=head1 NAME
perl58delta - what is new for perl v5.8.0
=head1 DESCRIPTION
This document describes differences between the 5.6.0 release and
the 5.8.0 release.
Many of the bug fixes in 5.8.0 were already seen in the 5.6.1
maintenance release since the two releases were kept closely
coordinated (while 5.8.0 was still called 5.7.something).
Changes that were integrated into the 5.6.1 release are marked C<[561]>.
Many of these changes have been further developed since 5.6.1 was released,
those are marked C<[561+]>.
You can see the list of changes in the 5.6.1 release (both from the
5.005_03 release and the 5.6.0 release) by reading L.
=head1 Highlights In 5.8.0
=over 4
=item *
Better Unicode support
=item *
New IO Implementation
=item *
New Thread Implementation
=item *
Better Numeric Accuracy
=item *
Safe Signals
=item *
Many New Modules
=item *
More Extensive Regression Testing
=back
=head1 Incompatible Changes
=head2 Binary Incompatibility
B
B
(Pure Perl modules should continue to work.)
The major reason for the discontinuity is the new IO architecture
called PerlIO. PerlIO is the default configuration because without
it many new features of Perl 5.8 cannot be used. In other words:
you just have to recompile your modules containing XS code, sorry
about that.
In future releases of Perl, non-PerlIO aware XS modules may become
completely unsupported. This shouldn't be too difficult for module
authors, however: PerlIO has been designed as a drop-in replacement
(at the source code level) for the stdio interface.
Depending on your platform, there are also other reasons why
we decided to break binary compatibility, please read on.
=head2 64-bit platforms and malloc
If your pointers are 64 bits wide, the Perl malloc is no longer being
used because it does not work well with 8-byte pointers. Also,
usually the system mallocs on such platforms are much better optimized
for such large memory models than the Perl malloc. Some memory-hungry
Perl applications like the PDL don't work well with Perl's malloc.
Finally, other applications than Perl (such as mod_perl) tend to prefer
the system malloc. Such platforms include Alpha and 64-bit HPPA,
MIPS, PPC, and Sparc.
=head2 AIX Dynaloading
The AIX dynaloading now uses in AIX releases 4.3 and newer the native
dlopen interface of AIX instead of the old emulated interface. This
change will probably break backward compatibility with compiled
modules. The change was made to make Perl more compliant with other
applications like mod_perl which are using the AIX native interface.
=head2 Attributes for C variables now handled at run-time
The C syntax now applies variable attributes at
run-time. (Subroutine and C variables still get attributes applied
at compile-time.) See L for additional details. In particular,
however, this allows variable attributes to be useful for C interfaces,
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
The Socket extension is now dynamically loaded instead of being
statically built in. This may or may not be a problem with ancient
TCP/IP stacks of VMS: we do not know since we weren't able to test
Perl in such configurations.
=head2 IEEE-format Floating Point Default on OpenVMS Alpha
Perl now uses IEEE format (T_FLOAT) as the default internal floating
point format on OpenVMS Alpha, potentially breaking binary compatibility
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 New Unicode Semantics (no more C, almost)
Previously in Perl 5.6 to use Unicode one would say "use utf8" and
then the operations (like string concatenation) were Unicode-aware
in that lexical scope.
This was found to be an inconvenient interface, and in Perl 5.8 the
Unicode model has completely changed: now the "Unicodeness" is bound
to the data itself, and for most of the time "use utf8" is not needed
at all. The only remaining use of "use utf8" is when the Perl script
itself has been written in the UTF-8 encoding of Unicode. (UTF-8 has
not been made the default since there are many Perl scripts out there
that are using various national eight-bit character sets, which would
be illegal in UTF-8.)
See L for the explanation of the current model,
and L for the current use of the utf8 pragma.
=head2 New Unicode Properties
Unicode I are now supported. Scripts are similar to (and superior
to) Unicode I. 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 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).
A number of other properties are now supported, including C<\p{L&}>,
C<\p{Any}> C<\p{Assigned}>, C<\p{Unassigned}>, C<\p{Blank}> [561] and
C<\p{SpacePerl}> [561] (along with their C<\P{...}> versions, of course).
See L for details, and more additions.
The C or C prefix to names used with the C<\p{...}> and C<\P{...}>
are now almost always optional. The only exception is that a C 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 from the block name (e.g. C<\p{BraillePatterns}>), but
to be safe, it's probably best to always use the C).
=head2 REF(...) Instead Of SCALAR(...)
A reference to a reference now stringifies as "REF(0x81485ec)" instead
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 d/f, but you never knew that.)
