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perltodo nit for SelfLoader
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1=head1 NAME
2
3perltodo - Perl TO-DO List
4
5=head1 DESCRIPTION
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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
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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
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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
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25The roadmap to 5.10 envisages feature based releases, as various items in this
26TODO are completed.
27
256ddcd0
YO
28=head2 Needed for the final 5.10.0 release
29
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30Review perlguts. Significant changes have occured since 5.8, and we can't
31release a new version without making sure these are covered.
32
0bdfc961 33=head1 Tasks that only need Perl knowledge
e50bb9a1 34
0bdfc961 35=head2 common test code for timed bail out
e50bb9a1 36
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37Write portable self destruct code for tests to stop them burning CPU in
38infinite loops. This needs to avoid using alarm, as some of the tests are
39testing alarm/sleep or timers.
e50bb9a1 40
0bdfc961 41=head2 POD -> HTML conversion in the core still sucks
e50bb9a1 42
938c8732 43Which is crazy given just how simple POD purports to be, and how simple HTML
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44can be. It's not actually I<as> simple as it sounds, particularly with the
45flexibility POD allows for C<=item>, but it would be good to improve the
46visual appeal of the HTML generated, and to avoid it having any validation
47errors. See also L</make HTML install work>, as the layout of installation tree
48is needed to improve the cross-linking.
938c8732 49
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50The addition of C<Pod::Simple> and its related modules may make this task
51easier to complete.
52
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53=head2 Parallel testing
54
b2e2905c 55(This probably impacts much more than the core: also the Test::Harness
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56and TAP::* modules on CPAN.)
57
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58The core regression test suite is getting ever more comprehensive, which has
59the side effect that it takes longer to run. This isn't so good. Investigate
60whether it would be feasible to give the harness script the B<option> of
61running sets of tests in parallel. This would be useful for tests in
62F<t/op/*.t> and F<t/uni/*.t> and maybe some sets of tests in F<lib/>.
63
64Questions to answer
65
66=over 4
67
68=item 1
69
70How does screen layout work when you're running more than one test?
71
72=item 2
73
74How does the caller of test specify how many tests to run in parallel?
75
76=item 3
77
78How do setup/teardown tests identify themselves?
79
80=back
81
82Pugs already does parallel testing - can their approach be re-used?
83
0bdfc961 84=head2 Make Schwern poorer
e50bb9a1 85
613bd4f7 86We should have tests for everything. When all the core's modules are tested,
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87Schwern has promised to donate to $500 to TPF. We may need volunteers to
88hold him upside down and shake vigorously in order to actually extract the
89cash.
3958b146 90
0bdfc961 91=head2 Improve the coverage of the core tests
e50bb9a1 92
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93Use Devel::Cover to ascertain the core modules's test coverage, then add
94tests that are currently missing.
30222c0f 95
0bdfc961 96=head2 test B
e50bb9a1 97
0bdfc961 98A full test suite for the B module would be nice.
e50bb9a1 99
0bdfc961 100=head2 A decent benchmark
e50bb9a1 101
617eabfa 102C<perlbench> seems impervious to any recent changes made to the perl core. It
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103would be useful to have a reasonable general benchmarking suite that roughly
104represented what current perl programs do, and measurably reported whether
105tweaks to the core improve, degrade or don't really affect performance, to
106guide people attempting to optimise the guts of perl. Gisle would welcome
107new tests for perlbench.
6168cf99 108
0bdfc961 109=head2 fix tainting bugs
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111Fix the bugs revealed by running the test suite with the C<-t> switch (via
112C<make test.taintwarn>).
e50bb9a1 113
0bdfc961 114=head2 Dual life everything
e50bb9a1 115
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116As part of the "dists" plan, anything that doesn't belong in the smallest perl
117distribution needs to be dual lifed. Anything else can be too. Figure out what
118changes would be needed to package that module and its tests up for CPAN, and
119do so. Test it with older perl releases, and fix the problems you find.
e50bb9a1 120
0bdfc961 121=head2 Improving C<threads::shared>
722d2a37 122
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123Investigate whether C<threads::shared> could share aggregates properly with
124only Perl level changes to shared.pm
722d2a37 125
0bdfc961 126=head2 POSIX memory footprint
e50bb9a1 127
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128Ilya observed that use POSIX; eats memory like there's no tomorrow, and at
129various times worked to cut it down. There is probably still fat to cut out -
130for example POSIX passes Exporter some very memory hungry data structures.
e50bb9a1 131
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132=head2 embed.pl/makedef.pl
133
134There is a script F<embed.pl> that generates several header files to prefix
135all of Perl's symbols in a consistent way, to provide some semblance of
136namespace support in C<C>. Functions are declared in F<embed.fnc>, variables
137in F<interpvar.h> and F<thrdvar.h>. Quite a few of the functions and variables
138are conditionally declared there, using C<#ifdef>. However, F<embed.pl>
139doesn't understand the C macros, so the rules about which symbols are present
140when is duplicated in F<makedef.pl>. Writing things twice is bad, m'kay.
