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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 | |
0bdfc961 | 111 | =head2 Improving C<threads::shared> |
722d2a37 | 112 | |
0bdfc961 NC |
113 | Investigate whether C<threads::shared> could share aggregates properly with |
114 | only Perl level changes to shared.pm | |
722d2a37 | 115 | |
0bdfc961 | 116 | =head2 POSIX memory footprint |
e50bb9a1 | 117 | |
0bdfc961 NC |
118 | Ilya observed that use POSIX; eats memory like there's no tomorrow, and at |
119 | various times worked to cut it down. There is probably still fat to cut out - | |
120 | for example POSIX passes Exporter some very memory hungry data structures. | |
e50bb9a1 | 121 | |
eed36644 NC |
122 | =head2 embed.pl/makedef.pl |
123 | ||
124 | There is a script F<embed.pl> that generates several header files to prefix | |
125 | all of Perl's symbols in a consistent way, to provide some semblance of | |
126 | namespace support in C<C>. Functions are declared in F<embed.fnc>, variables | |
907b3e23 | 127 | in F<interpvar.h>. Quite a few of the functions and variables |
eed36644 NC |
128 | are conditionally declared there, using C<#ifdef>. However, F<embed.pl> |
129 | doesn't understand the C macros, so the rules about which symbols are present | |
130 | when is duplicated in F<makedef.pl>. Writing things twice is bad, m'kay. | |
131 | It would be good to teach C<embed.pl> to understand the conditional | |
132 | compilation, and hence remove the duplication, and the mistakes it has caused. | |
e50bb9a1 | 133 | |
801de10e NC |
134 | =head2 use strict; and AutoLoad |
135 | ||
136 | Currently if you write | |
137 | ||
138 | package Whack; | |
139 | use AutoLoader 'AUTOLOAD'; | |
140 | use strict; | |
141 | 1; | |
142 | __END__ | |
143 | sub bloop { | |
144 | print join (' ', No, strict, here), "!\n"; | |
145 | } | |
146 | ||
147 | then C<use strict;> isn't in force within the autoloaded subroutines. It would | |
148 | be more consistent (and less surprising) to arrange for all lexical pragmas | |
149 | in force at the __END__ block to be in force within each autoloaded subroutine. | |
150 | ||
773b3597 RGS |
151 | There's a similar problem with SelfLoader. |
152 | ||
0bdfc961 | 153 | =head1 Tasks that need a little sysadmin-type knowledge |
e50bb9a1 | 154 | |
0bdfc961 NC |
155 | Or if you prefer, tasks that you would learn from, and broaden your skills |
156 | base... | |
e50bb9a1 | 157 | |
cd793d32 | 158 | =head2 make HTML install work |
e50bb9a1 | 159 | |
adebf063 NC |
160 | There is an C<installhtml> target in the Makefile. It's marked as |
161 | "experimental". It would be good to get this tested, make it work reliably, and | |
162 | remove the "experimental" tag. This would include | |
163 | ||
164 | =over 4 | |
165 | ||
166 | =item 1 | |
167 | ||
168 | Checking that cross linking between various parts of the documentation works. | |
169 | In particular that links work between the modules (files with POD in F<lib/>) | |
170 | and the core documentation (files in F<pod/>) | |
171 | ||
172 | =item 2 | |
173 | ||
617eabfa NC |
174 | Work out how to split C<perlfunc> into chunks, preferably one per function |
175 | group, preferably with general case code that could be used elsewhere. | |
176 | Challenges here are correctly identifying the groups of functions that go | |
177 | together, and making the right named external cross-links point to the right | |
178 | page. Things to be aware of are C<-X>, groups such as C<getpwnam> to | |
179 | C<endservent>, two or more C<=items> giving the different parameter lists, such | |
180 | as | |
adebf063 NC |
181 | |
182 | =item substr EXPR,OFFSET,LENGTH,REPLACEMENT | |
adebf063 | 183 | =item substr EXPR,OFFSET,LENGTH |
adebf063 NC |
184 | =item substr EXPR,OFFSET |
185 | ||
186 | and different parameter lists having different meanings. (eg C<select>) | |
187 | ||
188 | =back | |
3a89a73c | 189 | |
0bdfc961 NC |
190 | =head2 compressed man pages |
191 | ||
192 | Be able to install them. This would probably need a configure test to see how | |
