perl58delta - what is new for perl v5.8.0
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 "[561]". Many of these changes have been further
developed since 5.6.1 was released, those are marked
"[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
perl561delta.
o Better Unicode support
o New IO Implementation
o New Thread Implementation
o Better Numeric Accuracy
o Safe Signals
o Many New Modules
o More Extensive Regression Testing
Binary Incompatibility
Perl 5.8 is not binary compatible with earlier releases of [Toc] [Back]
Perl.
You have to recompile your XS modules. [Toc] [Back]
(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.
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.
AIX Dynaloading [Toc] [Back]
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.
Attributes for "my" variables now handled at run-time
The "my EXPR : ATTRS" syntax now applies variable
attributes at run-time. (Subroutine and "our" variables
still get attributes applied at compile-time.) See
attributes for additional details. In particular, however,
this allows variable attributes to be useful for
"tie" 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).
Socket Extension Dynamic in VMS [Toc] [Back]
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.
IEEE-format Floating Point Default on OpenVMS Alpha [Toc] [Back]
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.
New Unicode Semantics (no more "use utf8", 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 eightbit
character sets, which would be illegal in UTF-8.)
See perluniintro for the explanation of the current model,
and utf8 for the current use of the utf8 pragma.
New Unicode Properties [Toc] [Back]
Unicode scripts are now supported. Scripts are similar to
(and superior to) Unicode 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 "Latin" includes
all the Latin characters and their various diacriticadorned
versions, it does not include the various punctuation
or digits (since they are not solely "Latin").
A number of other properties are now supported, including
"{L&}",
"{Any}"
"{Assigned}",
"{Unassigned}",
"{Blank}"
[561] and "{SpacePerl}"
[561] (along with
their "P{...}" versions, of course). See perlunicode for
details, and more additions.
The "In" or "Is" prefix to names used with the "{...}"
and "P{...}" are now almost always optional. The only
exception is that a "In" prefix is required to signify a
Unicode block when a block name conflicts with a script
name. For example, "{Tibetan}"
refers to the script,
while "{InTibetan}"
refers to the block. When there is
no name conflict, you can omit the "In" from the block
name (e.g. "{BraillePatterns}"),
but to be safe, it's
probably best to always use the "In").
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().
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.)
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]
Deprecations [Toc] [Back]
o The semantics of bless(REF, REF) were unclear and
until someone proves it to make some sense, it is forbidden.
o The obsolete chat2 library that should never have been
allowed to escape the laboratory has been decommissioned.
o 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.
o 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
"CORE::dump()", but in future releases the behaviour
of an unqualified "dump()" call may change.
o 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.
o The (bogus) escape sequences 8 and 9 now give an
optional warning ("Unrecognized escape passed
through"). There is no need to -escape any "0
character.
o The *glob{FILEHANDLE} is deprecated, use *glob{IO}
instead.
o The "package;" syntax ("package" 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, "use strict;" instead.
o 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.
o 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.
o Previous versions of perl and some readings of some
sections of Camel III implied that the ":raw" "discipline"
was the inverse of ":crlf". Turning off "clrfness"
is no longer enough to make a stream truly
binary. So the PerlIO ":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 ":raw" - will
now turn off both CRLF and UTF-8 translation and
remove other layers (e.g. :encoding()) which would
modify byte stream.
o The current user-visible implementation of pseudohashes
(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
"fields" pragma interface will remain available. The
restricted hashes interface is expected to be the
replacement interface (see Hash::Util). If your
existing programs depends on the underlying implementation,
consider using Class::PseudoHash from CPAN.
o The syntaxes "@a->[...]" and "%h->{...}" have now
been deprecated.
o 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.
o The 5.005 threads model (module "Thread") is deprecated
and expected to be removed in Perl 5.10. Multithreaded
code should be migrated to the new ithreads
model (see threads, threads::shared and perlthrtut).
o The long deprecated uppercase aliases for the string
comparison operators (EQ, NE, LT, LE, GE, GT) have now
been removed.
o 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]
o 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.
o The "exec LIST" and "system LIST" operations now produce
warnings on tainted data and in some future
release they will produce fatal errors.
o 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
"Localising Tied Arrays and Hashes Is Broken".