141It would be good to teach C<embed.pl> to understand the conditional
142compilation, and hence remove the duplication, and the mistakes it has caused.
e50bb9a1 143
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144=head2 use strict; and AutoLoad
145
146Currently if you write
147
148 package Whack;
149 use AutoLoader 'AUTOLOAD';
150 use strict;
151 1;
152 __END__
153 sub bloop {
154 print join (' ', No, strict, here), "!\n";
155 }
156
157then C<use strict;> isn't in force within the autoloaded subroutines. It would
158be more consistent (and less surprising) to arrange for all lexical pragmas
159in force at the __END__ block to be in force within each autoloaded subroutine.
160
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161There's a similar problem with SelfLoader.
162
0bdfc961 163=head1 Tasks that need a little sysadmin-type knowledge
e50bb9a1 164
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165Or if you prefer, tasks that you would learn from, and broaden your skills
166base...
e50bb9a1 167
cd793d32 168=head2 make HTML install work
e50bb9a1 169
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170There is an C<installhtml> target in the Makefile. It's marked as
171"experimental". It would be good to get this tested, make it work reliably, and
172remove the "experimental" tag. This would include
173
174=over 4
175
176=item 1
177
178Checking that cross linking between various parts of the documentation works.
179In particular that links work between the modules (files with POD in F<lib/>)
180and the core documentation (files in F<pod/>)
181
182=item 2
183
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184Work out how to split C<perlfunc> into chunks, preferably one per function
185group, preferably with general case code that could be used elsewhere.
186Challenges here are correctly identifying the groups of functions that go
187together, and making the right named external cross-links point to the right
188page. Things to be aware of are C<-X>, groups such as C<getpwnam> to
189C<endservent>, two or more C<=items> giving the different parameter lists, such
190as
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191
192 =item substr EXPR,OFFSET,LENGTH,REPLACEMENT
adebf063 193 =item substr EXPR,OFFSET,LENGTH
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194 =item substr EXPR,OFFSET
195
196and different parameter lists having different meanings. (eg C<select>)
197
198=back
3a89a73c 199
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200=head2 compressed man pages
201
202Be able to install them. This would probably need a configure test to see how
203the system does compressed man pages (same directory/different directory?
204same filename/different filename), as well as tweaking the F<installman> script
205to compress as necessary.
206
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207=head2 Add a code coverage target to the Makefile
208
209Make it easy for anyone to run Devel::Cover on the core's tests. The steps
210to do this manually are roughly
211
212=over 4
213
214=item *
215
216do a normal C<Configure>, but include Devel::Cover as a module to install
217(see F<INSTALL> for how to do this)
218
219=item *
220
221 make perl
222
223=item *
224
225 cd t; HARNESS_PERL_SWITCHES=-MDevel::Cover ./perl -I../lib harness
226
227=item *
228
229Process the resulting Devel::Cover database
230
231=back
232
233This just give you the coverage of the F<.pm>s. To also get the C level
234coverage you need to
235
236=over 4
237
238=item *
239
240Additionally tell C<Configure> to use the appropriate C compiler flags for
241C<gcov>
242
243=item *
244
245 make perl.gcov
246
247(instead of C<make perl>)
248
249=item *
250
251After running the tests run C<gcov> to generate all the F<.gcov> files.
252(Including down in the subdirectories of F<ext/>
253
254=item *
255
256(From the top level perl directory) run C<gcov2perl> on all the C<.gcov> files
257to get their stats into the cover_db directory.
258
259=item *
260
261Then process the Devel::Cover database
262
263=back
264
265It would be good to add a single switch to C<Configure> to specify that you
266wanted to perform perl level coverage, and another to specify C level
267coverage, and have C<Configure> and the F<Makefile> do all the right things
268automatically.
