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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 | |
4e577f8b | 23 | =head1 The roadmap to 5.10 |
938c8732 | 24 | |
4e577f8b NC |
25 | The roadmap to 5.10 envisages feature based releases, as various items in this |
26 | TODO are completed. | |
27 | ||
256ddcd0 YO |
28 | =head2 Needed for the final 5.10.0 release |
29 | ||
256ddcd0 YO |
30 | Review perlguts. Significant changes have occured since 5.8, and we can't |
31 | release 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 | |
0bdfc961 NC |
37 | Write portable self destruct code for tests to stop them burning CPU in |
38 | infinite loops. This needs to avoid using alarm, as some of the tests are | |
39 | testing alarm/sleep or timers. | |
e50bb9a1 | 40 | |
87a942b1 | 41 | =head2 POD -E<gt> HTML conversion in the core still sucks |
e50bb9a1 | 42 | |
938c8732 | 43 | Which is crazy given just how simple POD purports to be, and how simple HTML |
adebf063 NC |
44 | can be. It's not actually I<as> simple as it sounds, particularly with the |
45 | flexibility POD allows for C<=item>, but it would be good to improve the | |
46 | visual appeal of the HTML generated, and to avoid it having any validation | |
47 | errors. See also L</make HTML install work>, as the layout of installation tree | |
48 | is needed to improve the cross-linking. | |
938c8732 | 49 | |
dc0fb092 SP |
50 | The addition of C<Pod::Simple> and its related modules may make this task |
51 | easier to complete. | |
52 | ||
aa237293 NC |
53 | =head2 Parallel testing |
54 | ||
b2e2905c | 55 | (This probably impacts much more than the core: also the Test::Harness |
02f21748 RGS |
56 | and TAP::* modules on CPAN.) |
57 | ||
aa237293 NC |
58 | The core regression test suite is getting ever more comprehensive, which has |
59 | the side effect that it takes longer to run. This isn't so good. Investigate | |
60 | whether it would be feasible to give the harness script the B<option> of | |
61 | running sets of tests in parallel. This would be useful for tests in | |
62 | F<t/op/*.t> and F<t/uni/*.t> and maybe some sets of tests in F<lib/>. | |
63 | ||
64 | Questions to answer | |
65 | ||
66 | =over 4 | |
67 | ||
68 | =item 1 | |
69 | ||
70 | How does screen layout work when you're running more than one test? | |
71 | ||
72 | =item 2 | |
73 | ||
74 | How does the caller of test specify how many tests to run in parallel? | |
75 | ||
76 | =item 3 | |
77 | ||
78 | How do setup/teardown tests identify themselves? | |
79 | ||
80 | =back | |
81 | ||
82 | Pugs already does parallel testing - can their approach be re-used? | |
83 | ||
0bdfc961 | 84 | =head2 Make Schwern poorer |
e50bb9a1 | 85 | |
613bd4f7 | 86 | We should have tests for everything. When all the core's modules are tested, |
0bdfc961 NC |
87 | Schwern has promised to donate to $500 to TPF. We may need volunteers to |
88 | hold him upside down and shake vigorously in order to actually extract the | |
89 | cash. | |
3958b146 | 90 | |
0bdfc961 | 91 | =head2 Improve the coverage of the core tests |
e50bb9a1 | 92 | |
02f21748 RGS |
93 | Use Devel::Cover to ascertain the core modules's test coverage, then add |
94 | tests that are currently missing. | |
30222c0f | 95 | |
0bdfc961 | 96 | =head2 test B |
e50bb9a1 | 97 | |
0bdfc961 | 98 | A full test suite for the B module would be nice. |
e50bb9a1 | 99 | |
0bdfc961 | 100 | =head2 A decent benchmark |
e50bb9a1 | 101 | |
617eabfa | 102 | C<perlbench> seems impervious to any recent changes made to the perl core. It |
0bdfc961 NC |
103 | would be useful to have a reasonable general benchmarking suite that roughly |
104 | represented what current perl programs do, and measurably reported whether | |
105 | tweaks to the core improve, degrade or don't really affect performance, to | |
106 | guide people attempting to optimise the guts of perl. Gisle would welcome | |
107 | new tests for perlbench. | |
6168cf99 | 108 | |
0bdfc961 | 109 | =head2 fix tainting bugs |
6168cf99 | 110 | |
0bdfc961 NC |
