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1 | =head1 NAME |
2 | |
3 | perltodo - Perl TO-DO List |
4 | |
5 | =head1 DESCRIPTION |
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6 | |
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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. |
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11 | |
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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: |
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15 | |
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16 | http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/ |
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17 | |
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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? |
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22 | |
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23 | =head1 The roadmap to 5.10 |
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24 | |
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25 | The roadmap to 5.10 envisages feature based releases, as various items in this |
26 | TODO are completed. |
27 | |
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28 | =head2 Needed for a 5.9.5 release |
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29 | |
30 | =over |
31 | |
32 | =item * |
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33 | |
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34 | Review smart match semantics in light of Perl 6 developments. |
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35 | |
36 | =item * |
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37 | |
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38 | Review assertions. Review syntax to combine assertions. Assertions could take |
39 | advantage of the lexical pragmas work. L</What hooks would assertions need?> |
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40 | |
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41 | =item * |
42 | |
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43 | C<encoding> should be turned into a lexical pragma (probably). |
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44 | |
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45 | =back |
46 | |
47 | =head2 Needed for a 5.9.6 release |
48 | |
49 | Stabilisation. If all goes well, this will be the equivalent of a 5.10-beta. |
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50 | |
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51 | =head1 Tasks that only need Perl knowledge |
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52 | |
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53 | =head2 common test code for timed bail out |
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54 | |
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55 | Write portable self destruct code for tests to stop them burning CPU in |
56 | infinite loops. This needs to avoid using alarm, as some of the tests are |
57 | testing alarm/sleep or timers. |
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58 | |
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59 | =head2 POD -> HTML conversion in the core still sucks |
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60 | |
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61 | Which is crazy given just how simple POD purports to be, and how simple HTML |
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62 | can be. It's not actually I<as> simple as it sounds, particularly with the |
63 | flexibility POD allows for C<=item>, but it would be good to improve the |
64 | visual appeal of the HTML generated, and to avoid it having any validation |
65 | errors. See also L</make HTML install work>, as the layout of installation tree |
66 | is needed to improve the cross-linking. |
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67 | |
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68 | The addition of C<Pod::Simple> and its related modules may make this task |
69 | easier to complete. |
70 | |
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71 | =head2 Parallel testing |
72 | |
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73 | (This probably impacts much more than the core: also the Test::Harness |
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74 | and TAP::* modules on CPAN.) |
75 | |
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76 | The core regression test suite is getting ever more comprehensive, which has |
77 | the side effect that it takes longer to run. This isn't so good. Investigate |
78 | whether it would be feasible to give the harness script the B<option> of |
79 | running sets of tests in parallel. This would be useful for tests in |
80 | F<t/op/*.t> and F<t/uni/*.t> and maybe some sets of tests in F<lib/>. |
81 | |
82 | Questions to answer |
