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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 * | |
c1f116f6 | 33 | |
afe7bfd5 RGS |
34 | Implement L</state variables> (mostly done currently) |
35 | ||
36 | =item * | |
78ef48ad RGS |
37 | |
38 | Review assertions. Review syntax to combine assertions. Assertions could take | |
39 | advantage of the lexical pragmas work. L</What hooks would assertions need?> | |
4e577f8b | 40 | |
860f190d RGS |
41 | =item * |
42 | ||
25441cc9 | 43 | C<encoding> should be turned into a lexical pragma (probably). |
860f190d | 44 | |
4e577f8b NC |
45 | =back |
46 | ||
47 | =head2 Needed for a 5.9.5 release | |
48 | ||
49 | =over | |
50 | ||
51 | =item * | |
c1f116f6 | 52 | |
4e577f8b NC |
53 | Implement L</_ prototype character> |
54 | ||
c1f116f6 RGS |
55 | =item * |
56 | ||
57 | Review smart match semantics in light of Perl 6 developments. | |
58 | ||
4e577f8b NC |
59 | =back |
60 | ||
61 | =head2 Needed for a 5.9.6 release | |
62 | ||
63 | Stabilisation. If all goes well, this will be the equivalent of a 5.10-beta. | |
e50bb9a1 | 64 | |
0bdfc961 | 65 | =head1 Tasks that only need Perl knowledge |
e50bb9a1 | 66 | |
0bdfc961 | 67 | =head2 common test code for timed bail out |
e50bb9a1 | 68 | |
0bdfc961 NC |
69 | Write portable self destruct code for tests to stop them burning CPU in |
70 | infinite loops. This needs to avoid using alarm, as some of the tests are | |
71 | testing alarm/sleep or timers. | |
e50bb9a1 | 72 | |
0bdfc961 | 73 | =head2 POD -> HTML conversion in the core still sucks |
e50bb9a1 | 74 | |
938c8732 | 75 | Which is crazy given just how simple POD purports to be, and how simple HTML |
adebf063 NC |
76 | can be. It's not actually I<as> simple as it sounds, particularly with the |
77 | flexibility POD allows for C<=item>, but it would be good to improve the | |
78 | visual appeal of the HTML generated, and to avoid it having any validation | |
79 | errors. See also L</make HTML install work>, as the layout of installation tree | |
80 | is needed to improve the cross-linking. | |
938c8732 | 81 | |
dc0fb092 SP |
82 | The addition of C<Pod::Simple> and its related modules may make this task |
83 | easier to complete. | |
84 | ||
aa237293 NC |
85 | =head2 Parallel testing |
86 | ||
87 | The core regression test suite is getting ever more comprehensive, which has | |
88 | the side effect that it takes longer to run. This isn't so good. Investigate | |
89 | whether it would be feasible to give the harness script the B<option> of | |
90 | running sets of tests in parallel. This would be useful for tests in | |
91 | F<t/op/*.t> and F<t/uni/*.t> and maybe some sets of tests in F<lib/>. | |
92 | ||
93 | Questions to answer | |
94 | ||
95 | =over 4 | |
96 | ||
97 | =item 1 | |
98 | ||
99 | How does screen layout work when you're running more than one test? | |
100 | ||
101 | =item 2 | |
102 | ||
103 | How does the caller of test specify how many tests to run in parallel? | |
104 | ||
105 | =item 3 | |
106 | ||
107 | How do setup/teardown tests identify themselves? | |
108 | ||
109 | =back | |
110 | ||
111 | Pugs already does parallel testing - can their approach be re-used? | |
112 | ||
0bdfc961 | 113 | =head2 Make Schwern poorer |
e50bb9a1 | 114 | |
613bd4f7 | 115 | We should have tests for everything. When all the core's modules are tested, |
0bdfc961 NC |
116 | Schwern has promised to donate to $500 to TPF. We may need volunteers to |
117 | hold him upside down and shake vigorously in order to actually extract the | |
118 | cash. | |
3958b146 | 119 | |
0bdfc961 | 120 | See F<t/lib/1_compile.t> for the 3 remaining modules that need tests. |
e50bb9a1 | 121 | |
0bdfc961 | 122 | =head2 Improve the coverage of the core tests |
e50bb9a1 | 123 | |
0bdfc961 NC |
124 | Use Devel::Cover to ascertain the core's test coverage, then add tests that |
125 | are currently missing. | |
30222c0f | 126 | |
0bdfc961 | 127 | =head2 test B |
e50bb9a1 | 128 | |