111 | Fix the bugs revealed by running the test suite with the C<-t> switch (via |
112 | C<make test.taintwarn>). | |
e50bb9a1 | 113 | |
0bdfc961 | 114 | =head2 Dual life everything |
e50bb9a1 | 115 | |
0bdfc961 NC |
116 | As part of the "dists" plan, anything that doesn't belong in the smallest perl |
117 | distribution needs to be dual lifed. Anything else can be too. Figure out what | |
118 | changes would be needed to package that module and its tests up for CPAN, and | |
119 | do so. Test it with older perl releases, and fix the problems you find. | |
e50bb9a1 | 120 | |
0bdfc961 | 121 | =head2 Improving C<threads::shared> |
722d2a37 | 122 | |
0bdfc961 NC |
123 | Investigate whether C<threads::shared> could share aggregates properly with |
124 | only Perl level changes to shared.pm | |
722d2a37 | 125 | |
0bdfc961 | 126 | =head2 POSIX memory footprint |
e50bb9a1 | 127 | |
0bdfc961 NC |
128 | Ilya observed that use POSIX; eats memory like there's no tomorrow, and at |
129 | various times worked to cut it down. There is probably still fat to cut out - | |
130 | for example POSIX passes Exporter some very memory hungry data structures. | |
e50bb9a1 | 131 | |
eed36644 NC |
132 | =head2 embed.pl/makedef.pl |
133 | ||
134 | There is a script F<embed.pl> that generates several header files to prefix | |
135 | all of Perl's symbols in a consistent way, to provide some semblance of | |
136 | namespace support in C<C>. Functions are declared in F<embed.fnc>, variables | |
907b3e23 | 137 | in F<interpvar.h>. Quite a few of the functions and variables |
eed36644 NC |
138 | are conditionally declared there, using C<#ifdef>. However, F<embed.pl> |
139 | doesn't understand the C macros, so the rules about which symbols are present | |
140 | when is duplicated in F<makedef.pl>. Writing things twice is bad, m'kay. | |
141 | It would be good to teach C<embed.pl> to understand the conditional | |
142 | compilation, and hence remove the duplication, and the mistakes it has caused. | |
e50bb9a1 | 143 | |
801de10e NC |
144 | =head2 use strict; and AutoLoad |
145 | ||
146 | Currently 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 | ||
157 | then C<use strict;> isn't in force within the autoloaded subroutines. It would | |
158 | be more consistent (and less surprising) to arrange for all lexical pragmas | |
159 | in force at the __END__ block to be in force within each autoloaded subroutine. | |
160 | ||
773b3597 RGS |
161 | There's a similar problem with SelfLoader. |
162 | ||
0bdfc961 | 163 | =head1 Tasks that need a little sysadmin-type knowledge |
e50bb9a1 | 164 | |
0bdfc961 NC |
165 | Or if you prefer, tasks that you would learn from, and broaden your skills |
166 | base... | |
e50bb9a1 | 167 | |
cd793d32 | 168 | =head2 make HTML install work |
e50bb9a1 | 169 | |
adebf063 NC |
170 | There 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 | |
172 | remove the "experimental" tag. This would include | |
173 | ||
174 | =over 4 | |
175 | ||
176 | =item 1 | |
177 | ||
178 | Checking that cross linking between various parts of the documentation works. | |
179 | In particular that links work between the modules (files with POD in F<lib/>) | |
180 | and the core documentation (files in F<pod/>) | |
181 | ||
182 | =item 2 | |
183 | ||
617eabfa NC |
184 | Work out how to split C<perlfunc> into chunks, preferably one per function |
185 | group, preferably with general case code that could be used elsewhere. | |
186 | Challenges here are correctly identifying the groups of functions that go | |
187 | together, and making the right named external cross-links point to the right | |
188 | page. Things to be aware of are C<-X>, groups such as C<getpwnam> to | |
189 | C<endservent>, two or more C<=items> giving the different parameter lists, such | |
190 | as | |
adebf063 NC |
191 | |
192 | =item substr EXPR,OFFSET,LENGTH,REPLACEMENT | |
adebf063 | 193 | =item substr EXPR,OFFSET,LENGTH |
adebf063 NC |
194 | =item substr EXPR,OFFSET |
195 | ||
196 | and different parameter lists having different meanings. (eg C<select>) | |
