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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 | ||
4e577f8b NC |
28 | =head2 Needed for a 5.9.4 release |
29 | ||
30 | =over | |
31 | ||
32 | =item * | |
78ef48ad RGS |
33 | |
34 | Review assertions. Review syntax to combine assertions. Assertions could take | |
35 | advantage of the lexical pragmas work. L</What hooks would assertions need?> | |
4e577f8b | 36 | |
860f190d RGS |
37 | =item * |
38 | ||
39 | C<encoding::warnings> should be turned into a lexical pragma. | |
0d720714 | 40 | C<encoding> should, too (probably). |
860f190d | 41 | |
4e577f8b NC |
42 | =back |
43 | ||
44 | =head2 Needed for a 5.9.5 release | |
45 | ||
46 | =over | |
47 | ||
48 | =item * | |
49 | Implement L</_ prototype character> | |
50 | ||
51 | =item * | |
52 | Implement L</state variables> | |
53 | ||
54 | =back | |
55 | ||
56 | =head2 Needed for a 5.9.6 release | |
57 | ||
58 | Stabilisation. If all goes well, this will be the equivalent of a 5.10-beta. | |
e50bb9a1 | 59 | |
0bdfc961 | 60 | =head1 Tasks that only need Perl knowledge |
e50bb9a1 | 61 | |
0bdfc961 | 62 | =head2 common test code for timed bail out |
e50bb9a1 | 63 | |
0bdfc961 NC |
64 | Write portable self destruct code for tests to stop them burning CPU in |
65 | infinite loops. This needs to avoid using alarm, as some of the tests are | |
66 | testing alarm/sleep or timers. | |
e50bb9a1 | 67 | |
0bdfc961 | 68 | =head2 POD -> HTML conversion in the core still sucks |
e50bb9a1 | 69 | |
938c8732 | 70 | Which is crazy given just how simple POD purports to be, and how simple HTML |
adebf063 NC |
71 | can be. It's not actually I<as> simple as it sounds, particularly with the |
72 | flexibility POD allows for C<=item>, but it would be good to improve the | |
73 | visual appeal of the HTML generated, and to avoid it having any validation | |
74 | errors. See also L</make HTML install work>, as the layout of installation tree | |
75 | is needed to improve the cross-linking. | |
938c8732 | 76 | |
dc0fb092 SP |
77 | The addition of C<Pod::Simple> and its related modules may make this task |
78 | easier to complete. | |
79 | ||
aa237293 NC |
80 | =head2 Parallel testing |
81 | ||
82 | The core regression test suite is getting ever more comprehensive, which has | |
83 | the side effect that it takes longer to run. This isn't so good. Investigate | |
84 | whether it would be feasible to give the harness script the B<option> of | |
85 | running sets of tests in parallel. This would be useful for tests in | |
86 | F<t/op/*.t> and F<t/uni/*.t> and maybe some sets of tests in F<lib/>. | |
87 | ||
88 | Questions to answer | |
89 | ||
90 | =over 4 | |
91 | ||
92 | =item 1 | |
93 | ||
94 | How does screen layout work when you're running more than one test? | |
95 | ||
96 | =item 2 | |
97 | ||
98 | How does the caller of test specify how many tests to run in parallel? | |
99 | ||
100 | =item 3 | |
101 | ||
102 | How do setup/teardown tests identify themselves? | |
103 | ||
104 | =back | |
105 | ||
106 | Pugs already does parallel testing - can their approach be re-used? | |
107 | ||
0bdfc961 | 108 | =head2 Make Schwern poorer |
e50bb9a1 | 109 | |
0bdfc961 NC |
110 | We should have for everything. When all the core's modules are tested, |
111 | Schwern has promised to donate to $500 to TPF. We may need volunteers to | |
112 | hold him upside down and shake vigorously in order to actually extract the | |
113 | cash. | |
3958b146 | 114 | |
0bdfc961 | 115 | See F<t/lib/1_compile.t> for the 3 remaining modules that need tests. |
e50bb9a1 | 116 | |
0bdfc961 | 117 | =head2 Improve the coverage of the core tests |
e50bb9a1 | 118 | |
0bdfc961 NC |
119 | Use Devel::Cover to ascertain the core's test coverage, then add tests that |
120 | are currently missing. | |
30222c0f | 121 | |