0bdfc961 | 129 | A full test suite for the B module would be nice. |
e50bb9a1 | 130 | |
0bdfc961 | 131 | =head2 A decent benchmark |
e50bb9a1 | 132 | |
617eabfa | 133 | C<perlbench> seems impervious to any recent changes made to the perl core. It |
0bdfc961 NC |
134 | would be useful to have a reasonable general benchmarking suite that roughly |
135 | represented what current perl programs do, and measurably reported whether | |
136 | tweaks to the core improve, degrade or don't really affect performance, to | |
137 | guide people attempting to optimise the guts of perl. Gisle would welcome | |
138 | new tests for perlbench. | |
6168cf99 | 139 | |
0bdfc961 | 140 | =head2 fix tainting bugs |
6168cf99 | 141 | |
0bdfc961 NC |
142 | Fix the bugs revealed by running the test suite with the C<-t> switch (via |
143 | C<make test.taintwarn>). | |
e50bb9a1 | 144 | |
0bdfc961 | 145 | =head2 Dual life everything |
e50bb9a1 | 146 | |
0bdfc961 NC |
147 | As part of the "dists" plan, anything that doesn't belong in the smallest perl |
148 | distribution needs to be dual lifed. Anything else can be too. Figure out what | |
149 | changes would be needed to package that module and its tests up for CPAN, and | |
150 | do so. Test it with older perl releases, and fix the problems you find. | |
e50bb9a1 | 151 | |
0bdfc961 | 152 | =head2 Improving C<threads::shared> |
722d2a37 | 153 | |
0bdfc961 NC |
154 | Investigate whether C<threads::shared> could share aggregates properly with |
155 | only Perl level changes to shared.pm | |
722d2a37 | 156 | |
0bdfc961 | 157 | =head2 POSIX memory footprint |
e50bb9a1 | 158 | |
0bdfc961 NC |
159 | Ilya observed that use POSIX; eats memory like there's no tomorrow, and at |
160 | various times worked to cut it down. There is probably still fat to cut out - | |
161 | for example POSIX passes Exporter some very memory hungry data structures. | |
e50bb9a1 | 162 | |
eed36644 NC |
163 | =head2 embed.pl/makedef.pl |
164 | ||
165 | There is a script F<embed.pl> that generates several header files to prefix | |
166 | all of Perl's symbols in a consistent way, to provide some semblance of | |
167 | namespace support in C<C>. Functions are declared in F<embed.fnc>, variables | |
168 | in F<interpvar.h> and F<thrdvar.h>. Quite a few of the functions and variables | |
169 | are conditionally declared there, using C<#ifdef>. However, F<embed.pl> | |
170 | doesn't understand the C macros, so the rules about which symbols are present | |
171 | when is duplicated in F<makedef.pl>. Writing things twice is bad, m'kay. | |
172 | It would be good to teach C<embed.pl> to understand the conditional | |
173 | compilation, and hence remove the duplication, and the mistakes it has caused. | |
e50bb9a1 | 174 | |
e50bb9a1 | 175 | |
e50bb9a1 | 176 | |
e50bb9a1 | 177 | |
adebf063 | 178 | |
adebf063 | 179 | |
0bdfc961 | 180 | =head1 Tasks that need a little sysadmin-type knowledge |
e50bb9a1 | 181 | |
0bdfc961 NC |
182 | Or if you prefer, tasks that you would learn from, and broaden your skills |
183 | base... | |
e50bb9a1 | 184 | |
cd793d32 | 185 | =head2 make HTML install work |
e50bb9a1 | 186 | |
adebf063 NC |
187 | There is an C<installhtml> target in the Makefile. It's marked as |
188 | "experimental". It would be good to get this tested, make it work reliably, and | |
189 | remove the "experimental" tag. This would include | |
190 | ||
191 | =over 4 | |
192 | ||
193 | =item 1 | |
194 | ||
195 | Checking that cross linking between various parts of the documentation works. | |
196 | In particular that links work between the modules (files with POD in F<lib/>) | |
197 | and the core documentation (files in F<pod/>) | |
198 | ||
199 | =item 2 | |
200 | ||
617eabfa NC |
201 | Work out how to split C<perlfunc> into chunks, preferably one per function |
202 | group, preferably with general case code that could be used elsewhere. | |
203 | Challenges here are correctly identifying the groups of functions that go | |
204 | together, and making the right named external cross-links point to the right | |