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 perluniintro for introduction and perlunicode
for details.
o 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.)
o 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 considerations,
is the Unihan database.
o The properties {Blank}
and {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 "{Space} isn't, since
that includes the vertical tabulator character,
whereas "oesn't.)
See "New Unicode Properties" earlier in this document
for additional information on changes with Unicode
properties.
PerlIO is Now The Default [Toc] [Back]
o 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', $path) || ...
or on already opened handles via extended "binmode":
binmode($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 <=> "0 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 "Installation and Configuration Improvements" for
the effects of PerlIO on your architecture name.
o If your platform supports fork(), you can use the list
form of "open" for pipes. For example:
open KID_PS, "-|", "ps", "aux" or die $!;
forks the ps(1) command (without spawning a shell, as
there are more than three arguments to open()), and
reads its standard output via the "KID_PS" filehandle.
See perlipc.
o File handles can be marked as accepting Perl's internal
encoding of Unicode (UTF-8 or UTF-EBCDIC depending
on platform) by a pseudo layer ":utf8" :
open($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 perlunicode,
utf8, and http://www.unicode.org/uni-
code/reports/tr16/ for more information. In future
releases this naming may change. See perluniintro for
more information about UTF-8.
o If your environment variables (LC_ALL, LC_CTYPE, LANG)
look like you want to use UTF-8 (any of the variables
match "/utf-?8/i"), your STDIN, STDOUT, STDERR handles
and the default open layer (see open) 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 ":bytes" (see "open" in perlfunc and
"binmode" in perlfunc), or you can just use "binmode(FH)"
(nice for pre-5.8.0 backward compatibility).
o File handles can translate character encodings from/to
Perl's internal Unicode form on read/write via the
":encoding()" layer.
o File handles can be opened to "in memory" files held
in Perl scalars via:
open($fh,'>', ariable) || ...
o Anonymous temporary files are available without need
to 'use FileHandle' or other module via
open($fh,"+>", undef) || ...
That is a literal undef, not an undefined value.
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 threads and threads::shared, and perlthrtut.
As a part of the ithreads implementation Perl will also
use any necessary and detectable reentrant libc interfaces.
Restricted Hashes [Toc] [Back]
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.
Safe Signals [Toc] [Back]
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.
Understanding of Numbers [Toc] [Back]
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 "strtoul()" and "atof()" 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.)
Arrays now always interpolate into double-quoted strings [Toc] [Back]
[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
"[email protected]" when they wanted a literal "@" sign,
just as they have always written "Give me back my "
when they wanted a literal "$" sign.
Starting with 5.6.1, when Perl now sees an "@" sign in a
double-quoted string, it always 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 "[email protected]" is going to turn
into "fred.com" if you don't backslash the "@". See
http://www.plover.com/~mjd/perl/at-error.html for more
details about the history here.
Miscellaneous Changes [Toc] [Back]
o AUTOLOAD is now lvaluable, meaning that you can add
the :lvalue attribute to AUTOLOAD subroutines and you
can assign to the AUTOLOAD return value.
o 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.
o "perl -d:Module=arg,arg,arg" now works (previously one
couldn't pass in multiple arguments.)
o "do" followed by a bareword now ensures that this
bareword isn't a keyword (to avoid a bug where "do
q(foo.pl)" tried to call a subroutine called "q").
This means that for example instead of "do format()"
you must write "do &format()".
o The builtin dump() now gives an optional warning
"dump() better written as CORE::dump()", meaning that
by default "dump(...)" is resolved as the builtin
dump() which dumps core and aborts, not as (possibly)
user-defined "sub dump". To call the latter, qualify
the call as "&dump(...)". (The whole dump() feature
is to considered deprecated, and possibly
removed/changed in future releases.)
o chomp() and chop() are now overridable. Note, however,
that their prototype (as given by "prototype("CORE::chomp")"
is undefined, because it cannot
be expressed and therefore one cannot really write
replacements to override these builtins.
o 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 perlembed.
o Formats now support zero-padded decimal fields.
o 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 "Performance Enhancements".
o lstat(FILEHANDLE) now gives a warning because the
operation makes no sense. In future releases this may
become a fatal error.
o Spurious syntax errors generated in certain situations,
when glob() caused File::Glob to be loaded for
the first time, have been fixed. [561]
o Lvalue subroutines can now return "undef" in list context.
