| =head1 NAME |
| |
| perl595delta - what is new for perl v5.9.5 |
| |
| =head1 DESCRIPTION |
| |
| This document describes differences between the 5.9.4 and the 5.9.5 |
| development releases. See L<perl590delta>, L<perl591delta>, |
| L<perl592delta>, L<perl593delta> and L<perl594delta> for the differences |
| between 5.8.0 and 5.9.4. |
| |
| =head1 Incompatible Changes |
| |
| =head2 Tainting and printf |
| |
| When perl is run under taint mode, C<printf()> and C<sprintf()> will now |
| 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<$bar> shall be proper references there.) |
| (Nicholas Clark) |
| |
| (However, C<defined(@foo)> and C<defined(%bar)> are discouraged constructs |
| anyway.) |
| |
| =head2 C<(?p{})> has been removed |
| |
| The regular expression construct C<(?p{})>, which was deprecated in perl |
| 5.8, has been removed. Use C<(??{})> instead. (Rafael) |
| |
| =head2 Pseudo-hashes have been removed |
| |
| Support for pseudo-hashes has been removed from Perl 5.9. (The C<fields> |
| pragma remains here, but uses an alternate implementation.) |
| |
| =head2 Removal of the bytecode compiler and of perlcc |
| |
| C<perlcc>, the byteloader and the supporting modules (B::C, B::CC, |
| B::Bytecode, etc.) are no longer distributed with the perl sources. Those |
| experimental tools have never worked reliably, and, due to the lack of |
| volunteers to keep them in line with the perl interpreter developments, it |
| was decided to remove them instead of shipping a broken version of those. |
| The last version of those modules can be found with perl 5.9.4. |
| |
| However the B compiler framework stays supported in the perl core, as with |
| the more useful modules it has permitted (among others, B::Deparse and |
| B::Concise). |
| |
| =head2 Removal of the JPL |
| |
| The JPL (Java-Perl Linguo) has been removed from the perl sources tarball. |
| |
| =head2 Recursive inheritance detected earlier |
| |
| Perl will now immediately throw an exception if you modify any package's |
| C<@ISA> in such a way that it would cause recursive inheritance. |
| |
| Previously, the exception would not occur until Perl attempted to make |
| use of the recursive inheritance while resolving a method or doing a |
| C<$foo-E<gt>isa($bar)> lookup. |
| |
| =head1 Core Enhancements |
| |
| =head2 Regular expressions |
| |
| =over 4 |
| |
| =item Recursive Patterns |
| |
| It is now possible to write recursive patterns without using the C<(??{})> |
| construct. This new way is more efficient, and in many cases easier to |
| read. |
| |
| Each capturing parenthesis can now be treated as an independent pattern |
| that can be entered by using the C<(?PARNO)> syntax (C<PARNO> standing for |
| "parenthesis number"). For example, the following pattern will match |
| nested balanced angle brackets: |
| |
| / |
| ^ # start of line |
| ( # start capture buffer 1 |
| < # match an opening angle bracket |
| (?: # match one of: |
| (?> # don't backtrack over the inside of this group |
| [^<>]+ # one or more non angle brackets |
| ) # end non backtracking group |
| | # ... or ... |
| (?1) # recurse to bracket 1 and try it again |
| )* # 0 or more times. |
| > # match a closing angle bracket |
| ) # end capture buffer one |
| $ # end of line |
| /x |
| |
| Note, users experienced with PCRE will find that the Perl implementation |
| of this feature differs from the PCRE one in that it is possible to |
| backtrack into a recursed pattern, whereas in PCRE the recursion is |
| atomic or "possessive" in nature. (Yves Orton) |
| |
| =item Named Capture Buffers |
| |
| 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 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 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 |
| |
| /(A)(?<B>B)(C)(?<D>D)/ |
| |
| $1 will be 'A', $2 will be 'B', $3 will be 'C' and $4 will be 'D' and not |
| $1 is 'A', $2 is 'C' and $3 is 'B' and $4 is 'D' that a .NET programmer |
| would expect. This is considered a feature. :-) (Yves Orton) |
| |
| =item Possessive Quantifiers |
| |
| 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 |
| 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: (*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/$1/g |
| |
| that can now be converted to |
| |
| s/foo\Kbar//g |
| |
| which is much more efficient. (Yves Orton) |
| |
| =item Vertical and horizontal whitespace, and linebreak |
| |
| Regular expressions now recognize the C<\v> and C<\h> escapes, that match |
| vertical and horizontal whitespace, respectively. C<\V> and C<\H> |
| logically match their complements. |
| |
| C<\R> matches a generic linebreak, that is, vertical whitespace, plus |
| the multi-character sequence C<"\x0D\x0A">. |
| |
| =back |
| |
| =head2 The C<_> prototype |
| |
| A new prototype character has been added. C<_> is equivalent to C<$> (it |
| denotes a scalar), but defaults to C<$_> if the corresponding argument |