205 | page. Things to be aware of are C<-X>, groups such as C<getpwnam> to | |
206 | C<endservent>, two or more C<=items> giving the different parameter lists, such | |
207 | as | |
adebf063 NC |
208 | |
209 | =item substr EXPR,OFFSET,LENGTH,REPLACEMENT | |
adebf063 | 210 | =item substr EXPR,OFFSET,LENGTH |
adebf063 NC |
211 | =item substr EXPR,OFFSET |
212 | ||
213 | and different parameter lists having different meanings. (eg C<select>) | |
214 | ||
215 | =back | |
3a89a73c | 216 | |
0bdfc961 NC |
217 | =head2 compressed man pages |
218 | ||
219 | Be able to install them. This would probably need a configure test to see how | |
220 | the system does compressed man pages (same directory/different directory? | |
221 | same filename/different filename), as well as tweaking the F<installman> script | |
222 | to compress as necessary. | |
223 | ||
30222c0f NC |
224 | =head2 Add a code coverage target to the Makefile |
225 | ||
226 | Make it easy for anyone to run Devel::Cover on the core's tests. The steps | |
227 | to do this manually are roughly | |
228 | ||
229 | =over 4 | |
230 | ||
231 | =item * | |
232 | ||
233 | do a normal C<Configure>, but include Devel::Cover as a module to install | |
234 | (see F<INSTALL> for how to do this) | |
235 | ||
236 | =item * | |
237 | ||
238 | make perl | |
239 | ||
240 | =item * | |
241 | ||
242 | cd t; HARNESS_PERL_SWITCHES=-MDevel::Cover ./perl -I../lib harness | |
243 | ||
244 | =item * | |
245 | ||
246 | Process the resulting Devel::Cover database | |
247 | ||
248 | =back | |
249 | ||
250 | This just give you the coverage of the F<.pm>s. To also get the C level | |
251 | coverage you need to | |
252 | ||
253 | =over 4 | |
254 | ||
255 | =item * | |
256 | ||
257 | Additionally tell C<Configure> to use the appropriate C compiler flags for | |
258 | C<gcov> | |
259 | ||
260 | =item * | |
261 | ||
262 | make perl.gcov | |
263 | ||
264 | (instead of C<make perl>) | |
265 | ||
266 | =item * | |
267 | ||
268 | After running the tests run C<gcov> to generate all the F<.gcov> files. | |
269 | (Including down in the subdirectories of F<ext/> | |
270 | ||
271 | =item * | |
272 | ||
273 | (From the top level perl directory) run C<gcov2perl> on all the C<.gcov> files | |
274 | to get their stats into the cover_db directory. | |
275 | ||
276 | =item * | |
277 | ||
278 | Then process the Devel::Cover database | |
279 | ||
280 | =back | |
281 | ||
282 | It would be good to add a single switch to C<Configure> to specify that you | |
283 | wanted to perform perl level coverage, and another to specify C level | |
284 | coverage, and have C<Configure> and the F<Makefile> do all the right things | |
285 | automatically. | |
286 | ||
0bdfc961 NC |
287 | =head2 Make Config.pm cope with differences between build and installed perl |
288 | ||
289 | Quite often vendors ship a perl binary compiled with their (pay-for) | |
290 | compilers. People install a free compiler, such as gcc. To work out how to | |
291 | build extensions, Perl interrogates C<%Config>, so in this situation | |
292 | C<%Config> describes compilers that aren't there, and extension building | |
293 | fails. This forces people into choosing between re-compiling perl themselves | |
294 | using the compiler they have, or only using modules that the vendor ships. | |
295 | ||
296 | It would be good to find a way teach C<Config.pm> about the installation setup, | |
297 | possibly involving probing at install time or later, so that the C<%Config> in | |
298 | a binary distribution better describes the installed machine, when the | |
299 | installed machine differs from the build machine in some significant way. | |
300 | ||
728f4ecd NC |
301 | =head2 linker specification files |
302 | ||
303 | Some platforms mandate that you provide a list of a shared library's external | |
304 | symbols to the linker, so the core already has the infrastructure in place to | |
305 | do this for generating shared perl libraries. My understanding is that the | |