83 | |
84 | =over 4 |
85 | |
86 | =item 1 |
87 | |
88 | How does screen layout work when you're running more than one test? |
89 | |
90 | =item 2 |
91 | |
92 | How does the caller of test specify how many tests to run in parallel? |
93 | |
94 | =item 3 |
95 | |
96 | How do setup/teardown tests identify themselves? |
97 | |
98 | =back |
99 | |
100 | Pugs already does parallel testing - can their approach be re-used? |
101 | |
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102 | =head2 Make Schwern poorer |
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103 | |
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104 | We should have tests for everything. When all the core's modules are tested, |
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105 | Schwern has promised to donate to $500 to TPF. We may need volunteers to |
106 | hold him upside down and shake vigorously in order to actually extract the |
107 | cash. |
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108 | |
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109 | =head2 Improve the coverage of the core tests |
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110 | |
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111 | Use Devel::Cover to ascertain the core modules's test coverage, then add |
112 | tests that are currently missing. |
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113 | |
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114 | =head2 test B |
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115 | |
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116 | A full test suite for the B module would be nice. |
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117 | |
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118 | =head2 A decent benchmark |
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119 | |
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120 | C<perlbench> seems impervious to any recent changes made to the perl core. It |
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121 | would be useful to have a reasonable general benchmarking suite that roughly |
122 | represented what current perl programs do, and measurably reported whether |
123 | tweaks to the core improve, degrade or don't really affect performance, to |
124 | guide people attempting to optimise the guts of perl. Gisle would welcome |
125 | new tests for perlbench. |
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126 | |
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127 | =head2 fix tainting bugs |
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128 | |
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129 | Fix the bugs revealed by running the test suite with the C<-t> switch (via |
130 | C<make test.taintwarn>). |
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131 | |
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132 | =head2 Dual life everything |
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133 | |
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134 | As part of the "dists" plan, anything that doesn't belong in the smallest perl |
135 | distribution needs to be dual lifed. Anything else can be too. Figure out what |
136 | changes would be needed to package that module and its tests up for CPAN, and |
137 | do so. Test it with older perl releases, and fix the problems you find. |
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138 | |
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139 | =head2 Improving C<threads::shared> |
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140 | |
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141 | Investigate whether C<threads::shared> could share aggregates properly with |
142 | only Perl level changes to shared.pm |
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143 | |
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144 | =head2 POSIX memory footprint |
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145 | |
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146 | Ilya observed that use POSIX; eats memory like there's no tomorrow, and at |
147 | various times worked to cut it down. There is probably still fat to cut out - |
148 | for example POSIX passes Exporter some very memory hungry data structures. |
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149 | |
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150 | =head2 embed.pl/makedef.pl |
151 | |
152 | There is a script F<embed.pl> that generates several header files to prefix |
153 | all of Perl's symbols in a consistent way, to provide some semblance of |
154 | namespace support in C<C>. Functions are declared in F<embed.fnc>, variables |
155 | in F<interpvar.h> and F<thrdvar.h>. Quite a few of the functions and variables |
156 | are conditionally declared there, using C<#ifdef>. However, F<embed.pl> |