193 | the system does compressed man pages (same directory/different directory? | |
194 | same filename/different filename), as well as tweaking the F<installman> script | |
195 | to compress as necessary. | |
196 | ||
30222c0f NC |
197 | =head2 Add a code coverage target to the Makefile |
198 | ||
199 | Make it easy for anyone to run Devel::Cover on the core's tests. The steps | |
200 | to do this manually are roughly | |
201 | ||
202 | =over 4 | |
203 | ||
204 | =item * | |
205 | ||
206 | do a normal C<Configure>, but include Devel::Cover as a module to install | |
207 | (see F<INSTALL> for how to do this) | |
208 | ||
209 | =item * | |
210 | ||
211 | make perl | |
212 | ||
213 | =item * | |
214 | ||
215 | cd t; HARNESS_PERL_SWITCHES=-MDevel::Cover ./perl -I../lib harness | |
216 | ||
217 | =item * | |
218 | ||
219 | Process the resulting Devel::Cover database | |
220 | ||
221 | =back | |
222 | ||
223 | This just give you the coverage of the F<.pm>s. To also get the C level | |
224 | coverage you need to | |
225 | ||
226 | =over 4 | |
227 | ||
228 | =item * | |
229 | ||
230 | Additionally tell C<Configure> to use the appropriate C compiler flags for | |
231 | C<gcov> | |
232 | ||
233 | =item * | |
234 | ||
235 | make perl.gcov | |
236 | ||
237 | (instead of C<make perl>) | |
238 | ||
239 | =item * | |
240 | ||
241 | After running the tests run C<gcov> to generate all the F<.gcov> files. | |
242 | (Including down in the subdirectories of F<ext/> | |
243 | ||
244 | =item * | |
245 | ||
246 | (From the top level perl directory) run C<gcov2perl> on all the C<.gcov> files | |
247 | to get their stats into the cover_db directory. | |
248 | ||
249 | =item * | |
250 | ||
251 | Then process the Devel::Cover database | |
252 | ||
253 | =back | |
254 | ||
255 | It would be good to add a single switch to C<Configure> to specify that you | |
256 | wanted to perform perl level coverage, and another to specify C level | |
257 | coverage, and have C<Configure> and the F<Makefile> do all the right things | |
258 | automatically. | |
259 | ||
02f21748 | 260 | =head2 Make Config.pm cope with differences between built and installed perl |
0bdfc961 NC |
261 | |
262 | Quite often vendors ship a perl binary compiled with their (pay-for) | |
263 | compilers. People install a free compiler, such as gcc. To work out how to | |
264 | build extensions, Perl interrogates C<%Config>, so in this situation | |
265 | C<%Config> describes compilers that aren't there, and extension building | |
266 | fails. This forces people into choosing between re-compiling perl themselves | |
267 | using the compiler they have, or only using modules that the vendor ships. | |
268 | ||
269 | It would be good to find a way teach C<Config.pm> about the installation setup, | |
270 | possibly involving probing at install time or later, so that the C<%Config> in | |
271 | a binary distribution better describes the installed machine, when the | |
272 | installed machine differs from the build machine in some significant way. | |
273 | ||
728f4ecd NC |
274 | =head2 linker specification files |
275 | ||
276 | Some platforms mandate that you provide a list of a shared library's external | |
277 | symbols to the linker, so the core already has the infrastructure in place to | |
278 | do this for generating shared perl libraries. My understanding is that the | |
279 | GNU toolchain can accept an optional linker specification file, and restrict | |
280 | visibility just to symbols declared in that file. It would be good to extend | |
281 | F<makedef.pl> to support this format, and to provide a means within | |
282 | C<Configure> to enable it. This would allow Unix users to test that the | |
283 | export list is correct, and to build a perl that does not pollute the global | |
284 | namespace with private symbols. | |
285 | ||
a229ae3b RGS |
286 | =head2 Cross-compile support |
287 | ||
288 | Currently C<Configure> understands C<-Dusecrosscompile> option. This option | |
289 | arranges for building C<miniperl> for TARGET machine, so this C<miniperl> is | |
290 | assumed then to be copied to TARGET machine and used as a replacement of full | |