306 | GNU toolchain can accept an optional linker specification file, and restrict | |
307 | visibility just to symbols declared in that file. It would be good to extend | |
308 | F<makedef.pl> to support this format, and to provide a means within | |
309 | C<Configure> to enable it. This would allow Unix users to test that the | |
310 | export list is correct, and to build a perl that does not pollute the global | |
311 | namespace with private symbols. | |
312 | ||
a229ae3b RGS |
313 | =head2 Cross-compile support |
314 | ||
315 | Currently C<Configure> understands C<-Dusecrosscompile> option. This option | |
316 | arranges for building C<miniperl> for TARGET machine, so this C<miniperl> is | |
317 | assumed then to be copied to TARGET machine and used as a replacement of full | |
318 | C<perl> executable. | |
319 | ||
320 | This should be done litle differently. Namely C<miniperl> should be built for | |
321 | HOST and then full C<perl> with extensions should be compiled for TARGET. | |
8523e164 | 322 | |
0bdfc961 NC |
323 | |
324 | ||
325 | =head1 Tasks that need a little C knowledge | |
326 | ||
327 | These tasks would need a little C knowledge, but don't need any specific | |
328 | background or experience with XS, or how the Perl interpreter works | |
329 | ||
330 | =head2 Make it clear from -v if this is the exact official release | |
89007cb3 | 331 | |
617eabfa NC |
332 | Currently perl from C<p4>/C<rsync> ships with a F<patchlevel.h> file that |
333 | usually defines one local patch, of the form "MAINT12345" or "RC1". The output | |
334 | of perl -v doesn't report that a perl isn't an official release, and this | |
89007cb3 | 335 | information can get lost in bugs reports. Because of this, the minor version |
fa11829f | 336 | isn't bumped up until RC time, to minimise the possibility of versions of perl |
89007cb3 NC |
337 | escaping that believe themselves to be newer than they actually are. |
338 | ||
339 | It would be useful to find an elegant way to have the "this is an interim | |
340 | maintenance release" or "this is a release candidate" in the terse -v output, | |
341 | and have it so that it's easy for the pumpking to remove this just as the | |
342 | release tarball is rolled up. This way the version pulled out of rsync would | |
343 | always say "I'm a development release" and it would be safe to bump the | |
344 | reported minor version as soon as a release ships, which would aid perl | |
345 | developers. | |
346 | ||
0bdfc961 NC |
347 | This task is really about thinking of an elegant way to arrange the C source |
348 | such that it's trivial for the Pumpking to flag "this is an official release" | |
349 | when making a tarball, yet leave the default source saying "I'm not the | |
350 | official release". | |
351 | ||
0f788cd2 NC |
352 | =head2 Ordering of "global" variables. |
353 | ||
354 | F<thrdvar.h> and F<intrpvarh> define the "global" variables that need to be | |
355 | per-thread under ithreads, where the variables are actually elements in a | |
356 | structure. As C dictates, the variables must be laid out in order of | |
357 | declaration. There is a comment | |
358 | C</* Important ones in the first cache line (if alignment is done right) */> | |
359 | which implies that at some point in the past the ordering was carefully chosen | |
360 | (at least in part). However, it's clear that the ordering is less than perfect, | |
361 | as currently there are things such as 7 C<bool>s in a row, then something | |
362 | typically requiring 4 byte alignment, and then an odd C<bool> later on. | |
363 | (C<bool>s are typically defined as C<char>s). So it would be good for someone | |
364 | to review the ordering of the variables, to see how much alignment padding can | |
365 | be removed. | |
366 | ||
d7939546 NC |
367 | It's also worth checking that all variables are actually used. Perl 5.8.0 |
368 | shipped with C<PL_nrs> still defined in F<thrdvar.h>, despite it being unused | |
