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diff --git a/Master/tlpkg/tlperl/lib/pods/perl5100delta.pod b/Master/tlpkg/tlperl/lib/pods/perl5100delta.pod deleted file mode 100644 index 4e5c6d3a2b6..00000000000 --- a/Master/tlpkg/tlperl/lib/pods/perl5100delta.pod +++ /dev/null @@ -1,1612 +0,0 @@ -=encoding utf8 - -=head1 NAME - -perl5100delta - what is new for perl 5.10.0 - -=head1 DESCRIPTION - -This document describes the differences between the 5.8.8 release and -the 5.10.0 release. - -Many of the bug fixes in 5.10.0 were already seen in the 5.8.X maintenance -releases; they are not duplicated here and are documented in the set of -man pages named perl58[1-8]?delta. - -=head1 Core Enhancements - -=head2 The C<feature> pragma - -The C<feature> pragma is used to enable new syntax that would break Perl's -backwards-compatibility with older releases of the language. It's a lexical -pragma, like C<strict> or C<warnings>. - -Currently the following new features are available: C<switch> (adds a -switch statement), C<say> (adds a C<say> built-in function), and C<state> -(adds a C<state> keyword for declaring "static" variables). Those -features are described in their own sections of this document. - -The C<feature> pragma is also implicitly loaded when you require a minimal -perl version (with the C<use VERSION> construct) greater than, or equal -to, 5.9.5. See L<feature> for details. - -=head2 New B<-E> command-line switch - -B<-E> is equivalent to B<-e>, but it implicitly enables all -optional features (like C<use feature ":5.10">). - -=head2 Defined-or operator - -A new operator C<//> (defined-or) has been implemented. -The following expression: - - $a // $b - -is merely equivalent to - - defined $a ? $a : $b - -and the statement - - $c //= $d; - -can now be used instead of - - $c = $d unless defined $c; - -The C<//> operator has the same precedence and associativity as C<||>. -Special care has been taken to ensure that this operator Do What You Mean -while not breaking old code, but some edge cases involving the empty -regular expression may now parse differently. See L<perlop> for -details. - -=head2 Switch and Smart Match operator - -Perl 5 now has a switch statement. It's available when C<use feature -'switch'> is in effect. This feature introduces three new keywords, -C<given>, C<when>, and C<default>: - - given ($foo) { - when (/^abc/) { $abc = 1; } - when (/^def/) { $def = 1; } - when (/^xyz/) { $xyz = 1; } - default { $nothing = 1; } - } - -A more complete description of how Perl matches the switch variable -against the C<when> conditions is given in L<perlsyn/"Switch statements">. - -This kind of match is called I<smart match>, and it's also possible to use -it outside of switch statements, via the new C<~~> operator. See -L<perlsyn/"Smart matching in detail">. - -This feature was contributed by Robin Houston. - -=head2 Regular expressions - -=over 4 - -=item Recursive Patterns - -It is now possible to write recursive patterns without using the C<(??{})> -construct. This new way is more efficient, and in many cases easier to -read. - -Each capturing parenthesis can now be treated as an independent pattern -that can be entered by using the C<(?PARNO)> syntax (C<PARNO> standing for -"parenthesis number"). For example, the following pattern will match -nested balanced angle brackets: - - / - ^ # start of line - ( # start capture buffer 1 - < # match an opening angle bracket - (?: # match one of: - (?> # don't backtrack over the inside of this group - [^<>]+ # one or more non angle brackets - ) # end non backtracking group - | # ... or ... - (?1) # recurse to bracket 1 and try it again - )* # 0 or more times. - > # match a closing angle bracket - ) # end capture buffer one - $ # end of line - /x - -PCRE users should note that Perl's recursive regex feature allows -backtracking into a recursed pattern, whereas in PCRE the recursion is -atomic or "possessive" in nature. As in the example above, you can -add (?>) to control this selectively. (Yves Orton) - -=item Named Capture Buffers - -It is now possible to name capturing parenthesis in a pattern and refer to -the captured contents by name. The naming syntax is C<< (?<NAME>....) >>. -It's possible to backreference to a named buffer with the C<< \k<NAME> >> -syntax. In code, the new magical hashes C<%+> and C<%-> can be used to -access the contents of the capture buffers. - -Thus, to replace all doubled chars with a single copy, one could write - - s/(?<letter>.)\k<letter>/$+{letter}/g - -Only buffers with defined contents will be "visible" in the C<%+> hash, so -it's possible to do something like - - foreach my $name (keys %+) { - print "content of buffer '$name' is $+{$name}\n"; - } - -The C<%-> hash is a bit more complete, since it will contain array refs -holding values from all capture buffers similarly named, if there should -be many of them. - -C<%+> and C<%-> are implemented as tied hashes through the new module -C<Tie::Hash::NamedCapture>. - -Users exposed to the .NET regex engine will find that the perl -implementation differs in that the numerical ordering of the buffers -is sequential, and not "unnamed first, then named". Thus in the pattern - - /(A)(?<B>B)(C)(?<D>D)/ - -$1 will be 'A', $2 will be 'B', $3 will be 'C' and $4 will be 'D' and not -$1 is 'A', $2 is 'C' and $3 is 'B' and $4 is 'D' that a .NET programmer -would expect. This is considered a feature. :-) (Yves Orton) - -=item Possessive Quantifiers - -Perl now supports the "possessive quantifier" syntax of the "atomic match" -pattern. Basically a possessive quantifier matches as much as it can and never -gives any back. Thus it can be used to control backtracking. The syntax is -similar to non-greedy matching, except instead of using a '?' as the modifier -the '+' is used. Thus C<?+>, C<*+>, C<++>, C<{min,max}+> are now legal -quantifiers. (Yves Orton) - -=item Backtracking control verbs - -The regex engine now supports a number of special-purpose backtrack -control verbs: (*THEN), (*PRUNE), (*MARK), (*SKIP), (*COMMIT), (*FAIL) -and (*ACCEPT). See L<perlre> for their descriptions. (Yves Orton) - -=item Relative backreferences - -A new syntax C<\g{N}> or C<\gN> where "N" is a decimal integer allows a -safer form of back-reference notation as well as allowing relative -backreferences. This should make it easier to generate and embed patterns -that contain backreferences. See L<perlre/"Capture buffers">. (Yves Orton) - -=item C<\K> escape - -The functionality of Jeff Pinyan's module Regexp::Keep has been added to -the core. In regular expressions you can now use the special escape C<\K> -as a way to do something like floating length positive lookbehind. It is -also useful in substitutions like: - - s/(foo)bar/$1/g - -that can now be converted to - - s/foo\Kbar//g - -which is much more efficient. (Yves Orton) - -=item Vertical and horizontal whitespace, and linebreak - -Regular expressions now recognize the C<\v> and C<\h> escapes that match -vertical and horizontal