This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
Coderefs in @INC are done and documented.
[perl5.git] / pod / perltodo.pod
CommitLineData
7711098a
GS
1=head1 NAME
2
3perltodo - Perl TO-DO List
4
5=head1 DESCRIPTION
e50bb9a1 6
0bdfc961
NC
7This is a list of wishes for Perl. The tasks we think are smaller or easier
8are listed first. Anyone is welcome to work on any of these, but it's a good
9idea to first contact I<perl5-porters@perl.org> to avoid duplication of
10effort. By all means contact a pumpking privately first if you prefer.
e50bb9a1 11
0bdfc961
NC
12Whilst patches to make the list shorter are most welcome, ideas to add to
13the list are also encouraged. Check the perl5-porters archives for past
14ideas, and any discussion about them. One set of archives may be found at:
e50bb9a1 15
0bdfc961 16 http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/
938c8732 17
617eabfa
NC
18What can we offer you in return? Fame, fortune, and everlasting glory? Maybe
19not, but if your patch is incorporated, then we'll add your name to the
20F<AUTHORS> file, which ships in the official distribution. How many other
21programming languages offer you 1 line of immortality?
938c8732 22
4e577f8b 23=head1 The roadmap to 5.10
938c8732 24
4e577f8b
NC
25The roadmap to 5.10 envisages feature based releases, as various items in this
26TODO are completed.
27
4e577f8b
NC
28=head2 Needed for a 5.9.4 release
29
30=over
31
32=item *
78ef48ad
RGS
33
34Review assertions. Review syntax to combine assertions. Assertions could take
35advantage of the lexical pragmas work. L</What hooks would assertions need?>
4e577f8b 36
860f190d
RGS
37=item *
38
39C<encoding::warnings> should be turned into a lexical pragma.
0d720714 40C<encoding> should, too (probably).
860f190d 41
4e577f8b
NC
42=back
43
44=head2 Needed for a 5.9.5 release
45
46=over
47
48=item *
49Implement L</_ prototype character>
50
51=item *
52Implement L</state variables>
53
54=back
55
56=head2 Needed for a 5.9.6 release
57
58Stabilisation. If all goes well, this will be the equivalent of a 5.10-beta.
e50bb9a1 59
0bdfc961 60=head1 Tasks that only need Perl knowledge
e50bb9a1 61
0bdfc961 62=head2 common test code for timed bail out
e50bb9a1 63
0bdfc961
NC
64Write portable self destruct code for tests to stop them burning CPU in
65infinite loops. This needs to avoid using alarm, as some of the tests are
66testing alarm/sleep or timers.
e50bb9a1 67
0bdfc961 68=head2 POD -> HTML conversion in the core still sucks
e50bb9a1 69
938c8732 70Which is crazy given just how simple POD purports to be, and how simple HTML
adebf063
NC
71can be. It's not actually I<as> simple as it sounds, particularly with the
72flexibility POD allows for C<=item>, but it would be good to improve the
73visual appeal of the HTML generated, and to avoid it having any validation
74errors. See also L</make HTML install work>, as the layout of installation tree
75is needed to improve the cross-linking.
938c8732 76
dc0fb092
SP
77The addition of C<Pod::Simple> and its related modules may make this task
78easier to complete.
79
aa237293
NC
80=head2 Parallel testing
81
82The core regression test suite is getting ever more comprehensive, which has
83the side effect that it takes longer to run. This isn't so good. Investigate
84whether it would be feasible to give the harness script the B<option> of
85running sets of tests in parallel. This would be useful for tests in
86F<t/op/*.t> and F<t/uni/*.t> and maybe some sets of tests in F<lib/>.
87
88Questions to answer
89
90=over 4
91
92=item 1
93
94How does screen layout work when you're running more than one test?
95
96=item 2
97
98How does the caller of test specify how many tests to run in parallel?
99
100=item 3
101
102How do setup/teardown tests identify themselves?
103
104=back
105
106Pugs already does parallel testing - can their approach be re-used?
107
0bdfc961 108=head2 Make Schwern poorer
e50bb9a1 109
0bdfc961
NC
110We should have for everything. When all the core's modules are tested,
111Schwern has promised to donate to $500 to TPF. We may need volunteers to
112hold him upside down and shake vigorously in order to actually extract the
113cash.