369 | since a change over a year earlier. Had this been spotted before release, it | |
370 | could have been removed, but now it has to remain in the 5.8.x releases to | |
371 | keep the structure the same size, to retain binary compatibility. | |
372 | ||
c1ab7b38 NC |
373 | It's probably worth checking if all need to be the types they are. For example |
374 | ||
375 | PERLVAR(Ierror_count, I32) /* how many errors so far, max 10 */ | |
376 | ||
377 | might work as well if stored in a signed (or unsigned) 8 bit value, if the | |
378 | comment is accurate. C<PL_multi_open> and C<PL_multi_close> can probably | |
379 | become C<char>s. Finding variables to downsize coupled with rearrangement | |
380 | could shrink the interpreter structure; a size saving which is multiplied by | |
381 | the number of threads running. | |
382 | ||
fee0a0f7 | 383 | =head2 Profile Perl - am I hot or not? |
62403a3c | 384 | |
fee0a0f7 NC |
385 | The Perl source code is stable enough that it makes sense to profile it, |
386 | identify and optimise the hotspots. It would be good to measure the | |
387 | performance of the Perl interpreter using free tools such as cachegrind, | |
388 | gprof, and dtrace, and work to reduce the bottlenecks they reveal. | |
389 | ||
390 | As part of this, the idea of F<pp_hot.c> is that it contains the I<hot> ops, | |
391 | the ops that are most commonly used. The idea is that by grouping them, their | |
392 | object code will be adjacent in the executable, so they have a greater chance | |
393 | of already being in the CPU cache (or swapped in) due to being near another op | |
394 | already in use. | |
62403a3c NC |
395 | |
396 | Except that it's not clear if these really are the most commonly used ops. So | |
fee0a0f7 NC |
397 | as part of exercising your skills with coverage and profiling tools you might |
398 | want to determine what ops I<really> are the most commonly used. And in turn | |
399 | suggest evictions and promotions to achieve a better F<pp_hot.c>. | |
62403a3c | 400 | |
98fed0ad NC |
401 | =head2 Shrink struct context |
402 | ||
403 | In F<cop.h>, we have | |
404 | ||
405 | struct context { | |
406 | U32 cx_type; /* what kind of context this is */ | |
407 | union { | |
408 | struct block cx_blk; | |
409 | struct subst cx_subst; | |
410 | } cx_u; | |
411 | }; | |
412 | ||
413 | There are less than 256 values for C<cx_type>, and the constituent parts | |
414 | C<struct block> and C<struct subst> both contain some C<U8> and C<U16> fields, | |
415 | so it should be possible to move them to the first word, and share space with | |
416 | a C<U8> C<cx_type>, saving 1 word. | |
417 | ||
418 | =head2 Allocate OPs from arenas | |
419 | ||
420 | Currently all new OP structures are individually malloc()ed and free()d. | |
421 | All C<malloc> implementations have space overheads, and are now as fast as | |
422 | custom allocates so it would both use less memory and less CPU to allocate | |
423 | the various OP structures from arenas. The SV arena code can probably be | |
424 | re-used for this. | |
425 | ||
a229ae3b | 426 | =head2 Improve win32/wince.c |
0bdfc961 | 427 | |
a229ae3b RGS |
428 | Currently, numerous functions look virtually, if not completely, |
429 | identical in both C<win32/wince.c> and C<win32/win32.c> files, which can't be good. | |
0bdfc961 NC |
430 | |
431 | ||
0bdfc961 | 432 | =head1 Tasks that need a knowledge of XS |
e50bb9a1 | 433 | |
0bdfc961 NC |
434 | These tasks would need C knowledge, and roughly the level of knowledge of |
435 | the perl API that comes from writing modules that use XS to interface to | |
436 | C. | |
437 | ||
f23930d5 | 438 | =head2 shrink C<PVBM>s |
4a750395 | 439 | |
35b64ab6 | 440 | By removing unused elements and careful re-ordering, the structures for C<AV>s, |
f23930d5 NC |
441 | C<HV>s, C<CV>s and C<GV>s have recently been shrunk considerably. C<PVIO>s |
442 | probably aren't worth it, as typical programs don't use more than 8, and | |