0bdfc961 | 122 | =head2 test B |
e50bb9a1 | 123 | |
0bdfc961 | 124 | A full test suite for the B module would be nice. |
e50bb9a1 | 125 | |
0bdfc961 | 126 | =head2 A decent benchmark |
e50bb9a1 | 127 | |
617eabfa | 128 | C<perlbench> seems impervious to any recent changes made to the perl core. It |
0bdfc961 NC |
129 | would be useful to have a reasonable general benchmarking suite that roughly |
130 | represented what current perl programs do, and measurably reported whether | |
131 | tweaks to the core improve, degrade or don't really affect performance, to | |
132 | guide people attempting to optimise the guts of perl. Gisle would welcome | |
133 | new tests for perlbench. | |
6168cf99 | 134 | |
0bdfc961 | 135 | =head2 fix tainting bugs |
6168cf99 | 136 | |
0bdfc961 NC |
137 | Fix the bugs revealed by running the test suite with the C<-t> switch (via |
138 | C<make test.taintwarn>). | |
e50bb9a1 | 139 | |
0bdfc961 | 140 | =head2 Dual life everything |
e50bb9a1 | 141 | |
0bdfc961 NC |
142 | As part of the "dists" plan, anything that doesn't belong in the smallest perl |
143 | distribution needs to be dual lifed. Anything else can be too. Figure out what | |
144 | changes would be needed to package that module and its tests up for CPAN, and | |
145 | do so. Test it with older perl releases, and fix the problems you find. | |
e50bb9a1 | 146 | |
0bdfc961 | 147 | =head2 Improving C<threads::shared> |
722d2a37 | 148 | |
0bdfc961 NC |
149 | Investigate whether C<threads::shared> could share aggregates properly with |
150 | only Perl level changes to shared.pm | |
722d2a37 | 151 | |
0bdfc961 | 152 | =head2 POSIX memory footprint |
e50bb9a1 | 153 | |
0bdfc961 NC |
154 | Ilya observed that use POSIX; eats memory like there's no tomorrow, and at |
155 | various times worked to cut it down. There is probably still fat to cut out - | |
156 | for example POSIX passes Exporter some very memory hungry data structures. | |
e50bb9a1 | 157 | |
e50bb9a1 | 158 | |
e50bb9a1 | 159 | |
e50bb9a1 | 160 | |
e50bb9a1 | 161 | |
adebf063 | 162 | |
adebf063 | 163 | |
0bdfc961 | 164 | =head1 Tasks that need a little sysadmin-type knowledge |
e50bb9a1 | 165 | |
0bdfc961 NC |
166 | Or if you prefer, tasks that you would learn from, and broaden your skills |
167 | base... | |
e50bb9a1 | 168 | |
617eabfa NC |
169 | =head2 Relocatable perl |
170 | ||
171 | The C level patches needed to create a relocatable perl binary are done, as | |
172 | is the work on F<Config.pm>. All that's left to do is the C<Configure> tweaking | |
173 | to let people specify how they want to do the install. | |
174 | ||
cd793d32 | 175 | =head2 make HTML install work |
e50bb9a1 | 176 | |
adebf063 NC |
177 | There is an C<installhtml> target in the Makefile. It's marked as |
178 | "experimental". It would be good to get this tested, make it work reliably, and | |
179 | remove the "experimental" tag. This would include | |
180 | ||
181 | =over 4 | |
182 | ||
183 | =item 1 | |
184 | ||
185 | Checking that cross linking between various parts of the documentation works. | |
186 | In particular that links work between the modules (files with POD in F<lib/>) | |
187 | and the core documentation (files in F<pod/>) | |
188 | ||
189 | =item 2 | |
190 | ||
617eabfa NC |
191 | Work out how to split C<perlfunc> into chunks, preferably one per function |
192 | group, preferably with general case code that could be used elsewhere. | |
193 | Challenges here are correctly identifying the groups of functions that go | |
194 | together, and making the right named external cross-links point to the right | |
195 | page. Things to be aware of are C<-X>, groups such as C<getpwnam> to | |
196 | C<endservent>, two or more C<=items> giving the different parameter lists, such | |
197 | as | |
adebf063 NC |
198 | |
