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7711098a GS |
1 | =head1 NAME |
2 | ||
3 | perltodo - Perl TO-DO List | |
4 | ||
5 | =head1 DESCRIPTION | |
e50bb9a1 | 6 | |
0bdfc961 NC |
7 | This is a list of wishes for Perl. The tasks we think are smaller or easier |
8 | are listed first. Anyone is welcome to work on any of these, but it's a good | |
9 | idea to first contact I<perl5-porters@perl.org> to avoid duplication of | |
10 | effort. By all means contact a pumpking privately first if you prefer. | |
e50bb9a1 | 11 | |
0bdfc961 NC |
12 | Whilst patches to make the list shorter are most welcome, ideas to add to |
13 | the list are also encouraged. Check the perl5-porters archives for past | |
14 | ideas, 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 |
18 | What can we offer you in return? Fame, fortune, and everlasting glory? Maybe |
19 | not, but if your patch is incorporated, then we'll add your name to the | |
20 | F<AUTHORS> file, which ships in the official distribution. How many other | |
21 | programming languages offer you 1 line of immortality? | |
938c8732 | 22 | |
0bdfc961 | 23 | =head1 Tasks that only need Perl knowledge |
e50bb9a1 | 24 | |
0bdfc961 | 25 | =head2 common test code for timed bail out |
e50bb9a1 | 26 | |
0bdfc961 NC |
27 | Write portable self destruct code for tests to stop them burning CPU in |
28 | infinite loops. This needs to avoid using alarm, as some of the tests are | |
29 | testing alarm/sleep or timers. | |
e50bb9a1 | 30 | |
87a942b1 | 31 | =head2 POD -E<gt> HTML conversion in the core still sucks |
e50bb9a1 | 32 | |
938c8732 | 33 | Which is crazy given just how simple POD purports to be, and how simple HTML |
adebf063 NC |
34 | can be. It's not actually I<as> simple as it sounds, particularly with the |
35 | flexibility POD allows for C<=item>, but it would be good to improve the | |
36 | visual appeal of the HTML generated, and to avoid it having any validation | |
37 | errors. See also L</make HTML install work>, as the layout of installation tree | |
38 | is needed to improve the cross-linking. | |
938c8732 | 39 | |
dc0fb092 SP |
40 | The addition of C<Pod::Simple> and its related modules may make this task |
41 | easier to complete. | |
42 | ||
aa237293 NC |
43 | =head2 Parallel testing |
44 | ||
b2e2905c | 45 | (This probably impacts much more than the core: also the Test::Harness |
02f21748 RGS |
46 | and TAP::* modules on CPAN.) |
47 | ||
aa237293 NC |
48 | The core regression test suite is getting ever more comprehensive, which has |
49 | the side effect that it takes longer to run. This isn't so good. Investigate | |
50 | whether it would be feasible to give the harness script the B<option> of | |
51 | running sets of tests in parallel. This would be useful for tests in | |
52 | F<t/op/*.t> and F<t/uni/*.t> and maybe some sets of tests in F<lib/>. | |
53 | ||
54 | Questions to answer | |
55 | ||
56 | =over 4 | |
57 | ||
58 | =item 1 | |
59 | ||
60 | How does screen layout work when you're running more than one test? | |
61 | ||
62 | =item 2 | |
63 | ||
64 | How does the caller of test specify how many tests to run in parallel? | |
65 | ||
66 | =item 3 | |
67 | ||
68 | How do setup/teardown tests identify themselves? | |
69 | ||
70 | =back | |
71 | ||
72 | Pugs already does parallel testing - can their approach be re-used? | |
73 | ||
0bdfc961 | 74 | =head2 Make Schwern poorer |
e50bb9a1 | 75 | |
613bd4f7 | 76 | We should have tests for everything. When all the core's modules are tested, |
0bdfc961 NC |
77 | Schwern has promised to donate to $500 to TPF. We may need volunteers to |
78 | hold him upside down and shake vigorously in order to actually extract the | |
79 | cash. | |
3958b146 | 80 | |
0bdfc961 | 81 | =head2 Improve the coverage of the core tests |
e50bb9a1 | 82 | |
02f21748 RGS |
83 | Use Devel::Cover to ascertain the core modules's test coverage, then add |
84 | tests that are currently missing. | |
30222c0f | 85 | |
0bdfc961 | 86 | =head2 test B |
e50bb9a1 | 87 | |
0bdfc961 | 88 | A full test suite for the B module would be nice. |
e50bb9a1 | 89 | |
0bdfc961 | 90 | =head2 A decent benchmark |
e50bb9a1 | 91 | |
617eabfa | 92 | C<perlbench> seems impervious to any recent changes made to the perl core. It |
0bdfc961 NC |
93 | would be useful to have a reasonable general benchmarking suite that roughly |