443 | (at least) C<Filter::Util::Call> uses C<SvPVX>/C<SvCUR>/C<SvLEN> on a C<PVIO>, | |
444 | so it would mean code changes to modules on CPAN. C<PVBM>s might have some | |
445 | savings to win. | |
4a750395 | 446 | |
0bdfc961 NC |
447 | =head2 Implicit Latin 1 => Unicode translation |
448 | ||
449 | Conversions from byte strings to UTF-8 currently map high bit characters | |
450 | to Unicode without translation (or, depending on how you look at it, by | |
451 | implicitly assuming that the byte strings are in Latin-1). As perl assumes | |
452 | the C locale by default, upgrading a string to UTF-8 may change the | |
453 | meaning of its contents regarding character classes, case mapping, etc. | |
454 | This should probably emit a warning (at least). | |
455 | ||
456 | This task is incremental - even a little bit of work on it will help. | |
e50bb9a1 | 457 | |
cd793d32 | 458 | =head2 autovivification |
e50bb9a1 | 459 | |
cd793d32 | 460 | Make all autovivification consistent w.r.t LVALUE/RVALUE and strict/no strict; |
e50bb9a1 | 461 | |
0bdfc961 | 462 | This task is incremental - even a little bit of work on it will help. |
e50bb9a1 | 463 | |
0bdfc961 | 464 | =head2 Unicode in Filenames |
e50bb9a1 | 465 | |
0bdfc961 NC |
466 | chdir, chmod, chown, chroot, exec, glob, link, lstat, mkdir, open, |
467 | opendir, qx, readdir, readlink, rename, rmdir, stat, symlink, sysopen, | |
468 | system, truncate, unlink, utime, -X. All these could potentially accept | |
469 | Unicode filenames either as input or output (and in the case of system | |
470 | and qx Unicode in general, as input or output to/from the shell). | |
471 | Whether a filesystem - an operating system pair understands Unicode in | |
472 | filenames varies. | |
e50bb9a1 | 473 | |
0bdfc961 NC |
474 | Known combinations that have some level of understanding include |
475 | Microsoft NTFS, Apple HFS+ (In Mac OS 9 and X) and Apple UFS (in Mac | |
476 | OS X), NFS v4 is rumored to be Unicode, and of course Plan 9. How to | |
477 | create Unicode filenames, what forms of Unicode are accepted and used | |
478 | (UCS-2, UTF-16, UTF-8), what (if any) is the normalization form used, | |
479 | and so on, varies. Finding the right level of interfacing to Perl | |
480 | requires some thought. Remember that an OS does not implicate a | |
481 | filesystem. | |
e50bb9a1 | 482 | |
0bdfc961 NC |
483 | (The Windows -C command flag "wide API support" has been at least |
484 | temporarily retired in 5.8.1, and the -C has been repurposed, see | |
485 | L<perlrun>.) | |
969e704b | 486 | |
0bdfc961 | 487 | =head2 Unicode in %ENV |
969e704b | 488 | |
0bdfc961 | 489 | Currently the %ENV entries are always byte strings. |
e50bb9a1 | 490 | |
0bdfc961 | 491 | =head2 use less 'memory' |
e50bb9a1 | 492 | |
0bdfc961 NC |
493 | Investigate trade offs to switch out perl's choices on memory usage. |
494 | Particularly perl should be able to give memory back. | |
e50bb9a1 | 495 | |
0bdfc961 | 496 | This task is incremental - even a little bit of work on it will help. |
0abe3f7c | 497 | |
0bdfc961 | 498 | =head2 Re-implement C<:unique> in a way that is actually thread-safe |
0abe3f7c | 499 | |
0bdfc961 NC |
500 | The old implementation made bad assumptions on several levels. A good 90% |
501 | solution might be just to make C<:unique> work to share the string buffer | |
502 | of SvPVs. That way large constant strings can be shared between ithreads, | |
503 | such as the configuration information in F<Config>. | |
0abe3f7c | 504 | |
0bdfc961 | 505 | =head2 Make tainting consistent |
0abe3f7c | 506 | |
0bdfc961 NC |
507 | Tainting would be easier to use if it didn't take documented shortcuts and |
508 | allow taint to "leak" everywhere within an expression. | |
0abe3f7c | 509 | |
0bdfc961 | 510 | =head2 readpipe(LIST) |
0abe3f7c | 511 | |
0bdfc961 NC |
512 | system() accepts a LIST syntax (and a PROGRAM LIST syntax) to avoid |
513 | running a shell. readpipe() (the function behind qx//) could be similarly | |
514 | extended. | |