197 | ||
198 | =back | |
3a89a73c | 199 | |
0bdfc961 NC |
200 | =head2 compressed man pages |
201 | ||
202 | Be able to install them. This would probably need a configure test to see how | |
203 | the system does compressed man pages (same directory/different directory? | |
204 | same filename/different filename), as well as tweaking the F<installman> script | |
205 | to compress as necessary. | |
206 | ||
30222c0f NC |
207 | =head2 Add a code coverage target to the Makefile |
208 | ||
209 | Make it easy for anyone to run Devel::Cover on the core's tests. The steps | |
210 | to do this manually are roughly | |
211 | ||
212 | =over 4 | |
213 | ||
214 | =item * | |
215 | ||
216 | do 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 | ||
229 | Process the resulting Devel::Cover database | |
230 | ||
231 | =back | |
232 | ||
233 | This just give you the coverage of the F<.pm>s. To also get the C level | |
234 | coverage you need to | |
235 | ||
236 | =over 4 | |
237 | ||
238 | =item * | |
239 | ||
240 | Additionally tell C<Configure> to use the appropriate C compiler flags for | |
241 | C<gcov> | |
242 | ||
243 | =item * | |
244 | ||
245 | make perl.gcov | |
246 | ||
247 | (instead of C<make perl>) | |
248 | ||
249 | =item * | |
250 | ||
251 | After 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 | |
257 | to get their stats into the cover_db directory. | |
258 | ||
259 | =item * | |
260 | ||
261 | Then process the Devel::Cover database | |
262 | ||
263 | =back | |
264 | ||
265 | It would be good to add a single switch to C<Configure> to specify that you | |
266 | wanted to perform perl level coverage, and another to specify C level | |
267 | coverage, and have C<Configure> and the F<Makefile> do all the right things | |
268 | automatically. | |
269 | ||
02f21748 | 270 | =head2 Make Config.pm cope with differences between built and installed perl |
0bdfc961 NC |
271 | |
272 | Quite often vendors ship a perl binary compiled with their (pay-for) | |
273 | compilers. People install a free compiler, such as gcc. To work out how to | |
274 | build extensions, Perl interrogates C<%Config>, so in this situation | |
275 | C<%Config> describes compilers that aren't there, and extension building | |
276 | fails. This forces people into choosing between re-compiling perl themselves | |
277 | using the compiler they have, or only using modules that the vendor ships. | |
278 | ||
279 | It would be good to find a way teach C<Config.pm> about the installation setup, | |
280 | possibly involving probing at install time or later, so that the C<%Config> in | |
281 | a binary distribution better describes the installed machine, when the | |
282 | installed machine differs from the build machine in some significant way. | |
283 | ||
728f4ecd NC |
284 | =head2 linker specification files |
285 | ||
286 | Some platforms mandate that you provide a list of a shared library's external | |
287 | symbols to the linker, so the core already has the infrastructure in place to | |
288 | do this for generating shared perl libraries. My understanding is that the | |
289 | GNU toolchain can accept an optional linker specification file, and restrict | |
290 | visibility just to symbols declared in that file. It would be good to extend | |
291 | F<makedef.pl> to support this format, and to provide a means within | |
292 | C<Configure> to enable it. This would allow Unix users to test that the | |
293 | export list is correct, and to build a perl that does not pollute the global | |
294 | namespace with private symbols. | |
295 | ||
a229ae3b RGS |
296 | =head2 Cross-compile support |
297 | ||
298 | Currently C<Configure> understands C<-Dusecrosscompile> option. This option | |
299 | arranges for building C<miniperl> for TARGET machine, so this C<miniperl> is | |
300 | assumed then to be copied to TARGET machine and used as a replacement of full | |
301 | C<perl> executable. | |
302 | ||
d1307786 | 303 | This could be done little differently. Namely C<miniperl> should be built for |