| isn't supplied. Due to the optional nature of the argument, you can only |
| use it at the end of a prototype, or before a semicolon. |
| |
| This has a small incompatible consequence: the prototype() function has |
| been adjusted to return C<_> for some built-ins in appropriate cases (for |
| example, C<prototype('CORE::rmdir')>). (Rafael) |
| |
| =head2 UNITCHECK blocks |
| |
| C<UNITCHECK>, a new special code block has been introduced, in addition to |
| C<BEGIN>, C<CHECK>, C<INIT> and C<END>. |
| |
| C<CHECK> and C<INIT> blocks, while useful for some specialized purposes, |
| are always executed at the transition between the compilation and the |
| execution of the main program, and thus are useless whenever code is |
| loaded at runtime. On the other hand, C<UNITCHECK> blocks are executed |
| just after the unit which defined them has been compiled. See L<perlmod> |
| for more information. (Alex Gough) |
| |
| =head2 readpipe() is now overridable |
| |
| The built-in function readpipe() is now overridable. Overriding it permits |
| also to override its operator counterpart, C<qx//> (a.k.a. C<``>). |
| Moreover, it now defaults to C<$_> if no argument is provided. (Rafael) |
| |
| =head2 default argument for readline() |
| |
| readline() now defaults to C<*ARGV> if no argument is provided. (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) |
| |
| =head2 Implicit loading of C<feature> |
| |
| The C<feature> pragma is now implicitly loaded when you require a minimal |
| perl version (with the C<use VERSION> construct) greater than, or equal |
| to, 5.9.5. |
| |
| =head1 Modules and Pragmas |
| |
| =head2 New Pragma, C<mro> |
| |
| A new pragma, C<mro> (for Method Resolution Order) has been added. It |
| permits to switch, on a per-class basis, the algorithm that perl uses to |
| find inherited methods in case of a multiple inheritance hierarchy. The |
| default MRO hasn't changed (DFS, for Depth First Search). Another MRO is |
| available: the C3 algorithm. See L<mro> for more information. |
| (Brandon Black) |
| |
| Note that, due to changes in the implementation of class hierarchy search, |
| code that used to undef the C<*ISA> glob will most probably break. Anyway, |
| undef'ing C<*ISA> had the side-effect of removing the magic on the @ISA |
| array and should not have been done in the first place. |
| |
| =head2 bignum, bigint, bigrat |
| |
| The three numeric pragmas C<bignum>, C<bigint> and C<bigrat> are now |
| lexically scoped. (Tels) |
| |
| =head2 Math::BigInt/Math::BigFloat |
| |
| Many bugs have been fixed; noteworthy are comparisons with NaN, which |
| no longer warn about undef values. |
| |
| The following things are new: |
| |
| =over 4 |
| |
| =item config() |
| |
| The config() method now also supports the calling-style |
| C<< config('lib') >> in addition to C<< config()->{'lib'} >>. |
| |
| =item import() |
| |
| Upon import, using C<< lib => 'Foo' >> now warns if the low-level library |
| cannot be found. To suppress the warning, you can use C<< try => 'Foo' >> |
| instead. To convert the warning into a die, use C<< only => 'Foo' >> |
| instead. |
| |
| =item roundmode common |
| |
| A rounding mode of C<common> is now supported. |
| |
| =back |
| |
| Also, support for the following methods has been added: |
| |
| =over 4 |
| |
| =item bpi(), bcos(), bsin(), batan(), batan2() |
| |
| =item bmuladd() |
| |
| =item bexp(), bnok() |
| |
| =item from_hex(), from_oct(), and from_bin() |
| |
| =item as_oct() |
| |
| =back |
| |
| In addition, the default math-backend (Calc (Perl) and FastCalc (XS)) now |
| support storing numbers in parts with 9 digits instead of 7 on Perls with |
| either 64bit integer or long double support. This means math operations |
| scale better and are thus faster for really big numbers. |
| |
| =head2 New Core Modules |
| |
| =over 4 |
| |
| =item * |
| |
| C<Locale::Maketext::Simple>, needed by CPANPLUS, is a simple wrapper around |
| C<Locale::Maketext::Lexicon>. Note that C<Locale::Maketext::Lexicon> isn't |
| included in the perl core; the behaviour of C<Locale::Maketext::Simple> |
| gracefully degrades when the later isn't present. |
| |
| =item * |
| |
| 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<Log::Message> and C<Log::Message::Simple> are used by the log facility |
| of C<CPANPLUS>. |
| |
| =item * |
| |
| C<Archive::Extract> is a generic archive extraction mechanism |
| for F<.tar> (plain, gziped or bzipped) or F<.zip> files. |
| |
| =item * |
| |
| C<CPANPLUS> provides an API and a command-line tool to access the CPAN |
| mirrors. |
| |
| =back |
| |
| =head2 Module changes |
| |
| =over 4 |
| |
| =item C<assertions> |
| |
| The C<assertions> pragma, its submodules C<assertions::activate> and |
| C<assertions::compat> and the B<-A> command-line switch have been removed. |
| The interface was not judged mature enough for inclusion in a stable |
| release. |
| |
| =item C<base> |
| |
| The C<base> pragma now warns if a class tries to inherit from itself. |