=head2 glob() now returns filenames in alphabetical order
The list of filenames from glob() (or <...>) is now by default sorted
alphabetically to be csh-compliant (which is what happened before
in most UNIX platforms). (bsd_glob() does still sort platform
natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.) [561]
=head2 Deprecations
=over 4
=item *
The semantics of bless(REF, REF) were unclear and until someone proves
it to make some sense, it is forbidden.
=item *
The obsolete chat2 library that should never have been allowed
to escape the laboratory has been decommissioned.
=item *
Using chdir("") or chdir(undef) instead of explicit chdir() is
doubtful. A failure (think chdir(some_function()) can lead into
unintended chdir() to the home directory, therefore this behaviour
is deprecated.
=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, but in future
releases the behaviour of an unqualified C 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)
maintained.
=item *
The (bogus) escape sequences \8 and \9 now give an optional warning
("Unrecognized escape passed through"). There is no need to \-escape
any C<\w> character.
=item *
The *glob{FILEHANDLE} is deprecated, use *glob{IO} instead.
=item *
The C syntax (C without an argument) has been
deprecated. Its semantics were never that clear and its
implementation even less so. If you have used that feature to
disallow all but fully qualified variables, C instead.
=item *
The unimplemented POSIX regex features [[.cc.]] and [[=c=]] are still
recognised but now cause fatal errors. The previous behaviour of
ignoring them by default and warning if requested was unacceptable
since it, in a way, falsely promised that the features could be used.
=item *
In future releases, non-PerlIO aware XS modules may become completely
unsupported. Since PerlIO is a drop-in replacement for stdio at the
source code level, this shouldn't be that drastic a change.
=item *
Previous versions of perl and some readings of some sections of Camel
III implied that the C<:raw> "discipline" was the inverse of C<:crlf>.
Turning off "clrfness" is no longer enough to make a stream truly
binary. So the PerlIO C<:raw> layer (or "discipline", to use the Camel
book's older terminology) is now formally defined as being equivalent
to binmode(FH) - which is in turn defined as doing whatever is
necessary to pass each byte as-is without any translation. In
particular binmode(FH) - and hence C<:raw> - will now turn off both
CRLF and UTF-8 translation and remove other layers (e.g. :encoding())
which would modify byte stream.
=item *
The current user-visible implementation of pseudo-hashes (the weird
use of the first array element) is deprecated starting from Perl 5.8.0
and will be removed in Perl 5.10.0, and the feature will be
implemented differently. Not only is the current interface rather
ugly, but the current implementation slows down normal array and hash
use quite noticeably. The C pragma interface will remain
available. The I interface is expected to
be the replacement interface (see L). If your existing
programs depends on the underlying implementation, consider using
L from CPAN.
=item *
The syntaxes C<< @a->[...] >> and C<< %h->{...} >> have now been deprecated.
=item *
After years of trying, suidperl is considered to be too complex to
ever be considered truly secure. The suidperl functionality is likely
to be removed in a future release.
=item *
The 5.005 threads model (module C) is deprecated and expected
to be removed in Perl 5.10. Multithreaded code should be migrated to
the new ithreads model (see L, L and
L).
=item *
The long deprecated uppercase aliases for the string comparison
operators (EQ, NE, LT, LE, GE, GT) have now been removed.
=item *
The tr///C and tr///U features have been removed and will not return;
the interface was a mistake. Sorry about that. For similar
functionality, see pack('U0', ...) and pack('C0', ...). [561]
=item *
Earlier Perls treated "sub foo (@bar)" as equivalent to "sub foo (@)".
The prototypes are now checked better at compile-time for invalid
syntax. An optional warning is generated ("Illegal character in
prototype...") but this may be upgraded to a fatal error in a future
release.
=item *
The C and C operations now produce warnings on
tainted data and in some future release they will produce fatal errors.
=item *
The existing behaviour when localising tied arrays and hashes is wrong,
and will be changed in a future release, so do not rely on the existing
behaviour. See L<"Localising Tied Arrays and Hashes Is Broken">.
=back
=head1 Core Enhancements
=head2 Unicode Overhaul
Unicode in general should be now much more usable than in Perl 5.6.0
(or even in 5.6.1). Unicode can be used in hash keys, Unicode in
regular expressions should work now, Unicode in tr/// should work now,
Unicode in I/O should work now. See L for introduction
and L for details.
=over 4
=item *
The Unicode Character Database coming with Perl has been upgraded
to Unicode 3.2.0. For more information, see http://www.unicode.org/ .
[561+] (5.6.1 has UCD 3.0.1.)
=item *
For developers interested in enhancing Perl's Unicode capabilities:
almost all the UCD files are included with the Perl distribution in
the F subdirectory. The most notable omission, for space
considerations, is the Unihan database.