a229ae3b | 304 | HOST and then full C<perl> with extensions should be compiled for TARGET. |
d1307786 | 305 | This, however, might require extra trickery for %Config: we have one config |
87a942b1 JH |
306 | first for HOST and then another for TARGET. Tools like MakeMaker will be |
307 | mightily confused. Having around two different types of executables and | |
308 | libraries (HOST and TARGET) makes life interesting for Makefiles and | |
309 | shell (and Perl) scripts. There is $Config{run}, normally empty, which | |
310 | can be used as an execution wrapper. Also note that in some | |
311 | cross-compilation/execution environments the HOST and the TARGET do | |
312 | not see the same filesystem(s), the $Config{run} may need to do some | |
313 | file/directory copying back and forth. | |
0bdfc961 NC |
314 | |
315 | =head1 Tasks that need a little C knowledge | |
316 | ||
317 | These tasks would need a little C knowledge, but don't need any specific | |
318 | background or experience with XS, or how the Perl interpreter works | |
319 | ||
320 | =head2 Make it clear from -v if this is the exact official release | |
89007cb3 | 321 | |
617eabfa NC |
322 | Currently perl from C<p4>/C<rsync> ships with a F<patchlevel.h> file that |
323 | usually defines one local patch, of the form "MAINT12345" or "RC1". The output | |
324 | of perl -v doesn't report that a perl isn't an official release, and this | |
89007cb3 | 325 | information can get lost in bugs reports. Because of this, the minor version |
fa11829f | 326 | isn't bumped up until RC time, to minimise the possibility of versions of perl |
89007cb3 NC |
327 | escaping that believe themselves to be newer than they actually are. |
328 | ||
329 | It would be useful to find an elegant way to have the "this is an interim | |
330 | maintenance release" or "this is a release candidate" in the terse -v output, | |
331 | and have it so that it's easy for the pumpking to remove this just as the | |
332 | release tarball is rolled up. This way the version pulled out of rsync would | |
333 | always say "I'm a development release" and it would be safe to bump the | |
334 | reported minor version as soon as a release ships, which would aid perl | |
335 | developers. | |
336 | ||
0bdfc961 NC |
337 | This task is really about thinking of an elegant way to arrange the C source |
338 | such that it's trivial for the Pumpking to flag "this is an official release" | |
339 | when making a tarball, yet leave the default source saying "I'm not the | |
340 | official release". | |
341 | ||
fee0a0f7 | 342 | =head2 Profile Perl - am I hot or not? |
62403a3c | 343 | |
fee0a0f7 NC |
344 | The Perl source code is stable enough that it makes sense to profile it, |
345 | identify and optimise the hotspots. It would be good to measure the | |
346 | performance of the Perl interpreter using free tools such as cachegrind, | |
347 | gprof, and dtrace, and work to reduce the bottlenecks they reveal. | |
348 | ||
349 | As part of this, the idea of F<pp_hot.c> is that it contains the I<hot> ops, | |
350 | the ops that are most commonly used. The idea is that by grouping them, their | |
351 | object code will be adjacent in the executable, so they have a greater chance | |
352 | of already being in the CPU cache (or swapped in) due to being near another op | |
353 | already in use. | |
62403a3c NC |
354 | |
355 | Except that it's not clear if these really are the most commonly used ops. So | |
fee0a0f7 NC |
356 | as part of exercising your skills with coverage and profiling tools you might |
357 | want to determine what ops I<really> are the most commonly used. And in turn | |
358 | suggest evictions and promotions to achieve a better F<pp_hot.c>. | |
62403a3c | 359 | |
98fed0ad NC |
360 | =head2 Allocate OPs from arenas |
361 | ||
362 | Currently all new OP structures are individually malloc()ed and free()d. | |
363 | All C<malloc> implementations have space overheads, and are now as fast as | |
364 | custom allocates so it would both use less memory and less CPU to allocate | |