269
02f21748 270=head2 Make Config.pm cope with differences between built and installed perl
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271
272Quite often vendors ship a perl binary compiled with their (pay-for)
273compilers. People install a free compiler, such as gcc. To work out how to
274build extensions, Perl interrogates C<%Config>, so in this situation
275C<%Config> describes compilers that aren't there, and extension building
276fails. This forces people into choosing between re-compiling perl themselves
277using the compiler they have, or only using modules that the vendor ships.
278
279It would be good to find a way teach C<Config.pm> about the installation setup,
280possibly involving probing at install time or later, so that the C<%Config> in
281a binary distribution better describes the installed machine, when the
282installed machine differs from the build machine in some significant way.
283
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284=head2 linker specification files
285
286Some platforms mandate that you provide a list of a shared library's external
287symbols to the linker, so the core already has the infrastructure in place to
288do this for generating shared perl libraries. My understanding is that the
289GNU toolchain can accept an optional linker specification file, and restrict
290visibility just to symbols declared in that file. It would be good to extend
291F<makedef.pl> to support this format, and to provide a means within
292C<Configure> to enable it. This would allow Unix users to test that the
293export list is correct, and to build a perl that does not pollute the global
294namespace with private symbols.
295
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296=head2 Cross-compile support
297
298Currently C<Configure> understands C<-Dusecrosscompile> option. This option
299arranges for building C<miniperl> for TARGET machine, so this C<miniperl> is
300assumed then to be copied to TARGET machine and used as a replacement of full
301C<perl> executable.
302
d1307786 303This could be done little differently. Namely C<miniperl> should be built for
a229ae3b 304HOST and then full C<perl> with extensions should be compiled for TARGET.
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305This, however, might require extra trickery for %Config: we have one config
306first for HOST and then another for TARGET.
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307
308=head1 Tasks that need a little C knowledge
309
310These tasks would need a little C knowledge, but don't need any specific
311background or experience with XS, or how the Perl interpreter works
312
313=head2 Make it clear from -v if this is the exact official release
89007cb3 314
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315Currently perl from C<p4>/C<rsync> ships with a F<patchlevel.h> file that
316usually defines one local patch, of the form "MAINT12345" or "RC1". The output
317of perl -v doesn't report that a perl isn't an official release, and this
89007cb3 318information can get lost in bugs reports. Because of this, the minor version
fa11829f 319isn't bumped up until RC time, to minimise the possibility of versions of perl
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320escaping that believe themselves to be newer than they actually are.
321
322It would be useful to find an elegant way to have the "this is an interim
323maintenance release" or "this is a release candidate" in the terse -v output,
324and have it so that it's easy for the pumpking to remove this just as the
325release tarball is rolled up. This way the version pulled out of rsync would
326always say "I'm a development release" and it would be safe to bump the
327reported minor version as soon as a release ships, which would aid perl
328developers.
329
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330This task is really about thinking of an elegant way to arrange the C source
331such that it's trivial for the Pumpking to flag "this is an official release"
332when making a tarball, yet leave the default source saying "I'm not the
333official release".
334
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335=head2 Ordering of "global" variables.
336
337F<thrdvar.h> and F<intrpvarh> define the "global" variables that need to be
338per-thread under ithreads, where the variables are actually elements in a
339structure. As C dictates, the variables must be laid out in order of
340declaration. There is a comment
341C</* Important ones in the first cache line (if alignment is done right) */>
342which implies that at some point in the past the ordering was carefully chosen
343(at least in part). However, it's clear that the ordering is less than perfect,
344as currently there are things such as 7 C<bool>s in a row, then something
345typically requiring 4 byte alignment, and then an odd C<bool> later on.
346(C<bool>s are typically defined as C<char>s). So it would be good for someone
347to review the ordering of the variables, to see how much alignment padding can
348be removed.
349
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350It's also worth checking that all variables are actually used. Perl 5.8.0
351shipped with C<PL_nrs> still defined in F<thrdvar.h>, despite it being unused
352since a change over a year earlier. Had this been spotted before release, it
353could have been removed, but now it has to remain in the 5.8.x releases to
354keep the structure the same size, to retain binary compatibility.