However, the lvalue subroutine feature still
remains experimental. [561+]
o A lost warning "Can't declare ... dereference in my"
has been restored (Perl had it earlier but it became
lost in later releases.)
o A new special regular expression variable has been
introduced: $^N, which contains the most-recently
closed group (submatch).
o "no Module;" does not produce an error even if Module
does not have an unimport() method. This parallels
the behavior of "use" vis-a-vis "import". [561]
o The numerical comparison operators return "undef" if
either operand is a NaN. Previously the behaviour was
unspecified.
o "our" can now have an experimental optional attribute
"unique" that affects how global variables are shared
among multiple interpreters, see "our" in perlfunc.
o The following builtin functions are now overridable:
each(), keys(), pop(), push(), shift(), splice(),
unshift(). [561]
o "pack() / unpack()" can now group template letters
with "()" and then apply repetition/count modifiers on
the groups.
o "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 "j", "J", "F", and "D".
o "pack('U0a*', ...)" can now be used to force a string
to UTF-8.
o my __PACKAGE__ $obj now works. [561]
o POSIX::sleep() now returns the number of unslept seconds
(as the POSIX standard says), as opposed to
CORE::sleep() which returns the number of slept seconds.
o printf() and sprintf() now support parameter reordering
using the "%+ and "*+ syntaxes. For
example
printf "%2 %10, "foo", "bar";
will print "bar foo0. This feature helps in writing
internationalised software, and in general when the
order of the parameters can vary.
o The () prototype now works properly. [561]
o prototype() is now available to implicitly create
references (useful for example if you want to emulate
the tie() interface).
o A new command-line option, "-t" is available. It is
the little brother of "-T": instead of dying on taint
violations, lexical warnings are given. This is only
meant as a temporary debugging aid while securing the
code of old legacy applications. This is not a sub-
stitute for -T.
o In other taint news, the "exec LIST" and "system LIST"
have now been considered too risky (think "exec
@ARGV": 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.
o Tied hash interfaces are now required to have the
EXISTS and DELETE methods (either own or inherited).
o If tr/// is just counting characters, it doesn't
attempt to modify its target.
o untie() will now call an UNTIE() hook if it exists.
See perltie for details. [561]
o utime now supports "utime undef, undef, @files" to
change the file timestamps to the current time.
o The rules for allowing underscores (underbars) in
numeric constants have been relaxed and simplified:
now you can have an underscore simply between digits.
o Rather than relying on C's argv[0] (which may not contain
a full pathname) where possible $^X is now set by
asking the operating system. (eg by reading
/proc/self/exe on Linux, /proc/curproc/file on
FreeBSD)
o A new variable, "${^TAINT}", indicates whether taint
mode is enabled.
o You can now override the readline() builtin, and this
overrides also the <FILEHANDLE> angle bracket operator.
o The command-line options -s and -F are now recognized
on the shebang (#!) line.
o Use of the "/c" match modifier without an accompanying
"/g" modifier elicits a new warning: "Use of /c modifier
is meaningless without /g".
Use of "/c" in substitutions, even with "/g", elicits
"Use of /c modifier is meaningless in s///".