365 | the various OP structures from arenas. The SV arena code can probably be | |
366 | re-used for this. | |
367 | ||
a229ae3b | 368 | =head2 Improve win32/wince.c |
0bdfc961 | 369 | |
a229ae3b | 370 | Currently, numerous functions look virtually, if not completely, |
02f21748 | 371 | identical in both C<win32/wince.c> and C<win32/win32.c> files, which can't |
6d71adcd NC |
372 | be good. |
373 | ||
c5b31784 SH |
374 | =head2 Use secure CRT functions when building with VC8 on Win32 |
375 | ||
376 | Visual C++ 2005 (VC++ 8.x) deprecated a number of CRT functions on the basis | |
377 | that they were "unsafe" and introduced differently named secure versions of | |
378 | them as replacements, e.g. instead of writing | |
379 | ||
380 | FILE* f = fopen(__FILE__, "r"); | |
381 | ||
382 | one should now write | |
383 | ||
384 | FILE* f; | |
385 | errno_t err = fopen_s(&f, __FILE__, "r"); | |
386 | ||
387 | Currently, the warnings about these deprecations have been disabled by adding | |
388 | -D_CRT_SECURE_NO_DEPRECATE to the CFLAGS. It would be nice to remove that | |
389 | warning suppressant and actually make use of the new secure CRT functions. | |
390 | ||
391 | There is also a similar issue with POSIX CRT function names like fileno having | |
392 | been deprecated in favour of ISO C++ conformant names like _fileno. These | |
393 | warnings are also currently suppressed with the compiler option /wd4996. It | |
394 | might be nice to do as Microsoft suggest here too, although, unlike the secure | |
395 | functions issue, there is presumably little or no benefit in this case. | |
396 | ||
6d71adcd NC |
397 | =head1 Tasks that need a knowledge of XS |
398 | ||
399 | These tasks would need C knowledge, and roughly the level of knowledge of | |
400 | the perl API that comes from writing modules that use XS to interface to | |
401 | C. | |
402 | ||
6d71adcd NC |
403 | =head2 autovivification |
404 | ||
405 | Make all autovivification consistent w.r.t LVALUE/RVALUE and strict/no strict; | |
406 | ||
407 | This task is incremental - even a little bit of work on it will help. | |
408 | ||
409 | =head2 Unicode in Filenames | |
410 | ||
411 | chdir, chmod, chown, chroot, exec, glob, link, lstat, mkdir, open, | |
412 | opendir, qx, readdir, readlink, rename, rmdir, stat, symlink, sysopen, | |
413 | system, truncate, unlink, utime, -X. All these could potentially accept | |
414 | Unicode filenames either as input or output (and in the case of system | |
415 | and qx Unicode in general, as input or output to/from the shell). | |
416 | Whether a filesystem - an operating system pair understands Unicode in | |
417 | filenames varies. | |
418 | ||
419 | Known combinations that have some level of understanding include | |
420 | Microsoft NTFS, Apple HFS+ (In Mac OS 9 and X) and Apple UFS (in Mac | |
421 | OS X), NFS v4 is rumored to be Unicode, and of course Plan 9. How to | |
422 | create Unicode filenames, what forms of Unicode are accepted and used | |
423 | (UCS-2, UTF-16, UTF-8), what (if any) is the normalization form used, | |
424 | and so on, varies. Finding the right level of interfacing to Perl | |
425 | requires some thought. Remember that an OS does not implicate a | |
426 | filesystem. | |
427 | ||
428 | (The Windows -C command flag "wide API support" has been at least | |
429 | temporarily retired in 5.8.1, and the -C has been repurposed, see | |
430 | L<perlrun>.) | |
431 | ||
87a942b1 JH |
432 | Most probably the right way to do this would be this: |
433 | L</"Virtualize operating system access">. | |
434 | ||
6d71adcd NC |
435 | =head2 Unicode in %ENV |
436 | ||
437 | Currently the %ENV entries are always byte strings. | |
87a942b1 | 438 | See L</"Virtualize operating system access">. |
6d71adcd | 439 | |
1f2e7916 JD |
440 | =head2 Unicode and glob() |
441 | ||
442 | Currently glob patterns and filenames returned from File::Glob::glob() | |
87a942b1 | 443 | are always byte strings. See L</"Virtualize operating system access">. |
1f2e7916 | 444 | |
6d71adcd NC |
445 | =head2 use less 'memory' |