94 | represented what current perl programs do, and measurably reported whether | |
95 | tweaks to the core improve, degrade or don't really affect performance, to | |
96 | guide people attempting to optimise the guts of perl. Gisle would welcome | |
97 | new tests for perlbench. | |
6168cf99 | 98 | |
0bdfc961 | 99 | =head2 fix tainting bugs |
6168cf99 | 100 | |
0bdfc961 NC |
101 | Fix the bugs revealed by running the test suite with the C<-t> switch (via |
102 | C<make test.taintwarn>). | |
e50bb9a1 | 103 | |
0bdfc961 | 104 | =head2 Dual life everything |
e50bb9a1 | 105 | |
0bdfc961 NC |
106 | As part of the "dists" plan, anything that doesn't belong in the smallest perl |
107 | distribution needs to be dual lifed. Anything else can be too. Figure out what | |
108 | changes would be needed to package that module and its tests up for CPAN, and | |
109 | do so. Test it with older perl releases, and fix the problems you find. | |
e50bb9a1 | 110 | |
a393eb28 RGS |
111 | To make a minimal perl distribution, it's useful to look at |
112 | F<t/lib/commonsense.t>. | |
113 | ||
0bdfc961 | 114 | =head2 Improving C<threads::shared> |
722d2a37 | 115 | |
0bdfc961 NC |
116 | Investigate whether C<threads::shared> could share aggregates properly with |
117 | only Perl level changes to shared.pm | |
722d2a37 | 118 | |
0bdfc961 | 119 | =head2 POSIX memory footprint |
e50bb9a1 | 120 | |
0bdfc961 NC |
121 | Ilya observed that use POSIX; eats memory like there's no tomorrow, and at |
122 | various times worked to cut it down. There is probably still fat to cut out - | |
123 | for example POSIX passes Exporter some very memory hungry data structures. | |
e50bb9a1 | 124 | |
eed36644 NC |
125 | =head2 embed.pl/makedef.pl |
126 | ||
127 | There is a script F<embed.pl> that generates several header files to prefix | |
128 | all of Perl's symbols in a consistent way, to provide some semblance of | |
129 | namespace support in C<C>. Functions are declared in F<embed.fnc>, variables | |
907b3e23 | 130 | in F<interpvar.h>. Quite a few of the functions and variables |
eed36644 NC |
131 | are conditionally declared there, using C<#ifdef>. However, F<embed.pl> |
132 | doesn't understand the C macros, so the rules about which symbols are present | |
133 | when is duplicated in F<makedef.pl>. Writing things twice is bad, m'kay. | |
134 | It would be good to teach C<embed.pl> to understand the conditional | |
135 | compilation, and hence remove the duplication, and the mistakes it has caused. | |
e50bb9a1 | 136 | |
801de10e NC |
137 | =head2 use strict; and AutoLoad |
138 | ||
139 | Currently if you write | |
140 | ||
141 | package Whack; | |
142 | use AutoLoader 'AUTOLOAD'; | |
143 | use strict; | |
144 | 1; | |
145 | __END__ | |
146 | sub bloop { | |
147 | print join (' ', No, strict, here), "!\n"; | |
148 | } | |
149 | ||
150 | then C<use strict;> isn't in force within the autoloaded subroutines. It would | |
151 | be more consistent (and less surprising) to arrange for all lexical pragmas | |
152 | in force at the __END__ block to be in force within each autoloaded subroutine. | |
153 | ||
773b3597 RGS |
154 | There's a similar problem with SelfLoader. |
155 | ||
0bdfc961 | 156 | =head1 Tasks that need a little sysadmin-type knowledge |
e50bb9a1 | 157 | |
0bdfc961 NC |
158 | Or if you prefer, tasks that you would learn from, and broaden your skills |
159 | base... | |
e50bb9a1 | 160 | |
cd793d32 | 161 | =head2 make HTML install work |
e50bb9a1 | 162 | |
adebf063 NC |
163 | There is an C<installhtml> target in the Makefile. It's marked as |
164 | "experimental". It would be good to get this tested, make it work reliably, and | |
165 | remove the "experimental" tag. This would include | |
166 | ||
167 | =over 4 | |
168 | ||
169 | =item 1 | |
170 | ||
171 | Checking that cross linking between various parts of the documentation works. | |
172 | In particular that links work between the modules (files with POD in F<lib/>) | |
173 | and the core documentation (files in F<pod/>) | |
174 | ||
175 | =item 2 | |
176 | ||
617eabfa NC |
177 | Work out how to split C<perlfunc> into chunks, preferably one per function |
178 | group, preferably with general case code that could be used elsewhere. | |
179 | Challenges here are correctly identifying the groups of functions that go | |
180 | together, and making the right named external cross-links point to the right | |