whitespace, respectively. C<\V> and C<\H> -logically match their complements. - -C<\R> matches a generic linebreak, that is, vertical whitespace, plus -the multi-character sequence C<"\x0D\x0A">. - -=back - -=head2 C<say()> - -say() is a new built-in, only available when C<use feature 'say'> is in -effect, that is similar to print(), but that implicitly appends a newline -to the printed string. See L<perlfunc/say>. (Robin Houston) - -=head2 Lexical C<$_> - -The default variable C<$_> can now be lexicalized, by declaring it like -any other lexical variable, with a simple - - my $_; - -The operations that default on C<$_> will use the lexically-scoped -version of C<$_> when it exists, instead of the global C<$_>. - -In a C<map> or a C<grep> block, if C<$_> was previously my'ed, then the -C<$_> inside the block is lexical as well (and scoped to the block). - -In a scope where C<$_> has been lexicalized, you can still have access to -the global version of C<$_> by using C<$::_>, or, more simply, by -overriding the lexical declaration with C<our $_>. (Rafael Garcia-Suarez) - -=head2 The C<_> prototype - -A new prototype character has been added. C<_> is equivalent to C<$> but -defaults to C<$_> if the corresponding argument isn't supplied (both C<$> -and C<_> denote a scalar). Due to the optional nature of the argument, -you can only use it at the end of a prototype, or before a semicolon. - -This has a small incompatible consequence: the prototype() function has -been adjusted to return C<_> for some built-ins in appropriate cases (for -example, C<prototype('CORE::rmdir')>). (Rafael Garcia-Suarez) - -=head2 UNITCHECK blocks - -C<UNITCHECK>, a new special code block has been introduced, in addition to -C<BEGIN>, C<CHECK>, C<INIT> and C<END>. - -C<CHECK> and C<INIT> blocks, while useful for some specialized purposes, -are always executed at the transition between the compilation and the -execution of the main program, and thus are useless whenever code is -loaded at runtime. On the other hand, C<UNITCHECK> blocks are executed -just after the unit which defined them has been compiled. See L<perlmod> -for more information. (Alex Gough) - -=head2 New Pragma, C<mro> - -A new pragma, C<mro> (for Method Resolution Order) has been added. It -permits to switch, on a per-class basis, the algorithm that perl uses to -find inherited methods in case of a multiple inheritance hierarchy. The -default MRO hasn't changed (DFS, for Depth First Search). Another MRO is -available: the C3 algorithm. See L<mro> for more information. -(Brandon Black) - -Note that, due to changes in the implementation of class hierarchy search, -code that used to undef the C<*ISA> glob will most probably break. Anyway, -undef'ing C<*ISA> had the side-effect of removing the magic on the @ISA -array and should not have been done in the first place. Also, the -cache C<*::ISA::CACHE::> no longer exists; to force reset the @ISA cache, -you now need to use the C<mro> API, or more simply to assign to @ISA -(e.g. with C<@ISA = @ISA>). - -=head2 readdir() may return a "short filename" on Windows - -The readdir() function may return a "short filename" when the long -filename contains characters outside the ANSI codepage. Similarly -Cwd::cwd() may return a short directory name, and glob() may return short -names as well. On the NTFS file system these short names can always be -represented in the ANSI codepage. This will not be true for all other file -system drivers; e.g. the FAT filesystem stores short filenames in the OEM -codepage, so some files on FAT volumes remain unaccessible through the -ANSI APIs. - -Similarly, $^X, @INC, and $ENV{PATH} are preprocessed at startup to make -sure all paths are valid in the ANSI codepage (if possible). - -The Win32::GetLongPathName() function now returns the UTF-8 encoded -correct long file name instead of using replacement characters to force -the name into the ANSI codepage. The new Win32::GetANSIPathName() -function can be used to turn a long pathname into a short one only if the -long one cannot be represented in the ANSI codepage. - -Many other functions in the C<Win32> module have been improved to accept -UTF-8 encoded arguments. Please see L<Win32> for details. - -=head2 readpipe() is now overridable - -The built-in function readpipe() is now overridable. Overriding it permits -also to override its operator counterpart, C<qx//> (a.k.a. C<``>). -Moreover, it now defaults to C<$_> if no argument is provided. (Rafael -Garcia-Suarez) - -=head2 Default argument for readline() - -readline() now defaults to C<*ARGV> if no argument is provided. (Rafael -Garcia-Suarez) - -=head2 state() variables - -A new class of variables has been introduced. State variables are similar -to C<my> variables, but are declared with the C<state> keyword in place of -C<my>. They're visible only in their lexical scope, but their value is -persistent: unlike C<my> variables, they're not undefined at scope entry, -but retain their previous value. (Rafael Garcia-Suarez, Nicholas Clark) - -To use state variables, one needs to enable them by using - - use feature 'state'; - -or by using the C<-E> command-line switch in one-liners. -See L<perlsub/"Persistent Private Variables">. - -=head2 Stacked filetest operators - -As a new form of syntactic sugar, it's now possible to stack up filetest -operators. You can now write C<-f -w -x $file> in a row to mean -C<-x $file && -w _ && -f _>. See L<perlfunc/-X>. - -=head2 UNIVERSAL::DOES() - -The C<UNIVERSAL> class has a new method, C<DOES()>. It has been added to -solve semantic problems with the C<isa()> method. C<isa()> checks for -inheritance, while C<DOES()> has been designed to be overridden when -module authors use other types of relations between classes (in addition -to inheritance). (chromatic) - -See L<< UNIVERSAL/"$obj->DOES( ROLE )" >>. - -=head2 Formats - -Formats were improved in several ways. A new field, C<^*>, can be used for -variable-width, one-line-at-a-time text. Null characters are now handled -correctly in picture lines. Using C<@#> and C<~~> together will now -produce a compile-time error, as those format fields are incompatible. -L<perlform> has been improved, and miscellaneous bugs fixed. - -=head2 Byte-order modifiers for pack() and unpack() - -There are two new byte-order modifiers, C<E<gt>> (big-endian) and C<E<lt>> -(little-endian), that can be appended to most pack() and unpack() template -characters and groups to force a certain byte-order for that type or group. -See L<perlfunc/pack> and L<perlpacktut> for details. - -=head2 C<no VERSION> - -You can now use C<no> followed by a version number to specify that you -want to use a version of perl older than the specified one. - -=head2 C<chdir>, C<chmod> and C<chown> on filehandles - -C<chdir>, C<chmod> and C<chown> can now work on filehandles as well as -filenames, if the system supports respectively C<fchdir>, C<fchmod> and -C<fchown>, thanks to a patch provided by Gisle Aas. - -=head2 OS groups - -C<$(> and C<$)> now