199 | =item substr EXPR,OFFSET,LENGTH,REPLACEMENT | |
200 | ||
201 | =item substr EXPR,OFFSET,LENGTH | |
202 | ||
203 | =item substr EXPR,OFFSET | |
204 | ||
205 | and different parameter lists having different meanings. (eg C<select>) | |
206 | ||
207 | =back | |
3a89a73c | 208 | |
0bdfc961 NC |
209 | =head2 compressed man pages |
210 | ||
211 | Be able to install them. This would probably need a configure test to see how | |
212 | the system does compressed man pages (same directory/different directory? | |
213 | same filename/different filename), as well as tweaking the F<installman> script | |
214 | to compress as necessary. | |
215 | ||
30222c0f NC |
216 | =head2 Add a code coverage target to the Makefile |
217 | ||
218 | Make it easy for anyone to run Devel::Cover on the core's tests. The steps | |
219 | to do this manually are roughly | |
220 | ||
221 | =over 4 | |
222 | ||
223 | =item * | |
224 | ||
225 | do a normal C<Configure>, but include Devel::Cover as a module to install | |
226 | (see F<INSTALL> for how to do this) | |
227 | ||
228 | =item * | |
229 | ||
230 | make perl | |
231 | ||
232 | =item * | |
233 | ||
234 | cd t; HARNESS_PERL_SWITCHES=-MDevel::Cover ./perl -I../lib harness | |
235 | ||
236 | =item * | |
237 | ||
238 | Process the resulting Devel::Cover database | |
239 | ||
240 | =back | |
241 | ||
242 | This just give you the coverage of the F<.pm>s. To also get the C level | |
243 | coverage you need to | |
244 | ||
245 | =over 4 | |
246 | ||
247 | =item * | |
248 | ||
249 | Additionally tell C<Configure> to use the appropriate C compiler flags for | |
250 | C<gcov> | |
251 | ||
252 | =item * | |
253 | ||
254 | make perl.gcov | |
255 | ||
256 | (instead of C<make perl>) | |
257 | ||
258 | =item * | |
259 | ||
260 | After running the tests run C<gcov> to generate all the F<.gcov> files. | |
261 | (Including down in the subdirectories of F<ext/> | |
262 | ||
263 | =item * | |
264 | ||
265 | (From the top level perl directory) run C<gcov2perl> on all the C<.gcov> files | |
266 | to get their stats into the cover_db directory. | |
267 | ||
268 | =item * | |
269 | ||
270 | Then process the Devel::Cover database | |
271 | ||
272 | =back | |
273 | ||
274 | It would be good to add a single switch to C<Configure> to specify that you | |
275 | wanted to perform perl level coverage, and another to specify C level | |
276 | coverage, and have C<Configure> and the F<Makefile> do all the right things | |
277 | automatically. | |
278 | ||
0bdfc961 NC |
279 | =head2 Make Config.pm cope with differences between build and installed perl |
280 | ||
281 | Quite often vendors ship a perl binary compiled with their (pay-for) | |
282 | compilers. People install a free compiler, such as gcc. To work out how to | |
283 | build extensions, Perl interrogates C<%Config>, so in this situation | |
284 | C<%Config> describes compilers that aren't there, and extension building | |
285 | fails. This forces people into choosing between re-compiling perl themselves | |
286 | using the compiler they have, or only using modules that the vendor ships. | |
287 | ||
288 | It would be good to find a way teach C<Config.pm> about the installation setup, | |
289 | possibly involving probing at install time or later, so that the C<%Config> in | |
290 | a binary distribution better describes the installed machine, when the | |
291 | installed machine differs from the build machine in some significant way. | |
292 | ||
46925299 | 293 | =head2 make parallel builds work |
0bdfc961 | 294 | |
46925299 NC |
295 | Currently parallel builds (such as C<make -j3>) don't work reliably. We believe |
296 | that this is due to incomplete dependency specification in the F<Makefile>. | |
297 | It would be good if someone were able to track down the causes of these | |
298 | problems, so that parallel builds worked properly. | |