181 | page. Things to be aware of are C<-X>, groups such as C<getpwnam> to | |
182 | C<endservent>, two or more C<=items> giving the different parameter lists, such | |
183 | as | |
adebf063 NC |
184 | |
185 | =item substr EXPR,OFFSET,LENGTH,REPLACEMENT | |
adebf063 | 186 | =item substr EXPR,OFFSET,LENGTH |
adebf063 NC |
187 | =item substr EXPR,OFFSET |
188 | ||
189 | and different parameter lists having different meanings. (eg C<select>) | |
190 | ||
191 | =back | |
3a89a73c | 192 | |
0bdfc961 NC |
193 | =head2 compressed man pages |
194 | ||
195 | Be able to install them. This would probably need a configure test to see how | |
196 | the system does compressed man pages (same directory/different directory? | |
197 | same filename/different filename), as well as tweaking the F<installman> script | |
198 | to compress as necessary. | |
199 | ||
30222c0f NC |
200 | =head2 Add a code coverage target to the Makefile |
201 | ||
202 | Make it easy for anyone to run Devel::Cover on the core's tests. The steps | |
203 | to do this manually are roughly | |
204 | ||
205 | =over 4 | |
206 | ||
207 | =item * | |
208 | ||
209 | do a normal C<Configure>, but include Devel::Cover as a module to install | |
210 | (see F<INSTALL> for how to do this) | |
211 | ||
212 | =item * | |
213 | ||
214 | make perl | |
215 | ||
216 | =item * | |
217 | ||
218 | cd t; HARNESS_PERL_SWITCHES=-MDevel::Cover ./perl -I../lib harness | |
219 | ||
220 | =item * | |
221 | ||
222 | Process the resulting Devel::Cover database | |
223 | ||
224 | =back | |
225 | ||
226 | This just give you the coverage of the F<.pm>s. To also get the C level | |
227 | coverage you need to | |
228 | ||
229 | =over 4 | |
230 | ||
231 | =item * | |
232 | ||
233 | Additionally tell C<Configure> to use the appropriate C compiler flags for | |
234 | C<gcov> | |
235 | ||
236 | =item * | |
237 | ||
238 | make perl.gcov | |
239 | ||
240 | (instead of C<make perl>) | |
241 | ||
242 | =item * | |
243 | ||
244 | After running the tests run C<gcov> to generate all the F<.gcov> files. | |
245 | (Including down in the subdirectories of F<ext/> | |
246 | ||
247 | =item * | |
248 | ||
249 | (From the top level perl directory) run C<gcov2perl> on all the C<.gcov> files | |
250 | to get their stats into the cover_db directory. | |
251 | ||
252 | =item * | |
253 | ||
254 | Then process the Devel::Cover database | |
255 | ||
256 | =back | |
257 | ||
258 | It would be good to add a single switch to C<Configure> to specify that you | |
259 | wanted to perform perl level coverage, and another to specify C level | |
260 | coverage, and have C<Configure> and the F<Makefile> do all the right things | |
261 | automatically. | |
262 | ||
02f21748 | 263 | =head2 Make Config.pm cope with differences between built and installed perl |
0bdfc961 NC |
264 | |
265 | Quite often vendors ship a perl binary compiled with their (pay-for) | |
266 | compilers. People install a free compiler, such as gcc. To work out how to | |
267 | build extensions, Perl interrogates C<%Config>, so in this situation | |
268 | C<%Config> describes compilers that aren't there, and extension building | |
269 | fails. This forces people into choosing between re-compiling perl themselves | |
270 | using the compiler they have, or only using modules that the vendor ships. | |
271 | ||
272 | It would be good to find a way teach C<Config.pm> about the installation setup, | |
273 | possibly involving probing at install time or later, so that the C<%Config> in | |
274 | a binary distribution better describes the installed machine, when the | |
275 | installed machine differs from the build machine in some significant way. | |
276 | ||
728f4ecd NC |
277 | =head2 linker specification files |
278 | ||
279 | Some platforms mandate that you provide a list of a shared library's external | |
280 | symbols to the linker, so the core already has the infrastructure in place to | |
281 | do this for generating shared perl libraries. My understanding is that the | |
282 | GNU toolchain can accept an optional linker specification file, and restrict | |
283 | visibility just to symbols declared in that file. It would be good to extend | |
284 | F<makedef.pl> to support this format, and to provide a means within | |
285 | C<Configure> to enable it. This would allow Unix users to test that the | |
286 | export list is correct, and to build a perl that does not pollute the global | |