Use of "/g" with "split" elicits "Use of /g modifier
is meaningless in split".
o Support for the "CLONE" 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 "CLONE" you can do whatever
you need to do, like for example handle the
cloning of non-Perl data, if necessary. "CLONE" 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 perlmod
New Modules and Pragmata
o "Attribute::Handlers", 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!0 }
# 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
Attribute::Handlers.
o "B::Concise", 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 B::Concise. [561+]
o The new bignum, bigint, and bigrat pragmas, by Tels,
implement transparent bignum support (using the
Math::BigInt, Math::BigFloat, and Math::BigRat backends).
o "Class::ISA", by Sean Burke, is a module for reporting
the search path for a class's ISA tree. See
Class::ISA.
o "Cwd" 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.
o "Devel::PPPort", originally by Kenneth Albanowski and
now maintained by Paul Marquess, has been added. It
is primarily used by "h2xs" to enhance portability of
XS modules between different versions of Perl. See
Devel::PPPort.
o "Digest", frontend module for calculating digests
(checksums), from Gisle Aas, has been added. See
Digest.
o "Digest::MD5" for calculating MD5 digests (checksums)
as defined in RFC 1321, from Gisle Aas, has been
added. See Digest::MD5.
use Digest::MD5 'md5_hex';
$digest = md5_hex("Thirsty Camel");
print $digest, "0; #
01d19d9d2045e005c3f1b80e8b164de1
NOTE: the "MD5" backward compatibility module is
deliberately not included since its further use is
discouraged.
See also PerlIO::via::QuotedPrint.
o "Encode", originally by Nick Ing-Simmons and now maintained
by Dan Kogai, provides a mechanism to translate
between different character encodings. Support for
Unicode, ISO-8859-1, and ASCII are compiled in to the
module. Several other encodings (like the rest of the
ISO-8859, CP*/Win*, Mac, KOI8-R, three variants
EBCDIC, Chinese, Japanese, and Korean encodings) are
included and can be loaded at runtime. (For space
considerations, the largest Chinese encodings have
been separated into their own CPAN module,
Encode::HanExtra, which Encode will use if available).
See Encode.
Any encoding supported by Encode module is also available
to the ":encoding()" layer if PerlIO is used.
o "Hash::Util" is the interface to the new restricted
hashes feature. (Implemented by Jeffrey Friedl, Nick
Ing-Simmons, and Michael Schwern.) See Hash::Util.
o "I18N::Langinfo" can be used to query locale information.
See I18N::Langinfo.
o "I18N::LangTags", by Sean Burke, has functions for
dealing with RFC3066-style language tags. See
I18N::LangTags.
o "ExtUtils::Constant", by Nicholas Clark, is a new tool
for extension writers for generating XS code to import
C header constants. See ExtUtils::Constant.
o "Filter::Simple", by Damian Conway, is an easy-to-use
frontend to Filter::Util::Call. See Filter::Simple.
# in MyFilter.pm:
package MyFilter;
use Filter::Simple sub {
while (my ($from, $to) = splice @_, 0, 2) {
s/$from/$to/g;
}
};
1;
# in user's code:
use MyFilter qr/red/ => 'green';
print "red0; # this code is filtered, will print
"green0
print "bored0; # this code is filtered, will print
"bogreen0
no MyFilter;
print "red0; # this code is not filtered, will
print "red0
o "File::Temp", by Tim Jenness, allows one to create
temporary files and directories in an easy, portable,
and secure way. See File::Temp. [561+]
o "Filter::Util::Call", by Paul Marquess, provides you
with the framework to write source filters in Perl.
For most uses, the frontend Filter::Simple is to be
preferred. See Filter::Util::Call.
o "if", by Ilya Zakharevich, is a new pragma for conditional
inclusion of modules.
o libnet, by Graham Barr, is a collection of perl5 modules
related to network programming. See Net::FTP,
Net::NNTP, Net::Ping (not part of libnet, but
related), Net::POP3, Net::SMTP, and Net::Time.
Perl installation leaves libnet unconfigured; use lib-
netcfg to configure it.
o "List::Util", by Graham Barr, is a selection of general-utility
list subroutines, such as sum(), min(),
first(), and shuffle(). See List::Util.
o "Locale::Constants", "Locale::Country", "Locale::Currency"
"Locale::Language", and Locale::Script, 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 Locale::Constants, Locale::Country, Locale::Currency,
and Locale::Language.
o "Locale::Maketext", by Sean Burke, is a localization
framework. See Locale::Maketext, and Locale::Maketext::TPJ13.