446 | ||
447 | Investigate trade offs to switch out perl's choices on memory usage. | |
448 | Particularly perl should be able to give memory back. | |
449 | ||
450 | This task is incremental - even a little bit of work on it will help. | |
451 | ||
452 | =head2 Re-implement C<:unique> in a way that is actually thread-safe | |
453 | ||
454 | The old implementation made bad assumptions on several levels. A good 90% | |
455 | solution might be just to make C<:unique> work to share the string buffer | |
456 | of SvPVs. That way large constant strings can be shared between ithreads, | |
457 | such as the configuration information in F<Config>. | |
458 | ||
459 | =head2 Make tainting consistent | |
460 | ||
461 | Tainting would be easier to use if it didn't take documented shortcuts and | |
462 | allow taint to "leak" everywhere within an expression. | |
463 | ||
464 | =head2 readpipe(LIST) | |
465 | ||
466 | system() accepts a LIST syntax (and a PROGRAM LIST syntax) to avoid | |
467 | running a shell. readpipe() (the function behind qx//) could be similarly | |
468 | extended. | |
469 | ||
470 | =head2 strcat(), strcpy(), strncat(), strncpy(), sprintf(), vsprintf() | |
471 | ||
472 | Maybe create a utility that checks after each libperl.a creation that | |
473 | none of the above (nor sprintf(), vsprintf(), or *SHUDDER* gets()) | |
474 | ever creep back to libperl.a. | |
475 | ||
476 | nm libperl.a | ./miniperl -alne '$o = $F[0] if /:$/; print "$o $F[1]" if $F[0] eq "U" && $F[1] =~ /^(?:strn?c(?:at|py)|v?sprintf|gets)$/' | |
477 | ||
478 | Note, of course, that this will only tell whether B<your> platform | |
479 | is using those naughty interfaces. | |
480 | ||
481 | =head2 Audit the code for destruction ordering assumptions | |
482 | ||
483 | Change 25773 notes | |
484 | ||
485 | /* Need to check SvMAGICAL, as during global destruction it may be that | |
486 | AvARYLEN(av) has been freed before av, and hence the SvANY() pointer | |
487 | is now part of the linked list of SV heads, rather than pointing to | |
488 | the original body. */ | |
489 | /* FIXME - audit the code for other bugs like this one. */ | |
490 | ||
491 | adding the C<SvMAGICAL> check to | |
492 | ||
493 | if (AvARYLEN(av) && SvMAGICAL(AvARYLEN(av))) { | |
494 | MAGIC *mg = mg_find (AvARYLEN(av), PERL_MAGIC_arylen); | |
495 | ||
496 | Go through the core and look for similar assumptions that SVs have particular | |
497 | types, as all bets are off during global destruction. | |
498 | ||
749904bf JH |
499 | =head2 Extend PerlIO and PerlIO::Scalar |
500 | ||
501 | PerlIO::Scalar doesn't know how to truncate(). Implementing this | |
502 | would require extending the PerlIO vtable. | |
503 | ||
504 | Similarly the PerlIO vtable doesn't know about formats (write()), or | |
505 | about stat(), or chmod()/chown(), utime(), or flock(). | |
506 | ||
507 | (For PerlIO::Scalar it's hard to see what e.g. mode bits or ownership | |
508 | would mean.) | |
509 | ||
510 | PerlIO doesn't do directories or symlinks, either: mkdir(), rmdir(), | |
511 | opendir(), closedir(), seekdir(), rewinddir(), glob(); symlink(), | |
512 | readlink(). | |
513 | ||
3236f110 NC |
514 | =head2 -C on the #! line |
515 | ||
516 | It should be possible to make -C work correctly if found on the #! line, | |
517 | given that all perl command line options are strict ASCII, and -C changes | |
518 | only the interpretation of non-ASCII characters, and not for the script file | |
519 | handle. To make it work needs some investigation of the ordering of function | |
520 | calls during startup, and (by implication) a bit of tweaking of that order. | |
521 | ||
522 | ||
0bdfc961 | 523 | =head1 Tasks that need a knowledge of the interpreter |
3298bd4d | 524 | |
0bdfc961 NC |
525 | These tasks would need C knowledge, and knowledge of how the interpreter works, |
526 | or a willingness to learn. | |
3298bd4d | 527 | |
4fedb12c RGS |
528 | =head2 Implement $value ~~ 0 .. $range |
529 | ||
530 | It would be nice to extend the syntax of the C<~~> operator to also | |