287 | namespace with private symbols. | |
288 | ||
a229ae3b RGS |
289 | =head2 Cross-compile support |
290 | ||
291 | Currently C<Configure> understands C<-Dusecrosscompile> option. This option | |
292 | arranges for building C<miniperl> for TARGET machine, so this C<miniperl> is | |
293 | assumed then to be copied to TARGET machine and used as a replacement of full | |
294 | C<perl> executable. | |
295 | ||
d1307786 | 296 | This could be done little differently. Namely C<miniperl> should be built for |
a229ae3b | 297 | HOST and then full C<perl> with extensions should be compiled for TARGET. |
d1307786 | 298 | This, however, might require extra trickery for %Config: we have one config |
87a942b1 JH |
299 | first for HOST and then another for TARGET. Tools like MakeMaker will be |
300 | mightily confused. Having around two different types of executables and | |
301 | libraries (HOST and TARGET) makes life interesting for Makefiles and | |
302 | shell (and Perl) scripts. There is $Config{run}, normally empty, which | |
303 | can be used as an execution wrapper. Also note that in some | |
304 | cross-compilation/execution environments the HOST and the TARGET do | |
305 | not see the same filesystem(s), the $Config{run} may need to do some | |
306 | file/directory copying back and forth. | |
0bdfc961 NC |
307 | |
308 | =head1 Tasks that need a little C knowledge | |
309 | ||
310 | These tasks would need a little C knowledge, but don't need any specific | |
311 | background 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 | |
617eabfa NC |
315 | Currently perl from C<p4>/C<rsync> ships with a F<patchlevel.h> file that |
316 | usually defines one local patch, of the form "MAINT12345" or "RC1". The output | |
317 | of perl -v doesn't report that a perl isn't an official release, and this | |
89007cb3 | 318 | information can get lost in bugs reports. Because of this, the minor version |
fa11829f | 319 | isn't bumped up until RC time, to minimise the possibility of versions of perl |
89007cb3 NC |
320 | escaping that believe themselves to be newer than they actually are. |
321 | ||
322 | It would be useful to find an elegant way to have the "this is an interim | |
323 | maintenance release" or "this is a release candidate" in the terse -v output, | |
324 | and have it so that it's easy for the pumpking to remove this just as the | |
325 | release tarball is rolled up. This way the version pulled out of rsync would | |
326 | always say "I'm a development release" and it would be safe to bump the | |
327 | reported minor version as soon as a release ships, which would aid perl | |
328 | developers. | |
329 | ||
0bdfc961 NC |
330 | This task is really about thinking of an elegant way to arrange the C source |
331 | such that it's trivial for the Pumpking to flag "this is an official release" | |
332 | when making a tarball, yet leave the default source saying "I'm not the | |
333 | official release". | |
334 | ||
fee0a0f7 | 335 | =head2 Profile Perl - am I hot or not? |
62403a3c | 336 | |
fee0a0f7 NC |
337 | The Perl source code is stable enough that it makes sense to profile it, |
338 | identify and optimise the hotspots. It would be good to measure the | |
339 | performance of the Perl interpreter using free tools such as cachegrind, | |
340 | gprof, and dtrace, and work to reduce the bottlenecks they reveal. | |
341 | ||
342 | As part of this, the idea of F<pp_hot.c> is that it contains the I<hot> ops, | |
343 | the ops that are most commonly used. The idea is that by grouping them, their | |
344 | object code will be adjacent in the executable, so they have a greater chance | |
345 | of already being in the CPU cache (or swapped in) due to being near another op | |
346 | already in use. | |
62403a3c NC |
347 | |
348 | Except that it's not clear if these really are the most commonly used ops. So | |
fee0a0f7 NC |
349 | as part of exercising your skills with coverage and profiling tools you might |
350 | want to determine what ops I<really> are the most commonly used. And in turn | |
351 | suggest evictions and promotions to achieve a better F<pp_hot.c>. | |
62403a3c | 352 | |
98fed0ad NC |
353 | =head2 Allocate OPs from arenas |
354 | ||
355 | Currently all new OP structures are individually malloc()ed and free()d. | |
356 | All C<malloc> implementations have space overheads, and are now as fast as | |