0bdfc961 | 299 | |
728f4ecd NC |
300 | =head2 linker specification files |
301 | ||
302 | Some platforms mandate that you provide a list of a shared library's external | |
303 | symbols to the linker, so the core already has the infrastructure in place to | |
304 | do this for generating shared perl libraries. My understanding is that the | |
305 | GNU toolchain can accept an optional linker specification file, and restrict | |
306 | visibility just to symbols declared in that file. It would be good to extend | |
307 | F<makedef.pl> to support this format, and to provide a means within | |
308 | C<Configure> to enable it. This would allow Unix users to test that the | |
309 | export list is correct, and to build a perl that does not pollute the global | |
310 | namespace with private symbols. | |
311 | ||
8523e164 | 312 | |
0bdfc961 NC |
313 | |
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 | ||
0f788cd2 NC |
342 | =head2 Ordering of "global" variables. |
343 | ||
344 | F<thrdvar.h> and F<intrpvarh> define the "global" variables that need to be | |
345 | per-thread under ithreads, where the variables are actually elements in a | |
346 | structure. As C dictates, the variables must be laid out in order of | |
347 | declaration. There is a comment | |
348 | C</* Important ones in the first cache line (if alignment is done right) */> | |
349 | which implies that at some point in the past the ordering was carefully chosen | |
350 | (at least in part). However, it's clear that the ordering is less than perfect, | |
351 | as currently there are things such as 7 C<bool>s in a row, then something | |
352 | typically requiring 4 byte alignment, and then an odd C<bool> later on. | |
353 | (C<bool>s are typically defined as C<char>s). So it would be good for someone | |
354 | to review the ordering of the variables, to see how much alignment padding can | |
355 | be removed. | |
356 | ||
d7939546 NC |
357 | It's also worth checking that all variables are actually used. Perl 5.8.0 |
358 | shipped with C<PL_nrs> still defined in F<thrdvar.h>, despite it being unused | |
359 | since a change over a year earlier. Had this been spotted before release, it | |
360 | could have been removed, but now it has to remain in the 5.8.x releases to | |
361 | keep the structure the same size, to retain binary compatibility. | |
362 | ||
62403a3c NC |
363 | =head2 am I hot or not? |
364 | ||
365 | The idea of F<pp_hot.c> is that it contains the I<hot> ops, the ops that are | |
366 | most commonly used. The idea is that by grouping them, their object code will | |
367 | be adjacent in the executable, so they have a greater chance of already being | |
368 | in the CPU cache (or swapped in) due to being near another op already in use. | |
369 | ||
370 | Except that it's not clear if these really are the most commonly used ops. So | |
371 | anyone feeling like exercising their skill with coverage and profiling tools | |
372 | might want to determine what ops I<really> are the most commonly used. And in | |
373 | turn suggest evictions and promotions to achieve a better F<pp_hot.c>. | |
374 | ||
98fed0ad NC |
375 | =head2 Shrink struct context |
376 | ||
377 | In F<cop.h>, we have | |
378 | ||
379 | struct context { | |
380 | U32 cx_type; /* what kind of context this is */ | |
381 | union { | |
382 | struct block cx_blk; | |
383 | struct subst cx_subst; | |
384 | } cx_u; | |
385 | }; | |
386 | ||
387 | There are less than 256 values for C<cx_type>, and the constituent parts | |
388 | C<struct block> and C<struct subst> both contain some C<U8> and C<U16> fields, | |
389 | so it should be possible to move them to the first word, and share space with | |
390 | a C<U8> C<cx_type>, saving 1 word. | |
391 | ||
392 | =head2 Allocate OPs from arenas | |