=item *
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
=head2 PerlIO is Now The Default
=over 4
=item *
IO is now by default done via PerlIO rather than system's "stdio".
PerlIO allows "layers" to be "pushed" onto a file handle to alter the
handle's behaviour. Layers can be specified at open time via 3-arg
form of open:
open($fh,'>:crlf :utf8', $path) || ...
or on already opened handles via extended C:
binmode($fh,':encoding(iso-8859-7)');
The built-in layers are: unix (low level read/write), stdio (as in
previous Perls), perlio (re-implementation of stdio buffering in a
portable manner), crlf (does CRLF <=> "\n" translation as on Win32,
but available on any platform). A mmap layer may be available if
platform supports it (mostly UNIXes).
Layers to be applied by default may be specified via the 'open' pragma.
See L for the effects
of PerlIO on your architecture name.
=item *
If your platform supports fork(), you can use the list form of C
for pipes. For example:
open KID_PS, "-|", "ps", "aux" or die $!;
forks the ps(1) command (without spawning a shell, as there are more
than three arguments to open()), and reads its standard output via the
C filehandle. See L.
=item *
File handles can be marked as accepting Perl's internal encoding of Unicode
(UTF-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" :
open($fh,">:utf8","Uni.txt");
Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
for you since it's not UTF-8 what you will be getting but instead
UTF-EBCDIC. See L, L, and
http://www.unicode.org/unicode/reports/tr16/ for more information.
In future releases this naming may change. See L
for more information about UTF-8.
=item *
If your environment variables (LC_ALL, LC_CTYPE, LANG) look like you
want to use UTF-8 (any of the variables match C), your
STDIN, STDOUT, STDERR handles and the default open layer (see L)
are marked as UTF-8. (This feature, like other new features that
combine Unicode and I/O, work only if you are using PerlIO, but that's
the default.)
Note that after this Perl really does assume that everything is UTF-8:
for example if some input handle is not, Perl will probably very soon
complain about the input data like this "Malformed UTF-8 ..." since
any old eight-bit data is not legal UTF-8.
Note for code authors: if you want to enable your users to use UTF-8
as their default encoding but in your code still have eight-bit I/O streams
(such as images or zip files), you need to explicitly open() or binmode()
with C<:bytes> (see L and L), or you
can just use C (nice for pre-5.8.0 backward compatibility).
=item *
File handles can translate character encodings from/to Perl's internal
Unicode form on read/write via the ":encoding()" layer.
=item *
File handles can be opened to "in memory" files held in Perl scalars via:
open($fh,'>', \$variable) || ...
=item *
Anonymous temporary files are available without need to
'use FileHandle' or other module via
open($fh,"+>", undef) || ...
That is a literal undef, not an undefined value.
=back
=head2 ithreads
The new interpreter threads ("ithreads" for short) implementation of
multithreading, by Arthur Bergman, replaces the old "5.005 threads"
implementation. In the ithreads model any data sharing between
threads must be explicit, as opposed to the model where data sharing
was implicit. See L and L, and
L.
As a part of the ithreads implementation Perl will also use
any necessary and detectable reentrant libc interfaces.
=head2 Restricted Hashes
A restricted hash is restricted to a certain set of keys, no keys
outside the set can be added. Also individual keys can be restricted
so that the key cannot be deleted and the value cannot be changed.
No new syntax is involved: the Hash::Util module is the interface.
=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 (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. Note that breaking
out from potentially blocking operations should still work, though.
=head2 Understanding of Numbers
In general a lot of fixing has happened in the area of Perl's
understanding of numbers, both integer and floating point. Since in
many systems the standard number parsing functions like C
and C seem to have bugs, Perl tries to work around their
deficiencies. This results hopefully in more accurate numbers.
Perl now tries internally to use integer values in numeric conversions
and basic arithmetics (+ - * /) if the arguments are integers, and
tries also to keep the results stored internally as integers.
This change leads to often slightly faster and always less lossy
arithmetics. (Previously Perl always preferred floating point numbers
in its math.)
=head2 Arrays now always interpolate into double-quoted strings [561]
In double-quoted strings, arrays now interpolate, no matter what. The
behavior in earlier versions of perl 5 was that arrays would interpolate
into strings if the array had been mentioned before the string was
compiled, and otherwise Perl would raise a fatal compile-time error.
In versions 5.000 through 5.003, the error was
Literal @example now requires backslash
In versions 5.004_01 through 5.6.0, the error was
In string, @example now must be written as \@example
The idea here was to get people into the habit of writing
C<"fred\@example.com"> when they wanted a literal C<@> sign, just as
they have always written C<"Give me back my \$5"> when they wanted a
literal C<$> sign.