357 | custom allocates so it would both use less memory and less CPU to allocate | |
358 | the various OP structures from arenas. The SV arena code can probably be | |
359 | re-used for this. | |
360 | ||
a229ae3b | 361 | =head2 Improve win32/wince.c |
0bdfc961 | 362 | |
a229ae3b | 363 | Currently, numerous functions look virtually, if not completely, |
02f21748 | 364 | identical in both C<win32/wince.c> and C<win32/win32.c> files, which can't |
6d71adcd NC |
365 | be good. |
366 | ||
c5b31784 SH |
367 | =head2 Use secure CRT functions when building with VC8 on Win32 |
368 | ||
369 | Visual C++ 2005 (VC++ 8.x) deprecated a number of CRT functions on the basis | |
370 | that they were "unsafe" and introduced differently named secure versions of | |
371 | them as replacements, e.g. instead of writing | |
372 | ||
373 | FILE* f = fopen(__FILE__, "r"); | |
374 | ||
375 | one should now write | |
376 | ||
377 | FILE* f; | |
378 | errno_t err = fopen_s(&f, __FILE__, "r"); | |
379 | ||
380 | Currently, the warnings about these deprecations have been disabled by adding | |
381 | -D_CRT_SECURE_NO_DEPRECATE to the CFLAGS. It would be nice to remove that | |
382 | warning suppressant and actually make use of the new secure CRT functions. | |
383 | ||
384 | There is also a similar issue with POSIX CRT function names like fileno having | |
385 | been deprecated in favour of ISO C++ conformant names like _fileno. These | |
26a6faa8 | 386 | warnings are also currently suppressed by adding -D_CRT_NONSTDC_NO_DEPRECATE. It |
c5b31784 SH |
387 | might be nice to do as Microsoft suggest here too, although, unlike the secure |
388 | functions issue, there is presumably little or no benefit in this case. | |
389 | ||
6d71adcd NC |
390 | =head1 Tasks that need a knowledge of XS |
391 | ||
392 | These tasks would need C knowledge, and roughly the level of knowledge of | |
393 | the perl API that comes from writing modules that use XS to interface to | |
394 | C. | |
395 | ||
6d71adcd NC |
396 | =head2 autovivification |
397 | ||
398 | Make all autovivification consistent w.r.t LVALUE/RVALUE and strict/no strict; | |
399 | ||
400 | This task is incremental - even a little bit of work on it will help. | |
401 | ||
402 | =head2 Unicode in Filenames | |
403 | ||
404 | chdir, chmod, chown, chroot, exec, glob, link, lstat, mkdir, open, | |
405 | opendir, qx, readdir, readlink, rename, rmdir, stat, symlink, sysopen, | |
406 | system, truncate, unlink, utime, -X. All these could potentially accept | |
407 | Unicode filenames either as input or output (and in the case of system | |
408 | and qx Unicode in general, as input or output to/from the shell). | |
409 | Whether a filesystem - an operating system pair understands Unicode in | |
410 | filenames varies. | |
411 | ||
412 | Known combinations that have some level of understanding include | |
413 | Microsoft NTFS, Apple HFS+ (In Mac OS 9 and X) and Apple UFS (in Mac | |
414 | OS X), NFS v4 is rumored to be Unicode, and of course Plan 9. How to | |
415 | create Unicode filenames, what forms of Unicode are accepted and used | |
416 | (UCS-2, UTF-16, UTF-8), what (if any) is the normalization form used, | |
417 | and so on, varies. Finding the right level of interfacing to Perl | |
418 | requires some thought. Remember that an OS does not implicate a | |
419 | filesystem. | |
420 | ||
421 | (The Windows -C command flag "wide API support" has been at least | |
422 | temporarily retired in 5.8.1, and the -C has been repurposed, see | |
423 | L<perlrun>.) | |
424 | ||
87a942b1 JH |
425 | Most probably the right way to do this would be this: |
426 | L</"Virtualize operating system access">. | |
427 | ||
6d71adcd NC |
428 | =head2 Unicode in %ENV |
429 | ||
430 | Currently the %ENV entries are always byte strings. | |
87a942b1 | 431 | See L</"Virtualize operating system access">. |
6d71adcd | 432 | |
1f2e7916 JD |
433 | =head2 Unicode and glob() |
434 | ||
435 | Currently glob patterns and filenames returned from File::Glob::glob() | |
87a942b1 | 436 | are always byte strings. See L</"Virtualize operating system access">. |
1f2e7916 | 437 | |
dbb0c492 RGS |
438 | =head2 Unicode and lc/uc operators |
439 | ||
440 | Some built-in operators (C<lc>, C<uc>, etc.) behave differently, based on | |
441 | what the internal encoding of their argument is. That should not be the | |