531 | understand numeric (and maybe alphanumeric) ranges. | |
532 | ||
d10fc472 | 533 | =head2 Attach/detach debugger from running program |
1626a787 | 534 | |
cd793d32 NC |
535 | The old perltodo notes "With C<gdb>, you can attach the debugger to a running |
536 | program if you pass the process ID. It would be good to do this with the Perl | |
0bdfc961 NC |
537 | debugger on a running Perl program, although I'm not sure how it would be |
538 | done." ssh and screen do this with named pipes in /tmp. Maybe we can too. | |
1626a787 | 539 | |
0bdfc961 NC |
540 | =head2 LVALUE functions for lists |
541 | ||
542 | The old perltodo notes that lvalue functions don't work for list or hash | |
543 | slices. This would be good to fix. | |
544 | ||
545 | =head2 LVALUE functions in the debugger | |
546 | ||
547 | The old perltodo notes that lvalue functions don't work in the debugger. This | |
548 | would be good to fix. | |
549 | ||
0bdfc961 NC |
550 | =head2 regexp optimiser optional |
551 | ||
552 | The regexp optimiser is not optional. It should configurable to be, to allow | |
553 | its performance to be measured, and its bugs to be easily demonstrated. | |
554 | ||
02f21748 RGS |
555 | =head2 delete &function |
556 | ||
557 | Allow to delete functions. One can already undef them, but they're still | |
558 | in the stash. | |
559 | ||
ef36c6a7 RGS |
560 | =head2 C</w> regex modifier |
561 | ||
562 | That flag would enable to match whole words, and also to interpolate | |
563 | arrays as alternations. With it, C</P/w> would be roughly equivalent to: | |
564 | ||
565 | do { local $"='|'; /\b(?:P)\b/ } | |
566 | ||
567 | See L<http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2007-01/msg00400.html> | |
568 | for the discussion. | |
569 | ||
0bdfc961 NC |
570 | =head2 optional optimizer |
571 | ||
572 | Make the peephole optimizer optional. Currently it performs two tasks as | |
573 | it walks the optree - genuine peephole optimisations, and necessary fixups of | |
574 | ops. It would be good to find an efficient way to switch out the | |
575 | optimisations whilst keeping the fixups. | |
576 | ||
577 | =head2 You WANT *how* many | |
578 | ||
579 | Currently contexts are void, scalar and list. split has a special mechanism in | |
580 | place to pass in the number of return values wanted. It would be useful to | |
581 | have a general mechanism for this, backwards compatible and little speed hit. | |
582 | This would allow proposals such as short circuiting sort to be implemented | |
583 | as a module on CPAN. | |
584 | ||
585 | =head2 lexical aliases | |
586 | ||
587 | Allow lexical aliases (maybe via the syntax C<my \$alias = \$foo>. | |
588 | ||
589 | =head2 entersub XS vs Perl | |
590 | ||
591 | At the moment pp_entersub is huge, and has code to deal with entering both | |
592 | perl and XS subroutines. Subroutine implementations rarely change between | |
593 | perl and XS at run time, so investigate using 2 ops to enter subs (one for | |
594 | XS, one for perl) and swap between if a sub is redefined. | |
2810d901 NC |
595 | |
596 | =head2 Self ties | |
597 | ||
598 | self ties are currently illegal because they caused too many segfaults. Maybe | |
599 | the causes of these could be tracked down and self-ties on all types re- | |
600 | instated. | |
0bdfc961 NC |
601 | |
602 | =head2 Optimize away @_ | |
603 | ||
604 | The old perltodo notes "Look at the "reification" code in C<av.c>". | |
605 | ||
0bdfc961 NC |
606 | =head2 What hooks would assertions need? |
607 | ||
608 | Assertions are in the core, and work. However, assertions needed to be added | |
609 | as a core patch, rather than an XS module in ext, or a CPAN module, because | |
610 | the core has no hooks in the necessary places. It would be useful to | |
611 | investigate what hooks would need to be added to make it possible to provide | |
612 | the full assertion support from a CPAN module, so that we aren't constraining | |
613 | the imagination of future CPAN authors. | |
614 | ||
16fc99ce NC |