Starting with 5.6.1, when Perl now sees an C<@> sign in a
double-quoted string, it I attempts to interpolate an array,
regardless of whether or not the array has been used or declared
already. The fatal error has been downgraded to an optional warning:
Possible unintended interpolation of @example in string
This warns you that C<"fred@example.com"> is going to turn into
C if you don't backslash the C<@>.
See http://www.plover.com/~mjd/perl/at-error.html for more details
about the history here.
=head2 Miscellaneous Changes
=over 4
=item *
AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
=item *
The $Config{byteorder} (and corresponding BYTEORDER in config.h) was
previously wrong in platforms if sizeof(long) was 4, but sizeof(IV)
was 8. The byteorder was only sizeof(long) bytes long (1234 or 4321),
but now it is correctly sizeof(IV) bytes long, (12345678 or 87654321).
(This problem didn't affect Windows platforms.)
Also, $Config{byteorder} is now computed dynamically--this is more
robust with "fat binaries" where an executable image contains binaries
for more than one binary platform, and when cross-compiling.
=item *
C now works (previously one couldn't pass
in multiple arguments.)
=item *
C followed by a bareword now ensures that this bareword isn't
a keyword (to avoid a bug where C tried to call a
subroutine called C). This means that for example instead of
C you must write C.
=item *
The builtin dump() now gives an optional warning
C,
meaning that by default C is resolved as the builtin
dump() which dumps core and aborts, not as (possibly) user-defined
C. 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() are now overridable. Note, however, that their
prototype (as given by C is undefined,
because it cannot be expressed and therefore one cannot really 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
behaviour for Perl embedders. This will default in 5.10. See
L.
=item *
Formats now support zero-padded decimal fields.
=item *
Although "you shouldn't do that", it was possible to write code that
depends on Perl's hashed key order (Data::Dumper does this). The new
algorithm "One-at-a-Time" produces a different hashed key order.
More details are in L.
=item *
lstat(FILEHANDLE) now gives a warning because the operation makes no sense.
In future releases this may become a fatal error.
=item *
Spurious syntax errors generated in certain situations, when glob()
caused File::Glob to be loaded for the first time, have been fixed. [561]
=item *
Lvalue subroutines can now return C in list context. However,
the lvalue subroutine feature still remains experimental. [561+]
=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 does not produce an error even if Module does not have an
unimport() method. This parallels the behavior of C vis-a-vis
C. [561]
=item *
The numerical comparison operators return C if either operand
is a NaN. Previously the behaviour was unspecified.
=item *
C can now have an experimental optional attribute C that
affects how global variables are shared among multiple interpreters,
see L.
=item *
The following builtin functions are now overridable: each(), keys(),
pop(), push(), shift(), splice(), unshift(). [561]
=item *
C can now group template letters with C<()> and then
apply repetition/count modifiers on the groups.
=item *
C 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, C, C, and C.
=item *
C can now be used to force a string to UTF-8.
=item *
my __PACKAGE__ $obj now works. [561]
=item *
POSIX::sleep() now returns the number of I seconds
(as the POSIX standard says), as opposed to CORE::sleep() which
returns the number of slept seconds.
=item *
printf() and sprintf() now support parameter reordering using the
C<%\d+\$> and C<*\d+\$> syntaxes. For example
printf "%2\$s %1\$s\n", "foo", "bar";
will print "bar foo\n". This feature helps in writing
internationalised software, and in general when the order
of the parameters can vary.
=item *
The (\&) prototype now works properly. [561]
=item *
prototype(\[$@%&]) is now available to implicitly create references
(useful for example if you want to emulate the tie() interface).
=item *
A new command-line option, C<-t> is available. It is the
little brother of C<-T>: instead of dying on taint violations,
lexical warnings are given. B
=item *
In other taint news, the C and C have now been
considered too risky (think C: it can start any program
with any arguments), and now the said forms cause a warning under
lexical warnings. 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 *
Tied hash interfaces are now required to have the EXISTS and DELETE
methods (either own or inherited).
=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
for details. [561]
=item *
L now supports C to change the
file timestamps to the current time.
=item *
The rules for allowing underscores (underbars) in numeric constants
have been relaxed and simplified: now you can have an underscore
simply B.
=item *
Rather than relying on C's argv[0] (which may not contain a full pathname)
where possible $^X is now set by asking the operating system.
(eg by reading F on Linux, F on FreeBSD)
=item *
A new variable, C<${^TAINT}>, indicates whether taint mode is enabled.
=item *
You can now override the readline() builtin, and this overrides also
the angle bracket operator.
=item *
The command-line options -s and -F are now recognized on the shebang
(#!) line.
=item *
Use of the C match modifier without an accompanying C modifier
elicits a new warning: C.
Use of C in substitutions, even with C, elicits
C elicits C.
