run-time. (Subroutine and C<our> variables still get attributes applied
at compile-time.) See L<attributes> for additional details. In particular,
however, this allows variable attributes to be useful for C<tie> interfaces,
-which was a deficiency of earlier releaes.
+which was a deficiency of earlier releases. Note that the new semantics
+doesn't work with the Attribute::Handlers module (as of version 0.76).
=head2 Socket Extension Dynamic in VMS
with external libraries or existing data. G_FLOAT is still available as
a configuration option. The default on VAX (D_FLOAT) has not changed.
-=head2 Different Definition of the Unicode Character Classes \p{In...}
-
-As suggested by the Unicode consortium, the Unicode character classes
-now prefer I<scripts> as opposed to I<blocks> (as defined by Unicode);
-in Perl, when the C<\p{In....}> and the C<\p{In....}> regular expression
-constructs are used. This has changed the definition of some of those
-character classes.
-
-The difference between scripts and blocks is that scripts are the
-glyphs used by a language or a group of languages, while the blocks
-are more artificial groupings of 256 characters based on the Unicode
-numbering.
-
-In general this change results in more inclusive Unicode character
-classes, but changes to the other direction also do take place:
-for example while the script C<Latin> includes all the Latin
-characters and their various diacritic-adorned versions, it
-does not include the various punctuation or digits (since they
-are not solely C<Latin>).
-
-Changes in the character class semantics may have happened if a script
-and a block happen to have the same name, for example C<Hebrew>.
-In such cases the script wins and C<\p{InHebrew}> now means the script
-definition of Hebrew. The block definition in still available,
-though, by appending C<Block> to the name: C<\p{InHebrewBlock}> means
-what C<\p{InHebrew}> meant in perl 5.6.0. For the full list
-of affected character classes, see L<perlunicode/Blocks>.
+=head2 New Unicode Properties
+
+Unicode I<scripts> are now supported. Scripts are similar to (and superior
+to) Unicode I<blocks>. The difference between scripts and blocks is that
+scripts are the glyphs used by a language or a group of languages, while
+the blocks are more artificial groupings of (mostly) 256 characters based
+on the Unicode numbering.
+
+In general, scripts are more inclusive, but not universally so. For
+example, while the script C<Latin> includes all the Latin characters and
+their various diacritic-adorned versions, it does not include the various
+punctuation or digits (since they are not solely C<Latin>).
+
+A number of other properties are now supported, including C<\p{L&}>,
+C<\p{Any}> C<\p{Assigned}>, C<\p{Unassigned}>, C<\p{Blank}> and
+C<\p{SpacePerl}> (along with their C<\P{...}> versions, of course).
+See L<perlunicode> for details, and more additions.
+
+The C<In> or C<Is> prefix to names used with the C<\p{...}> and C<\P{...}>
+are now almost always optional. The only exception is that a C<In> prefix
+is required to signify a Unicode block when a block name conflicts with a
+script name. For example, C<\p{Tibetan}> refers to the script, while
+C<\p{InTibetan}> refers to the block. When there is no name conflict, you
+can omit the C<In> from the block name (e.g. C<\p{BraillePatterns}>), but
+to be safe, it's probably best to always use the C<In>).
=head2 Perl Parser Stress Tested
of "SCALAR(0x81485ec)" in order to be more consistent with the return
value of ref().
+=head2 pack/unpack D/F recycled
+
+The undocumented pack/unpack template letters D/F have been recycled
+for better use: now they stand for long double (if supported by the
+platform) and NV (Perl internal floating point type). (They used
+to be aliases for f/d, but you never knew that.)
+
=head2 Deprecations
=over 4
=item *
+The builtin dump() function has probably outlived most of its
+usefulness. The core-dumping functionality will remain in future
+available as an explicit call to C<CORE::dump()>, but in future
+releases the behaviour of an unqualified C<dump()> call may change.
+
+=item *
+
The very dusty examples in the eg/ directory have been removed.
Suggestions for new shiny examples welcome but the main issue is that
the examples need to be documented, tested and (most importantly)
the interface was a mistake. Sorry about that. For similar
functionality, see pack('U0', ...) and pack('C0', ...).
+=item *
+
+Earlier Perls treated "sub foo (@bar)" as equivalent to "sub foo (@)".
+The prototypes are now checked at compile-time for invalid characters.
+An optional warning is generated ("Illegal character in prototype...")
+but this may be upgraded to a fatal error in a future release.
+
=back
=head1 Core Enhancements
=back
-=head2 Signals Are Now Safe
+=head2 Safe Signals
Perl used to be fragile in that signals arriving at inopportune moments
could corrupt Perl's internal state. Now Perl postpones handling of
-signals until it's safe.
+signals until it's safe (between opcodes).