291 | C<perl> executable. | |
292 | ||
d1307786 | 293 | This could be done little differently. Namely C<miniperl> should be built for |
a229ae3b | 294 | HOST and then full C<perl> with extensions should be compiled for TARGET. |
d1307786 | 295 | This, however, might require extra trickery for %Config: we have one config |
87a942b1 JH |
296 | first for HOST and then another for TARGET. Tools like MakeMaker will be |
297 | mightily confused. Having around two different types of executables and | |
298 | libraries (HOST and TARGET) makes life interesting for Makefiles and | |
299 | shell (and Perl) scripts. There is $Config{run}, normally empty, which | |
300 | can be used as an execution wrapper. Also note that in some | |
301 | cross-compilation/execution environments the HOST and the TARGET do | |
302 | not see the same filesystem(s), the $Config{run} may need to do some | |
303 | file/directory copying back and forth. | |
0bdfc961 NC |
304 | |
305 | =head1 Tasks that need a little C knowledge | |
306 | ||
307 | These tasks would need a little C knowledge, but don't need any specific | |
308 | background or experience with XS, or how the Perl interpreter works | |
309 | ||
310 | =head2 Make it clear from -v if this is the exact official release | |
89007cb3 | 311 | |
617eabfa NC |
312 | Currently perl from C<p4>/C<rsync> ships with a F<patchlevel.h> file that |
313 | usually defines one local patch, of the form "MAINT12345" or "RC1". The output | |
314 | of perl -v doesn't report that a perl isn't an official release, and this | |
89007cb3 | 315 | information can get lost in bugs reports. Because of this, the minor version |
fa11829f | 316 | isn't bumped up until RC time, to minimise the possibility of versions of perl |
89007cb3 NC |
317 | escaping that believe themselves to be newer than they actually are. |
318 | ||
319 | It would be useful to find an elegant way to have the "this is an interim | |
320 | maintenance release" or "this is a release candidate" in the terse -v output, | |
321 | and have it so that it's easy for the pumpking to remove this just as the | |
322 | release tarball is rolled up. This way the version pulled out of rsync would | |
323 | always say "I'm a development release" and it would be safe to bump the | |
324 | reported minor version as soon as a release ships, which would aid perl | |
325 | developers. | |
326 | ||
0bdfc961 NC |
327 | This task is really about thinking of an elegant way to arrange the C source |
328 | such that it's trivial for the Pumpking to flag "this is an official release" | |
329 | when making a tarball, yet leave the default source saying "I'm not the | |
330 | official release". | |
331 | ||
fee0a0f7 | 332 | =head2 Profile Perl - am I hot or not? |
62403a3c | 333 | |
fee0a0f7 NC |
334 | The Perl source code is stable enough that it makes sense to profile it, |
335 | identify and optimise the hotspots. It would be good to measure the | |
336 | performance of the Perl interpreter using free tools such as cachegrind, | |
337 | gprof, and dtrace, and work to reduce the bottlenecks they reveal. | |
338 | ||
339 | As part of this, the idea of F<pp_hot.c> is that it contains the I<hot> ops, | |
340 | the ops that are most commonly used. The idea is that by grouping them, their | |
341 | object code will be adjacent in the executable, so they have a greater chance | |
342 | of already being in the CPU cache (or swapped in) due to being near another op | |
343 | already in use. | |
62403a3c NC |
344 | |
345 | Except that it's not clear if these really are the most commonly used ops. So | |
fee0a0f7 NC |
346 | as part of exercising your skills with coverage and profiling tools you might |
347 | want to determine what ops I<really> are the most commonly used. And in turn | |
348 | suggest evictions and promotions to achieve a better F<pp_hot.c>. | |
62403a3c | 349 | |
98fed0ad NC |
350 | =head2 Allocate OPs from arenas |
351 | ||
352 | Currently all new OP structures are individually malloc()ed and free()d. | |
353 | All C<malloc> implementations have space overheads, and are now as fast as | |