=item *
Support for the C special subroutine had been added.
With ithreads, when a new thread is created, all Perl data is cloned,
however non-Perl data cannot be cloned automatically. In C you
can do whatever you need to do, like for example handle the cloning of
non-Perl data, if necessary. C will be executed once for every
package that has it defined or inherited. It will be called in the
context of the new thread, so all modifications are made in the new area.
See L
=back
=head1 Modules and Pragmata
=head2 New Modules and Pragmata
=over 4
=item *
C, originally by Damian Conway and now maintained
by Arthur Bergman, 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).
See L.
=item *
C, by Stephen McCamant, is a new compiler backend for
walking the Perl syntax tree, printing concise info about ops.
The output is highly customisable. See L. [561+]
=item *
The new bignum, bigint, and bigrat pragmas, by Tels, implement
transparent bignum support (using the Math::BigInt, Math::BigFloat,
and Math::BigRat backends).
=item *
C, by Sean Burke, is a module for reporting the search
path for a class's ISA tree. See L.
=item *
C now has a split personality: if possible, an XS extension is
used, (this will hopefully be faster, more secure, and more robust)
but if not possible, the familiar Perl implementation is used.
=item *
C, originally by Kenneth Albanowski and now
maintained by Paul Marquess, has been added. It is primarily used
by C to enhance portability of XS modules between different
versions of Perl. See L.
=item *
C, frontend module for calculating digests (checksums), from
Gisle Aas, has been added. See L.
=item *
C for calculating MD5 digests (checksums) as defined in
RFC 1321, from Gisle Aas, has been added. See L.
use Digest::MD5 'md5_hex';
$digest = md5_hex("Thirsty Camel");
print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
NOTE: the C backward compatibility module is deliberately not
included since its further use is discouraged.
See also L.
=item *
C, originally by Nick Ing-Simmons and now maintained by Dan
Kogai, provides a mechanism to translate between different character
encodings. Support for Unicode, ISO-8859-1, and ASCII are compiled in
to the module. Several other encodings (like the rest of the
ISO-8859, CP*/Win*, Mac, KOI8-R, three variants EBCDIC, Chinese,
Japanese, and Korean encodings) are included and can be loaded at
runtime. (For space considerations, the largest Chinese encodings
have been separated into their own CPAN module, Encode::HanExtra,
which Encode will use if available). See L.
Any encoding supported by Encode module is also available to the
":encoding()" layer if PerlIO is used.
=item *
C is the interface to the new I
feature. (Implemented by Jeffrey Friedl, Nick Ing-Simmons, and
Michael Schwern.) See L.
=item *
C can be used to query locale information.
See L.
=item *
C, by Sean Burke, has functions for dealing with
RFC3066-style language tags. See L.
=item *
C, by Nicholas Clark, is a new tool for extension
writers for generating XS code to import C header constants.
See L.
=item *
C, by Damian Conway, is an easy-to-use frontend to
Filter::Util::Call. See L.
# in MyFilter.pm:
package MyFilter;
use Filter::Simple sub {
while (my ($from, $to) = splice @_, 0, 2) {
s/$from/$to/g;
}
};
1;
# in user's code:
use MyFilter qr/red/ => 'green';
print "red\n"; # this code is filtered, will print "green\n"
print "bored\n"; # this code is filtered, will print "bogreen\n"
no MyFilter;
print "red\n"; # this code is not filtered, will print "red\n"
=item *
C, by Tim Jenness, allows one to create temporary files
and directories in an easy, portable, and secure way. See L.
[561+]
=item *
C, by Paul Marquess, provides you with the
framework to write I in Perl. For most uses, the
frontend Filter::Simple is to be preferred. See L.
=item *
C, by Ilya Zakharevich, is a new pragma for conditional inclusion
of modules.
=item *
L, by Graham Barr, is a collection of perl5 modules related
to network programming. See L, L, L
(not part of libnet, but related), L, L,
and L.
Perl installation leaves libnet unconfigured; use F
to configure it.
=item *
C, by Graham Barr, is a selection of general-utility
list subroutines, such as sum(), min(), first(), and shuffle().
See L.
=item *
C, C, C
C, and L, by Neil Bowers, have
been added. They provide the codes for various locale standards, such
as "fr" for France, "usd" for US Dollar, and "ja" for Japanese.
use Locale::Country;
$country = code2country('jp'); # $country gets 'Japan'
$code = country2code('Norway'); # $code gets 'no'
See L, L, L,
and L.
=item *
C, by Sean Burke, is a localization framework. See
L, and L. The latter is an
article about software localization, originally published in The Perl
Journal #13, and republished here with kind permission.