157 | doesn't understand the C macros, so the rules about which symbols are present |
158 | when is duplicated in F<makedef.pl>. Writing things twice is bad, m'kay. |
159 | It would be good to teach C<embed.pl> to understand the conditional |
160 | compilation, and hence remove the duplication, and the mistakes it has caused. |
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161 | |
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162 | =head1 Tasks that need a little sysadmin-type knowledge |
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163 | |
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164 | Or if you prefer, tasks that you would learn from, and broaden your skills |
165 | base... |
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166 | |
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167 | =head2 make HTML install work |
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168 | |
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169 | There is an C<installhtml> target in the Makefile. It's marked as |
170 | "experimental". It would be good to get this tested, make it work reliably, and |
171 | remove the "experimental" tag. This would include |
172 | |
173 | =over 4 |
174 | |
175 | =item 1 |
176 | |
177 | Checking that cross linking between various parts of the documentation works. |
178 | In particular that links work between the modules (files with POD in F<lib/>) |
179 | and the core documentation (files in F<pod/>) |
180 | |
181 | =item 2 |
182 | |
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183 | Work out how to split C<perlfunc> into chunks, preferably one per function |
184 | group, preferably with general case code that could be used elsewhere. |
185 | Challenges here are correctly identifying the groups of functions that go |
186 | together, and making the right named external cross-links point to the right |
187 | page. Things to be aware of are C<-X>, groups such as C<getpwnam> to |
188 | C<endservent>, two or more C<=items> giving the different parameter lists, such |
189 | as |
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190 | |
191 | =item substr EXPR,OFFSET,LENGTH,REPLACEMENT |
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192 | =item substr EXPR,OFFSET,LENGTH |
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193 | =item substr EXPR,OFFSET |
194 | |
195 | and different parameter lists having different meanings. (eg C<select>) |
196 | |
197 | =back |
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198 | |
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199 | =head2 compressed man pages |
200 | |
201 | Be able to install them. This would probably need a configure test to see how |
202 | the system does compressed man pages (same directory/different directory? |
203 | same filename/different filename), as well as tweaking the F<installman> script |
204 | to compress as necessary. |
205 | |
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206 | =head2 Add a code coverage target to the Makefile |
207 | |
208 | Make it easy for anyone to run Devel::Cover on the core's tests. The steps |
209 | to do this manually are roughly |
210 | |
211 | =over 4 |
212 | |
213 | =item * |
214 | |
215 | do a normal C<Configure>, but include Devel::Cover as a module to install |
216 | (see F<INSTALL> for how to do this) |
217 | |
218 | =item * |
219 | |
220 | make perl |
221 | |
222 | =item * |
223 | |
224 | cd t; HARNESS_PERL_SWITCHES=-MDevel::Cover ./perl -I../lib harness |
225 | |
226 | =item * |
227 | |
228 | Process the resulting Devel::Cover database |
229 | |
230 | =back |
231 | |
232 | This just give you the coverage of the F<.pm>s. To also get the C level |
233 | coverage you need to |
234 | |
235 | =over 4 |
236 | |
237 | =item * |
238 | |
239 | Additionally tell C<Configure> to use the appropriate C compiler flags for |
240 | C<gcov> |
241 | |
242 | =item * |
243 | |
244 | make perl.gcov |
245 | |
246 | (instead of C<make perl>) |
247 | |
248 | =item * |
249 | |
250 | After running the tests run C<gcov> to generate all the F<.gcov> files. |
251 | (Including down in the subdirectories of F<ext/> |
252 | |
253 | =item * |
254 | |
255 | (From the top level perl directory) run C<gcov2perl> on all the C<.gcov> files |
256 | to get their stats into the cover_db directory. |
257 | |
258 | =item * |
259 | |
260 | Then process the Devel::Cover database |
261 | |
262 | =back |
263 | |
264 | It would be good to add a single switch to C<Configure> to specify that you |
265 | wanted to perform perl level coverage, and another to specify C level |
266 | coverage, and have C<Configure> and the F<Makefile> do all the right things |
267 | automatically. |
268 | |
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269 | =head2 Make Config.pm cope with differences between built and installed perl |
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270 | |