354 | custom allocates so it would both use less memory and less CPU to allocate | |
355 | the various OP structures from arenas. The SV arena code can probably be | |
356 | re-used for this. | |
357 | ||
a229ae3b | 358 | =head2 Improve win32/wince.c |
0bdfc961 | 359 | |
a229ae3b | 360 | Currently, numerous functions look virtually, if not completely, |
02f21748 | 361 | identical in both C<win32/wince.c> and C<win32/win32.c> files, which can't |
6d71adcd NC |
362 | be good. |
363 | ||
c5b31784 SH |
364 | =head2 Use secure CRT functions when building with VC8 on Win32 |
365 | ||
366 | Visual C++ 2005 (VC++ 8.x) deprecated a number of CRT functions on the basis | |
367 | that they were "unsafe" and introduced differently named secure versions of | |
368 | them as replacements, e.g. instead of writing | |
369 | ||
370 | FILE* f = fopen(__FILE__, "r"); | |
371 | ||
372 | one should now write | |
373 | ||
374 | FILE* f; | |
375 | errno_t err = fopen_s(&f, __FILE__, "r"); | |
376 | ||
377 | Currently, the warnings about these deprecations have been disabled by adding | |
378 | -D_CRT_SECURE_NO_DEPRECATE to the CFLAGS. It would be nice to remove that | |
379 | warning suppressant and actually make use of the new secure CRT functions. | |
380 | ||
381 | There is also a similar issue with POSIX CRT function names like fileno having | |
382 | been deprecated in favour of ISO C++ conformant names like _fileno. These | |
383 | warnings are also currently suppressed with the compiler option /wd4996. It | |
384 | might be nice to do as Microsoft suggest here too, although, unlike the secure | |
385 | functions issue, there is presumably little or no benefit in this case. | |
386 | ||
6d71adcd NC |
387 | =head1 Tasks that need a knowledge of XS |
388 | ||
389 | These tasks would need C knowledge, and roughly the level of knowledge of | |
390 | the perl API that comes from writing modules that use XS to interface to | |
391 | C. | |
392 | ||
6d71adcd NC |
393 | =head2 autovivification |
394 | ||
395 | Make all autovivification consistent w.r.t LVALUE/RVALUE and strict/no strict; | |
396 | ||
397 | This task is incremental - even a little bit of work on it will help. | |
398 | ||
399 | =head2 Unicode in Filenames | |
400 | ||
401 | chdir, chmod, chown, chroot, exec, glob, link, lstat, mkdir, open, | |
402 | opendir, qx, readdir, readlink, rename, rmdir, stat, symlink, sysopen, | |
403 | system, truncate, unlink, utime, -X. All these could potentially accept | |
404 | Unicode filenames either as input or output (and in the case of system | |
405 | and qx Unicode in general, as input or output to/from the shell). | |
406 | Whether a filesystem - an operating system pair understands Unicode in | |
407 | filenames varies. | |
408 | ||
409 | Known combinations that have some level of understanding include | |
410 | Microsoft NTFS, Apple HFS+ (In Mac OS 9 and X) and Apple UFS (in Mac | |
411 | OS X), NFS v4 is rumored to be Unicode, and of course Plan 9. How to | |
412 | create Unicode filenames, what forms of Unicode are accepted and used | |
413 | (UCS-2, UTF-16, UTF-8), what (if any) is the normalization form used, | |
414 | and so on, varies. Finding the right level of interfacing to Perl | |
415 | requires some thought. Remember that an OS does not implicate a | |
416 | filesystem. | |
417 | ||
418 | (The Windows -C command flag "wide API support" has been at least | |
419 | temporarily retired in 5.8.1, and the -C has been repurposed, see | |
420 | L<perlrun>.) | |
421 | ||
87a942b1 JH |
422 | Most probably the right way to do this would be this: |
423 | L</"Virtualize operating system access">. | |
424 | ||
6d71adcd NC |
425 | =head2 Unicode in %ENV |
426 | ||
427 | Currently the %ENV entries are always byte strings. | |
87a942b1 | 428 | See L</"Virtualize operating system access">. |
6d71adcd | 429 | |
1f2e7916 JD |
430 | =head2 Unicode and glob() |
431 | ||
432 | Currently glob patterns and filenames returned from File::Glob::glob() | |
87a942b1 | 433 | are always byte strings. See L</"Virtualize operating system access">. |