=item *
C for big rational numbers, to accompany Math::BigInt and
Math::BigFloat, from Tels. See L.
=item *
C can make your functions faster by trading space for time,
from Mark-Jason Dominus. See L.
=item *
C, by Gisle Aas, allows you to encode data in base64,
as defined in RFC 2045 - I.
use MIME::Base64;
$encoded = encode_base64('Aladdin:open sesame');
$decoded = decode_base64($encoded);
print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
See L.
=item *
C, by Gisle Aas, allows you to encode data
in quoted-printable encoding, as defined in RFC 2045 - I.
use MIME::QuotedPrint;
$encoded = encode_qp("\xDE\xAD\xBE\xEF");
$decoded = decode_qp($encoded);
print $encoded, "\n"; # "=DE=AD=BE=EF\n"
print $decoded, "\n"; # "\xDE\xAD\xBE\xEF\n"
See also L.
=item *
C, by Damian Conway, is a pseudo-class for method redispatch.
See L.
=item *
C is a new pragma for setting the default I/O layers
for open().
=item *
C, by Nick Ing-Simmons, provides the implementation
of IO to "in memory" Perl scalars as discussed above. It also serves
as an example of a loadable PerlIO layer. Other future possibilities
include PerlIO::Array and PerlIO::Code. See L.
=item *
C, by Nick Ing-Simmons, acts as a PerlIO layer and wraps
PerlIO layer functionality provided by a class (typically implemented
in Perl code).
=item *
C, by Elizabeth Mattijsen, is an example
of a C class:
use PerlIO::via::QuotedPrint;
open($fh,">:via(QuotedPrint)",$path);
This will automatically convert everything output to C<$fh> to
Quoted-Printable. See L and L.
=item *
C, by Russ Allbery, has been added,
to parse LZ<><> links in pods as described in the new
perlpodspec.
=item *
C, by Joe Smith, has been added.
It converts POD data to formatted overstrike text.
See L. [561+]
=item *
C is a selection of general-utility scalar subroutines,
such as blessed(), reftype(), and tainted(). See L.
=item *
C is a new pragma for controlling the behaviour of sort().
=item *
C gives persistence to Perl data structures by allowing the
storage and retrieval of Perl data to and from files in a fast and
compact binary format. Because in effect Storable does serialisation
of Perl data structures, with it you can also clone deep, hierarchical
datastructures. Storable was originally created by Raphael Manfredi,
but it is now maintained by Abhijit Menon-Sen. Storable has been
enhanced to understand the two new hash features, Unicode keys and
restricted hashes. See L.
=item *
C, by Damian Conway, has been added. Just by saying
use Switch;
you have C and C available in Perl.
use Switch;
switch ($val) {
case 1 { print "number 1" }
case "a" { print "string a" }
case [1..10,42] { print "number in list" }
case (@array) { print "number in list" }
case /\w+/ { print "pattern" }
case qr/\w+/ { print "pattern" }
case (%hash) { print "entry in hash" }
case (\%hash) { print "entry in hash" }
case (\&sub) { print "arg to subroutine" }
else { print "previous case not true" }
}
See L.
=item *
C, by Michael Schwern, is yet another framework for writing
test scripts, more extensive than Test::Simple. See L.
=item *
C, by Michael Schwern, has basic utilities for writing
tests. See L.
=item *
C, by Damian Conway, has been added, for extracting
delimited text sequences from strings.
use Text::Balanced 'extract_delimited';
($a, $b) = extract_delimited("'never say never', he never said", "'", '');
$a will be "'never say never'", $b will be ', he never said'.
In addition to extract_delimited(), there are also extract_bracketed(),
extract_quotelike(), extract_codeblock(), extract_variable(),
extract_tagged(), extract_multiple(), gen_delimited_pat(), and
gen_extract_tagged(). With these, you can implement rather advanced
parsing algorithms. See L.
=item *
C, by Arthur Bergman, is an interface to interpreter threads.
Interpreter threads (ithreads) is the new thread model introduced in
Perl 5.6 but only available as an internal interface for extension
writers (and for Win32 Perl for C emulation). See L,
L, and L.
=item *
C, by Arthur Bergman, allows data sharing for
interpreter threads. See L.
=item *
C, by Mark-Jason Dominus, associates a Perl array with the
lines of a file. See L.
=item *
C, by Ilya Zakharevich, provides on-demand loaded hashes.
See L.
=item *
C, by Edward Avis, allows storing hash
references (unlike the standard Tie::RefHash) The module is contained
within Tie::RefHash. See L.
=item *
C, by Douglas E. Wegscheid, provides high resolution
timing (ualarm, usleep, and gettimeofday). See L.
=item *
C offers a querying interface to the Unicode Character
Database. See L.