return groups in the order where the OS returns them, -thanks to Gisle Aas. This wasn't previously the case. - -=head2 Recursive sort subs - -You can now use recursive subroutines with sort(), thanks to Robin Houston. - -=head2 Exceptions in constant folding - -The constant folding routine is now wrapped in an exception handler, and -if folding throws an exception (such as attempting to evaluate 0/0), perl -now retains the current optree, rather than aborting the whole program. -Without this change, programs would not compile if they had expressions that -happened to generate exceptions, even though those expressions were in code -that could never be reached at runtime. (Nicholas Clark, Dave Mitchell) - -=head2 Source filters in @INC - -It's possible to enhance the mechanism of subroutine hooks in @INC by -adding a source filter on top of the filehandle opened and returned by the -hook. This feature was planned a long time ago, but wasn't quite working -until now. See L<perlfunc/require> for details. (Nicholas Clark) - -=head2 New internal variables - -=over 4 - -=item C<${^RE_DEBUG_FLAGS}> - -This variable controls what debug flags are in effect for the regular -expression engine when running under C<use re "debug">. See L<re> for -details. - -=item C<${^CHILD_ERROR_NATIVE}> - -This variable gives the native status returned by the last pipe close, -backtick command, successful call to wait() or waitpid(), or from the -system() operator. See L<perlvar> for details. (Contributed by Gisle Aas.) - -=item C<${^RE_TRIE_MAXBUF}> - -See L</"Trie optimisation of literal string alternations">. - -=item C<${^WIN32_SLOPPY_STAT}> - -See L</"Sloppy stat on Windows">. - -=back - -=head2 Miscellaneous - -C<unpack()> now defaults to unpacking the C<$_> variable. - -C<mkdir()> without arguments now defaults to C<$_>. - -The internal dump output has been improved, so that non-printable characters -such as newline and backspace are output in C<\x> notation, rather than -octal. - -The B<-C> option can no longer be used on the C<#!> line. It wasn't -working there anyway, since the standard streams are already set up -at this point in the execution of the perl interpreter. You can use -binmode() instead to get the desired behaviour. - -=head2 UCD 5.0.0 - -The copy of the Unicode Character Database included in Perl 5 has -been updated to version 5.0.0. - -=head2 MAD - -MAD, which stands for I<Miscellaneous Attribute Decoration>, is a -still-in-development work leading to a Perl 5 to Perl 6 converter. To -enable it, it's necessary to pass the argument C<-Dmad> to Configure. The -obtained perl isn't binary compatible with a regular perl 5.10, and has -space and speed penalties; moreover not all regression tests still pass -with it. (Larry Wall, Nicholas Clark) - -=head2 kill() on Windows - -On Windows platforms, C<kill(-9, $pid)> now kills a process tree. -(On Unix, this delivers the signal to all processes in the same process -group.) - -=head1 Incompatible Changes - -=head2 Packing and UTF-8 strings - -The semantics of pack() and unpack() regarding UTF-8-encoded data has been -changed. Processing is now by default character per character instead of -byte per byte on the underlying encoding. Notably, code that used things -like C<pack("a*", $string)> to see through the encoding of string will now -simply get back the original $string. Packed strings can also get upgraded -during processing when you store upgraded characters. You can get the old -behaviour by using C<use bytes>. - -To be consistent with pack(), the C<C0> in unpack() templates indicates -that the data is to be processed in character mode, i.e. character by -character; on the contrary, C<U0> in unpack() indicates UTF-8 mode, where -the packed string is processed in its UTF-8-encoded Unicode form on a byte -by byte basis. This is reversed with regard to perl 5.8.X, but now consistent -between pack() and unpack(). - -Moreover, C<C0> and C<U0> can also be used in pack() templates to specify -respectively character and byte modes. - -C<C0> and C<U0> in the middle of a pack or unpack format now switch to the -specified encoding mode, honoring parens grouping. Previously, parens were -ignored. - -Also, there is a new pack() character format, C<W>, which is intended to -replace the old C<C>. C<C> is kept for unsigned chars coded as bytes in -the strings internal representation. C<W> represents unsigned (logical) -character values, which can be greater than 255. It is therefore more -robust when dealing with potentially UTF-8-encoded data (as C<C> will wrap -values outside the range 0..255, and not respect the string encoding). - -In practice, that means that pack formats are now encoding-neutral, except -C<C>. - -For consistency, C<A> in unpack() format now trims all Unicode whitespace -from the end of the string. Before perl 5.9.2, it used to strip only the -classical ASCII space characters. - -=head2 Byte/character count feature in unpack() - -A new unpack() template character, C<".">, returns the number of bytes or -characters (depending on the selected encoding mode, see above) read so far. - -=head2 The C<$*> and C<$#> variables have been removed - -C<$*>, which was deprecated in favor of the C</s> and C</m> regexp -modifiers, has been removed. - -The deprecated C<$#> variable (output format for numbers) has been -removed. - -Two new severe warnings, C<$#/$* is no longer supported>, have been added. - -=head2 substr() lvalues are no longer fixed-length - -The lvalues returned by the three argument form of substr() used to be a -"fixed length window" on the original string. In some cases this could -cause surprising action at distance or other undefined behaviour. Now the -length of the window adjusts itself to the length of the string assigned to -it. - -=head2 Parsing of C<-f _> - -The identifier C<_> is now forced to be a bareword after a filetest -operator. This solves a number of misparsing issues when a global C<_> -subroutine is defined. - -=head2 C<:unique> - -The C<:unique> attribute has been made a no-op, since its current -implementation was fundamentally flawed and not threadsafe. - -=head2 Effect of pragmas in eval - -The compile-time value of the C<%^H> hint variable can now propagate into -eval("")uated code. This makes it more useful to implement lexical -pragmas. - -As a side-effect of this, the overloaded-ness of constants now propagates -into eval(""). - -=head2 chdir FOO - -A bareword argument to chdir() is now recognized as a file handle. -Earlier releases interpreted the bareword as a directory name. -(Gisle Aas) - -=head2 Handling of .pmc files - -An old feature of perl was that before C<require> or C<use> look for a -file with a F<.pm> extension, they will first look for a similar filename -with a F<.pmc> extension. If this file is found, it will be loaded in -place of any potentially existing file ending in a F<.pm> extension. - -Previously, F<.pmc> files were loaded only if more recent than the -matching F<.pm> file. Starting with 