271 | Quite often vendors ship a perl binary compiled with their (pay-for) |
272 | compilers. People install a free compiler, such as gcc. To work out how to |
273 | build extensions, Perl interrogates C<%Config>, so in this situation |
274 | C<%Config> describes compilers that aren't there, and extension building |
275 | fails. This forces people into choosing between re-compiling perl themselves |
276 | using the compiler they have, or only using modules that the vendor ships. |
277 | |
278 | It would be good to find a way teach C<Config.pm> about the installation setup, |
279 | possibly involving probing at install time or later, so that the C<%Config> in |
280 | a binary distribution better describes the installed machine, when the |
281 | installed machine differs from the build machine in some significant way. |
282 | |
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283 | =head2 linker specification files |
284 | |
285 | Some platforms mandate that you provide a list of a shared library's external |
286 | symbols to the linker, so the core already has the infrastructure in place to |
287 | do this for generating shared perl libraries. My understanding is that the |
288 | GNU toolchain can accept an optional linker specification file, and restrict |
289 | visibility just to symbols declared in that file. It would be good to extend |
290 | F<makedef.pl> to support this format, and to provide a means within |
291 | C<Configure> to enable it. This would allow Unix users to test that the |
292 | export list is correct, and to build a perl that does not pollute the global |
293 | namespace with private symbols. |
294 | |
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295 | =head2 Cross-compile support |
296 | |
297 | Currently C<Configure> understands C<-Dusecrosscompile> option. This option |
298 | arranges for building C<miniperl> for TARGET machine, so this C<miniperl> is |
299 | assumed then to be copied to TARGET machine and used as a replacement of full |
300 | C<perl> executable. |
301 | |
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302 | This could be done little differently. Namely C<miniperl> should be built for |
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303 | HOST and then full C<perl> with extensions should be compiled for TARGET. |
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304 | This, however, might require extra trickery for %Config: we have one config |
305 | first for HOST and then another for TARGET. |
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306 | |
307 | =head1 Tasks that need a little C knowledge |
308 | |
309 | These tasks would need a little C knowledge, but don't need any specific |
310 | background or experience with XS, or how the Perl interpreter works |
311 | |
312 | =head2 Make it clear from -v if this is the exact official release |
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313 | |
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314 | Currently perl from C<p4>/C<rsync> ships with a F<patchlevel.h> file that |
315 | usually defines one local patch, of the form "MAINT12345" or "RC1". The output |
316 | of perl -v doesn't report that a perl isn't an official release, and this |
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317 | information can get lost in bugs reports. Because of this, the minor version |
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318 | isn't bumped up until RC time, to minimise the possibility of versions of perl |
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319 | escaping that believe themselves to be newer than they actually are. |
320 | |
321 | It would be useful to find an elegant way to have the "this is an interim |
322 | maintenance release" or "this is a release candidate" in the terse -v output, |
323 | and have it so that it's easy for the pumpking to remove this just as the |
324 | release tarball is rolled up. This way the version pulled out of rsync would |
325 | always say "I'm a development release" and it would be safe to bump the |
326 | reported minor version as soon as a release ships, which would aid perl |
327 | developers. |
328 | |
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329 | This task is really about thinking of an elegant way to arrange the C source |
330 | such that it's trivial for the Pumpking to flag "this is an official release" |
331 | when making a tarball, yet leave the default source saying "I'm not the |
332 | official release". |
333 | |
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334 | =head2 Ordering of "global" variables. |
335 | |
336 | F<thrdvar.h> and F<intrpvarh> define the "global" variables that need to be |
337 | per-thread under ithreads, where the variables are actually elements in a |
338 | structure. As C dictates, the variables must be laid out in order of |
339 | declaration. There is a comment |