=item *
C, by SADAHIRO Tomoyuki, implements the UCA
(Unicode Collation Algorithm) for sorting Unicode strings.
See L.
=item *
C, by SADAHIRO Tomoyuki, implements the various
Unicode normalization forms. See L.
=item *
C, by Tim Jenness, is a test extension that exercises XS
APIs. Currently only C is tested: how to output various
basic data types from XS.
=item *
C, by Tim Jenness, is a test extension that exercises
XS typemaps. Nothing gets installed, but the code is worth studying
for extension writers.
=back
=head2 Updated And Improved Modules and Pragmata
=over 4
=item *
The following independently supported modules have been updated to the
newest versions from CPAN: CGI, CPAN, DB_File, File::Spec, File::Temp,
Getopt::Long, Math::BigFloat, Math::BigInt, the podlators bundle
(Pod::Man, Pod::Text), Pod::LaTeX [561+], Pod::Parser, Storable,
Term::ANSIColor, Test, Text-Tabs+Wrap.
=item *
attributes::reftype() now works on tied arguments.
=item *
AutoLoader can now be disabled with C.
=item *
B::Deparse has been significantly enhanced by Robin Houston. It can
now deparse almost all of the standard test suite (so that the tests
still succeed). There is a make target "test.deparse" for trying this
out.
=item *
Carp now has better interface documentation, and the @CARP_NOT
interface has been added to get optional control over where errors
are reported independently of @ISA, by Ben Tilly.
=item *
Class::Struct can now define the classes in compile time.
=item *
Class::Struct now assigns the array/hash element if the accessor
is called with an array/hash element as the B argument.
=item *
The return value of Cwd::fastcwd() is now tainted.
=item *
Data::Dumper now has an option to sort hashes.
=item *
Data::Dumper now has an option to dump code references
using B::Deparse.
=item *
DB_File now supports newer Berkeley DB versions, among
other improvements.
=item *
Devel::Peek now has an interface for the Perl memory statistics
(this works only if you are using perl's malloc, and if you have
compiled with debugging).
=item *
The English module can now be used without the infamous performance
hit by saying
use English '-no_match_vars';
(Assuming, of course, that you don't need the troublesome variables
C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
=item *
ExtUtils::MakeMaker has been significantly cleaned up and fixed.
The enhanced version has also been backported to earlier releases
of Perl and submitted to CPAN so that the earlier releases can
enjoy the fixes.
=item *
The arguments of WriteMakefile() in Makefile.PL are now checked
for sanity much more carefully than before. This may cause new
warnings when modules are being installed. See L
for more details.
=item *
ExtUtils::MakeMaker now uses File::Spec internally, which hopefully
leads to better portability.
=item *
Fcntl, Socket, and Sys::Syslog have been rewritten by Nicholas Clark
to use the new-style constant dispatch section (see L).
This means that they will be more robust and hopefully faster.
=item *
File::Find now chdir()s correctly when chasing symbolic links. [561]
=item *
File::Find now has pre- and post-processing callbacks. It also
correctly changes directories when chasing symbolic links. Callbacks
(naughtily) exiting with "next;" instead of "return;" now work.
=item *
File::Find is now (again) reentrant. It also has been made
more portable.
=item *
The warnings issued by File::Find now belong to their own category.
You can enable/disable them with C.
=item *
File::Glob::glob() has been renamed to File::Glob::bsd_glob()
because the name clashes with the builtin glob(). The older
name is still available for compatibility, but is deprecated. [561]
=item *
File::Glob now supports C constant to limit the size of
the returned list of filenames.
=item *
IPC::Open3 now allows the use of numeric file descriptors.
=item *
IO::Socket now has an atmark() method, which returns true if the socket
is positioned at the out-of-band mark. The method is also exportable
as a sockatmark() function.
=item *
IO::Socket::INET failed to open the specified port if the service name
was not known. It now correctly uses the supplied port number as is. [561]
=item *
IO::Socket::INET has support for the ReusePort option (if your
platform supports it). The Reuse option now has an alias, ReuseAddr.
For clarity, you may want to prefer ReuseAddr.
=item *
IO::Socket::INET now supports a value of zero for C
(usually meaning that the operating system will make one up.)
=item *
'use lib' now works identically to @INC. Removing directories
with 'no lib' now works.
=item *
Math::BigFloat and Math::BigInt have undergone a full rewrite by Tels.
They are now magnitudes faster, and they support various bignum
libraries such as GMP and PARI as their backends.
=item *
Math::Complex handles inf, NaN etc., better.
=item *
Net::Ping has been considerably enhanced by Rob Brown: multihoming is
now supported, Win32 functionality is better, there is now time
measuring functionality (optionally high-resolution using
Time::HiRes), and there is now "external" protocol which uses
Net::Ping::External module which runs your external ping utility and
parses the output. A version of Net::Ping::External is available in
CPAN.