The latter is an article about software
localization, originally published in The Perl Journal
#13, and republished here with kind permission.
o "Math::BigRat" for big rational numbers, to accompany
Math::BigInt and Math::BigFloat, from Tels. See
Math::BigRat.
o "Memoize" can make your functions faster by trading
space for time, from Mark-Jason Dominus. See Memoize.
o "MIME::Base64", by Gisle Aas, allows you to encode
data in base64, as defined in RFC 2045 - MIME (Multi-
purpose Internet Mail Extensions).
use MIME::Base64;
$encoded = encode_base64('Aladdin:open sesame');
$decoded = decode_base64($encoded);
print $encoded, "0; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
See MIME::Base64.
o "MIME::QuotedPrint", by Gisle Aas, allows you to
encode data in quoted-printable encoding, as defined
in RFC 2045 - MIME (Multipurpose Internet Mail Exten-
sions).
use MIME::QuotedPrint;
$encoded = encode_qp("");
$decoded = decode_qp($encoded);
print $encoded, "0; # "=DE=AD=BE=EF0
print $decoded, "0; # "0
See also PerlIO::via::QuotedPrint.
o "NEXT", by Damian Conway, is a pseudo-class for method
redispatch. See NEXT.
o "open" is a new pragma for setting the default I/O
layers for open().
o "PerlIO::scalar", by Nick Ing-Simmons, provides the
implementation of IO to "in memory" Perl scalars as
discussed above. It also serves as an example of a
loadable PerlIO layer. Other future possibilities
include PerlIO::Array and PerlIO::Code. See PerlIO::scalar.
o "PerlIO::via", by Nick Ing-Simmons, acts as a PerlIO
layer and wraps PerlIO layer functionality provided by
a class (typically implemented in Perl code).
o "PerlIO::via::QuotedPrint", by Elizabeth Mattijsen, is
an example of a "PerlIO::via" class:
use PerlIO::via::QuotedPrint;
open($fh,">:via(QuotedPrint)",$path);
This will automatically convert everything output to
$fh to Quoted-Printable. See PerlIO::via and PerlIO::via::QuotedPrint.
o "Pod::ParseLink", by Russ Allbery, has been added, to
parse L<> links in pods as described in the new
perlpodspec.
o "Pod::Text::Overstrike", by Joe Smith, has been added.
It converts POD data to formatted overstrike text.
See Pod::Text::Overstrike. [561+]
o "Scalar::Util" is a selection of general-utility
scalar subroutines, such as blessed(), reftype(), and
tainted(). See Scalar::Util.
o "sort" is a new pragma for controlling the behaviour
of sort().
o "Storable" gives persistence to Perl data structures
by allowing the storage and retrieval of Perl data to
and from files in a fast and compact binary format.
Because in effect Storable does serialisation of Perl
data structures, with it you can also clone deep,
hierarchical datastructures. Storable was originally
created by Raphael Manfredi, but it is now maintained
by Abhijit Menon-Sen. Storable has been enhanced to
understand the two new hash features, Unicode keys and
restricted hashes. See Storable.
o "Switch", by Damian Conway, has been added. Just by
saying
use Switch;
you have "switch" and "case" available in Perl.
use Switch;
switch ($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 /624
case qr/576
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 Switch.
o "Test::More", by Michael Schwern, is yet another
framework for writing test scripts, more extensive
than Test::Simple. See Test::More.
o "Test::Simple", by Michael Schwern, has basic utilities
for writing tests. See Test::Simple.
o "Text::Balanced", 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_delim-
ited_pat(), and gen_extract_tagged(). With these, you
can implement rather advanced parsing algorithms. See
Text::Balanced.
o "threads", 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 "fork()" emulation).
