=head2 Tainting and printf
When perl is run under taint mode, C<printf()> and C<sprintf()> will now
-reject any tainted format argument.
+reject any tainted format argument. (Rafael Garcia-Suarez)
+
+=head2 undef and signal handlers
+
+Undefining or deleting a signal handler via C<undef $SIG{FOO}> is now
+equivalent to setting it to C<'DEFAULT'>. (Rafael)
+
+=head2 strictures and array/hash dereferencing in defined()
+
+C<defined @$foo> and C<defined %$bar> are now subject to C<strict 'refs'>
+(that is, C<$foo> and C<$bar> shall be proper references there.)
+(Nicholas Clark)
+
+(However, C<defined(@foo)> and C<defined(%bar)> are discouraged constructs
+anyway.)
=head2 Removal of the bytecode compiler and of perlcc
It is now possible to name capturing parenthesis in a pattern and refer to
the captured contents by name. The naming syntax is C<< (?<NAME>....) >>.
It's possible to backreference to a named buffer with the C<< \k<NAME> >>
-syntax. In code, the new magical hash C<%+> can be used to access the
-contents of the buffers.
+syntax. In code, the new magical hashes C<%+> and C<%-> can be used to
+access the contents of the capture buffers.
Thus, to replace all doubled chars, one could write
s/(?<letter>.)\k<letter>/$+{letter}/g
-Only buffers with defined contents will be "visible" in the hash, so
+Only buffers with defined contents will be "visible" in the C<%+> hash, so
it's possible to do something like
foreach my $name (keys %+) {
print "content of buffer '$name' is $+{$name}\n";
}
+The C<%-> hash is a bit more complete, since it will contain array refs
+holding values from all capture buffers similarly named, if there should
+be many of them.
+
+C<%+> and C<%-> are implemented as tied hashes through the new module
+C<Tie::Hash::NamedCapture>.
+
Users exposed to the .NET regex engine will find that the perl
implementation differs in that the numerical ordering of the buffers
is sequential, and not "unnamed first, then named". Thus in the pattern
=item Possessive Quantifiers
-Perl now supports the "possessive quantifier" syntax of the "atomic match"
+Perl now supports the "possessive quantifier" syntax of the "atomic match"
pattern. Basically a possessive quantifier matches as much as it can and never
-gives any back. Thus it can be used to control backtracking. The syntax is
+gives any back. Thus it can be used to control backtracking. The syntax is
similar to non-greedy matching, except instead of using a '?' as the modifier
the '+' is used. Thus C<?+>, C<*+>, C<++>, C<{min,max}+> are now legal
quantifiers. (Yves Orton)
=item Backtracking control verbs
-The regex engine now supports a number of special purpose backtrack
-control verbs: (*COMMIT), (*MARK), (*CUT), (*ERROR), (*FAIL) and
-(*ACCEPT). See L<perlre> for their descriptions.
+The regex engine now supports a number of special-purpose backtrack
+control verbs: (*THEN), (*PRUNE), (*MARK), (*SKIP), (*COMMIT), (*FAIL)
+and (*ACCEPT). See L<perlre> for their descriptions. (Yves Orton)
+
+=item Relative backreferences
+
+A new syntax C<\g{N}> or C<\gN> where "N" is a decimal integer allows a
+safer form of back-reference notation as well as allowing relative
+backreferences. This should make it easier to generate and embed patterns
+that contain backreferences. See L<perlre/"Capture buffers">. (Yves Orton)
+
+=item C<\K> escape
+
+The functionality of Jeff Pinyan's module Regexp::Keep has been added to
+the core. You can now use in regular expressions the special escape C<\K>
+as a way to do something like floating length positive lookbehind. It is
+also useful in substitutions like:
+
+ s/(foo)bar/$1/g
+
+that can now be converted to
+
+ s/foo\Kbar//g
+
+which is much more efficient. (Yves Orton)
=back
This has a small incompatible consequence: the prototype() function has
been adjusted to return C<_> for some built-ins in appropriate cases (for
-example, C<prototype('CORE::rmdir')>). (Rafael Garcia-Suarez)
+example, C<prototype('CORE::rmdir')>). (Rafael)
=head2 UNITCHECK blocks
just after the unit which defined them has been compiled. See L<perlmod>
for more information. (Alex Gough)
+=head2 readpipe() is now overridable
+
+The built-in function readpipe() is now overridable. Overriding it permits
+also to override its operator counterpart, C<qx//> (a.k.a. C<``>). (Rafael)
+
=head2 UCD 5.0.0
The copy of the Unicode Character Database included in Perl 5.9 has
been updated to version 5.0.0.