5.9.4, they'll be always loaded if -they exist. - -=head2 $^V is now a C<version> object instead of a v-string - -$^V can still be used with the C<%vd> format in printf, but any -character-level operations will now access the string representation -of the C<version> object and not the ordinals of a v-string. -Expressions like C<< substr($^V, 0, 2) >> or C<< split //, $^V >> -no longer work and must be rewritten. - -=head2 @- and @+ in patterns - -The special arrays C<@-> and C<@+> are no longer interpolated in regular -expressions. (Sadahiro Tomoyuki) - -=head2 $AUTOLOAD can now be tainted - -If you call a subroutine by a tainted name, and if it defers to an -AUTOLOAD function, then $AUTOLOAD will be (correctly) tainted. -(Rick Delaney) - -=head2 Tainting and printf - -When perl is run under taint mode, C<printf()> and C<sprintf()> will now -reject any tainted format argument. (Rafael Garcia-Suarez) - -=head2 undef and signal handlers - -Undefining or deleting a signal handler via C<undef $SIG{FOO}> is now -equivalent to setting it to C<'DEFAULT'>. (Rafael Garcia-Suarez) - -=head2 strictures and dereferencing in defined() - -C<use strict 'refs'> was ignoring taking a hard reference in an argument -to defined(), as in : - - use strict 'refs'; - my $x = 'foo'; - if (defined $$x) {...} - -This now correctly produces the run-time error C<Can't use string as a -SCALAR ref while "strict refs" in use>. - -C<defined @$foo> and C<defined %$bar> are now also subject to C<strict -'refs'> (that is, C<$foo> and C<$bar> shall be proper references there.) -(C<defined(@foo)> and C<defined(%bar)> are discouraged constructs anyway.) -(Nicholas Clark) - -=head2 C<(?p{})> has been removed - -The regular expression construct C<(?p{})>, which was deprecated in perl -5.8, has been removed. Use C<(??{})> instead. (Rafael Garcia-Suarez) - -=head2 Pseudo-hashes have been removed - -Support for pseudo-hashes has been removed from Perl 5.9. (The C<fields> -pragma remains here, but uses an alternate implementation.) - -=head2 Removal of the bytecode compiler and of perlcc - -C<perlcc>, the byteloader and the supporting modules (B::C, B::CC, -B::Bytecode, etc.) are no longer distributed with the perl sources. Those -experimental tools have never worked reliably, and, due to the lack of -volunteers to keep them in line with the perl interpreter developments, it -was decided to remove them instead of shipping a broken version of those. -The last version of those modules can be found with perl 5.9.4. - -However the B compiler framework stays supported in the perl core, as with -the more useful modules it has permitted (among others, B::Deparse and -B::Concise). - -=head2 Removal of the JPL - -The JPL (Java-Perl Lingo) has been removed from the perl sources tarball. - -=head2 Recursive inheritance detected earlier - -Perl will now immediately throw an exception if you modify any package's -C<@ISA> in such a way that it would cause recursive inheritance. - -Previously, the exception would not occur until Perl attempted to make -use of the recursive inheritance while resolving a method or doing a -C<$foo-E<gt>isa($bar)> lookup. - -=head2 warnings::enabled and warnings::warnif changed to favor users of modules - -The behaviour in 5.10.x favors the person using the module; -The behaviour in 5.8.x favors the module writer; - -Assume the following code: - - main calls Foo::Bar::baz() - Foo::Bar inherits from Foo::Base - Foo::Bar::baz() calls Foo::Base::_bazbaz() - Foo::Base::_bazbaz() calls: warnings::warnif('substr', 'some warning -message'); - -On 5.8.x, the code warns when Foo::Bar contains C<use warnings;> -It does not matter if Foo::Base or main have warnings enabled -to disable the warning one has to modify Foo::Bar. - -On 5.10.0 and newer, the code warns when main contains C<use warnings;> -It does not matter if Foo::Base or Foo::Bar have warnings enabled -to disable the warning one has to modify main. - -=head1 Modules and Pragmata - -=head2 Upgrading individual core modules - -Even more core modules are now also available separately through the -CPAN. If you wish to update one of these modules, you don't need to -wait for a new perl release. From within the cpan shell, running the -'r' command will report on modules with upgrades available. See -C<perldoc CPAN> for more information. - -=head2 Pragmata Changes - -=over 4 - -=item C<feature> - -The new pragma C<feature> is used to enable new features that might break -old code. See L</"The C<feature> pragma"> above. - -=item C<mro> - -This new pragma enables to change the algorithm used to resolve inherited -methods. See L</"New Pragma, C<mro>"> above. - -=item Scoping of the C<sort> pragma - -The C<sort> pragma is now lexically scoped. Its effect used to be global. - -=item Scoping of C<bignum>, C<bigint>, C<bigrat> - -The three numeric pragmas C<bignum>, C<bigint> and C<bigrat> are now -lexically scoped. (Tels) - -=item C<base> - -The C<base> pragma now warns if a class tries to inherit from itself. -(Curtis "Ovid" Poe) - -=item C<strict> and C<warnings> - -C<strict> and C<warnings> will now complain loudly if they are loaded via -incorrect casing (as in C<use Strict;>). (Johan Vromans) - -=item C<version> - -The C<version> module provides support for version objects. - -=item C<warnings> - -The C<warnings> pragma doesn't load C<Carp> anymore. That means that code -that used C<Carp> routines without having loaded it at compile time might -need to be adjusted; typically, the following (faulty) code won't work -anymore, and will require parentheses to be added after the function name: - - use warnings; - require Carp; - Carp::confess 'argh'; - -=item C<less> - -C<less> now does something useful (or at least it tries to). In fact, it -has been turned into a lexical pragma. So, in your modules, you can now -test whether your users have requested to use less CPU, or less memory, -less magic, or maybe even less fat. See L<less> for more. (Joshua ben -Jore) - -=back - -=head2 New modules - -=over 4 - -=item * - -C<encoding::warnings>, by Audrey Tang, is a module to emit warnings -whenever an ASCII character string containing high-bit bytes is implicitly -converted into UTF-8. It's a lexical pragma since Perl 5.9.4; on older -perls, its effect is global. - -=item * - -C<Module::CoreList>, by Richard Clamp, is a small handy module that tells -you what versions of core modules ship with any versions of Perl 5. It -comes with a command-line frontend, C<corelist>. - -=item * - -C<Math::BigInt::FastCalc> is an XS-enabled, and thus faster, version of -C<Math::BigInt::Calc>. - -=item * - -C<Compress::Zlib> is an interface to the zlib compression library. It -comes with a bundled version of zlib, so having a working zlib is not a -prerequisite to install it. It's used by C<Archive::Tar> (see below). - -=item * - -C<IO::Zlib> is an C<IO::>-style interface to C<Compress::Zlib>. - -=item * - -C<Archive::Tar> is a module to manipulate C<tar> archives. - -=item * - -C<Digest::SHA> is a module