393 | ||
394 | Currently all new OP structures are individually malloc()ed and free()d. | |
395 | All C<malloc> implementations have space overheads, and are now as fast as | |
396 | custom allocates so it would both use less memory and less CPU to allocate | |
397 | the various OP structures from arenas. The SV arena code can probably be | |
398 | re-used for this. | |
399 | ||
0bdfc961 NC |
400 | |
401 | ||
402 | ||
0bdfc961 | 403 | =head1 Tasks that need a knowledge of XS |
e50bb9a1 | 404 | |
0bdfc961 NC |
405 | These tasks would need C knowledge, and roughly the level of knowledge of |
406 | the perl API that comes from writing modules that use XS to interface to | |
407 | C. | |
408 | ||
409 | =head2 IPv6 | |
410 | ||
411 | Clean this up. Check everything in core works | |
412 | ||
35b64ab6 | 413 | =head2 shrink C<IO>s |
4a750395 | 414 | |
35b64ab6 NC |
415 | By removing unused elements and careful re-ordering, the structures for C<AV>s, |
416 | C<HV>s, C<CV>s and C<GV>s have recently been shrunk considerably. C<PVIO>s and | |
417 | C<PVBM>s might have some savings to win. | |
4a750395 | 418 | |
0bdfc961 NC |
419 | =head2 UTF8 caching code |
420 | ||
421 | The string position/offset cache is not optional. It should be. | |
422 | ||
423 | =head2 Implicit Latin 1 => Unicode translation | |
424 | ||
425 | Conversions from byte strings to UTF-8 currently map high bit characters | |
426 | to Unicode without translation (or, depending on how you look at it, by | |
427 | implicitly assuming that the byte strings are in Latin-1). As perl assumes | |
428 | the C locale by default, upgrading a string to UTF-8 may change the | |
429 | meaning of its contents regarding character classes, case mapping, etc. | |
430 | This should probably emit a warning (at least). | |
431 | ||
432 | This task is incremental - even a little bit of work on it will help. | |
e50bb9a1 | 433 | |
cd793d32 | 434 | =head2 autovivification |
e50bb9a1 | 435 | |
cd793d32 | 436 | Make all autovivification consistent w.r.t LVALUE/RVALUE and strict/no strict; |
e50bb9a1 | 437 | |
0bdfc961 | 438 | This task is incremental - even a little bit of work on it will help. |
e50bb9a1 | 439 | |
0bdfc961 | 440 | =head2 Unicode in Filenames |
e50bb9a1 | 441 | |
0bdfc961 NC |
442 | chdir, chmod, chown, chroot, exec, glob, link, lstat, mkdir, open, |
443 | opendir, qx, readdir, readlink, rename, rmdir, stat, symlink, sysopen, | |
444 | system, truncate, unlink, utime, -X. All these could potentially accept | |
445 | Unicode filenames either as input or output (and in the case of system | |
446 | and qx Unicode in general, as input or output to/from the shell). | |
447 | Whether a filesystem - an operating system pair understands Unicode in | |
448 | filenames varies. | |
e50bb9a1 | 449 | |
0bdfc961 NC |
450 | Known combinations that have some level of understanding include |
451 | Microsoft NTFS, Apple HFS+ (In Mac OS 9 and X) and Apple UFS (in Mac | |
452 | OS X), NFS v4 is rumored to be Unicode, and of course Plan 9. How to | |
453 | create Unicode filenames, what forms of Unicode are accepted and used | |
454 | (UCS-2, UTF-16, UTF-8), what (if any) is the normalization form used, | |
455 | and so on, varies. Finding the right level of interfacing to Perl | |
456 | requires some thought. Remember that an OS does not implicate a | |
457 | filesystem. | |
e50bb9a1 | 458 | |
0bdfc961 NC |
459 | (The Windows -C command flag "wide API support" has been at least |
460 | temporarily retired in 5.8.1, and the -C has been repurposed, see | |
461 | L<perlrun>.) | |
969e704b | 462 | |
0bdfc961 | 463 | =head2 Unicode in %ENV |
969e704b | 464 | |
0bdfc961 | 465 | Currently the %ENV entries are always byte strings. |
e50bb9a1 | 466 | |
0bdfc961 | 467 | =head2 use less 'memory' |
e50bb9a1 | 468 | |
0bdfc961 NC |