See threads, threads::shared, and perlthrtut.
o "threads::shared", by Arthur Bergman, allows data
sharing for interpreter threads. See threads::shared.
o "Tie::File", by Mark-Jason Dominus, associates a Perl
array with the lines of a file. See Tie::File.
o "Tie::Memoize", by Ilya Zakharevich, provides ondemand
loaded hashes. See Tie::Memoize.
o "Tie::RefHash::Nestable", by Edward Avis, allows storing
hash references (unlike the standard Tie::RefHash)
The module is contained within Tie::RefHash. See
Tie::RefHash.
o "Time::HiRes", by Douglas E. Wegscheid, provides high
resolution timing (ualarm, usleep, and gettimeofday).
See Time::HiRes.
o "Unicode::UCD" offers a querying interface to the Unicode
Character Database. See Unicode::UCD.
o "Unicode::Collate", by SADAHIRO Tomoyuki, implements
the UCA (Unicode Collation Algorithm) for sorting Unicode
strings. See Unicode::Collate.
o "Unicode::Normalize", by SADAHIRO Tomoyuki, implements
the various Unicode normalization forms. See Unicode::Normalize.
o "XS::APItest", by Tim Jenness, is a test extension
that exercises XS APIs. Currently only "printf()" is
tested: how to output various basic data types from
XS.
o "XS::Typemap", by Tim Jenness, is a test extension
that exercises XS typemaps. Nothing gets installed,
but the code is worth studying for extension writers.
Updated And Improved Modules and Pragmata [Toc] [Back]
o 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.
o attributes::reftype() now works on tied arguments.
o AutoLoader can now be disabled with "no AutoLoader;".
o 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.
o 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.
o Class::Struct can now define the classes in compile
time.
o Class::Struct now assigns the array/hash element if
the accessor is called with an array/hash element as
the sole argument.
o The return value of Cwd::fastcwd() is now tainted.
o Data::Dumper now has an option to sort hashes.
o Data::Dumper now has an option to dump code references
using B::Deparse.
o DB_File now supports newer Berkeley DB versions, among
other improvements.
o 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).
o 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 $`, $&, or $'.) Also, introduced
@LAST_MATCH_START and @LAST_MATCH_END English aliases
for "@-" and "@+".
o 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.
o 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 ExtUtils::MakeMaker for more
details.
o ExtUtils::MakeMaker now uses File::Spec internally,
which hopefully leads to better portability.
o Fcntl, Socket, and Sys::Syslog have been rewritten by
Nicholas Clark to use the new-style constant dispatch
section (see ExtUtils::Constant). This means that
they will be more robust and hopefully faster.
o File::Find now chdir()s correctly when chasing symbolic
links. [561]
o 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.
o File::Find is now (again) reentrant. It also has been
made more portable.
o The warnings issued by File::Find now belong to their
own category. You can enable/disable them with
"use/no warnings 'File::Find';".
o 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]
o File::Glob now supports "GLOB_LIMIT" constant to limit
the size of the returned list of filenames.
o IPC::Open3 now allows the use of numeric file descriptors.
o 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.
o 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]
o 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.
o IO::Socket::INET now supports a value of zero for
"LocalPort" (usually meaning that the operating system
will make one up.)
o 'use lib' now works identically to @INC. Removing
directories with 'no lib' now works.
o 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.
o Math::Complex handles inf, NaN etc., better.
o 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.
o 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.
o In Safe, %INC is now localised in a Safe compartment
so that use/require work.
o 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.
o In Search::Dict one can now have a pre-processing hook
for the lines being searched.
o The Shell module now has an OO interface.
o In Sys::Syslog there is now a failover mechanism that
will go through alternative connection mechanisms
until the message is successfully logged.
o The Test module has been significantly enhanced.
o 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.
o The vars pragma now supports declaring fully qualified
variables. (Something that "our()" does not and will
not support.)
o The "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. o Emacs perl mode (emacs/cperl-mode.el) has been updated
to version 4.31.
o emacs/e2ctags.pl is now much faster.
o "enc2xs" is a tool for people adding their own encodings
to the Encode module.
o "h2ph" now supports C trigraphs.
o "h2xs" now produces a template README.
o "h2xs" now uses "Devel::PPPort" for better portability
between different versions of Perl.
o "h2xs" uses the new ExtUtils::Constant module which
will affect newly created extensions that define constants.
Since the new code is more cor
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