used to calculate many types of SHA digests, -has been included for SHA support in the CPAN module. - -=item * - -C<ExtUtils::CBuilder> and C<ExtUtils::ParseXS> have been added. - -=item * - -C<Hash::Util::FieldHash>, by Anno Siegel, has been added. This module -provides support for I<field hashes>: hashes that maintain an association -of a reference with a value, in a thread-safe garbage-collected way. -Such hashes are useful to implement inside-out objects. - -=item * - -C<Module::Build>, by Ken Williams, has been added. It's an alternative to -C<ExtUtils::MakeMaker> to build and install perl modules. - -=item * - -C<Module::Load>, by Jos Boumans, has been added. It provides a single -interface to load Perl modules and F<.pl> files. - -=item * - -C<Module::Loaded>, by Jos Boumans, has been added. It's used to mark -modules as loaded or unloaded. - -=item * - -C<Package::Constants>, by Jos Boumans, has been added. It's a simple -helper to list all constants declared in a given package. - -=item * - -C<Win32API::File>, by Tye McQueen, has been added (for Windows builds). -This module provides low-level access to Win32 system API calls for -files/dirs. - -=item * - -C<Locale::Maketext::Simple>, needed by CPANPLUS, is a simple wrapper around -C<Locale::Maketext::Lexicon>. Note that C<Locale::Maketext::Lexicon> isn't -included in the perl core; the behaviour of C<Locale::Maketext::Simple> -gracefully degrades when the later isn't present. - -=item * - -C<Params::Check> implements a generic input parsing/checking mechanism. It -is used by CPANPLUS. - -=item * - -C<Term::UI> simplifies the task to ask questions at a terminal prompt. - -=item * - -C<Object::Accessor> provides an interface to create per-object accessors. - -=item * - -C<Module::Pluggable> is a simple framework to create modules that accept -pluggable sub-modules. - -=item * - -C<Module::Load::Conditional> provides simple ways to query and possibly -load installed modules. - -=item * - -C<Time::Piece> provides an object oriented interface to time functions, -overriding the built-ins localtime() and gmtime(). - -=item * - -C<IPC::Cmd> helps to find and run external commands, possibly -interactively. - -=item * - -C<File::Fetch> provide a simple generic file fetching mechanism. - -=item * - -C<Log::Message> and C<Log::Message::Simple> are used by the log facility -of C<CPANPLUS>. - -=item * - -C<Archive::Extract> is a generic archive extraction mechanism -for F<.tar> (plain, gzipped or bzipped) or F<.zip> files. - -=item * - -C<CPANPLUS> provides an API and a command-line tool to access the CPAN -mirrors. - -=item * - -C<Pod::Escapes> provides utilities that are useful in decoding Pod -EE<lt>...E<gt> sequences. - -=item * - -C<Pod::Simple> is now the backend for several of the Pod-related modules -included with Perl. - -=back - -=head2 Selected Changes to Core Modules - -=over 4 - -=item C<Attribute::Handlers> - -C<Attribute::Handlers> can now report the caller's file and line number. -(David Feldman) - -All interpreted attributes are now passed as array references. (Damian -Conway) - -=item C<B::Lint> - -C<B::Lint> is now based on C<Module::Pluggable>, and so can be extended -with plugins. (Joshua ben Jore) - -=item C<B> - -It's now possible to access the lexical pragma hints (C<%^H>) by using the -method B::COP::hints_hash(). It returns a C<B::RHE> object, which in turn -can be used to get a hash reference via the method B::RHE::HASH(). (Joshua -ben Jore) - -=item C<Thread> - -As the old 5005thread threading model has been removed, in favor of the -ithreads scheme, the C<Thread> module is now a compatibility wrapper, to -be used in old code only. It has been removed from the default list of -dynamic extensions. - -=back - -=head1 Utility Changes - -=over 4 - -=item perl -d - -The Perl debugger can now save all debugger commands for sourcing later; -notably, it can now emulate stepping backwards, by restarting and -rerunning all bar the last command from a saved command history. - -It can also display the parent inheritance tree of a given class, with the -C<i> command. - -=item ptar - -C<ptar> is a pure perl implementation of C<tar> that comes with -C<Archive::Tar>. - -=item ptardiff - -C<ptardiff> is a small utility used to generate a diff between the contents -of a tar archive and a directory tree. Like C<ptar>, it comes with -C<Archive::Tar>. - -=item shasum - -C<shasum> is a command-line utility, used to print or to check SHA -digests. It comes with the new C<Digest::SHA> module. - -=item corelist - -The C<corelist> utility is now installed with perl (see L</"New modules"> -above). - -=item h2ph and h2xs - -C<h2ph> and C<h2xs> have been made more robust with regard to -"modern" C code. - -C<h2xs> implements a new option C<--use-xsloader> to force use of -C<XSLoader> even in backwards compatible modules. - -The handling of authors' names that had apostrophes has been fixed. - -Any enums with negative values are now skipped. - -=item perlivp - -C<perlivp> no longer checks for F<*.ph> files by default. Use the new C<-a> -option to run I<all> tests. - -=item find2perl - -C<find2perl> now assumes C<-print> as a default action. Previously, it -needed to be specified explicitly. - -Several bugs have been fixed in C<find2perl>, regarding C<-exec> and -C<-eval>. Also the options C<-path>, C<-ipath> and C<-iname> have been -added. - -=item config_data - -C<config_data> is a new utility that comes with C<Module::Build>. It -provides a command-line interface to the configuration of Perl modules -that use Module::Build's framework of configurability (that is, -C<*::ConfigData> modules that contain local configuration information for -their parent modules.) - -=item cpanp - -C<cpanp>, the CPANPLUS shell, has been added. (C<cpanp-run-perl>, a -helper for CPANPLUS operation, has been added too, but isn't intended for -direct use). - -=item cpan2dist - -C<cpan2dist> is a new utility that comes with CPANPLUS. It's a tool to -create distributions (or packages) from CPAN modules. - -=item pod2html - -The output of C<pod2html> has been enhanced to be more customizable via -CSS. Some formatting problems were also corrected. (Jari Aalto) - -=back - -=head1 New Documentation - -The L<perlpragma> manpage documents how to write one's own lexical -pragmas in pure Perl (something that is possible starting with 5.9.4). - -The new L<perlglossary> manpage is a glossary of terms used in the Perl -documentation, technical and otherwise, kindly provided by O'Reilly Media, -Inc. - -The L<perlreguts> manpage, courtesy of Yves Orton, describes internals of the -Perl regular expression engine. - -The L<perlreapi> manpage describes the interface to the perl interpreter -used to write pluggable regular expression engines (by Ævar Arnfjörð -Bjarmason). - -The L<perlunitut> manpage is an tutorial for programming with Unicode and -string encodings in Perl, courtesy of Juerd Waalboer. - -A new manual page, L<perlunifaq> (the Perl Unicode FAQ), has been added -(Juerd Waalboer). - -The L<perlcommunity> manpage gives a description of the Perl community -on the Internet and in real life. (Edgar "Trizor" Bering) - -The L<CORE> manual page documents the C<CORE::> namespace. (Tels) - -The long-existing feature of C</(?