442 | case. Maybe add a pragma to switch behaviour. | |
443 | ||
6d71adcd NC |
444 | =head2 use less 'memory' |
445 | ||
446 | Investigate trade offs to switch out perl's choices on memory usage. | |
447 | Particularly perl should be able to give memory back. | |
448 | ||
449 | This task is incremental - even a little bit of work on it will help. | |
450 | ||
451 | =head2 Re-implement C<:unique> in a way that is actually thread-safe | |
452 | ||
453 | The old implementation made bad assumptions on several levels. A good 90% | |
454 | solution might be just to make C<:unique> work to share the string buffer | |
455 | of SvPVs. That way large constant strings can be shared between ithreads, | |
456 | such as the configuration information in F<Config>. | |
457 | ||
458 | =head2 Make tainting consistent | |
459 | ||
460 | Tainting would be easier to use if it didn't take documented shortcuts and | |
461 | allow taint to "leak" everywhere within an expression. | |
462 | ||
463 | =head2 readpipe(LIST) | |
464 | ||
465 | system() accepts a LIST syntax (and a PROGRAM LIST syntax) to avoid | |
466 | running a shell. readpipe() (the function behind qx//) could be similarly | |
467 | extended. | |
468 | ||
469 | =head2 strcat(), strcpy(), strncat(), strncpy(), sprintf(), vsprintf() | |
470 | ||
471 | Maybe create a utility that checks after each libperl.a creation that | |
472 | none of the above (nor sprintf(), vsprintf(), or *SHUDDER* gets()) | |
473 | ever creep back to libperl.a. | |
474 | ||
475 | nm libperl.a | ./miniperl -alne '$o = $F[0] if /:$/; print "$o $F[1]" if $F[0] eq "U" && $F[1] =~ /^(?:strn?c(?:at|py)|v?sprintf|gets)$/' | |
476 | ||
477 | Note, of course, that this will only tell whether B<your> platform | |
478 | is using those naughty interfaces. | |
479 | ||
480 | =head2 Audit the code for destruction ordering assumptions | |
481 | ||
482 | Change 25773 notes | |
483 | ||
484 | /* Need to check SvMAGICAL, as during global destruction it may be that | |
485 | AvARYLEN(av) has been freed before av, and hence the SvANY() pointer | |
486 | is now part of the linked list of SV heads, rather than pointing to | |
487 | the original body. */ | |
488 | /* FIXME - audit the code for other bugs like this one. */ | |
489 | ||
490 | adding the C<SvMAGICAL> check to | |
491 | ||
492 | if (AvARYLEN(av) && SvMAGICAL(AvARYLEN(av))) { | |
493 | MAGIC *mg = mg_find (AvARYLEN(av), PERL_MAGIC_arylen); | |
494 | ||
495 | Go through the core and look for similar assumptions that SVs have particular | |
496 | types, as all bets are off during global destruction. | |
497 | ||
749904bf JH |
498 | =head2 Extend PerlIO and PerlIO::Scalar |
499 | ||
500 | PerlIO::Scalar doesn't know how to truncate(). Implementing this | |
501 | would require extending the PerlIO vtable. | |
502 | ||
503 | Similarly the PerlIO vtable doesn't know about formats (write()), or | |
504 | about stat(), or chmod()/chown(), utime(), or flock(). | |
505 | ||
506 | (For PerlIO::Scalar it's hard to see what e.g. mode bits or ownership | |
507 | would mean.) | |
508 | ||
509 | PerlIO doesn't do directories or symlinks, either: mkdir(), rmdir(), | |
510 | opendir(), closedir(), seekdir(), rewinddir(), glob(); symlink(), | |
511 | readlink(). | |
512 | ||
94da6c29 JH |
513 | See also L</"Virtualize operating system access">. |
514 | ||
3236f110 NC |
515 | =head2 -C on the #! line |
516 | ||
517 | It should be possible to make -C work correctly if found on the #! line, | |
518 | given that all perl command line options are strict ASCII, and -C changes | |
519 | only the interpretation of non-ASCII characters, and not for the script file | |
520 | handle. To make it work needs some investigation of the ordering of function | |
521 | calls during startup, and (by implication) a bit of tweaking of that order. | |
522 | ||
523 | ||
0bdfc961 | 524 | =head1 Tasks that need a knowledge of the interpreter |
3298bd4d | 525 | |
0bdfc961 NC |
526 | These tasks would need C knowledge, and knowledge of how the interpreter works, |
527 | or a willingness to learn. | |
3298bd4d | 528 | |
4fedb12c RGS |
529 | =head2 Implement $value ~~ 0 .. $range |
530 | ||
531 | It would be nice to extend the syntax of the C<~~> operator to also | |
532 | understand numeric (and maybe alphanumeric) ranges. | |
a393eb28 RGS |
533 | |
534 | =head2 A does() built-in | |
535 | ||