615 | =head2 Properly Unicode safe tokeniser and pads. |
616 | ||
617 | The tokeniser isn't actually very UTF-8 clean. C<use utf8;> is a hack - | |
618 | variable names are stored in stashes as raw bytes, without the utf-8 flag | |
619 | set. The pad API only takes a C<char *> pointer, so that's all bytes too. The | |
620 | tokeniser ignores the UTF-8-ness of C<PL_rsfp>, or any SVs returned from | |
621 | source filters. All this could be fixed. | |
622 | ||
f092b1f4 RGS |
623 | =head2 The yada yada yada operators |
624 | ||
625 | Perl 6's Synopsis 3 says: | |
626 | ||
627 | I<The ... operator is the "yada, yada, yada" list operator, which is used as | |
628 | the body in function prototypes. It complains bitterly (by calling fail) | |
629 | if it is ever executed. Variant ??? calls warn, and !!! calls die.> | |
630 | ||
631 | Those would be nice to add to Perl 5. That could be done without new ops. | |
632 | ||
87a942b1 JH |
633 | =head2 Virtualize operating system access |
634 | ||
635 | Implement a set of "vtables" that virtualizes operating system access | |
636 | (open(), mkdir(), unlink(), readdir(), getenv(), etc.) At the very | |
637 | least these interfaces should take SVs as "name" arguments instead of | |
638 | bare char pointers; probably the most flexible and extensible way | |
639 | would be for the interfaces to accept HVs. The system needs to be | |
640 | per-operating-system and per-file-system hookable/filterable | |
641 | (L<perlport/"Files and Filesystems"> is good reading at this point, | |
642 | in fact, all of L<perlport> is.) | |
643 | ||
644 | A less ambitious form of this has actually already been implemented | |
645 | (but only for Win32), take a look at F<iperlsys.h>. While Win32 | |
646 | systems go through a set of "vtables" for operating system access, | |
647 | non-Win32 systems go straight for the POSIX/UNIX-style system/library | |
648 | call. Similar system should be implemented for all platforms. | |
649 | The existing Win32 implementation probably does not need to survive | |
650 | alongside this proposed new implementation, they could be merged. | |
651 | ||
652 | What would this give us? One often-asked-for feature this would | |
653 | enable is using Unicode for filenames (and other "names" like %ENV, | |
654 | usernames, hostnames, and so forth.) But this would also allow for | |
655 | things like virtual filesystems and "sandboxes" (though as long as | |
656 | dynamic loading of random object code is allowed, not very safe | |
657 | sandboxes since external code of course know not of Perl's vtables). | |
658 | ||
0bdfc961 NC |
659 | =head1 Big projects |
660 | ||
661 | Tasks that will get your name mentioned in the description of the "Highlights | |
87a942b1 | 662 | of 5.12" |
0bdfc961 NC |
663 | |
664 | =head2 make ithreads more robust | |
665 | ||
4e577f8b | 666 | Generally make ithreads more robust. See also L</iCOW> |
0bdfc961 NC |
667 | |
668 | This task is incremental - even a little bit of work on it will help, and | |
669 | will be greatly appreciated. | |
670 | ||
6c047da7 YST |
671 | One bit would be to write the missing code in sv.c:Perl_dirp_dup. |
672 | ||
59c7f7d5 RGS |
673 | Fix Perl_sv_dup, et al so that threads can return objects. |
674 | ||
0bdfc961 NC |
675 | =head2 iCOW |
676 | ||
677 | Sarathy and Arthur have a proposal for an improved Copy On Write which | |
678 | specifically will be able to COW new ithreads. If this can be implemented | |
679 | it would be a good thing. | |
680 | ||
681 | =head2 (?{...}) closures in regexps | |
682 | ||
683 | Fix (or rewrite) the implementation of the C</(?{...})/> closures. | |
684 | ||
685 | =head2 A re-entrant regexp engine | |
686 | ||
687 | This will allow the use of a regex from inside (?{ }), (??{ }) and | |
688 | (?(?{ })|) constructs. | |
6bda09f9 | 689 | |
6bda09f9 YO |
690 | =head2 Add class set operations to regexp engine |
691 | ||
692 | Apparently these are quite useful. Anyway, Jeffery Friedl wants them. | |
693 | ||
694 | demerphq has this on his todo list, but right at the bottom. |