469 | Investigate trade offs to switch out perl's choices on memory usage. |
470 | Particularly perl should be able to give memory back. | |
e50bb9a1 | 471 | |
0bdfc961 | 472 | This task is incremental - even a little bit of work on it will help. |
0abe3f7c | 473 | |
0bdfc961 | 474 | =head2 Re-implement C<:unique> in a way that is actually thread-safe |
0abe3f7c | 475 | |
0bdfc961 NC |
476 | The old implementation made bad assumptions on several levels. A good 90% |
477 | solution might be just to make C<:unique> work to share the string buffer | |
478 | of SvPVs. That way large constant strings can be shared between ithreads, | |
479 | such as the configuration information in F<Config>. | |
0abe3f7c | 480 | |
0bdfc961 | 481 | =head2 Make tainting consistent |
0abe3f7c | 482 | |
0bdfc961 NC |
483 | Tainting would be easier to use if it didn't take documented shortcuts and |
484 | allow taint to "leak" everywhere within an expression. | |
0abe3f7c | 485 | |
0bdfc961 | 486 | =head2 readpipe(LIST) |
0abe3f7c | 487 | |
0bdfc961 NC |
488 | system() accepts a LIST syntax (and a PROGRAM LIST syntax) to avoid |
489 | running a shell. readpipe() (the function behind qx//) could be similarly | |
490 | extended. | |
0abe3f7c | 491 | |
e50bb9a1 | 492 | |
e50bb9a1 | 493 | |
e50bb9a1 | 494 | |
f86a8bc5 | 495 | |
0bdfc961 | 496 | =head1 Tasks that need a knowledge of the interpreter |
3298bd4d | 497 | |
0bdfc961 NC |
498 | These tasks would need C knowledge, and knowledge of how the interpreter works, |
499 | or a willingness to learn. | |
3298bd4d | 500 | |
0bdfc961 NC |
501 | =head2 lexical pragmas |
502 | ||
78ef48ad RGS |
503 | Document the new support for lexical pragmas in 5.9.3 and how %^H works. |
504 | Maybe C<re>, C<encoding>, maybe other pragmas could be made lexical. | |
0562c0e3 | 505 | |
d10fc472 | 506 | =head2 Attach/detach debugger from running program |
1626a787 | 507 | |
cd793d32 NC |
508 | The old perltodo notes "With C<gdb>, you can attach the debugger to a running |
509 | program if you pass the process ID. It would be good to do this with the Perl | |
0bdfc961 NC |
510 | debugger on a running Perl program, although I'm not sure how it would be |
511 | done." ssh and screen do this with named pipes in /tmp. Maybe we can too. | |
1626a787 | 512 | |
0bdfc961 | 513 | =head2 Constant folding |
80b46460 | 514 | |
0bdfc961 NC |
515 | The peephole optimiser should trap errors during constant folding, and give |
516 | up on the folding, rather than bailing out at compile time. It is quite | |
517 | possible that the unfoldable constant is in unreachable code, eg something | |
518 | akin to C<$a = 0/0 if 0;> | |
519 | ||
520 | =head2 LVALUE functions for lists | |
521 | ||
522 | The old perltodo notes that lvalue functions don't work for list or hash | |
523 | slices. This would be good to fix. | |
524 | ||
525 | =head2 LVALUE functions in the debugger | |
526 | ||
527 | The old perltodo notes that lvalue functions don't work in the debugger. This | |
528 | would be good to fix. | |
529 | ||
530 | =head2 _ prototype character | |
531 | ||
532 | Study the possibility of adding a new prototype character, C<_>, meaning | |
533 | "this argument defaults to $_". | |
534 | ||
4e577f8b NC |
535 | =head2 state variables |
536 | ||
537 | C<my $foo if 0;> is deprecated, and should be replaced with | |
538 | C<state $x = "initial value\n";> the syntax from Perl 6. | |
539 | ||
0bdfc961 NC |
540 | =head2 @INC source filter to Filter::Simple |
541 | ||
542 | The second return value from a sub in @INC can be a source filter. This isn't | |
543 | documented. It should be changed to use Filter::Simple, tested and documented. | |
544 | ||
545 | =head2 regexp optimiser optional | |
546 | ||
547 | The regexp optimiser is not optional. It should configurable to be, to allow | |
