[p5sagit/p5-mst-13.2.git] / pod / perl5132delta.pod

=encoding utf8

=head1 NAME

perldelta - what is new for perl v5.13.2

=head1 DESCRIPTION

This document describes differences between the 5.13.2 release and
the 5.13.1 release.

If you are upgrading from an earlier release such as 5.10, first read
L<perl5120delta>, which describes differences between 5.10 and
5.12.

=head1 Notice

XXX Any important notices here

=head1 Incompatible Changes

=head2 localised tied scalars are tied again.

The change in behaviour in 5.13.1 of localising tied scalar values has
been reverted to the existing 5.12.0 and earlier behaviour (the change for
arrays and hashes remains).

=head1 Core Enhancements

XXX New core language features go here. Summarise user-visible core language
enhancements. Particularly prominent performance optimisations could go
here, but most should go in the L</Performance Enhancements> section.

=head2 Non-destructive substitution

The substitution operator now supports a C</r> option that
copies the input variable, carries out the substitution on
the copy and returns the result.  The original remains unmodified.

  my $old = 'cat';
  my $new = $old =~ s/cat/dog/r;
  # $old is 'cat' and $new is 'dog'

This is particularly useful with C<map>.  See L<perlop> for more examples.

=head2 package block syntax

A package declaration can now contain a code block, in which case the
declaration is in scope only inside that block.  So C<package Foo { ... }>
is precisely equivalent to C<{ package Foo; ... }>.  It also works with
a version number in the declaration, as in C<package Foo 1.2 { ... }>.
See L<perlfunc> (434da3..36f77d, 702646).

=head1 New Platforms

XXX List any platforms that this version of perl compiles on, that previous
versions did not. These will either be enabled by new files in the F<hints/>
directories, or new subdirectories and F<README> files at the top level of the
source tree.

=head1 Modules and Pragmata

XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
go here.  If Module::CoreList is updated, generate an initial draft of the
following sections using F<Porting/corelist-perldelta.pl>, which prints stub
entries to STDOUT.  Results can be pasted in place of the '=head2' entries
below.  A paragraph summary for important changes should then be added by hand.
In an ideal world, dual-life modules would have a F<Changes> file that could be
cribbed.

=head2 New Modules and Pragmata

=head2 Pragmata Changes

=head2 Updated Modules

=head2 Removed Modules and Pragmata

=head1 Utility Changes

XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go
here. Most of these are built within the directories F<utils> and F<x2p>.

=over 4

=item F<XXX>

XXX

=back

=head1 New Documentation

XXX Changes which create B<new> files in F<pod/> go here.

=over 4

=item L<XXX>

XXX

=back

=head1 Changes to Existing Documentation

XXX Changes which significantly change existing files in F<pod/> go here.
Any changes to F<pod/perldiag.pod> should go in L</New or Changed Diagnostics>.


=head1 Performance Enhancements

Multiple small improvements to threads:

Change the internal structured of thread->params from an SV (RV) to an AV
- so we now pass around and store the array directly, rather than creating,
holding and dereferencing a reference to it (78b7eff).

Change S_ithread_create() params from a single AV* to a pair of SV** pointers.
This saves creating, duplicating and freeing and AV, which is only ever used for
an internal calling convention (4cf5ea).

Remove redundant hv_exists() calls from ithread_create()'s spec parser (b1faab).

Skip unnecessary newAV() in ithread_create() (39f3f7).

=over 4

=item *

XXX

=back

=head1 Installation and Configuration Improvements

XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
go here.

=head2 Configuration improvements

XXX

=head2 Compilation improvements

XXX

=head2 Platform Specific Changes

=over 4

=item XXX-some-platform

XXX

=back

=head1 Selected Bug Fixes

XXX Important bug fixes in the core language are summarised here.
Bug fixes in files in F<ext/> and F<lib/> are best summarised in
L</Modules and Pragmata>.

Avoid loading feature.pm when 'no 5.13.2;' or similar is encountered (faee19).

Trap invalid use of SvIVX on SVt_REGEXP when assertions are on (e77da3)

=over 4

=item *

Overloading now works properly in conjunction with tied variables. What
formerly happened was that most ops checked their arguments for overloading
I<before> checking for magic, so for example an overloaded object returned
by a tied array access would usually be treated as not overloaded
(RT #57012).