+
+This change may have surprising side effects because signals no longer
+interrupt Perl instantly. Perl will now first finish whatever it was
+doing, like finishing an internal operation (like sort()) or an
+external operation (like an I/O operation), and only then look at any
+arrived signals (and before starting the next operation). No more corrupt
+internal state since the current operation is always finished first,
+but the signal may take more time to get heard.
=head2 Unicode Overhaul
For developers interested in enhancing Perl's Unicode capabilities:
almost all the UCD files are included with the Perl distribution in
-the lib/unicore subdirectory. The most notable omission, for space
+the F<lib/unicore subdirectory>. The most notable omission, for space
considerations, is the Unihan database.
=item *
-The Unicode character classes \p{Blank} and \p{SpacePerl} have been
-added. "Blank" is like C isblank(), that is, it contains only
-"horizontal whitespace" (the space character is, the newline isn't),
-and the "SpacePerl" is the Unicode equivalent of C<\s> (\p{Space}
-isn't, since that includes the vertical tabulator character, whereas
-C<\s> doesn't.)
+The properties \p{Blank} and \p{SpacePerl} have been added. "Blank" is like
+C isblank(), that is, it contains only "horizontal whitespace" (the space
+character is, the newline isn't), and the "SpacePerl" is the Unicode
+equivalent of C<\s> (\p{Space} isn't, since that includes the vertical
+tabulator character, whereas C<\s> doesn't.)
+
+See "New Unicode Properties" earlier in this document for additional
+information on changes with Unicode properties.
=back
arithmetics. (Previously Perl always preferred floating point numbers
in its math.)
-=head2 Miscellaneous Enhancements
+=head2 Miscellaneous Changes
=over 4
=item *
+The builtin dump() now gives an optional warning
+C<dump() better written as CORE::dump()>,
+meaning that by default C<dump(...)> is resolved as the builtin
+dump() which dumps core and aborts, not as (possibly) user-defined
+C<sub dump>. To call the latter, qualify the call as C<&dump(...)>.
+(The whole dump() feature is to considered deprecated, and possibly
+removed/changed in future releases.)
+
+=item *
+
+chomp() and chop() have been demoted back to I<not> being overridable
+because they cannot really be overridden-- the problem is that their
+prototype cannot be expressed and therefore one really cannot write
+replacements to override these builtins.
+
+=item *
+
END blocks are now run even if you exit/die in a BEGIN block.
Internally, the execution of END blocks is now controlled by
PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new
=item *
+A lost warning "Can't declare ... dereference in my" has been
+restored (Perl had it earlier but it became lost in later releases.)
+
+=item *
+
A new special regular expression variable has been introduced:
C<$^N>, which contains the most-recently closed group (submatch).
=item *
+C<pack() / unpack()> now can group template letters with C<()> and then
+apply repetition/count modifiers on the groups.
+
+=item *
+
+C<pack() / unpack()> can now process the Perl internal numeric types:
+IVs, UVs, NVs-- and also long doubles, if supported by the platform.
+The template letters are C<j>, C<J>, C<F>, and C<D>.
+
+=item *
+
C<pack('U0a*', ...)> can now be used to force a string to UTF8.
=item *
=item *
+A new command-line option, C<-t> is available. It is the
+little brother of C<-T>: instead of dieing on taint violations,
+lexical warnings are given. B<This is only meant as a temporary
+debugging aid while securing the code of old legacy applications.
+This is not a substitute for -T.>
+
+=item *
+
+In other taint news, the C<exec LIST> and C<system LIST> have now been
+considered too risky (think C<exec @ARGV>: it can start any program
+with any arguments), and now the said forms cause a warning.
+You should carefully launder the arguments to guarantee their
+validity. In future releases of Perl the forms will become fatal
+errors so consider starting laundering now.
+
+=item *
+
+If tr/// is just counting characters, it doesn't attempt to
+modify its target.
+
+=item *
+
untie() will now call an UNTIE() hook if it exists. See L<perltie>
for details.
=item *
+C<Attribute::Handlers> allows a class to define attribute handlers.
+
+ package MyPack;
+ use Attribute::Handlers;
+ sub Wolf :ATTR(SCALAR) { print "howl!\n" }
+
+ # later, in some package using or inheriting from MyPack...
+
+ my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called
+
+Both variables and routines can have attribute handlers. Handlers can
+be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific to the
+exact compilation phase (BEGIN, CHECK, INIT, or END).
+
+=item *
+
B<B::Concise> is a new compiler backend for walking the Perl syntax
tree, printing concise info about ops, from Stephen McCamant. The
output is highly customisable. See L<B::Concise>.
C<Devel::PPPort>, originally from Kenneth Albanowski and now
maintained by Paul Marquess, has been added. It is primarily used
-by C<h2xs> to enhance portability of of XS modules between different
+by C<h2xs> to enhance portability of XS modules between different
versions of Perl.
=item *
=item *
+C<if> is a new pragma for conditional inclusion of modules, from
+Ilya Zakharevich.