{...})/> regexps setting C<$_> and pos() -is now documented. - -=head1 Performance Enhancements - -=head2 In-place sorting - -Sorting arrays in place (C<@a = sort @a>) is now optimized to avoid -making a temporary copy of the array. - -Likewise, C<reverse sort ...> is now optimized to sort in reverse, -avoiding the generation of a temporary intermediate list. - -=head2 Lexical array access - -Access to elements of lexical arrays via a numeric constant between 0 and -255 is now faster. (This used to be only the case for global arrays.) - -=head2 XS-assisted SWASHGET - -Some pure-perl code that perl was using to retrieve Unicode properties and -transliteration mappings has been reimplemented in XS. - -=head2 Constant subroutines - -The interpreter internals now support a far more memory efficient form of -inlineable constants. Storing a reference to a constant value in a symbol -table is equivalent to a full typeglob referencing a constant subroutine, -but using about 400 bytes less memory. This proxy constant subroutine is -automatically upgraded to a real typeglob with subroutine if necessary. -The approach taken is analogous to the existing space optimisation for -subroutine stub declarations, which are stored as plain scalars in place -of the full typeglob. - -Several of the core modules have been converted to use this feature for -their system dependent constants - as a result C<use POSIX;> now takes about -200K less memory. - -=head2 C<PERL_DONT_CREATE_GVSV> - -The new compilation flag C<PERL_DONT_CREATE_GVSV>, introduced as an option -in perl 5.8.8, is turned on by default in perl 5.9.3. It prevents perl -from creating an empty scalar with every new typeglob. See L<perl589delta> -for details. - -=head2 Weak references are cheaper - -Weak reference creation is now I<O(1)> rather than I<O(n)>, courtesy of -Nicholas Clark. Weak reference deletion remains I<O(n)>, but if deletion only -happens at program exit, it may be skipped completely. - -=head2 sort() enhancements - -Salvador Fandiño provided improvements to reduce the memory usage of C<sort> -and to speed up some cases. - -=head2 Memory optimisations - -Several internal data structures (typeglobs, GVs, CVs, formats) have been -restructured to use less memory. (Nicholas Clark) - -=head2 UTF-8 cache optimisation - -The UTF-8 caching code is now more efficient, and used more often. -(Nicholas Clark) - -=head2 Sloppy stat on Windows - -On Windows, perl's stat() function normally opens the file to determine -the link count and update attributes that may have been changed through -hard links. Setting ${^WIN32_SLOPPY_STAT} to a true value speeds up -stat() by not performing this operation. (Jan Dubois) - -=head2 Regular expressions optimisations - -=over 4 - -=item Engine de-recursivised - -The regular expression engine is no longer recursive, meaning that -patterns that used to overflow the stack will either die with useful -explanations, or run to completion, which, since they were able to blow -the stack before, will likely take a very long time to happen. If you were -experiencing the occasional stack overflow (or segfault) and upgrade to -discover that now perl apparently hangs instead, look for a degenerate -regex. (Dave Mitchell) - -=item Single char char-classes treated as literals - -Classes of a single character are now treated the same as if the character -had been used as a literal, meaning that code that uses char-classes as an -escaping mechanism will see a speedup. (Yves Orton) - -=item Trie optimisation of literal string alternations - -Alternations, where possible, are optimised into more efficient matching -structures. String literal alternations are merged into a trie and are -matched simultaneously. This means that instead of O(N) time for matching -N alternations at a given point, the new code performs in O(1) time. -A new special variable, ${^RE_TRIE_MAXBUF}, has been added to fine-tune -this optimization. (Yves Orton) - -B<Note:> Much code exists that works around perl's historic poor -performance on alternations. Often the tricks used to do so will disable -the new optimisations. Hopefully the utility modules used for this purpose -will be educated about these new optimisations. - -=item Aho-Corasick start-point optimisation - -When a pattern starts with a trie-able alternation and there aren't -better optimisations available, the regex engine will use Aho-Corasick -matching to find the start point. (Yves Orton) - -=back - -=head1 Installation and Configuration Improvements - -=head2 Configuration improvements - -=over 4 - -=item C<-Dusesitecustomize> - -Run-time customization of @INC can be enabled by passing the -C<-Dusesitecustomize> flag to Configure. When enabled, this will make perl -run F<$sitelibexp/sitecustomize.pl> before anything else. This script can -then be set up to add additional entries to @INC. - -=item Relocatable installations - -There is now Configure support for creating a relocatable perl tree. If -you Configure with C<-Duserelocatableinc>, then the paths in @INC (and -everything else in %Config) can be optionally located via the path of the -perl executable. - -That means that, if the string C<".../"> is found at the start of any -path, it's substituted with the directory of $^X. So, the relocation can -be configured on a per-directory basis, although the default with -C<-Duserelocatableinc> is that everything is relocated. The initial -install is done to the original configured prefix. - -=item strlcat() and strlcpy() - -The configuration process now detects whether strlcat() and strlcpy() are -available. When they are not available, perl's own version is used (from -Russ Allbery's public domain implementation). Various places in the perl -interpreter now use them. (Steve Peters) - -=item C<d_pseudofork> and C<d_printf_format_null> - -A new configuration variable, available as C<$Config{d_pseudofork}> in -the L<Config> module, has been added, to distinguish real fork() support -from fake pseudofork used on Windows platforms. - -A new configuration variable, C<d_printf_format_null>, has been added, -to see if printf-like formats are allowed to be NULL. - -=item Configure help - -C<Configure -h> has been extended with the most commonly used options. - -=back - -=head2 Compilation improvements - -=over 4 - -=item Parallel build - -Parallel makes should work properly now, although there may still be problems -if C<make test> is instructed to run in parallel. - -=item Borland's compilers support - -Building with Borland's compilers on Win32 should work more smoothly. In -particular Steve Hay has worked to side step many warnings emitted by their -compilers and at least one C compiler internal error. - -=item Static build on Windows - -Perl extensions on Windows