=back

=head1 New or Changed Diagnostics

XXX New or changed warnings emitted by the core's C<C> code go here.

=over 4

=item C<XXX>

XXX

=back

=head1 Changed Internals

XXX Changes which affect the interface available to C<XS> code go here.

=over 4

=item *

The C<fund_rundefsvoffset> function has been deprecated. It appeared that
its design was insufficient to reliably get the lexical C<$_> at run-time.

Use the new C<find_rundefsv> function or the C<UNDERBAR> macro instead.
They directly return the right SV representing C<$_>, whether it's lexical
or dynamic.

=item *

The following new functions or macros have been added to the public API:
C<SvNV_nomg>,  C<sv_2nv_flags>, C<find_rundefsv>.

=item *

The C<UNDERBAR> macro now calls C<find_rundefsv>. C<dUNDERBAR> is now a
noop but should still be used to ensure past and future compatibility.

=back

=head1 New Tests

XXX Changes which create B<new> files in F<t/> go here. Changes to
existing files in F<t/> aren't worth summarising, although the bugs that
they represent may be.

=over 4

=item F<XXX>

XXX

=back

=head1 Known Problems

XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
tests that had to be C<TODO>ed for the release would be noted here, unless
they were specific to a particular platform (see below).

This is a list of some significant unfixed bugs, which are regressions
from either 5.XXX.XXX or 5.XXX.XXX.

=over 4

=item *

XXX

=back

=head1 Deprecations

XXX Add any new known deprecations here.

The following items are now deprecated.

=over 4

=item *

Omitting a space between a regex pattern or pattern modifiers and the following
word is deprecated.  For example, C<< m/foo/sand $bar >> will still be parsed
as C<< m/foo/s and $bar >> but will issue a warning.

=back

=head1 Platform Specific Notes

XXX Any changes specific to a particular platform. VMS and Win32 are the usual
stars here. It's probably best to group changes under the same section layout
as the main perldelta

=head1 Obituary

XXX If any significant core contributor has died, we've added a short obituary
here.

=head1 Acknowledgements

XXX The list of people to thank goes here.


=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/perlbug/ .  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.

If the bug you are reporting has security implications, which make it
inappropriate to send to a publicly archived mailing list, then please send
it to perl5-security-report@perl.org. This points to a closed subscription
unarchived mailing list, which includes all the core committers, who be able
to help assess the impact of issues, figure out a resolution, and help
co-ordinate the release of patches to mitigate or fix the problem across all
platforms on which Perl is supported. Please only use this address for
security issues in the Perl core, not for modules independently
distributed on CPAN.