355
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356It's probably worth checking if all need to be the types they are. For example
357
358 PERLVAR(Ierror_count, I32) /* how many errors so far, max 10 */
359
360might work as well if stored in a signed (or unsigned) 8 bit value, if the
361comment is accurate. C<PL_multi_open> and C<PL_multi_close> can probably
362become C<char>s. Finding variables to downsize coupled with rearrangement
363could shrink the interpreter structure; a size saving which is multiplied by
364the number of threads running.
365
fee0a0f7 366=head2 Profile Perl - am I hot or not?
62403a3c 367
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368The Perl source code is stable enough that it makes sense to profile it,
369identify and optimise the hotspots. It would be good to measure the
370performance of the Perl interpreter using free tools such as cachegrind,
371gprof, and dtrace, and work to reduce the bottlenecks they reveal.
372
373As part of this, the idea of F<pp_hot.c> is that it contains the I<hot> ops,
374the ops that are most commonly used. The idea is that by grouping them, their
375object code will be adjacent in the executable, so they have a greater chance
376of already being in the CPU cache (or swapped in) due to being near another op
377already in use.
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378
379Except that it's not clear if these really are the most commonly used ops. So
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380as part of exercising your skills with coverage and profiling tools you might
381want to determine what ops I<really> are the most commonly used. And in turn
382suggest evictions and promotions to achieve a better F<pp_hot.c>.
62403a3c 383
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384=head2 Allocate OPs from arenas
385
386Currently all new OP structures are individually malloc()ed and free()d.
387All C<malloc> implementations have space overheads, and are now as fast as
388custom allocates so it would both use less memory and less CPU to allocate
389the various OP structures from arenas. The SV arena code can probably be
390re-used for this.
391
a229ae3b 392=head2 Improve win32/wince.c
0bdfc961 393
a229ae3b 394Currently, numerous functions look virtually, if not completely,
02f21748 395identical in both C<win32/wince.c> and C<win32/win32.c> files, which can't
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396be good.
397
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398=head2 Use secure CRT functions when building with VC8 on Win32
399
400Visual C++ 2005 (VC++ 8.x) deprecated a number of CRT functions on the basis
401that they were "unsafe" and introduced differently named secure versions of
402them as replacements, e.g. instead of writing
403
404 FILE* f = fopen(__FILE__, "r");
405
406one should now write
407
408 FILE* f;
409 errno_t err = fopen_s(&f, __FILE__, "r");
410
411Currently, the warnings about these deprecations have been disabled by adding
412-D_CRT_SECURE_NO_DEPRECATE to the CFLAGS. It would be nice to remove that
413warning suppressant and actually make use of the new secure CRT functions.
414
415There is also a similar issue with POSIX CRT function names like fileno having
416been deprecated in favour of ISO C++ conformant names like _fileno. These
417warnings are also currently suppressed with the compiler option /wd4996. It
418might be nice to do as Microsoft suggest here too, although, unlike the secure
419functions issue, there is presumably little or no benefit in this case.
420
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421=head1 Tasks that need a knowledge of XS
422
423These tasks would need C knowledge, and roughly the level of knowledge of
424the perl API that comes from writing modules that use XS to interface to
425C.
426
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427=head2 autovivification
428
429Make all autovivification consistent w.r.t LVALUE/RVALUE and strict/no strict;
430
431This task is incremental - even a little bit of work on it will help.
432
433=head2 Unicode in Filenames
434
435chdir, chmod, chown, chroot, exec, glob, link, lstat, mkdir, open,
436opendir, qx, readdir, readlink, rename, rmdir, stat, symlink, sysopen,
437system, truncate, unlink, utime, -X. All these could potentially accept
438Unicode filenames either as input or output (and in the case of system
439and qx Unicode in general, as input or output to/from the shell).
440Whether a filesystem - an operating system pair understands Unicode in
441filenames varies.
442
443Known combinations that have some level of understanding include
444Microsoft NTFS, Apple HFS+ (In Mac OS 9 and X) and Apple UFS (in Mac
445OS X), NFS v4 is rumored to be Unicode, and of course Plan 9. How to
446create Unicode filenames, what forms of Unicode are accepted and used
447(UCS-2, UTF-16, UTF-8), what (if any) is the normalization form used,
448and so on, varies. Finding the right level of interfacing to Perl
449requires some thought. Remember that an OS does not implicate a
450filesystem.
451
452(The Windows -C command flag "wide API support" has been at least
453temporarily retired in 5.8.1, and the -C has been repurposed, see
454L<perlrun>.)
455
456=head2 Unicode in %ENV
457
458Currently the %ENV entries are always byte strings.