now can be statically built into the Perl DLL. - -Also, it's now possible to build a C<perl-static.exe> that doesn't depend -on the Perl DLL on Win32. See the Win32 makefiles for details. -(Vadim Konovalov) - -=item ppport.h files - -All F<ppport.h> files in the XS modules bundled with perl are now -autogenerated at build time. (Marcus Holland-Moritz) - -=item C++ compatibility - -Efforts have been made to make perl and the core XS modules compilable -with various C++ compilers (although the situation is not perfect with -some of the compilers on some of the platforms tested.) - -=item Support for Microsoft 64-bit compiler - -Support for building perl with Microsoft's 64-bit compiler has been -improved. (ActiveState) - -=item Visual C++ - -Perl can now be compiled with Microsoft Visual C++ 2005 (and 2008 Beta 2). - -=item Win32 builds - -All win32 builds (MS-Win, WinCE) have been merged and cleaned up. - -=back - -=head2 Installation improvements - -=over 4 - -=item Module auxiliary files - -README files and changelogs for CPAN modules bundled with perl are no -longer installed. - -=back - -=head2 New Or Improved Platforms - -Perl has been reported to work on Symbian OS. See L<perlsymbian> for more -information. - -Many improvements have been made towards making Perl work correctly on -z/OS. - -Perl has been reported to work on DragonFlyBSD and MidnightBSD. - -Perl has also been reported to work on NexentaOS -( http://www.gnusolaris.org/ ). - -The VMS port has been improved. See L<perlvms>. - -Support for Cray XT4 Catamount/Qk has been added. See -F<hints/catamount.sh> in the source code distribution for more -information. - -Vendor patches have been merged for RedHat and Gentoo. - -DynaLoader::dl_unload_file() now works on Windows. - -=head1 Selected Bug Fixes - -=over 4 - -=item strictures in regexp-eval blocks - -C<strict> wasn't in effect in regexp-eval blocks (C</(?{...})/>). - -=item Calling CORE::require() - -CORE::require() and CORE::do() were always parsed as require() and do() -when they were overridden. This is now fixed. - -=item Subscripts of slices - -You can now use a non-arrowed form for chained subscripts after a list -slice, like in: - - ({foo => "bar"})[0]{foo} - -This used to be a syntax error; a C<< -> >> was required. - -=item C<no warnings 'category'> works correctly with -w - -Previously when running with warnings enabled globally via C<-w>, selective -disabling of specific warning categories would actually turn off all warnings. -This is now fixed; now C<no warnings 'io';> will only turn off warnings in the -C<io> class. Previously it would erroneously turn off all warnings. - -=item threads improvements - -Several memory leaks in ithreads were closed. Also, ithreads were made -less memory-intensive. - -C<threads> is now a dual-life module, also available on CPAN. It has been -expanded in many ways. A kill() method is available for thread signalling. -One can get thread status, or the list of running or joinable threads. - -A new C<< threads->exit() >> method is used to exit from the application -(this is the default for the main thread) or from the current thread only -(this is the default for all other threads). On the other hand, the exit() -built-in now always causes the whole application to terminate. (Jerry -D. Hedden) - -=item chr() and negative values - -chr() on a negative value now gives C<\x{FFFD}>, the Unicode replacement -character, unless when the C<bytes> pragma is in effect, where the low -eight bits of the value are used. - -=item PERL5SHELL and tainting - -On Windows, the PERL5SHELL environment variable is now checked for -taintedness. (Rafael Garcia-Suarez) - -=item Using *FILE{IO} - -C<stat()> and C<-X> filetests now treat *FILE{IO} filehandles like *FILE -filehandles. (Steve Peters) - -=item Overloading and reblessing - -Overloading now works when references are reblessed into another class. -Internally, this has been implemented by moving the flag for "overloading" -from the reference to the referent, which logically is where it should -always have been. (Nicholas Clark) - -=item Overloading and UTF-8 - -A few bugs related to UTF-8 handling with objects that have -stringification overloaded have been fixed. (Nicholas Clark) - -=item eval memory leaks fixed - -Traditionally, C<eval 'syntax error'> has leaked badly. Many (but not all) -of these leaks have now been eliminated or reduced. (Dave Mitchell) - -=item Random device on Windows - -In previous versions, perl would read the file F</dev/urandom> if it -existed when seeding its random number generator. That file is unlikely -to exist on Windows, and if it did would probably not contain appropriate -data, so perl no longer tries to read it on Windows. (Alex Davies) - -=item PERLIO_DEBUG - -The C<PERLIO_DEBUG> environment variable no longer has any effect for -setuid scripts and for scripts run with B<-T>. - -Moreover, with a thread-enabled perl, using C<PERLIO_DEBUG> could lead to -an internal buffer overflow. This has been fixed. - -=item PerlIO::scalar and read-only scalars - -PerlIO::scalar will now prevent writing to read-only scalars. Moreover, -seek() is now supported with PerlIO::scalar-based filehandles, the -underlying string being zero-filled as needed. (Rafael, Jarkko Hietaniemi) - -=item study() and UTF-8 - -study() never worked for UTF-8 strings, but could lead to false results. -It's now a no-op on UTF-8 data. (Yves Orton) - -=item Critical signals - -The signals SIGILL, SIGBUS and SIGSEGV are now always delivered in an -"unsafe" manner (contrary to other signals, that are deferred until the -perl interpreter reaches a reasonably stable state; see -L<perlipc/"Deferred Signals (Safe Signals)">). (Rafael) - -=item @INC-hook fix - -When a module or a file is loaded through an @INC-hook, and when this hook -has set a filename entry in %INC, __FILE__ is now set for this module -accordingly to the contents of that %INC entry. (Rafael) - -=item C<-t> switch fix - -The C<-w> and C<-t> switches can now be used together without messing -up which categories of warnings are activated. (Rafael) - -=item Duping UTF-8 filehandles - -Duping a filehandle which has the C<:utf8> PerlIO layer set will now -properly carry that layer on the duped filehandle. (Rafael) - -=item Localisation of hash elements - -Localizing a hash element whose key was given as a variable didn't work -correctly if the variable was changed while the local() was in effect (as -in C<local $h{$x}; ++$x>). (Bo Lindbergh) - -=back - -=head1 New or Changed Diagnostics - -=over 4 - -=item Use of uninitialized value - -Perl will now try to tell you the name of the variable (if any) that was -undefined. - -=item Deprecated use of my() in false conditional - -A new deprecation warning, I<Deprecated use of my() in false conditional>, -has been added, to warn against the use of the dubious and deprecated -construct - - my $x if 0; - -See L<perldiag>. Use C<state> variables instead. - -=item !=~ should be !~ - -A new warning, C<!=~ should be !