536 | Like ref(), only useful. It would call the C<DOES> method on objects; it | |
537 | would also tell whether something can be dereferenced as an | |
538 | array/hash/etc., or used as a regexp, etc. | |
539 | L<http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2007-03/msg00481.html> | |
540 | ||
541 | =head2 Tied filehandles and write() don't mix | |
542 | ||
543 | There is no method on tied filehandles to allow them to be called back by | |
544 | formats. | |
4fedb12c | 545 | |
d10fc472 | 546 | =head2 Attach/detach debugger from running program |
1626a787 | 547 | |
cd793d32 NC |
548 | The old perltodo notes "With C<gdb>, you can attach the debugger to a running |
549 | program if you pass the process ID. It would be good to do this with the Perl | |
0bdfc961 NC |
550 | debugger on a running Perl program, although I'm not sure how it would be |
551 | done." ssh and screen do this with named pipes in /tmp. Maybe we can too. | |
1626a787 | 552 | |
a8cb5b9e RGS |
553 | =head2 Optimize away empty destructors |
554 | ||
555 | Defining an empty DESTROY method might be useful (notably in | |
556 | AUTOLOAD-enabled classes), but it's still a bit expensive to call. That | |
557 | could probably be optimized. | |
558 | ||
0bdfc961 NC |
559 | =head2 LVALUE functions for lists |
560 | ||
561 | The old perltodo notes that lvalue functions don't work for list or hash | |
562 | slices. This would be good to fix. | |
563 | ||
564 | =head2 LVALUE functions in the debugger | |
565 | ||
566 | The old perltodo notes that lvalue functions don't work in the debugger. This | |
567 | would be good to fix. | |
568 | ||
0bdfc961 NC |
569 | =head2 regexp optimiser optional |
570 | ||
571 | The regexp optimiser is not optional. It should configurable to be, to allow | |
572 | its performance to be measured, and its bugs to be easily demonstrated. | |
573 | ||
02f21748 RGS |
574 | =head2 delete &function |
575 | ||
576 | Allow to delete functions. One can already undef them, but they're still | |
577 | in the stash. | |
578 | ||
ef36c6a7 RGS |
579 | =head2 C</w> regex modifier |
580 | ||
581 | That flag would enable to match whole words, and also to interpolate | |
582 | arrays as alternations. With it, C</P/w> would be roughly equivalent to: | |
583 | ||
584 | do { local $"='|'; /\b(?:P)\b/ } | |
585 | ||
586 | See L<http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2007-01/msg00400.html> | |
587 | for the discussion. | |
588 | ||
0bdfc961 NC |
589 | =head2 optional optimizer |
590 | ||
591 | Make the peephole optimizer optional. Currently it performs two tasks as | |
592 | it walks the optree - genuine peephole optimisations, and necessary fixups of | |
593 | ops. It would be good to find an efficient way to switch out the | |
594 | optimisations whilst keeping the fixups. | |
595 | ||
596 | =head2 You WANT *how* many | |
597 | ||
598 | Currently contexts are void, scalar and list. split has a special mechanism in | |
599 | place to pass in the number of return values wanted. It would be useful to | |
600 | have a general mechanism for this, backwards compatible and little speed hit. | |
601 | This would allow proposals such as short circuiting sort to be implemented | |
602 | as a module on CPAN. | |
603 | ||
604 | =head2 lexical aliases | |
605 | ||
606 | Allow lexical aliases (maybe via the syntax C<my \$alias = \$foo>. | |
607 | ||
608 | =head2 entersub XS vs Perl | |
609 | ||
610 | At the moment pp_entersub is huge, and has code to deal with entering both | |
611 | perl and XS subroutines. Subroutine implementations rarely change between | |
612 | perl and XS at run time, so investigate using 2 ops to enter subs (one for | |
613 | XS, one for perl) and swap between if a sub is redefined. | |
2810d901 NC |
614 | |
615 | =head2 Self ties | |
616 | ||
617 | self ties are currently illegal because they caused too many segfaults. Maybe | |
618 | the causes of these could be tracked down and self-ties on all types re- | |
619 | instated. | |
0bdfc961 NC |
620 | |
621 | =head2 Optimize away @_ | |
622 | ||
623 | The old perltodo notes "Look at the "reification" code in C<av.c>". | |
624 | ||
16fc99ce NC |
625 | =head2 Properly Unicode safe tokeniser and pads. |
626 | ||
627 | The tokeniser isn't actually very UTF-8 clean. C<use utf8;> is a hack - | |
628 | variable names are stored in stashes as raw bytes, without the utf-8 flag | |