459
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460=head2 Unicode and glob()
461
462Currently glob patterns and filenames returned from File::Glob::glob()
463are always byte strings.
464
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465=head2 use less 'memory'
466
467Investigate trade offs to switch out perl's choices on memory usage.
468Particularly perl should be able to give memory back.
469
470This task is incremental - even a little bit of work on it will help.
471
472=head2 Re-implement C<:unique> in a way that is actually thread-safe
473
474The old implementation made bad assumptions on several levels. A good 90%
475solution might be just to make C<:unique> work to share the string buffer
476of SvPVs. That way large constant strings can be shared between ithreads,
477such as the configuration information in F<Config>.
478
479=head2 Make tainting consistent
480
481Tainting would be easier to use if it didn't take documented shortcuts and
482allow taint to "leak" everywhere within an expression.
483
484=head2 readpipe(LIST)
485
486system() accepts a LIST syntax (and a PROGRAM LIST syntax) to avoid
487running a shell. readpipe() (the function behind qx//) could be similarly
488extended.
489
490=head2 strcat(), strcpy(), strncat(), strncpy(), sprintf(), vsprintf()
491
492Maybe create a utility that checks after each libperl.a creation that
493none of the above (nor sprintf(), vsprintf(), or *SHUDDER* gets())
494ever creep back to libperl.a.
495
496 nm libperl.a | ./miniperl -alne '$o = $F[0] if /:$/; print "$o $F[1]" if $F[0] eq "U" && $F[1] =~ /^(?:strn?c(?:at|py)|v?sprintf|gets)$/'
497
498Note, of course, that this will only tell whether B<your> platform
499is using those naughty interfaces.
500
501=head2 Audit the code for destruction ordering assumptions
502
503Change 25773 notes
504
505 /* Need to check SvMAGICAL, as during global destruction it may be that
506 AvARYLEN(av) has been freed before av, and hence the SvANY() pointer
507 is now part of the linked list of SV heads, rather than pointing to
508 the original body. */
509 /* FIXME - audit the code for other bugs like this one. */
510
511adding the C<SvMAGICAL> check to
512
513 if (AvARYLEN(av) && SvMAGICAL(AvARYLEN(av))) {
514 MAGIC *mg = mg_find (AvARYLEN(av), PERL_MAGIC_arylen);
515
516Go through the core and look for similar assumptions that SVs have particular
517types, as all bets are off during global destruction.
518
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519=head2 Extend PerlIO and PerlIO::Scalar
520
521PerlIO::Scalar doesn't know how to truncate(). Implementing this
522would require extending the PerlIO vtable.
523
524Similarly the PerlIO vtable doesn't know about formats (write()), or
525about stat(), or chmod()/chown(), utime(), or flock().
526
527(For PerlIO::Scalar it's hard to see what e.g. mode bits or ownership
528would mean.)
529
530PerlIO doesn't do directories or symlinks, either: mkdir(), rmdir(),
531opendir(), closedir(), seekdir(), rewinddir(), glob(); symlink(),
532readlink().
533
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534=head2 -C on the #! line
535
536It should be possible to make -C work correctly if found on the #! line,
537given that all perl command line options are strict ASCII, and -C changes
538only the interpretation of non-ASCII characters, and not for the script file
539handle. To make it work needs some investigation of the ordering of function
540calls during startup, and (by implication) a bit of tweaking of that order.
541
542
0bdfc961 543=head1 Tasks that need a knowledge of the interpreter
3298bd4d 544
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545These tasks would need C knowledge, and knowledge of how the interpreter works,
546or a willingness to learn.
3298bd4d 547
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548=head2 Implement $value ~~ 0 .. $range
549
550It would be nice to extend the syntax of the C<~~> operator to also
551understand numeric (and maybe alphanumeric) ranges.
552
d10fc472 553=head2 Attach/detach debugger from running program
1626a787 554
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555The old perltodo notes "With C<gdb>, you can attach the debugger to a running
556program if you pass the process ID. It would be good to do this with the Perl
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557debugger on a running Perl program, although I'm not sure how it would be
558done." ssh and screen do this with named pipes in /tmp. Maybe we can too.
1626a787 559
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560=head2 LVALUE functions for lists
561
562The old perltodo notes that lvalue functions don't work for list or hash
563slices. This would be good to fix.