3958b146 114
0bdfc961 115See F<t/lib/1_compile.t> for the 3 remaining modules that need tests.
e50bb9a1 116
0bdfc961 117=head2 Improve the coverage of the core tests
e50bb9a1 118
0bdfc961
NC
119Use Devel::Cover to ascertain the core's test coverage, then add tests that
120are currently missing.
30222c0f 121
0bdfc961 122=head2 test B
e50bb9a1 123
0bdfc961 124A full test suite for the B module would be nice.
e50bb9a1 125
0bdfc961 126=head2 A decent benchmark
e50bb9a1 127
617eabfa 128C<perlbench> seems impervious to any recent changes made to the perl core. It
0bdfc961
NC
129would be useful to have a reasonable general benchmarking suite that roughly
130represented what current perl programs do, and measurably reported whether
131tweaks to the core improve, degrade or don't really affect performance, to
132guide people attempting to optimise the guts of perl. Gisle would welcome
133new tests for perlbench.
6168cf99 134
0bdfc961 135=head2 fix tainting bugs
6168cf99 136
0bdfc961
NC
137Fix the bugs revealed by running the test suite with the C<-t> switch (via
138C<make test.taintwarn>).
e50bb9a1 139
0bdfc961 140=head2 Dual life everything
e50bb9a1 141
0bdfc961
NC
142As part of the "dists" plan, anything that doesn't belong in the smallest perl
143distribution needs to be dual lifed. Anything else can be too. Figure out what
144changes would be needed to package that module and its tests up for CPAN, and
145do so. Test it with older perl releases, and fix the problems you find.
e50bb9a1 146
0bdfc961 147=head2 Improving C<threads::shared>
722d2a37 148
0bdfc961
NC
149Investigate whether C<threads::shared> could share aggregates properly with
150only Perl level changes to shared.pm
722d2a37 151
0bdfc961 152=head2 POSIX memory footprint
e50bb9a1 153
0bdfc961
NC
154Ilya observed that use POSIX; eats memory like there's no tomorrow, and at
155various times worked to cut it down. There is probably still fat to cut out -
156for example POSIX passes Exporter some very memory hungry data structures.
e50bb9a1 157
eed36644
NC
158=head2 embed.pl/makedef.pl
159
160There is a script F<embed.pl> that generates several header files to prefix
161all of Perl's symbols in a consistent way, to provide some semblance of
162namespace support in C<C>. Functions are declared in F<embed.fnc>, variables
163in F<interpvar.h> and F<thrdvar.h>. Quite a few of the functions and variables
164are conditionally declared there, using C<#ifdef>. However, F<embed.pl>
165doesn't understand the C macros, so the rules about which symbols are present
166when is duplicated in F<makedef.pl>. Writing things twice is bad, m'kay.
167It would be good to teach C<embed.pl> to understand the conditional
168compilation, and hence remove the duplication, and the mistakes it has caused.
e50bb9a1 169
e50bb9a1 170
e50bb9a1 171
e50bb9a1 172
adebf063 173
adebf063 174
0bdfc961 175=head1 Tasks that need a little sysadmin-type knowledge
e50bb9a1 176
0bdfc961
NC
177Or if you prefer, tasks that you would learn from, and broaden your skills
178base...
e50bb9a1 179
617eabfa
NC
180=head2 Relocatable perl
181
182The C level patches needed to create a relocatable perl binary are done, as
183is the work on F<Config.pm>. All that's left to do is the C<Configure> tweaking
184to let people specify how they want to do the install.
185
cd793d32 186=head2 make HTML install work
e50bb9a1 187
adebf063
NC
188There is an C<installhtml> target in the Makefile. It's marked as
189"experimental". It would be good to get this tested, make it work reliably, and
190remove the "experimental" tag. This would include
191
192=over 4
193
194=item 1
195
196Checking that cross linking between various parts of the documentation works.
197In particular that links work between the modules (files with POD in F<lib/>)
198and the core documentation (files in F<pod/>)
199
200=item 2
201
617eabfa
NC
202Work out how to split C<perlfunc> into chunks, preferably one per function
203group, preferably with general case code that could be used elsewhere.