Note that some of the Net::Ping tests are disabled when running
under the Perl distribution since one cannot assume one or more
of the following: enabled echo port at localhost, full Internet
connectivity, or sympathetic firewalls. You can set the environment
variable PERL_TEST_Net_Ping to "1" (one) before running the Perl test
suite to enable all the Net::Ping tests.
=item *
POSIX::sigaction() is now much more flexible and robust.
You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
handlers, installing new handlers was not atomic.
=item *
In Safe, C<%INC> is now localised in a Safe compartment so that
use/require work.
=item *
In SDBM_File on dosish platforms, some keys went missing because of
lack of support for files with "holes". A workaround for the problem
has been added.
=item *
In Search::Dict one can now have a pre-processing hook for the
lines being searched.
=item *
The Shell module now has an OO interface.
=item *
In Sys::Syslog there is now a failover mechanism that will go
through alternative connection mechanisms until the message
is successfully logged.
=item *
The Test module has been significantly enhanced.
=item *
Time::Local::timelocal() does not handle fractional seconds anymore.
The rationale is that neither does localtime(), and timelocal() and
localtime() are supposed to be inverses of each other.
=item *
The vars pragma now supports declaring fully qualified variables.
(Something that C does not and will not support.)
=item *
The C 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.
=back
=head1 Utility Changes
=over 4
=item *
Emacs perl mode (emacs/cperl-mode.el) has been updated to version
4.31.
=item *
F is now much faster.
=item *
C is a tool for people adding their own encodings to the
Encode module.
=item *
C now supports C trigraphs.
=item *
C now produces a template README.
=item *
C now uses C for better portability between
different versions of Perl.
=item *
C uses the new L module
which will affect newly created extensions that define constants.
Since the new code is more correct (if you have two constants where the
first one is a prefix of the second one, the first constant B
got defined), less lossy (it uses integers for integer constant,
as opposed to the old code that used floating point numbers even for
integer constants), and slightly faster, you might want to consider
regenerating your extension code (the new scheme makes regenerating
easy). L now also supports C trigraphs.
=item *
C has been added to configure libnet.
=item *
C is now much more robust. It also sends the bug report to
perl.org, not perl.com.
=item *
C has been rewritten and its user interface (that is,
command line) is much more like that of the UNIX C compiler, cc.
(The perlbc tools has been removed. Use C instead.)
B [561]
=item *
C is a new Installation Verification Procedure utility
for running any time after installing Perl.
=item *
C is an implementation of the character conversion utility
C, demonstrating the new Encode module.
=item *
C now allows specifying a cache directory.
=item *
C now produces XHTML 1.0.
=item *
C now understands POD written using different line endings
(PC-like CRLF versus UNIX-like LF versus MacClassic-like CR).
=item *
C has been completely rewritten in Perl. (It is in fact a full
implementation of sed in Perl: you can use the sed functionality by
using the C utility.)
=item *
C now understands POD documentation embedded in the *.xs
files. [561]
=item *
C now supports the OUT keyword.
=back
=head1 New Documentation
=over 4
=item *
perl56delta details the changes between the 5.005 release and the
5.6.0 release.
=item *
perlclib documents the internal replacements for standard C library
functions. (Interesting only for extension writers and Perl core
hackers.) [561+]
=item *
perldebtut is a Perl debugging tutorial. [561+]
=item *
perlebcdic contains considerations for running Perl on EBCDIC
platforms. [561+]
=item *
perlintro is a gentle introduction to Perl.
=item *
perliol documents the internals of PerlIO with layers.
=item *
perlmodstyle is a style guide for writing modules.
=item *
perlnewmod tells about writing and submitting a new module. [561+]
=item *
perlpacktut is a pack() tutorial.
=item *
perlpod has been rewritten to be clearer and to record the best
practices gathered over the years.
=item *
perlpodspec is a more formal specification of the pod format,
mainly of interest for writers of pod applications, not to
people writing in pod.
=item *
perlretut is a regular expression tutorial. [561+]
=item *
perlrequick is a regular expressions quick-start guide.
Yes, much quicker than perlretut. [561]
=item *
perltodo has been updated.
=item *
perltootc has been renamed as perltooc (to not to conflict
with perltoot in filesystems restricted to "8.3" names).
=item *
perluniintro is an introduction to using Unicode in Perl.
(perlunicode is more of a detailed reference and background
information)
=item *
perlutil explains the command line utilities packaged with the Perl
distribution. [561+]
=back
The following platform-specific documents are available before
the installation as README.I, and after the installation
as perlI