| (Curtis "Ovid" Poe) |
| |
| =item C<strict> and C<warnings> |
| |
| C<strict> and C<warnings> will now complain loudly if they are loaded via |
| incorrect casing (as in C<use Strict;>). (Johan Vromans) |
| |
| =item C<warnings> |
| |
| The C<warnings> pragma doesn't load C<Carp> anymore. That means that code |
| that used C<Carp> routines without having loaded it at compile time might |
| need to be adjusted; typically, the following (faulty) code won't work |
| anymore, and will require parentheses to be added after the function name: |
| |
| use 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 |
| |
| =item C<Thread> |
| |
| As the old 5005thread threading model has been removed, in favor of the |
| ithreads scheme, the C<Thread> module is now a compatibility wrapper, to |
| be used in old code only. It has been removed from the default list of |
| dynamic extensions. |
| |
| =back |
| |
| =head1 Utility Changes |
| |
| =head2 C<cpanp> |
| |
| C<cpanp>, the CPANPLUS shell, has been added. (C<cpanp-run-perl>, an |
| helper for CPANPLUS operation, has been added too, but isn't intended for |
| direct use). |
| |
| =head2 C<cpan2dist> |
| |
| C<cpan2dist> is a new utility, that comes with CPANPLUS. It's a tool to |
| create distributions (or packages) from CPAN modules. |
| |
| =head2 C<pod2html> |
| |
| The output of C<pod2html> has been enhanced to be more customizable via |
| CSS. Some formatting problems were also corrected. (Jari Aalto) |
| |
| =head1 Documentation |
| |
| =head2 New manpage, perlunifaq |
| |
| A new manual page, L<perlunifaq> (the Perl Unicode FAQ), has been added |
| (Juerd Waalboer). |
| |
| =head1 Performance Enhancements |
| |
| =head1 Installation and Configuration Improvements |
| |
| =head2 C++ compatibility |
| |
| Efforts have been made to make perl and the core XS modules compilable |
| with various C++ compilers (although the situation is not perfect with |
| some of the compilers on some of the platforms tested.) |
| |
| =head2 Visual C++ |
| |
| Perl now can be compiled with Microsoft Visual C++ 2005. |
| |
| =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 win32 builds |
| |
| All win32 builds (MS-Win, WinCE) have been merged and cleaned up. |
| |
| =head2 C<d_pseudofork> and C<d_printf_format_null> |
| |
| A new configuration variable, available as C<$Config{d_pseudofork}> in |
| the L<Config> module, has been added, to distinguish real fork() support |
| from fake pseudofork used on Windows platforms. |
| |
| A new configuration variable, C<d_printf_format_null>, has been added, |
| to see if printf-like formats are allowed to be NULL. |
| |
| =head2 Help |
| |
| C<Configure -h> has been extended with the most used option. |
| |
| Much less 'Whoa there' messages. |
| |
| =head2 64bit systems |
| |
| Better detection of 64bit(only) systems, and setting all the (library) |
| paths accordingly. |
| |
| =head2 Ports |
| |
| Perl has been reported to work on MidnightBSD. |
| |
| Support for Cray XT4 Catamount/Qk has been added. |
| |
| Vendor patches have been merged for RedHat and GenToo. |
| |
| =head1 Selected Bug Fixes |
| |
| 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. (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)">). (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) |
| |
| Duping a filehandle which has the C<:utf8> PerlIO layer set will now |
| properly carry that layer on the duped filehandle. (Rafael) |
| |
| Localizing an hash element whose key was given as a variable didn't work |
| correctly if the variable was changed while the local() was in effect (as |
| in C<local $h{$x}; ++$x>). (Bo Lindbergh) |
| |
| =head1 New or Changed Diagnostics |
| |
| =head2 Deprecations |
| |
| Two deprecation warnings have been added: (Rafael) |
| |
| Opening dirhandle %s also as a file |
| Opening filehandle %s also as a directory |
| |
| =head1 Changed Internals |
| |
| The anonymous hash and array constructors now take 1 op in the optree |
| 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 |
| |
| =head1 Reporting Bugs |
| |
| If you find what you think is a bug, you might check the articles |
| recently posted to the comp.lang.perl.misc newsgroup and the perl |
| bug database at http://rt.perl.org/rt3/ . There may also be |
| information at http://www.perl.org/ , the Perl Home Page. |
| |
| If you believe you have an unreported bug, please run the B<perlbug> |
| program included with your release. Be sure to trim your bug down |
| to a tiny but sufficient test case. Your bug report, along with the |
| output of C<perl -V>, will be sent off to perlbug@perl.org to be |
| analysed by the Perl porting team. |
| |
| =head1 SEE ALSO |
| |
| The F<Changes> file for exhaustive details on what changed. |
| |
| The F<INSTALL> file for how to build Perl. |
| |
| The F<README> file for general stuff. |
| |
| The F<Artistic> and F<Copying> files for copyright information. |
| |
| =cut |