204Challenges here are correctly identifying the groups of functions that go
205together, and making the right named external cross-links point to the right
206page. Things to be aware of are C<-X>, groups such as C<getpwnam> to
207C<endservent>, two or more C<=items> giving the different parameter lists, such
208as
adebf063
NC
209
210 =item substr EXPR,OFFSET,LENGTH,REPLACEMENT
211
212 =item substr EXPR,OFFSET,LENGTH
213
214 =item substr EXPR,OFFSET
215
216and different parameter lists having different meanings. (eg C<select>)
217
218=back
3a89a73c 219
0bdfc961
NC
220=head2 compressed man pages
221
222Be able to install them. This would probably need a configure test to see how
223the system does compressed man pages (same directory/different directory?
224same filename/different filename), as well as tweaking the F<installman> script
225to compress as necessary.
226
30222c0f
NC
227=head2 Add a code coverage target to the Makefile
228
229Make it easy for anyone to run Devel::Cover on the core's tests. The steps
230to do this manually are roughly
231
232=over 4
233
234=item *
235
236do a normal C<Configure>, but include Devel::Cover as a module to install
237(see F<INSTALL> for how to do this)
238
239=item *
240
241 make perl
242
243=item *
244
245 cd t; HARNESS_PERL_SWITCHES=-MDevel::Cover ./perl -I../lib harness
246
247=item *
248
249Process the resulting Devel::Cover database
250
251=back
252
253This just give you the coverage of the F<.pm>s. To also get the C level
254coverage you need to
255
256=over 4
257
258=item *
259
260Additionally tell C<Configure> to use the appropriate C compiler flags for
261C<gcov>
262
263=item *
264
265 make perl.gcov
266
267(instead of C<make perl>)
268
269=item *
270
271After running the tests run C<gcov> to generate all the F<.gcov> files.
272(Including down in the subdirectories of F<ext/>
273
274=item *
275
276(From the top level perl directory) run C<gcov2perl> on all the C<.gcov> files
277to get their stats into the cover_db directory.
278
279=item *
280
281Then process the Devel::Cover database
282
283=back
284
285It would be good to add a single switch to C<Configure> to specify that you
286wanted to perform perl level coverage, and another to specify C level
287coverage, and have C<Configure> and the F<Makefile> do all the right things
288automatically.
289
0bdfc961
NC
290=head2 Make Config.pm cope with differences between build and installed perl
291
292Quite often vendors ship a perl binary compiled with their (pay-for)
293compilers. People install a free compiler, such as gcc. To work out how to
294build extensions, Perl interrogates C<%Config>, so in this situation
295C<%Config> describes compilers that aren't there, and extension building
296fails. This forces people into choosing between re-compiling perl themselves
297using the compiler they have, or only using modules that the vendor ships.
298
299It would be good to find a way teach C<Config.pm> about the installation setup,
300possibly involving probing at install time or later, so that the C<%Config> in
301a binary distribution better describes the installed machine, when the
302installed machine differs from the build machine in some significant way.
303
46925299 304=head2 make parallel builds work
0bdfc961 305
46925299
NC
306Currently parallel builds (such as C<make -j3>) don't work reliably. We believe
307that this is due to incomplete dependency specification in the F<Makefile>.
308It would be good if someone were able to track down the causes of these
309problems, so that parallel builds worked properly.
0bdfc961 310
728f4ecd
NC
311=head2 linker specification files
312
313Some platforms mandate that you provide a list of a shared library's external
314symbols to the linker, so the core already has the infrastructure in place to
315do this for generating shared perl libraries. My understanding is that the
316GNU toolchain can accept an optional linker specification file, and restrict
317visibility just to symbols declared in that file. It would be good to extend
318F<makedef.pl> to support this format, and to provide a means within
319C<Configure> to enable it. This would allow Unix users to test that the
320export list is correct, and to build a perl that does not pollute the global
321namespace with private symbols.
322
8523e164 323
0bdfc961
NC
324
325
326=head1 Tasks that need a little C knowledge
327
328These tasks would need a little C knowledge, but don't need any specific
329background or experience with XS, or how the Perl interpreter works
330
331=head2 Make it clear from -v if this is the exact official release
89007cb3 332
617eabfa
NC
333Currently perl from C<p4>/C<rsync> ships with a F<patchlevel.h> file that
334usually defines one local patch, of the form "MAINT12345" or "RC1". The output
335of perl -v doesn't report that a perl isn't an official release, and this
89007cb3 336information can get lost in bugs reports. Because of this, the minor version
fa11829f 337isn't bumped up until RC time, to minimise the possibility of versions of perl
89007cb3
NC
338escaping that believe themselves to be newer than they actually are.