+
+=item *
+
L<libnet> is a collection of perl5 modules related to network
programming, from Graham Barr. See L<Net::FTP>, L<Net::NNTP>,
L<Net::Ping>, L<Net::POP3>, L<Net::SMTP>, and L<Net::Time>.
=item *
+C<Tie::File>, by Mark-Jason Dominus, associates a Perl array with the
+lines of a file.
+
+=item *
+
+C<Tie::Memoize>, by Ilya Zakharevich, provides on-demand loaded hashes.
+
+=item *
+
C<Tie::RefHash::Nestable>, by Edward Avis, allows storing hash
references (unlike the standard Tie::RefHash) The module is contained
within Tie::RefHash, see L<Tie::RefHash>.
The English module can now be used without the infamous performance
hit by saying
- use English '-no_performance_hit';
+ use English '-no_match_vars';
(Assuming, of course, that one doesn't need the troublesome variables
C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
=item *
+ExtUtils::MakeMaker now uses File::Spec internally, which hopefully
+leads into better portability.
+
+=item *
+
Math::BigFloat and Math::BigInt have undergone a full rewrite.
They are now magnitudes faster, and they support various
bignum libraries such as GMP and PARI as their backends.
=item *
-Net::Ping has been enhanced. There is now "external" protocol which
-uses Net::Ping::External module which runs external ping(1) and parses
-the output. A version of Net::Ping::External is available in CPAN.
+Net::Ping has been muchly enhanced. Multihoming is now supported.
+There is now "external" protocol which uses Net::Ping::External module
+which runs external ping(1) and parses the output. A version of
+Net::Ping::External is available in CPAN.
=item *
=item *
-The utf8:: name space (as in the pragma) provides various
+The C<utf8::> name space (as in the pragma) provides various
Perl-callable functions to provide low level access to Perl's
internal Unicode representation. At the moment only length()
has been implemented.
=item *
-perluniintro is an introduction to using Unicode in Perl
-(perlunicode is more of a reference)
+perluniintro is an introduction to using Unicode in Perl.
+(perlunicode is more of a detailed reference and background
+information)
=item *
=item *
+BeOS has been reclaimed.
+
+=item *
+
DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
=item *
=item *
+All the NetBSD specific patches (except for the installation
+specific ones) have been merged back to the main distribution.
+
+=item *
+
NetWare from Novell is now supported. See L<perlnetware>.
=item *
=item *
+All the OpenBSD specific patches (except for the installation
+specific ones) have been merged back to the main distribution.
+
+=item *
+
+Perl has been tested with the GNU pth userlevel thread package
+( http://www.gnu.org/software/pth/pth.html ) . All but one thread
+test worked, and that one failure was because of test results arriving
+in unexpected order.
+
+=item *
+
Amdahl UTS UNIX mainframe platform is now supported.
=item *
=item *
Comparing with utf8 data does not magically upgrade non-utf8 data
-into utf8.
+into utf8. (This was a problem for example if you were mixing data
+from I/O and Unicode data: your output might have got magically encoded
+as UTF-8.)
+
+=item *
+
+Generating illegal Unicode code points like U+FFFE, or the UTF-16
+surrogates, now also generates an optional warning.
=item *
=item *
+perl5db.pl has been modified to present a more consistent commands
+interface, via (CommandSet=580). perl5db.t was also added to test the
+changes, and as a placeholder for further tests.
+
+See L<perldebug>
+
+=item *
+
If an attempt to use a (non-blessed) reference as an array index
is made, a warning is given.
=back
+=head2 UNICOS and UNICOS/mk
+
+The io/fs test #31 is failing because in UNICOS and UNICOS/mk
+truncate() cannot be used to grow the size of filehandles, only
+to reduce the size. The workaround is to truncate files instead
+of filehandles.
+
=head2 UTS
There are a few known test failures, see L<perluts>.
=head2 VMS
There is one known test failure with a default configuration:
-
+
[.run]switches..........................FAILED on test 1
-
+
=head2 Win32
In multi-CPU boxes there are some problems with the I/O buffering:
The compiler suite is slowly getting better but it continues to be
highly experimental. Use in production environments is discouraged.
-=head2 The Long Double Support is Still Experimental
+=head2 The Long Double Support Is Still Experimental
The ability to configure Perl's numbers to use "long doubles",
floating point numbers of hopefully better accuracy, is still
operations are more likely to be executed by less optimised
libraries).
+=head2 Seen In Perl 5.7 But Gone Now
+
+C<Time::Piece> (previously known as C<Time::Object>) was removed
+because it was felt that it didn't have enough value in it to be a
+core module. It is still a useful module, though, and is available
+from the CPAN.
+
=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://bugs.perl.org. There may also be
-information at http://www.perl.com/perl/, the Perl Home Page.
+information at http://www.perl.com/, 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
https://perl5.git.perl.org / perl5.git / blobdiff