C<\R> matches a generic linebreak, that is, vertical whitespace, plus
the multi-character sequence C<"\x0D\x0A">.
+=item Unicode Character Classes
+
+Perl's regular expression engine now contains support for matching on the
+intersection of two Unicode character classes. You can also now refer to
+user-defined character classes from within other user defined character
+classes.
+
=back
=head2 C<say()>
The B<-C> option can no longer be used on the C<#!> line. It wasn't
working there anyway.
+=head2 PERLIO_DEBUG
+
+The C<PERLIO_DEBUG> environment variable has no longer any effect for
+setuid scripts and for scripts run with B<-T>.
+
+Moreover, with a thread-enabled perl, using C<PERLIO_DEBUG> could lead to
+an internal buffer overflow. This has been fixed.
+
=head2 UCD 5.0.0
The copy of the Unicode Character Database included in Perl 5 has
been updated to version 5.0.0.
-
=head2 MAD
MAD, which stands for I<Misc Attribute Decoration>, is a
=head1 Modules and Pragmata
+=head2 New modules
+
+=over 4
+
+=item *
+
+C<encoding::warnings>, by Audrey Tang, is a module to emit warnings
+whenever an ASCII character string containing high-bit bytes is implicitly
+converted into UTF-8.
+
+=item *
+
+C<Module::CoreList>, by Richard Clamp, is a small handy module that tells
+you what versions of core modules ship with any versions of Perl 5. It
+comes with a command-line frontend, C<corelist>.
+
+=back
+
=head1 Utility Changes
=over 4
Perl has a new -dt command-line flag, which enables threads support in the
debugger.
+=item *
+
+The C<corelist> utility is now installed with perl (see L</"New modules">
+above).
+
+=item *
+
+C<h2ph> and C<h2xs> have been made a bit more robust with regard to
+"modern" C code.
+
+=item *
+
+C<find2perl> now assumes C<-print> as a default action. Previously, it
+needed to be specified explicitly.
+
+Several bugs have been fixed in C<find2perl>, regarding C<-exec> and
+C<-eval>. Also the options C<-path>, C<-ipath> and C<-iname> have been
+added.
+
=back
=head1 New Documentation
=head1 Performance Enhancements
+=over 4
+
+=item *
+
Sorting arrays in place (C<@a = sort @a>) is now optimized to avoid
making a temporary copy of the array.
+Likewise, C<reverse sort ...> is now optimized to sort in reverse,
+avoiding the generation of a temporary intermediate list.
+
+=item *
+
Access to elements of lexical arrays via a numeric constant between 0 and
255 is now faster. (This used to be only the case for global arrays.)
+=item *
+
+The regexp engine now implements the trie optimization : it's able to
+factorize common prefixes and suffixes in regular expressions. A new
+special variable, ${^RE_TRIE_MAXBUF}, has been added to fine-tune this
+optimization.
+
+=back
+
=head1 Installation and Configuration Improvements
+Run-time customization of @INC can be enabled by passing the
+C<-Dusesitecustomize> flag to configure. When enabled, this will make perl
+run F<$sitelibexp/sitecustomize.pl> before anything else. This script can
+then be set up to add additional entries to @INC.
+
+There is alpha support for relocatable @INC entries.
+
=head1 Selected Bug Fixes
C<strict> wasn't in effect in regexp-eval blocks (C</(?{...})/>).
+C<$Foo::_> was wrongly forced as C<$main::_>.
+
=head1 New or Changed Diagnostics
A new deprecation warning, I<Deprecated use of my() in false conditional>,
See L<perldiag>. Use C<state> variables instead.
+A new warning, C<!=~ should be !~>, is emitted to prevent this misspelling
+of the non-matching operator.
+
+The warning I<Newline in left-justified string> has been removed.
+
+The error I<Too late for "-T" option> has been reformulated to be more
+descriptive.
+
+C<perl -V> has several improvements, making it more useable from shell
+scripts to get the value of configuration variables. See L<perlrun> for
+details.
+
=head1 Changed Internals
=head2 Reordering of SVt_* constants