1f2e7916 | 434 | |
6d71adcd NC |
435 | =head2 use less 'memory' |
436 | ||
437 | Investigate trade offs to switch out perl's choices on memory usage. | |
438 | Particularly perl should be able to give memory back. | |
439 | ||
440 | This task is incremental - even a little bit of work on it will help. | |
441 | ||
442 | =head2 Re-implement C<:unique> in a way that is actually thread-safe | |
443 | ||
444 | The old implementation made bad assumptions on several levels. A good 90% | |
445 | solution might be just to make C<:unique> work to share the string buffer | |
446 | of SvPVs. That way large constant strings can be shared between ithreads, | |
447 | such as the configuration information in F<Config>. | |
448 | ||
449 | =head2 Make tainting consistent | |
450 | ||
451 | Tainting would be easier to use if it didn't take documented shortcuts and | |
452 | allow taint to "leak" everywhere within an expression. | |
453 | ||
454 | =head2 readpipe(LIST) | |
455 | ||
456 | system() accepts a LIST syntax (and a PROGRAM LIST syntax) to avoid | |
457 | running a shell. readpipe() (the function behind qx//) could be similarly | |
458 | extended. | |
459 | ||
460 | =head2 strcat(), strcpy(), strncat(), strncpy(), sprintf(), vsprintf() | |
461 | ||
462 | Maybe create a utility that checks after each libperl.a creation that | |
463 | none of the above (nor sprintf(), vsprintf(), or *SHUDDER* gets()) | |
464 | ever creep back to libperl.a. | |
465 | ||
466 | nm libperl.a | ./miniperl -alne '$o = $F[0] if /:$/; print "$o $F[1]" if $F[0] eq "U" && $F[1] =~ /^(?:strn?c(?:at|py)|v?sprintf|gets)$/' | |
467 | ||
468 | Note, of course, that this will only tell whether B<your> platform | |
469 | is using those naughty interfaces. | |
470 | ||
471 | =head2 Audit the code for destruction ordering assumptions | |
472 | ||
473 | Change 25773 notes | |
474 | ||
475 | /* Need to check SvMAGICAL, as during global destruction it may be that | |
476 | AvARYLEN(av) has been freed before av, and hence the SvANY() pointer | |
477 | is now part of the linked list of SV heads, rather than pointing to | |
478 | the original body. */ | |
479 | /* FIXME - audit the code for other bugs like this one. */ | |
480 | ||
481 | adding the C<SvMAGICAL> check to | |
482 | ||
483 | if (AvARYLEN(av) && SvMAGICAL(AvARYLEN(av))) { | |
484 | MAGIC *mg = mg_find (AvARYLEN(av), PERL_MAGIC_arylen); | |
485 | ||
486 | Go through the core and look for similar assumptions that SVs have particular | |
487 | types, as all bets are off during global destruction. | |
488 | ||
749904bf JH |
489 | =head2 Extend PerlIO and PerlIO::Scalar |
490 | ||
491 | PerlIO::Scalar doesn't know how to truncate(). Implementing this | |
492 | would require extending the PerlIO vtable. | |
493 | ||
494 | Similarly the PerlIO vtable doesn't know about formats (write()), or | |
495 | about stat(), or chmod()/chown(), utime(), or flock(). | |
496 | ||
497 | (For PerlIO::Scalar it's hard to see what e.g. mode bits or ownership | |
498 | would mean.) | |
499 | ||
500 | PerlIO doesn't do directories or symlinks, either: mkdir(), rmdir(), | |
501 | opendir(), closedir(), seekdir(), rewinddir(), glob(); symlink(), | |
502 | readlink(). | |
503 | ||
94da6c29 JH |
504 | See also L</"Virtualize operating system access">. |
505 | ||
3236f110 NC |
506 | =head2 -C on the #! line |
507 | ||
508 | It should be possible to make -C work correctly if found on the #! line, | |
509 | given that all perl command line options are strict ASCII, and -C changes | |
510 | only the interpretation of non-ASCII characters, and not for the script file | |
511 | handle. To make it work needs some investigation of the ordering of function | |
512 | calls during startup, and (by implication) a bit of tweaking of that order. | |
513 | ||
514 | ||
0bdfc961 | 515 | =head1 Tasks that need a knowledge of the interpreter |
3298bd4d | 516 | |
0bdfc961 NC |
517 | These tasks would need C knowledge, and knowledge of how the interpreter works, |
518 | or a willingness to learn. | |
3298bd4d | 519 | |
4fedb12c RGS |