340 | C</* Important ones in the first cache line (if alignment is done right) */> |
341 | which implies that at some point in the past the ordering was carefully chosen |
342 | (at least in part). However, it's clear that the ordering is less than perfect, |
343 | as currently there are things such as 7 C<bool>s in a row, then something |
344 | typically requiring 4 byte alignment, and then an odd C<bool> later on. |
345 | (C<bool>s are typically defined as C<char>s). So it would be good for someone |
346 | to review the ordering of the variables, to see how much alignment padding can |
347 | be removed. |
348 | |
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349 | It's also worth checking that all variables are actually used. Perl 5.8.0 |
350 | shipped with C<PL_nrs> still defined in F<thrdvar.h>, despite it being unused |
351 | since a change over a year earlier. Had this been spotted before release, it |
352 | could have been removed, but now it has to remain in the 5.8.x releases to |
353 | keep the structure the same size, to retain binary compatibility. |
354 | |
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355 | It's probably worth checking if all need to be the types they are. For example |
356 | |
357 | PERLVAR(Ierror_count, I32) /* how many errors so far, max 10 */ |
358 | |
359 | might work as well if stored in a signed (or unsigned) 8 bit value, if the |
360 | comment is accurate. C<PL_multi_open> and C<PL_multi_close> can probably |
361 | become C<char>s. Finding variables to downsize coupled with rearrangement |
362 | could shrink the interpreter structure; a size saving which is multiplied by |
363 | the number of threads running. |
364 | |
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365 | =head2 Profile Perl - am I hot or not? |
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366 | |
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367 | The Perl source code is stable enough that it makes sense to profile it, |
368 | identify and optimise the hotspots. It would be good to measure the |
369 | performance of the Perl interpreter using free tools such as cachegrind, |
370 | gprof, and dtrace, and work to reduce the bottlenecks they reveal. |
371 | |
372 | As part of this, the idea of F<pp_hot.c> is that it contains the I<hot> ops, |
373 | the ops that are most commonly used. The idea is that by grouping them, their |
374 | object code will be adjacent in the executable, so they have a greater chance |
375 | of already being in the CPU cache (or swapped in) due to being near another op |
376 | already in use. |
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377 | |
378 | Except that it's not clear if these really are the most commonly used ops. So |
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379 | as part of exercising your skills with coverage and profiling tools you might |
380 | want to determine what ops I<really> are the most commonly used. And in turn |
381 | suggest evictions and promotions to achieve a better F<pp_hot.c>. |
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382 | |
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383 | =head2 Allocate OPs from arenas |
384 | |
385 | Currently all new OP structures are individually malloc()ed and free()d. |
386 | All C<malloc> implementations have space overheads, and are now as fast as |
387 | custom allocates so it would both use less memory and less CPU to allocate |
388 | the various OP structures from arenas. The SV arena code can probably be |
389 | re-used for this. |
390 | |
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391 | =head2 Improve win32/wince.c |
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392 | |
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393 | Currently, numerous functions look virtually, if not completely, |
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394 | identical in both C<win32/wince.c> and C<win32/win32.c> files, which can't |
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395 | be good. |
396 | |
397 | =head1 Tasks that need a knowledge of XS |
398 | |
399 | These tasks would need C knowledge, and roughly the level of knowledge of |
400 | the perl API that comes from writing modules that use XS to interface to |
401 | C. |
402 | |
403 | =head2 shrink C<PVBM>s |
404 | |
405 | By removing unused elements and careful re-ordering, the structures for C<AV>s, |
406 | C<HV>s, C<CV>s and C<GV>s have recently been shrunk considerably. C<PVIO>s |
407 | probably aren't worth it, as typical programs don't use more than 8, and |
408 | (at least) C<Filter::Util::Call> uses C<SvPVX>/C<SvCUR>/C<SvLEN> on a C<PVIO>, |
409 | so it would mean code changes to modules on CPAN. C<PVBM>s might have some |
410 | savings to win. |
411 | |
412 | =head2 autovivification |
413 | |
414 | Make all autovivification consistent w.r.t LVALUE/RVALUE and strict/no strict; |
415 | |