~>, is emitted to prevent this misspelling -of the non-matching operator. - -=item Newline in left-justified string - -The warning I<Newline in left-justified string> has been removed. - -=item Too late for "-T" option - -The error I<Too late for "-T" option> has been reformulated to be more -descriptive. - -=item "%s" variable %s masks earlier declaration - -This warning is now emitted in more consistent cases; in short, when one -of the declarations involved is a C<my> variable: - - my $x; my $x; # warns - my $x; our $x; # warns - our $x; my $x; # warns - -On the other hand, the following: - - our $x; our $x; - -now gives a C<"our" variable %s redeclared> warning. - -=item readdir()/closedir()/etc. attempted on invalid dirhandle - -These new warnings are now emitted when a dirhandle is used but is -either closed or not really a dirhandle. - -=item Opening dirhandle/filehandle %s also as a file/directory - -Two deprecation warnings have been added: (Rafael) - - Opening dirhandle %s also as a file - Opening filehandle %s also as a directory - -=item Use of -P is deprecated - -Perl's command-line switch C<-P> is now deprecated. - -=item v-string in use/require is non-portable - -Perl will warn you against potential backwards compatibility problems with -the C<use VERSION> syntax. - -=item perl -V - -C<perl -V> has several improvements, making it more useable from shell -scripts to get the value of configuration variables. See L<perlrun> for -details. - -=back - -=head1 Changed Internals - -In general, the source code of perl has been refactored, tidied up, -and optimized in many places. Also, memory management and allocation -has been improved in several points. - -When compiling the perl core with gcc, as many gcc warning flags are -turned on as is possible on the platform. (This quest for cleanliness -doesn't extend to XS code because we cannot guarantee the tidiness of -code we didn't write.) Similar strictness flags have been added or -tightened for various other C compilers. - -=head2 Reordering of SVt_* constants - -The relative ordering of constants that define the various types of C<SV> -have changed; in particular, C<SVt_PVGV> has been moved before C<SVt_PVLV>, -C<SVt_PVAV>, C<SVt_PVHV> and C<SVt_PVCV>. This is unlikely to make any -difference unless you have code that explicitly makes assumptions about that -ordering. (The inheritance hierarchy of C<B::*> objects has been changed -to reflect this.) - -=head2 Elimination of SVt_PVBM - -Related to this, the internal type C<SVt_PVBM> has been removed. This -dedicated type of C<SV> was used by the C<index> operator and parts of the -regexp engine to facilitate fast Boyer-Moore matches. Its use internally has -been replaced by C<SV>s of type C<SVt_PVGV>. - -=head2 New type SVt_BIND - -A new type C<SVt_BIND> has been added, in readiness for the project to -implement Perl 6 on 5. There deliberately is no implementation yet, and -they cannot yet be created or destroyed. - -=head2 Removal of CPP symbols - -The C preprocessor symbols C<PERL_PM_APIVERSION> and -C<PERL_XS_APIVERSION>, which were supposed to give the version number of -the oldest perl binary-compatible (resp. source-compatible) with the -present one, were not used, and sometimes had misleading values. They have -been removed. - -=head2 Less space is used by ops - -The C<BASEOP> structure now uses less space. The C<op_seq> field has been -removed and replaced by a single bit bit-field C<op_opt>. C<op_type> is now 9 -bits long. (Consequently, the C<B::OP> class doesn't provide an C<seq> -method anymore.) - -=head2 New parser - -perl's parser is now generated by bison (it used to be generated by -byacc.) As a result, it seems to be a bit more robust. - -Also, Dave Mitchell improved the lexer debugging output under C<-DT>. - -=head2 Use of C<const> - -Andy Lester supplied many improvements to determine which function -parameters and local variables could actually be declared C<const> to the C -compiler. Steve Peters provided new C<*_set> macros and reworked the core to -use these rather than assigning to macros in LVALUE context. - -=head2 Mathoms - -A new file, F<mathoms.c>, has been added. It contains functions that are -no longer used in the perl core, but that remain available for binary or -source compatibility reasons. However, those functions will not be -compiled in if you add C<-DNO_MATHOMS> in the compiler flags. - -=head2 C<AvFLAGS> has been removed - -The C<AvFLAGS> macro has been removed. - -=head2 C<av_*> changes - -The C<av_*()> functions, used to manipulate arrays, no longer accept null -C<AV*> parameters. - -=head2 $^H and %^H - -The implementation of the special variables $^H and %^H has changed, to -allow implementing lexical pragmas in pure Perl. - -=head2 B:: modules inheritance changed - -The inheritance hierarchy of C<B::> modules has changed; C<B::NV> now -inherits from C<B::SV> (it used to inherit from C<B::IV>). - -=head2 Anonymous hash and array constructors - -The anonymous hash and array constructors now take 1 op in the optree -instead of 3, now that pp_anonhash and pp_anonlist return a reference to -an hash/array when the op is flagged with OPf_SPECIAL. (Nicholas Clark) - -=head1 Known Problems - -There's still a remaining problem in the implementation of the lexical -C<$_>: it doesn't work inside C</(?{...})/> blocks. (See the TODO test in -F<t/op/mydef.t>.) - -Stacked filetest operators won't work when the C<filetest> pragma is in -effect, because they rely on the stat() buffer C<_> being populated, and -filetest bypasses stat(). - -=head2 UTF-8 problems - -The handling of Unicode still is unclean in several places, where it's -dependent on whether a string is internally flagged as UTF-8. This will -be made more consistent in perl 5.12, but that won't be possible without -a certain amount of backwards incompatibility. - -=head1 Platform Specific Problems - -When compiled with g++ and thread support on Linux, it's reported that the -C<$!> stops working correctly. This is related to the fact that the glibc -provides two strerror_r(3) implementation, and perl selects the wrong -one. - -=head1 Reporting Bugs - -If you find what you think is a bug, you might check the articles -recently posted to the comp.lang.perl.misc newsgroup and the perl -bug database at http://rt.perl.org/rt3/ . There may also be -information at http://www.perl.org/ , the Perl Home Page. - -If you believe you have an unreported bug, please run the B<perlbug> -program included with your release. Be sure to trim your bug down -to a tiny but sufficient test case. Your bug report, along with the -output of C<perl -V>, will be sent off to perlbug@perl.org to be -analysed by the Perl porting team. - -=head1 SEE ALSO - -The F<Changes> file and the perl590delta to perl595delta man pages for -exhaustive details on what changed. - -The F<INSTALL> file for how to build Perl. - -The F<README> file for general stuff. - -The F<Artistic> and F<Copying> files for copyright information. - -=cut |