=head1 SEE ALSO

The F<Changes> file for an explanation of how to view 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
Commit	Line	Data
f83c51e5	1	=encoding utf8
	2
	3	=head1 NAME
	4
	5	perldelta - what is new for perl v5.13.2
	6
	7	=head1 DESCRIPTION
	8
	9	This document describes differences between the 5.13.2 release and
	10	the 5.13.1 release.
	11
	12	If you are upgrading from an earlier release such as 5.10, first read
	13	L<perl5120delta>, which describes differences between 5.10 and
	14	5.12.
	15
	16	=head1 Notice
	17
	18	XXX Any important notices here
	19
	20	=head1 Incompatible Changes
	21
5f3e44b6	22	=head2 localised tied scalars are tied again.
f83c51e5	23
5f3e44b6	24	The change in behaviour in 5.13.1 of localising tied scalar values has
	25	been reverted to the existing 5.12.0 and earlier behaviour (the change for
	26	arrays and hashes remains).
f83c51e5	27
	28	=head1 Core Enhancements
	29
	30	XXX New core language features go here. Summarise user-visible core language
	31	enhancements. Particularly prominent performance optimisations could go
	32	here, but most should go in the L</Performance Enhancements> section.
	33
c4a65341	34	=head2 Non-destructive substitution
	35
	36	The substitution operator now supports a C</r> option that
	37	copies the input variable, carries out the substitution on
	38	the copy and returns the result. The original remains unmodified.
	39
	40	my $old = 'cat';
	41	my $new = $old =~ s/cat/dog/r;
	42	# $old is 'cat' and $new is 'dog'
	43
	44	This is particularly useful with C<map>. See L<perlop> for more examples.
	45
f5d8aca1	46	=head2 package block syntax
	47
	48	A package declaration can now contain a code block, in which case the
	49	declaration is in scope only inside that block. So C<package Foo { ... }>
	50	is precisely equivalent to C<{ package Foo; ... }>. It also works with
	51	a version number in the declaration, as in C<package Foo 1.2 { ... }>.
4baddafe	52	See L<perlfunc> (434da3..36f77d, 702646).
f5d8aca1	53
f83c51e5	54	=head1 New Platforms
	55
	56	XXX List any platforms that this version of perl compiles on, that previous
	57	versions did not. These will either be enabled by new files in the F<hints/>
	58	directories, or new subdirectories and F<README> files at the top level of the
	59	source tree.
	60
	61	=head1 Modules and Pragmata
	62
	63	XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
	64	go here. If Module::CoreList is updated, generate an initial draft of the
	65	following sections using F<Porting/corelist-perldelta.pl>, which prints stub
	66	entries to STDOUT. Results can be pasted in place of the '=head2' entries
	67	below. A paragraph summary for important changes should then be added by hand.
	68	In an ideal world, dual-life modules would have a F<Changes> file that could be
	69	cribbed.
	70
	71	=head2 New Modules and Pragmata
	72
	73	=head2 Pragmata Changes
	74
	75	=head2 Updated Modules
	76
	77	=head2 Removed Modules and Pragmata
	78
	79	=head1 Utility Changes
	80
	81	XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go
	82	here. Most of these are built within the directories F<utils> and F<x2p>.
	83
	84	=over 4
	85
	86	=item F<XXX>
	87
	88	XXX
	89
	90	=back
	91
	92	=head1 New Documentation
	93
	94	XXX Changes which create B<new> files in F<pod/> go here.
	95
	96	=over 4
	97
	98	=item L<XXX>
	99
	100	XXX
	101
	102	=back
	103
	104	=head1 Changes to Existing Documentation
	105
	106	XXX Changes which significantly change existing files in F<pod/> go here.
	107	Any changes to F<pod/perldiag.pod> should go in L</New or Changed Diagnostics>.
	108
	109
	110	=head1 Performance Enhancements
	111
bd0a6a63	112	Multiple small improvements to threads:
	113
	114	Change the internal structured of thread->params from an SV (RV) to an AV
	115	- so we now pass around and store the array directly, rather than creating,
	116	holding and dereferencing a reference to it (78b7eff).
	117
	118	Change S_ithread_create() params from a single AV* to a pair of SV** pointers.
	119	This saves creating, duplicating and freeing and AV, which is only ever used for
	120	an internal calling convention (4cf5ea).
	121
	122	Remove redundant hv_exists() calls from ithread_create()'s spec parser (b1faab).
	123
	124	Skip unnecessary newAV() in ithread_create() (39f3f7).
f83c51e5	125
	126	=over 4
	127
	128	=item *
	129
	130	XXX
	131
	132	=back
	133
	134	=head1 Installation and Configuration Improvements
	135
	136	XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
	137	go here.
	138
	139	=head2 Configuration improvements
	140
	141	XXX
	142
	143	=head2 Compilation improvements
	144
	145	XXX
	146
	147	=head2 Platform Specific Changes
	148
	149	=over 4
	150
	151	=item XXX-some-platform
	152
	153	XXX
	154
	155	=back
	156
	157	=head1 Selected Bug Fixes
	158
	159	XXX Important bug fixes in the core language are summarised here.
	160	Bug fixes in files in F<ext/> and F<lib/> are best summarised in