339
340It would be useful to find an elegant way to have the "this is an interim
341maintenance release" or "this is a release candidate" in the terse -v output,
342and have it so that it's easy for the pumpking to remove this just as the
343release tarball is rolled up. This way the version pulled out of rsync would
344always say "I'm a development release" and it would be safe to bump the
345reported minor version as soon as a release ships, which would aid perl
346developers.
347
0bdfc961
NC
348This task is really about thinking of an elegant way to arrange the C source
349such that it's trivial for the Pumpking to flag "this is an official release"
350when making a tarball, yet leave the default source saying "I'm not the
351official release".
352
0f788cd2
NC
353=head2 Ordering of "global" variables.
354
355F<thrdvar.h> and F<intrpvarh> define the "global" variables that need to be
356per-thread under ithreads, where the variables are actually elements in a
357structure. As C dictates, the variables must be laid out in order of
358declaration. There is a comment
359C</* Important ones in the first cache line (if alignment is done right) */>
360which implies that at some point in the past the ordering was carefully chosen
361(at least in part). However, it's clear that the ordering is less than perfect,
362as currently there are things such as 7 C<bool>s in a row, then something
363typically requiring 4 byte alignment, and then an odd C<bool> later on.
364(C<bool>s are typically defined as C<char>s). So it would be good for someone
365to review the ordering of the variables, to see how much alignment padding can
366be removed.
367
d7939546
NC
368It's also worth checking that all variables are actually used. Perl 5.8.0
369shipped with C<PL_nrs> still defined in F<thrdvar.h>, despite it being unused
370since a change over a year earlier. Had this been spotted before release, it
371could have been removed, but now it has to remain in the 5.8.x releases to
372keep the structure the same size, to retain binary compatibility.
373
c1ab7b38
NC
374It's probably worth checking if all need to be the types they are. For example
375
376 PERLVAR(Ierror_count, I32) /* how many errors so far, max 10 */
377
378might work as well if stored in a signed (or unsigned) 8 bit value, if the
379comment is accurate. C<PL_multi_open> and C<PL_multi_close> can probably
380become C<char>s. Finding variables to downsize coupled with rearrangement
381could shrink the interpreter structure; a size saving which is multiplied by
382the number of threads running.
383
62403a3c
NC
384=head2 am I hot or not?
385
386The idea of F<pp_hot.c> is that it contains the I<hot> ops, the ops that are
387most commonly used. The idea is that by grouping them, their object code will
388be adjacent in the executable, so they have a greater chance of already being
389in the CPU cache (or swapped in) due to being near another op already in use.
390
391Except that it's not clear if these really are the most commonly used ops. So
392anyone feeling like exercising their skill with coverage and profiling tools
393might want to determine what ops I<really> are the most commonly used. And in
394turn suggest evictions and promotions to achieve a better F<pp_hot.c>.
395
98fed0ad
NC
396=head2 Shrink struct context
397
398In F<cop.h>, we have
399
400 struct context {
401 U32 cx_type; /* what kind of context this is */
402 union {
403 struct block cx_blk;
404 struct subst cx_subst;
405 } cx_u;
406 };
407
408There are less than 256 values for C<cx_type>, and the constituent parts
409C<struct block> and C<struct subst> both contain some C<U8> and C<U16> fields,
410so it should be possible to move them to the first word, and share space with
411a C<U8> C<cx_type>, saving 1 word.
412
413=head2 Allocate OPs from arenas
414
415Currently all new OP structures are individually malloc()ed and free()d.
416All C<malloc> implementations have space overheads, and are now as fast as
417custom allocates so it would both use less memory and less CPU to allocate
418the various OP structures from arenas. The SV arena code can probably be
419re-used for this.
420
0bdfc961
NC
421
422
423
0bdfc961 424=head1 Tasks that need a knowledge of XS
e50bb9a1 425
0bdfc961
NC
426These tasks would need C knowledge, and roughly the level of knowledge of
427the perl API that comes from writing modules that use XS to interface to
428C.
429
f23930d5 430=head2 shrink C<PVBM>s
4a750395 431
35b64ab6 432By removing unused elements and careful re-ordering, the structures for C<AV>s,
f23930d5
NC
433C<HV>s, C<CV>s and C<GV>s have recently been shrunk considerably. C<PVIO>s
434probably aren't worth it, as typical programs don't use more than 8, and
435(at least) C<Filter::Util::Call> uses C<SvPVX>/C<SvCUR>/C<SvLEN> on a C<PVIO>,
436so it would mean code changes to modules on CPAN. C<PVBM>s might have some
437savings to win.