0abe3f7c | 515 | |
e50bb9a1 | 516 | |
e50bb9a1 | 517 | |
e50bb9a1 | 518 | |
f86a8bc5 | 519 | |
0bdfc961 | 520 | =head1 Tasks that need a knowledge of the interpreter |
3298bd4d | 521 | |
0bdfc961 NC |
522 | These tasks would need C knowledge, and knowledge of how the interpreter works, |
523 | or a willingness to learn. | |
3298bd4d | 524 | |
0bdfc961 NC |
525 | =head2 lexical pragmas |
526 | ||
78ef48ad RGS |
527 | Document the new support for lexical pragmas in 5.9.3 and how %^H works. |
528 | Maybe C<re>, C<encoding>, maybe other pragmas could be made lexical. | |
0562c0e3 | 529 | |
d10fc472 | 530 | =head2 Attach/detach debugger from running program |
1626a787 | 531 | |
cd793d32 NC |
532 | The old perltodo notes "With C<gdb>, you can attach the debugger to a running |
533 | program if you pass the process ID. It would be good to do this with the Perl | |
0bdfc961 NC |
534 | debugger on a running Perl program, although I'm not sure how it would be |
535 | done." ssh and screen do this with named pipes in /tmp. Maybe we can too. | |
1626a787 | 536 | |
0bdfc961 NC |
537 | =head2 LVALUE functions for lists |
538 | ||
539 | The old perltodo notes that lvalue functions don't work for list or hash | |
540 | slices. This would be good to fix. | |
541 | ||
542 | =head2 LVALUE functions in the debugger | |
543 | ||
544 | The old perltodo notes that lvalue functions don't work in the debugger. This | |
545 | would be good to fix. | |
546 | ||
547 | =head2 _ prototype character | |
548 | ||
549 | Study the possibility of adding a new prototype character, C<_>, meaning | |
550 | "this argument defaults to $_". | |
551 | ||
4e577f8b NC |
552 | =head2 state variables |
553 | ||
554 | C<my $foo if 0;> is deprecated, and should be replaced with | |
555 | C<state $x = "initial value\n";> the syntax from Perl 6. | |
16fc99ce | 556 | Rafael has sent a first cut patch to perl5-porters. |
4e577f8b | 557 | |
0bdfc961 NC |
558 | =head2 regexp optimiser optional |
559 | ||
560 | The regexp optimiser is not optional. It should configurable to be, to allow | |
561 | its performance to be measured, and its bugs to be easily demonstrated. | |
562 | ||
563 | =head2 UNITCHECK | |
564 | ||
565 | Introduce a new special block, UNITCHECK, which is run at the end of a | |
566 | compilation unit (module, file, eval(STRING) block). This will correspond to | |
567 | the Perl 6 CHECK. Perl 5's CHECK cannot be changed or removed because the | |
568 | O.pm/B.pm backend framework depends on it. | |
569 | ||
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 | ||
d7889f52 | 623 | =head2 Integrate Russ Allbery's strlcat/strlcpy implementation |
0bdfc961 | 624 | |
28f0d0ec SP |
625 | And remove the last remaining uses of strcat() and strcpy(). Also, add |
626 | my_strlcat() and my_strlcpy() to Devel::PPPort so previous versions of Perl can | |
627 | use these APIs. | |
0bdfc961 | 628 | |
0bdfc961 NC |
629 | =head1 Big projects |
630 | ||
631 | Tasks that will get your name mentioned in the description of the "Highlights | |
632 | of 5.10" | |
633 | ||
634 | =head2 make ithreads more robust | |
635 | ||
4e577f8b | 636 | Generally make ithreads more robust. See also L</iCOW> |
0bdfc961 NC |
637 | |
638 | This task is incremental - even a little bit of work on it will help, and | |
639 | will be greatly appreciated. | |
640 | ||
6c047da7 YST |
641 | One bit would be to write the missing code in sv.c:Perl_dirp_dup. |
642 | ||
0bdfc961 NC |
643 | =head2 iCOW |
644 | ||
645 | Sarathy and Arthur have a proposal for an improved Copy On Write which | |
646 | specifically will be able to COW new ithreads. If this can be implemented | |
647 | it would be a good thing. | |
648 | ||
649 | =head2 (?{...}) closures in regexps | |
650 | ||
651 | Fix (or rewrite) the implementation of the C</(?{...})/> closures. | |
652 | ||
653 | =head2 A re-entrant regexp engine | |
654 | ||
655 | This will allow the use of a regex from inside (?{ }), (??{ }) and | |
656 | (?(?{ })|) constructs. |