also:
+Introduced in Perl 5.005
-=item gv_try_downgrade
+Removed in Perl 5.10
-See also L<perlintern>
+=item perlcc
-=item Experimental Support for Sun Studio Compilers for Linux OS
+Introduced in Perl 5.005
-See also L<perllinux>
+Moved from Perl 5.9.0 to CPAN
-=item Pluggable keywords
+=item The pseudo-hash data type
-See L<perlapi/PL_keyword_plugin> for the mechanism.
+Introduced in Perl 5.6.0
-Introduced in: Perl 5.11.2
+Removed in Perl 5.9.0
-=back
+=item GetOpt::Long Options can now take multiple values at once (experimental)
-=head2 Accepted features
+C<Getopt::Long> upgraded to version 2.35
-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.
+Removed in Perl 5.8.8
-=over 8
+=item Assertions
-=item (none yet identified)
+The C<-A> command line switch
-=back
+Introduced in Perl 5.9.0
-=head2 Removed features
+Removed in Perl 5.9.5
-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 L<perlpolicy>).
+=item Test::Harness::Straps
-=over 8
+Moved from Perl 5.10.1 to CPAN
=item C<legacy>
=back
+=head1 SEE ALSO
+
+For a complete list of features check L<feature>.
+
=head1 AUTHORS
brian d foy C<< <brian.d.foy@gmail.com> >>
+SE<eacute>bastien Aperghis-Tramoni C<< <saper@cpan.org> >>
+
=head1 COPYRIGHT
Copyright 2010, brian d foy C<< <brian.d.foy@gmail.com> >>