416 | This task is incremental - even a little bit of work on it will help. |
417 | |
418 | =head2 Unicode in Filenames |
419 | |
420 | chdir, chmod, chown, chroot, exec, glob, link, lstat, mkdir, open, |
421 | opendir, qx, readdir, readlink, rename, rmdir, stat, symlink, sysopen, |
422 | system, truncate, unlink, utime, -X. All these could potentially accept |
423 | Unicode filenames either as input or output (and in the case of system |
424 | and qx Unicode in general, as input or output to/from the shell). |
425 | Whether a filesystem - an operating system pair understands Unicode in |
426 | filenames varies. |
427 | |
428 | Known combinations that have some level of understanding include |
429 | Microsoft NTFS, Apple HFS+ (In Mac OS 9 and X) and Apple UFS (in Mac |
430 | OS X), NFS v4 is rumored to be Unicode, and of course Plan 9. How to |
431 | create Unicode filenames, what forms of Unicode are accepted and used |
432 | (UCS-2, UTF-16, UTF-8), what (if any) is the normalization form used, |
433 | and so on, varies. Finding the right level of interfacing to Perl |
434 | requires some thought. Remember that an OS does not implicate a |
435 | filesystem. |
436 | |
437 | (The Windows -C command flag "wide API support" has been at least |
438 | temporarily retired in 5.8.1, and the -C has been repurposed, see |
439 | L<perlrun>.) |
440 | |
441 | =head2 Unicode in %ENV |
442 | |
443 | Currently the %ENV entries are always byte strings. |
444 | |
445 | =head2 use less 'memory' |
446 | |
447 | Investigate trade offs to switch out perl's choices on memory usage. |
448 | Particularly perl should be able to give memory back. |
449 | |
450 | This task is incremental - even a little bit of work on it will help. |
451 | |
452 | =head2 Re-implement C<:unique> in a way that is actually thread-safe |
453 | |
454 | The old implementation made bad assumptions on several levels. A good 90% |
455 | solution might be just to make C<:unique> work to share the string buffer |
456 | of SvPVs. That way large constant strings can be shared between ithreads, |
457 | such as the configuration information in F<Config>. |
458 | |
459 | =head2 Make tainting consistent |
460 | |
461 | Tainting would be easier to use if it didn't take documented shortcuts and |
462 | allow taint to "leak" everywhere within an expression. |
463 | |
464 | =head2 readpipe(LIST) |
465 | |
466 | system() accepts a LIST syntax (and a PROGRAM LIST syntax) to avoid |
467 | running a shell. readpipe() (the function behind qx//) could be similarly |
468 | extended. |
469 | |
470 | =head2 strcat(), strcpy(), strncat(), strncpy(), sprintf(), vsprintf() |
471 | |
472 | Maybe create a utility that checks after each libperl.a creation that |
473 | none of the above (nor sprintf(), vsprintf(), or *SHUDDER* gets()) |
474 | ever creep back to libperl.a. |
475 | |
476 | nm libperl.a | ./miniperl -alne '$o = $F[0] if /:$/; print "$o $F[1]" if $F[0] eq "U" && $F[1] =~ /^(?:strn?c(?:at|py)|v?sprintf|gets)$/' |
477 | |
478 | Note, of course, that this will only tell whether B<your> platform |
479 | is using those naughty interfaces. |
480 | |
481 | =head2 Audit the code for destruction ordering assumptions |
482 | |
483 | Change 25773 notes |
484 | |
485 | /* Need to check SvMAGICAL, as during global destruction it may be that |
486 | AvARYLEN(av) has been freed before av, and hence the SvANY() pointer |
487 | is now part of the linked list of SV heads, rather than pointing to |
488 | the original body. */ |
489 | /* FIXME - audit the code for other bugs like this one. */ |
490 | |
491 | adding the C<SvMAGICAL> check to |
492 | |
493 | if (AvARYLEN(av) && SvMAGICAL(AvARYLEN(av))) { |
494 | MAGIC *mg = mg_find (AvARYLEN(av), PERL_MAGIC_arylen); |
495 | |
496 | Go through the core and look for similar assumptions that SVs have particular |
497 | types, as all bets are off during global destruction. |
498 | |
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499 | =head1 Tasks that need a knowledge of the interpreter |
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500 | |
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501 | These tasks would need C knowledge, and knowledge of how the interpreter works, |
502 | or a willingness to learn. |
3298bd4d |
503 | |
d10fc472 |
504 | =head2 Attach/detach debugger from running program |
1626a787 |
505 | |
cd793d32 |
506 | The old perltodo notes "With C<gdb>, you can attach the debugger to a running |
507 | program if you pass the process ID. It would be good to do this with the Perl |
0bdfc961 |
508 | debugger on a running Perl program, although I'm not sure how it would be |
509 | done." ssh and screen do this with named pipes in /tmp. Maybe we can too. |
1626a787 |
510 | |
0bdfc961 |
511 | =head2 LVALUE functions for lists |
512 | |
513 | The old perltodo notes that lvalue functions don't work for list or hash |
514 | slices. This would be good to fix. |