548 | its performance to be measured, and its bugs to be easily demonstrated. | |
549 | ||
550 | =head2 UNITCHECK | |
551 | ||
552 | Introduce a new special block, UNITCHECK, which is run at the end of a | |
553 | compilation unit (module, file, eval(STRING) block). This will correspond to | |
554 | the Perl 6 CHECK. Perl 5's CHECK cannot be changed or removed because the | |
555 | O.pm/B.pm backend framework depends on it. | |
556 | ||
557 | =head2 optional optimizer | |
558 | ||
559 | Make the peephole optimizer optional. Currently it performs two tasks as | |
560 | it walks the optree - genuine peephole optimisations, and necessary fixups of | |
561 | ops. It would be good to find an efficient way to switch out the | |
562 | optimisations whilst keeping the fixups. | |
563 | ||
564 | =head2 You WANT *how* many | |
565 | ||
566 | Currently contexts are void, scalar and list. split has a special mechanism in | |
567 | place to pass in the number of return values wanted. It would be useful to | |
568 | have a general mechanism for this, backwards compatible and little speed hit. | |
569 | This would allow proposals such as short circuiting sort to be implemented | |
570 | as a module on CPAN. | |
571 | ||
572 | =head2 lexical aliases | |
573 | ||
574 | Allow lexical aliases (maybe via the syntax C<my \$alias = \$foo>. | |
575 | ||
576 | =head2 entersub XS vs Perl | |
577 | ||
578 | At the moment pp_entersub is huge, and has code to deal with entering both | |
579 | perl and XS subroutines. Subroutine implementations rarely change between | |
580 | perl and XS at run time, so investigate using 2 ops to enter subs (one for | |
581 | XS, one for perl) and swap between if a sub is redefined. | |
2810d901 NC |
582 | |
583 | =head2 Self ties | |
584 | ||
585 | self ties are currently illegal because they caused too many segfaults. Maybe | |
586 | the causes of these could be tracked down and self-ties on all types re- | |
587 | instated. | |
0bdfc961 NC |
588 | |
589 | =head2 Optimize away @_ | |
590 | ||
591 | The old perltodo notes "Look at the "reification" code in C<av.c>". | |
592 | ||
0bdfc961 NC |
593 | =head2 What hooks would assertions need? |
594 | ||
595 | Assertions are in the core, and work. However, assertions needed to be added | |
596 | as a core patch, rather than an XS module in ext, or a CPAN module, because | |
597 | the core has no hooks in the necessary places. It would be useful to | |
598 | investigate what hooks would need to be added to make it possible to provide | |
599 | the full assertion support from a CPAN module, so that we aren't constraining | |
600 | the imagination of future CPAN authors. | |
601 | ||
602 | ||
603 | ||
604 | ||
605 | ||
0bdfc961 NC |
606 | =head1 Big projects |
607 | ||
608 | Tasks that will get your name mentioned in the description of the "Highlights | |
609 | of 5.10" | |
610 | ||
611 | =head2 make ithreads more robust | |
612 | ||
4e577f8b | 613 | Generally make ithreads more robust. See also L</iCOW> |
0bdfc961 NC |
614 | |
615 | This task is incremental - even a little bit of work on it will help, and | |
616 | will be greatly appreciated. | |
617 | ||
6c047da7 YST |
618 | One bit would be to write the missing code in sv.c:Perl_dirp_dup. |
619 | ||
0bdfc961 NC |
620 | =head2 iCOW |
621 | ||
622 | Sarathy and Arthur have a proposal for an improved Copy On Write which | |
623 | specifically will be able to COW new ithreads. If this can be implemented | |
624 | it would be a good thing. | |
625 | ||
626 | =head2 (?{...}) closures in regexps | |
627 | ||
628 | Fix (or rewrite) the implementation of the C</(?{...})/> closures. | |
629 | ||
630 | =head2 A re-entrant regexp engine | |
631 | ||
632 | This will allow the use of a regex from inside (?{ }), (??{ }) and | |
633 | (?(?{ })|) constructs. |