520 | =head2 Implement $value ~~ 0 .. $range |
521 | ||
522 | It would be nice to extend the syntax of the C<~~> operator to also | |
523 | understand numeric (and maybe alphanumeric) ranges. | |
524 | ||
d10fc472 | 525 | =head2 Attach/detach debugger from running program |
1626a787 | 526 | |
cd793d32 NC |
527 | The old perltodo notes "With C<gdb>, you can attach the debugger to a running |
528 | program if you pass the process ID. It would be good to do this with the Perl | |
0bdfc961 NC |
529 | debugger on a running Perl program, although I'm not sure how it would be |
530 | done." ssh and screen do this with named pipes in /tmp. Maybe we can too. | |
1626a787 | 531 | |
0bdfc961 NC |
532 | =head2 LVALUE functions for lists |
533 | ||
534 | The old perltodo notes that lvalue functions don't work for list or hash | |
535 | slices. This would be good to fix. | |
536 | ||
537 | =head2 LVALUE functions in the debugger | |
538 | ||
539 | The old perltodo notes that lvalue functions don't work in the debugger. This | |
540 | would be good to fix. | |
541 | ||
0bdfc961 NC |
542 | =head2 regexp optimiser optional |
543 | ||
544 | The regexp optimiser is not optional. It should configurable to be, to allow | |
545 | its performance to be measured, and its bugs to be easily demonstrated. | |
546 | ||
02f21748 RGS |
547 | =head2 delete &function |
548 | ||
549 | Allow to delete functions. One can already undef them, but they're still | |
550 | in the stash. | |
551 | ||
ef36c6a7 RGS |
552 | =head2 C</w> regex modifier |
553 | ||
554 | That flag would enable to match whole words, and also to interpolate | |
555 | arrays as alternations. With it, C</P/w> would be roughly equivalent to: | |
556 | ||
557 | do { local $"='|'; /\b(?:P)\b/ } | |
558 | ||
559 | See L<http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2007-01/msg00400.html> | |
560 | for the discussion. | |
561 | ||
0bdfc961 NC |
562 | =head2 optional optimizer |
563 | ||
564 | Make the peephole optimizer optional. Currently it performs two tasks as | |
565 | it walks the optree - genuine peephole optimisations, and necessary fixups of | |
566 | ops. It would be good to find an efficient way to switch out the | |
567 | optimisations whilst keeping the fixups. | |
568 | ||
569 | =head2 You WANT *how* many | |
570 | ||
571 | Currently contexts are void, scalar and list. split has a special mechanism in | |
572 | place to pass in the number of return values wanted. It would be useful to | |
573 | have a general mechanism for this, backwards compatible and little speed hit. | |
574 | This would allow proposals such as short circuiting sort to be implemented | |
575 | as a module on CPAN. | |
576 | ||
577 | =head2 lexical aliases | |
578 | ||
579 | Allow lexical aliases (maybe via the syntax C<my \$alias = \$foo>. | |
580 | ||
581 | =head2 entersub XS vs Perl | |
582 | ||
583 | At the moment pp_entersub is huge, and has code to deal with entering both | |
584 | perl and XS subroutines. Subroutine implementations rarely change between | |
585 | perl and XS at run time, so investigate using 2 ops to enter subs (one for | |
586 | XS, one for perl) and swap between if a sub is redefined. | |
2810d901 NC |
587 | |
588 | =head2 Self ties | |
589 | ||
590 | self ties are currently illegal because they caused too many segfaults. Maybe | |
591 | the causes of these could be tracked down and self-ties on all types re- | |
592 | instated. | |
0bdfc961 NC |
593 | |
594 | =head2 Optimize away @_ | |
595 | ||
596 | The old perltodo notes "Look at the "reification" code in C<av.c>". | |
597 | ||
16fc99ce NC |
598 | =head2 Properly Unicode safe tokeniser and pads. |
599 | ||
600 | The tokeniser isn't actually very UTF-8 clean. C<use utf8;> is a hack - | |
601 | variable names are stored in stashes as raw bytes, without the utf-8 flag | |
602 | set. The pad API only takes a C<char *> pointer, so that's all bytes too. The | |
603 | tokeniser ignores the UTF-8-ness of C<PL_rsfp>, or any SVs returned from | |
604 | source filters. All this could be fixed. | |
605 | ||
f092b1f4 RGS |