4a750395 438
0bdfc961
NC
439=head2 Implicit Latin 1 => Unicode translation
440
441Conversions from byte strings to UTF-8 currently map high bit characters
442to Unicode without translation (or, depending on how you look at it, by
443implicitly assuming that the byte strings are in Latin-1). As perl assumes
444the C locale by default, upgrading a string to UTF-8 may change the
445meaning of its contents regarding character classes, case mapping, etc.
446This should probably emit a warning (at least).
447
448This task is incremental - even a little bit of work on it will help.
e50bb9a1 449
cd793d32 450=head2 autovivification
e50bb9a1 451
cd793d32 452Make all autovivification consistent w.r.t LVALUE/RVALUE and strict/no strict;
e50bb9a1 453
0bdfc961 454This task is incremental - even a little bit of work on it will help.
e50bb9a1 455
0bdfc961 456=head2 Unicode in Filenames
e50bb9a1 457
0bdfc961
NC
458chdir, chmod, chown, chroot, exec, glob, link, lstat, mkdir, open,
459opendir, qx, readdir, readlink, rename, rmdir, stat, symlink, sysopen,
460system, truncate, unlink, utime, -X. All these could potentially accept
461Unicode filenames either as input or output (and in the case of system
462and qx Unicode in general, as input or output to/from the shell).
463Whether a filesystem - an operating system pair understands Unicode in
464filenames varies.
e50bb9a1 465
0bdfc961
NC
466Known combinations that have some level of understanding include
467Microsoft NTFS, Apple HFS+ (In Mac OS 9 and X) and Apple UFS (in Mac
468OS X), NFS v4 is rumored to be Unicode, and of course Plan 9. How to
469create Unicode filenames, what forms of Unicode are accepted and used
470(UCS-2, UTF-16, UTF-8), what (if any) is the normalization form used,
471and so on, varies. Finding the right level of interfacing to Perl
472requires some thought. Remember that an OS does not implicate a
473filesystem.
e50bb9a1 474
0bdfc961
NC
475(The Windows -C command flag "wide API support" has been at least
476temporarily retired in 5.8.1, and the -C has been repurposed, see
477L<perlrun>.)
969e704b 478
0bdfc961 479=head2 Unicode in %ENV
969e704b 480
0bdfc961 481Currently the %ENV entries are always byte strings.
e50bb9a1 482
0bdfc961 483=head2 use less 'memory'
e50bb9a1 484
0bdfc961
NC
485Investigate trade offs to switch out perl's choices on memory usage.
486Particularly perl should be able to give memory back.
e50bb9a1 487
0bdfc961 488This task is incremental - even a little bit of work on it will help.
0abe3f7c 489
0bdfc961 490=head2 Re-implement C<:unique> in a way that is actually thread-safe
0abe3f7c 491
0bdfc961
NC
492The old implementation made bad assumptions on several levels. A good 90%
493solution might be just to make C<:unique> work to share the string buffer
494of SvPVs. That way large constant strings can be shared between ithreads,
495such as the configuration information in F<Config>.
0abe3f7c 496
0bdfc961 497=head2 Make tainting consistent
0abe3f7c 498
0bdfc961
NC
499Tainting would be easier to use if it didn't take documented shortcuts and
500allow taint to "leak" everywhere within an expression.
0abe3f7c 501
0bdfc961 502=head2 readpipe(LIST)
0abe3f7c 503
0bdfc961
NC
504system() accepts a LIST syntax (and a PROGRAM LIST syntax) to avoid
505running a shell. readpipe() (the function behind qx//) could be similarly
506extended.
0abe3f7c 507
e50bb9a1 508
e50bb9a1 509
e50bb9a1 510
f86a8bc5 511
0bdfc961 512=head1 Tasks that need a knowledge of the interpreter
3298bd4d 513
0bdfc961
NC
514These tasks would need C knowledge, and knowledge of how the interpreter works,
515or a willingness to learn.
3298bd4d 516
0bdfc961
NC
517=head2 lexical pragmas
518
78ef48ad
RGS
519Document the new support for lexical pragmas in 5.9.3 and how %^H works.
520Maybe C<re>, C<encoding>, maybe other pragmas could be made lexical.