+=head2 Smart match
+
+The smart match operator (C<~~>) is now available by default (you don't
+need to enable it with C<use feature> any longer). (Michael G Schwern)
+
=head1 Modules and Pragmas
=head2 New Core Modules
C<Params::Check> implements a generic input parsing/checking mechanism. It
is used by CPANPLUS.
+=item *
+
+C<Term::UI> simplifies the task to ask questions at a terminal prompt.
+
+=item *
+
+C<Object::Accessor> provides an interface to create per-object accessors.
+
+=item *
+
+C<Module::Pluggable> is a simple framework to create modules that accept
+pluggable sub-modules.
+
+=item *
+
+C<Module::Load::Conditional> provides simple ways to query and possibly
+load installed modules.
+
+=item *
+
+C<Time::Piece> provides an object oriented interface to time functions,
+overriding the built-ins localtime() and gmtime().
+
+=item *
+
+C<IPC::Cmd> helps to find and run external commands, possibly
+interactively.
+
+=item *
+
+C<File::Fetch> provide a simple generic file fetching mechanism.
+
+=item *
+
+C<Archive::Extract> is a generic archive extraction mechanism
+for F<.tar> (plain, gziped or bzipped) or F<.zip> files.
+
=back
=head2 Module changes
=item C<base>
The C<base> pragma now warns if a class tries to inherit from itself.
+(Curtis "Ovid" Poe)
=item C<warnings>
require Carp;
Carp::confess "argh";
+=item C<less>
+
+C<less> now does something useful (or at least it tries to). In fact, it
+has been turned into a lexical pragma. So, in your modules, you can now
+test whether your users have requested to use less CPU, or less memory,
+less magic, or maybe even less fat. See L<less> for more. (Joshua ben
+Jore)
+
+=item C<Attribute::Handlers>
+
+C<Attribute::Handlers> can now report the caller's file and line number.
+(David Feldman)
+
+=item C<B::Lint>
+
+C<B::Lint> is now based on C<Module::Pluggable>, and so can be extended
+with plugins. (Joshua ben Jore)
+
+=item C<B>
+
+It's now possible to access the lexical pragma hints (C<%^H>) by using the
+method B::COP::hints_hash(). It returns a C<B::RHE> object, which in turn
+can be used to get a hash reference via the method B::RHE::HASH(). (Joshua
+ben Jore)
+
+=for p5p XXX document this in B.pm too
+
=back
=head1 Utility Changes
with various C++ compilers (although the situation is not perfect with
some of the compilers on some of the platforms tested.)
+=head2 Static build on Win32
+
+It's now possible to build a C<perl-static.exe> that doesn't depend
+on C<perl59.dll> on Win32. See the Win32 makefiles for details.
+(Vadim Konovalov)
+
=head2 Ports
Perl has been reported to work on MidnightBSD.
PerlIO::scalar will now prevent writing to read-only scalars. Moreover,
seek() is now supported with PerlIO::scalar-based filehandles, the
-underlying string being zero-filled as needed.
+underlying string being zero-filled as needed. (Rafael, Jarkko Hietaniemi)
study() never worked for UTF-8 strings, but could lead to false results.
It's now a no-op on UTF-8 data. (Yves Orton)
The signals SIGILL, SIGBUS and SIGSEGV are now always delivered in an
"unsafe" manner (contrary to other signals, that are deferred until the
perl interpreter reaches a reasonably stable state; see
-L<perlipc/"Deferred Signals (Safe Signals)">).
+L<perlipc/"Deferred Signals (Safe Signals)">). (Rafael)
+
+When a module or a file is loaded through an @INC-hook, and when this hook
+has set a filename entry in %INC, __FILE__ is now set for this module
+accordingly to the contents of that %INC entry. (Rafael)
+
+The C<-w> and C<-t> switches can now be used together without messing
+up what categories of warnings are activated or not. (Rafael)
=head1 New or Changed Diagnostics
instead of 3, now that pp_anonhash and pp_anonlist return a reference to
an hash/array when the op is flagged with OPf_SPECIAL (Nicholas Clark).
+=for p5p XXX have we some docs on how to create regexp engine plugins, since that's now possible ? (perlreguts)
+
+=for p5p XXX new BIND SV type, #29544, #29642
+
=head1 Known Problems
=head2 Platform Specific Problems
projects / p5sagit/p5-mst-13.2.git / blobdiff