606 | =head2 The yada yada yada operators |
607 | ||
608 | Perl 6's Synopsis 3 says: | |
609 | ||
610 | I<The ... operator is the "yada, yada, yada" list operator, which is used as | |
611 | the body in function prototypes. It complains bitterly (by calling fail) | |
612 | if it is ever executed. Variant ??? calls warn, and !!! calls die.> | |
613 | ||
614 | Those would be nice to add to Perl 5. That could be done without new ops. | |
615 | ||
87a942b1 JH |
616 | =head2 Virtualize operating system access |
617 | ||
618 | Implement a set of "vtables" that virtualizes operating system access | |
619 | (open(), mkdir(), unlink(), readdir(), getenv(), etc.) At the very | |
620 | least these interfaces should take SVs as "name" arguments instead of | |
621 | bare char pointers; probably the most flexible and extensible way | |
e1a3d5d1 JH |
622 | would be for the Perl-facing interfaces to accept HVs. The system |
623 | needs to be per-operating-system and per-file-system | |
624 | hookable/filterable, preferably both from XS and Perl level | |
87a942b1 JH |
625 | (L<perlport/"Files and Filesystems"> is good reading at this point, |
626 | in fact, all of L<perlport> is.) | |
627 | ||
e1a3d5d1 JH |
628 | This has actually already been implemented (but only for Win32), |
629 | take a look at F<iperlsys.h> and F<win32/perlhost.h>. While all Win32 | |
630 | variants go through a set of "vtables" for operating system access, | |
631 | non-Win32 systems currently go straight for the POSIX/UNIX-style | |
632 | system/library call. Similar system as for Win32 should be | |
633 | implemented for all platforms. The existing Win32 implementation | |
634 | probably does not need to survive alongside this proposed new | |
635 | implementation, the approaches could be merged. | |
87a942b1 JH |
636 | |
637 | What would this give us? One often-asked-for feature this would | |
94da6c29 JH |
638 | enable is using Unicode for filenames, and other "names" like %ENV, |
639 | usernames, hostnames, and so forth. | |
640 | (See L<perlunicode/"When Unicode Does Not Happen">.) | |
641 | ||
642 | But this kind of virtualization would also allow for things like | |
643 | virtual filesystems, virtual networks, and "sandboxes" (though as long | |
644 | as dynamic loading of random object code is allowed, not very safe | |
645 | sandboxes since external code of course know not of Perl's vtables). | |
646 | An example of a smaller "sandbox" is that this feature can be used to | |
647 | implement per-thread working directories: Win32 already does this. | |
648 | ||
649 | See also L</"Extend PerlIO and PerlIO::Scalar">. | |
87a942b1 | 650 | |
0bdfc961 NC |
651 | =head1 Big projects |
652 | ||
653 | Tasks that will get your name mentioned in the description of the "Highlights | |
87a942b1 | 654 | of 5.12" |
0bdfc961 NC |
655 | |
656 | =head2 make ithreads more robust | |
657 | ||
4e577f8b | 658 | Generally make ithreads more robust. See also L</iCOW> |
0bdfc961 NC |
659 | |
660 | This task is incremental - even a little bit of work on it will help, and | |
661 | will be greatly appreciated. | |
662 | ||
6c047da7 YST |
663 | One bit would be to write the missing code in sv.c:Perl_dirp_dup. |
664 | ||
59c7f7d5 RGS |
665 | Fix Perl_sv_dup, et al so that threads can return objects. |
666 | ||
0bdfc961 NC |
667 | =head2 iCOW |
668 | ||
669 | Sarathy and Arthur have a proposal for an improved Copy On Write which | |
670 | specifically will be able to COW new ithreads. If this can be implemented | |
671 | it would be a good thing. | |
672 | ||
673 | =head2 (?{...}) closures in regexps | |
674 | ||
675 | Fix (or rewrite) the implementation of the C</(?{...})/> closures. | |
676 | ||
677 | =head2 A re-entrant regexp engine | |
678 | ||
679 | This will allow the use of a regex from inside (?{ }), (??{ }) and | |
680 | (?(?{ })|) constructs. | |
6bda09f9 | 681 | |
6bda09f9 YO |
682 | =head2 Add class set operations to regexp engine |
683 | ||
684 | Apparently these are quite useful. Anyway, Jeffery Friedl wants them. | |
685 | ||
686 | demerphq has this on his todo list, but right at the bottom. |