	161	L</Modules and Pragmata>.
	162
76125158	163	Avoid loading feature.pm when 'no 5.13.2;' or similar is encountered (faee19).
76125158	164
5266dd11	165	Trap invalid use of SvIVX on SVt_REGEXP when assertions are on (e77da3)
5266dd11	166
f83c51e5	167	=over 4
	168
	169	=item *
	170
ebe8e111	171	Overloading now works properly in conjunction with tied variables. What
	172	formerly happened was that most ops checked their arguments for overloading
	173	I<before> checking for magic, so for example an overloaded object returned
	174	by a tied array access would usually be treated as not overloaded
	175	(RT #57012).
f83c51e5	176
	177	=back
	178
	179	=head1 New or Changed Diagnostics
	180
	181	XXX New or changed warnings emitted by the core's C<C> code go here.
	182
	183	=over 4
	184
	185	=item C<XXX>
	186
	187	XXX
	188
	189	=back
	190
	191	=head1 Changed Internals
	192
	193	XXX Changes which affect the interface available to C<XS> code go here.
	194
	195	=over 4
	196
	197	=item *
	198
03d5bcf8	199	The C<fund_rundefsvoffset> function has been deprecated. It appeared that
	200	its design was insufficient to reliably get the lexical C<$_> at run-time.
	201
	202	Use the new C<find_rundefsv> function or the C<UNDERBAR> macro instead.
	203	They directly return the right SV representing C<$_>, whether it's lexical
	204	or dynamic.
	205
	206	=item *
	207
ebe8e111	208	The following new functions or macros have been added to the public API:
789bd863	209	C<SvNV_nomg>, C<sv_2nv_flags>, C<find_rundefsv>.
f83c51e5	210
483ce06a	211	=item *
	212
	213	The C<UNDERBAR> macro now calls C<find_rundefsv>. C<dUNDERBAR> is now a
	214	noop but should still be used to ensure past and future compatibility.
	215
f83c51e5	216	=back
	217
	218	=head1 New Tests
	219
	220	XXX Changes which create B<new> files in F<t/> go here. Changes to
	221	existing files in F<t/> aren't worth summarising, although the bugs that
	222	they represent may be.
	223
	224	=over 4
	225
	226	=item F<XXX>
	227
	228	XXX
	229
	230	=back
	231
	232	=head1 Known Problems
	233
	234	XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
	235	tests that had to be C<TODO>ed for the release would be noted here, unless
	236	they were specific to a particular platform (see below).
	237
	238	This is a list of some significant unfixed bugs, which are regressions
	239	from either 5.XXX.XXX or 5.XXX.XXX.
	240
	241	=over 4
	242
	243	=item *
	244
	245	XXX
	246
	247	=back
	248
	249	=head1 Deprecations
	250
	251	XXX Add any new known deprecations here.
	252
	253	The following items are now deprecated.
	254
	255	=over 4
	256
	257	=item *
	258
7c8a36d1	259	Omitting a space between a regex pattern or pattern modifiers and the following
	260	word is deprecated. For example, C<< m/foo/sand $bar >> will still be parsed
	261	as C<< m/foo/s and $bar >> but will issue a warning.
f83c51e5	262
	263	=back
	264
	265	=head1 Platform Specific Notes
	266
	267	XXX Any changes specific to a particular platform. VMS and Win32 are the usual
	268	stars here. It's probably best to group changes under the same section layout
	269	as the main perldelta
	270
	271	=head1 Obituary
	272
	273	XXX If any significant core contributor has died, we've added a short obituary
	274	here.
	275
	276	=head1 Acknowledgements
	277
	278	XXX The list of people to thank goes here.
	279
	280
	281	=head1 Reporting Bugs
	282
	283	If you find what you think is a bug, you might check the articles
	284	recently posted to the comp.lang.perl.misc newsgroup and the perl
	285	bug database at http://rt.perl.org/perlbug/ . There may also be
	286	information at http://www.perl.org/ , the Perl Home Page.
	287
	288	If you believe you have an unreported bug, please run the B<perlbug>
	289	program included with your release. Be sure to trim your bug down
	290	to a tiny but sufficient test case. Your bug report, along with the
	291	output of C<perl -V>, will be sent off to perlbug@perl.org to be
	292	analysed by the Perl porting team.
	293
	294	If the bug you are reporting has security implications, which make it
	295	inappropriate to send to a publicly archived mailing list, then please send
	296	it to perl5-security-report@perl.org. This points to a closed subscription
	297	unarchived mailing list, which includes all the core committers, who be able
	298	to help assess the impact of issues, figure out a resolution, and help
	299	co-ordinate the release of patches to mitigate or fix the problem across all
	300	platforms on which Perl is supported. Please only use this address for
	301	security issues in the Perl core, not for modules independently
	302	distributed on CPAN.
	303
	304	=head1 SEE ALSO
	305
	306	The F<Changes> file for an explanation of how to view exhaustive details
	307	on what changed.
	308
	309	The F<INSTALL> file for how to build Perl.
	310
	311	The F<README> file for general stuff.
	312
	313	The F<Artistic> and F<Copying> files for copyright information.
	314
	315	=cut