629 | set. The pad API only takes a C<char *> pointer, so that's all bytes too. The | |
630 | tokeniser ignores the UTF-8-ness of C<PL_rsfp>, or any SVs returned from | |
631 | source filters. All this could be fixed. | |
632 | ||
f092b1f4 RGS |
633 | =head2 The yada yada yada operators |
634 | ||
635 | Perl 6's Synopsis 3 says: | |
636 | ||
637 | I<The ... operator is the "yada, yada, yada" list operator, which is used as | |
638 | the body in function prototypes. It complains bitterly (by calling fail) | |
639 | if it is ever executed. Variant ??? calls warn, and !!! calls die.> | |
640 | ||
641 | Those would be nice to add to Perl 5. That could be done without new ops. | |
642 | ||
87a942b1 JH |
643 | =head2 Virtualize operating system access |
644 | ||
645 | Implement a set of "vtables" that virtualizes operating system access | |
646 | (open(), mkdir(), unlink(), readdir(), getenv(), etc.) At the very | |
647 | least these interfaces should take SVs as "name" arguments instead of | |
648 | bare char pointers; probably the most flexible and extensible way | |
e1a3d5d1 JH |
649 | would be for the Perl-facing interfaces to accept HVs. The system |
650 | needs to be per-operating-system and per-file-system | |
651 | hookable/filterable, preferably both from XS and Perl level | |
87a942b1 JH |
652 | (L<perlport/"Files and Filesystems"> is good reading at this point, |
653 | in fact, all of L<perlport> is.) | |
654 | ||
e1a3d5d1 JH |
655 | This has actually already been implemented (but only for Win32), |
656 | take a look at F<iperlsys.h> and F<win32/perlhost.h>. While all Win32 | |
657 | variants go through a set of "vtables" for operating system access, | |
658 | non-Win32 systems currently go straight for the POSIX/UNIX-style | |
659 | system/library call. Similar system as for Win32 should be | |
660 | implemented for all platforms. The existing Win32 implementation | |
661 | probably does not need to survive alongside this proposed new | |
662 | implementation, the approaches could be merged. | |
87a942b1 JH |
663 | |
664 | What would this give us? One often-asked-for feature this would | |
94da6c29 JH |
665 | enable is using Unicode for filenames, and other "names" like %ENV, |
666 | usernames, hostnames, and so forth. | |
667 | (See L<perlunicode/"When Unicode Does Not Happen">.) | |
668 | ||
669 | But this kind of virtualization would also allow for things like | |
670 | virtual filesystems, virtual networks, and "sandboxes" (though as long | |
671 | as dynamic loading of random object code is allowed, not very safe | |
672 | sandboxes since external code of course know not of Perl's vtables). | |
673 | An example of a smaller "sandbox" is that this feature can be used to | |
674 | implement per-thread working directories: Win32 already does this. | |
675 | ||
676 | See also L</"Extend PerlIO and PerlIO::Scalar">. | |
87a942b1 | 677 | |
0bdfc961 NC |
678 | =head1 Big projects |
679 | ||
680 | Tasks that will get your name mentioned in the description of the "Highlights | |
87a942b1 | 681 | of 5.12" |
0bdfc961 NC |
682 | |
683 | =head2 make ithreads more robust | |
684 | ||
4e577f8b | 685 | Generally make ithreads more robust. See also L</iCOW> |
0bdfc961 NC |
686 | |
687 | This task is incremental - even a little bit of work on it will help, and | |
688 | will be greatly appreciated. | |
689 | ||
6c047da7 YST |
690 | One bit would be to write the missing code in sv.c:Perl_dirp_dup. |
691 | ||
59c7f7d5 RGS |
692 | Fix Perl_sv_dup, et al so that threads can return objects. |
693 | ||
0bdfc961 NC |
694 | =head2 iCOW |
695 | ||
696 | Sarathy and Arthur have a proposal for an improved Copy On Write which | |
697 | specifically will be able to COW new ithreads. If this can be implemented | |
698 | it would be a good thing. | |
699 | ||
700 | =head2 (?{...}) closures in regexps | |
701 | ||
702 | Fix (or rewrite) the implementation of the C</(?{...})/> closures. | |
703 | ||
704 | =head2 A re-entrant regexp engine | |
705 | ||
706 | This will allow the use of a regex from inside (?{ }), (??{ }) and | |
707 | (?(?{ })|) constructs. | |
6bda09f9 | 708 | |
6bda09f9 YO |
709 | =head2 Add class set operations to regexp engine |
710 | ||
711 | Apparently these are quite useful. Anyway, Jeffery Friedl wants them. | |
712 | ||
713 | demerphq has this on his todo list, but right at the bottom. |