564
565=head2 LVALUE functions in the debugger
566
567The old perltodo notes that lvalue functions don't work in the debugger. This
568would be good to fix.
569
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570=head2 regexp optimiser optional
571
572The regexp optimiser is not optional. It should configurable to be, to allow
573its performance to be measured, and its bugs to be easily demonstrated.
574
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575=head2 delete &function
576
577Allow to delete functions. One can already undef them, but they're still
578in the stash.
579
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580=head2 C</w> regex modifier
581
582That flag would enable to match whole words, and also to interpolate
583arrays as alternations. With it, C</P/w> would be roughly equivalent to:
584
585 do { local $"='|'; /\b(?:P)\b/ }
586
587See L<http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2007-01/msg00400.html>
588for the discussion.
589
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590=head2 optional optimizer
591
592Make the peephole optimizer optional. Currently it performs two tasks as
593it walks the optree - genuine peephole optimisations, and necessary fixups of
594ops. It would be good to find an efficient way to switch out the
595optimisations whilst keeping the fixups.
596
597=head2 You WANT *how* many
598
599Currently contexts are void, scalar and list. split has a special mechanism in
600place to pass in the number of return values wanted. It would be useful to
601have a general mechanism for this, backwards compatible and little speed hit.
602This would allow proposals such as short circuiting sort to be implemented
603as a module on CPAN.
604
605=head2 lexical aliases
606
607Allow lexical aliases (maybe via the syntax C<my \$alias = \$foo>.
608
609=head2 entersub XS vs Perl
610
611At the moment pp_entersub is huge, and has code to deal with entering both
612perl and XS subroutines. Subroutine implementations rarely change between
613perl and XS at run time, so investigate using 2 ops to enter subs (one for
614XS, one for perl) and swap between if a sub is redefined.
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615
616=head2 Self ties
617
618self ties are currently illegal because they caused too many segfaults. Maybe
619the causes of these could be tracked down and self-ties on all types re-
620instated.
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621
622=head2 Optimize away @_
623
624The old perltodo notes "Look at the "reification" code in C<av.c>".
625
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626=head2 What hooks would assertions need?
627
628Assertions are in the core, and work. However, assertions needed to be added
629as a core patch, rather than an XS module in ext, or a CPAN module, because
630the core has no hooks in the necessary places. It would be useful to
631investigate what hooks would need to be added to make it possible to provide
632the full assertion support from a CPAN module, so that we aren't constraining
633the imagination of future CPAN authors.
634
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635=head2 Properly Unicode safe tokeniser and pads.
636
637The tokeniser isn't actually very UTF-8 clean. C<use utf8;> is a hack -
638variable names are stored in stashes as raw bytes, without the utf-8 flag
639set. The pad API only takes a C<char *> pointer, so that's all bytes too. The
640tokeniser ignores the UTF-8-ness of C<PL_rsfp>, or any SVs returned from
641source filters. All this could be fixed.
642
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643=head2 The yada yada yada operators
644
645Perl 6's Synopsis 3 says:
646
647I<The ... operator is the "yada, yada, yada" list operator, which is used as
648the body in function prototypes. It complains bitterly (by calling fail)
649if it is ever executed. Variant ??? calls warn, and !!! calls die.>
650
651Those would be nice to add to Perl 5. That could be done without new ops.
652
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653=head1 Big projects
654
655Tasks that will get your name mentioned in the description of the "Highlights
656of 5.10"
657
658=head2 make ithreads more robust
659
4e577f8b 660Generally make ithreads more robust. See also L</iCOW>
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661
662This task is incremental - even a little bit of work on it will help, and
663will be greatly appreciated.
664
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665One bit would be to write the missing code in sv.c:Perl_dirp_dup.
666
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667Fix Perl_sv_dup, et al so that threads can return objects.
668
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669=head2 iCOW
670
671Sarathy and Arthur have a proposal for an improved Copy On Write which
672specifically will be able to COW new ithreads. If this can be implemented
673it would be a good thing.
674
675=head2 (?{...}) closures in regexps
676
677Fix (or rewrite) the implementation of the C</(?{...})/> closures.
678
679=head2 A re-entrant regexp engine
680
681This will allow the use of a regex from inside (?{ }), (??{ }) and
682(?(?{ })|) constructs.
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684=head2 Add class set operations to regexp engine
685
686Apparently these are quite useful. Anyway, Jeffery Friedl wants them.
687
688demerphq has this on his todo list, but right at the bottom.