0562c0e3 521
d10fc472 522=head2 Attach/detach debugger from running program
1626a787 523
cd793d32
NC
524The old perltodo notes "With C<gdb>, you can attach the debugger to a running
525program if you pass the process ID. It would be good to do this with the Perl
0bdfc961
NC
526debugger on a running Perl program, although I'm not sure how it would be
527done." ssh and screen do this with named pipes in /tmp. Maybe we can too.
1626a787 528
0bdfc961
NC
529=head2 LVALUE functions for lists
530
531The old perltodo notes that lvalue functions don't work for list or hash
532slices. This would be good to fix.
533
534=head2 LVALUE functions in the debugger
535
536The old perltodo notes that lvalue functions don't work in the debugger. This
537would be good to fix.
538
539=head2 _ prototype character
540
541Study the possibility of adding a new prototype character, C<_>, meaning
542"this argument defaults to $_".
543
4e577f8b
NC
544=head2 state variables
545
546C<my $foo if 0;> is deprecated, and should be replaced with
547C<state $x = "initial value\n";> the syntax from Perl 6.
548
0bdfc961
NC
549=head2 regexp optimiser optional
550
551The regexp optimiser is not optional. It should configurable to be, to allow
552its performance to be measured, and its bugs to be easily demonstrated.
553
554=head2 UNITCHECK
555
556Introduce a new special block, UNITCHECK, which is run at the end of a
557compilation unit (module, file, eval(STRING) block). This will correspond to
558the Perl 6 CHECK. Perl 5's CHECK cannot be changed or removed because the
559O.pm/B.pm backend framework depends on it.
560
561=head2 optional optimizer
562
563Make the peephole optimizer optional. Currently it performs two tasks as
564it walks the optree - genuine peephole optimisations, and necessary fixups of
565ops. It would be good to find an efficient way to switch out the
566optimisations whilst keeping the fixups.
567
568=head2 You WANT *how* many
569
570Currently contexts are void, scalar and list. split has a special mechanism in
571place to pass in the number of return values wanted. It would be useful to
572have a general mechanism for this, backwards compatible and little speed hit.
573This would allow proposals such as short circuiting sort to be implemented
574as a module on CPAN.
575
576=head2 lexical aliases
577
578Allow lexical aliases (maybe via the syntax C<my \$alias = \$foo>.
579
580=head2 entersub XS vs Perl
581
582At the moment pp_entersub is huge, and has code to deal with entering both
583perl and XS subroutines. Subroutine implementations rarely change between
584perl and XS at run time, so investigate using 2 ops to enter subs (one for
585XS, one for perl) and swap between if a sub is redefined.
2810d901
NC
586
587=head2 Self ties
588
589self ties are currently illegal because they caused too many segfaults. Maybe
590the causes of these could be tracked down and self-ties on all types re-
591instated.
0bdfc961
NC
592
593=head2 Optimize away @_
594
595The old perltodo notes "Look at the "reification" code in C<av.c>".
596
0bdfc961
NC
597=head2 What hooks would assertions need?
598
599Assertions are in the core, and work. However, assertions needed to be added
600as a core patch, rather than an XS module in ext, or a CPAN module, because
601the core has no hooks in the necessary places. It would be useful to
602investigate what hooks would need to be added to make it possible to provide
603the full assertion support from a CPAN module, so that we aren't constraining
604the imagination of future CPAN authors.
605
606
607
608
609
0bdfc961
NC
610=head1 Big projects
611
612Tasks that will get your name mentioned in the description of the "Highlights
613of 5.10"
614
615=head2 make ithreads more robust
616
4e577f8b 617Generally make ithreads more robust. See also L</iCOW>
0bdfc961
NC
618
619This task is incremental - even a little bit of work on it will help, and
620will be greatly appreciated.
621
6c047da7
YST
622One bit would be to write the missing code in sv.c:Perl_dirp_dup.
623
0bdfc961
NC
624=head2 iCOW
625
626Sarathy and Arthur have a proposal for an improved Copy On Write which
627specifically will be able to COW new ithreads. If this can be implemented
628it would be a good thing.
629
630=head2 (?{...}) closures in regexps
631
632Fix (or rewrite) the implementation of the C</(?{...})/> closures.
633
634=head2 A re-entrant regexp engine
635
636This will allow the use of a regex from inside (?{ }), (??{ }) and
637(?(?{ })|) constructs.