515 | |
516 | =head2 LVALUE functions in the debugger |
517 | |
518 | The old perltodo notes that lvalue functions don't work in the debugger. This |
519 | would be good to fix. |
520 | |
0bdfc961 |
521 | =head2 regexp optimiser optional |
522 | |
523 | The regexp optimiser is not optional. It should configurable to be, to allow |
524 | its performance to be measured, and its bugs to be easily demonstrated. |
525 | |
02f21748 |
526 | =head2 delete &function |
527 | |
528 | Allow to delete functions. One can already undef them, but they're still |
529 | in the stash. |
530 | |
0bdfc961 |
531 | =head2 optional optimizer |
532 | |
533 | Make the peephole optimizer optional. Currently it performs two tasks as |
534 | it walks the optree - genuine peephole optimisations, and necessary fixups of |
535 | ops. It would be good to find an efficient way to switch out the |
536 | optimisations whilst keeping the fixups. |
537 | |
538 | =head2 You WANT *how* many |
539 | |
540 | Currently contexts are void, scalar and list. split has a special mechanism in |
541 | place to pass in the number of return values wanted. It would be useful to |
542 | have a general mechanism for this, backwards compatible and little speed hit. |
543 | This would allow proposals such as short circuiting sort to be implemented |
544 | as a module on CPAN. |
545 | |
546 | =head2 lexical aliases |
547 | |
548 | Allow lexical aliases (maybe via the syntax C<my \$alias = \$foo>. |
549 | |
550 | =head2 entersub XS vs Perl |
551 | |
552 | At the moment pp_entersub is huge, and has code to deal with entering both |
553 | perl and XS subroutines. Subroutine implementations rarely change between |
554 | perl and XS at run time, so investigate using 2 ops to enter subs (one for |
555 | XS, one for perl) and swap between if a sub is redefined. |
2810d901 |
556 | |
557 | =head2 Self ties |
558 | |
559 | self ties are currently illegal because they caused too many segfaults. Maybe |
560 | the causes of these could be tracked down and self-ties on all types re- |
561 | instated. |
0bdfc961 |
562 | |
563 | =head2 Optimize away @_ |
564 | |
565 | The old perltodo notes "Look at the "reification" code in C<av.c>". |
566 | |
0bdfc961 |
567 | =head2 What hooks would assertions need? |
568 | |
569 | Assertions are in the core, and work. However, assertions needed to be added |
570 | as a core patch, rather than an XS module in ext, or a CPAN module, because |
571 | the core has no hooks in the necessary places. It would be useful to |
572 | investigate what hooks would need to be added to make it possible to provide |
573 | the full assertion support from a CPAN module, so that we aren't constraining |
574 | the imagination of future CPAN authors. |
575 | |
16fc99ce |
576 | =head2 Properly Unicode safe tokeniser and pads. |
577 | |
578 | The tokeniser isn't actually very UTF-8 clean. C<use utf8;> is a hack - |
579 | variable names are stored in stashes as raw bytes, without the utf-8 flag |
580 | set. The pad API only takes a C<char *> pointer, so that's all bytes too. The |
581 | tokeniser ignores the UTF-8-ness of C<PL_rsfp>, or any SVs returned from |
582 | source filters. All this could be fixed. |
583 | |
0bdfc961 |
584 | =head1 Big projects |
585 | |
586 | Tasks that will get your name mentioned in the description of the "Highlights |
587 | of 5.10" |
588 | |
589 | =head2 make ithreads more robust |
590 | |
4e577f8b |
591 | Generally make ithreads more robust. See also L</iCOW> |
0bdfc961 |
592 | |
593 | This task is incremental - even a little bit of work on it will help, and |
594 | will be greatly appreciated. |
595 | |
6c047da7 |
596 | One bit would be to write the missing code in sv.c:Perl_dirp_dup. |
597 | |
0bdfc961 |
598 | =head2 iCOW |
599 | |
600 | Sarathy and Arthur have a proposal for an improved Copy On Write which |
601 | specifically will be able to COW new ithreads. If this can be implemented |
602 | it would be a good thing. |
603 | |
604 | =head2 (?{...}) closures in regexps |
605 | |
606 | Fix (or rewrite) the implementation of the C</(?{...})/> closures. |
607 | |
608 | =head2 A re-entrant regexp engine |
609 | |
610 | This will allow the use of a regex from inside (?{ }), (??{ }) and |
611 | (?(?{ })|) constructs. |
6bda09f9 |
612 | |
6bda09f9 |
613 | =head2 Add (?YES) (?NO) to regexp enigne |
614 | |
615 | YES/NO would allow a subpattern to be passed/failed but allow backtracking. |
616 | Basically a more efficient (?=), (?!). |
617 | |
618 | demerphq has this on his todo list |
619 | |
620 | =head2 Add (?SUCCEED) (?FAIL) to regexp engine |
621 | |
622 | SUCCEED/FAIL would allow a pattern to be passed/failed but without backtracking. |
623 | Thus you could signal that a pattern has matched or not, and return (regardless |
624 | that there is more pattern following). |
625 | |
626 | demerphq has this on his todo list |
627 | |
628 | =head2 Add (?CUT) (?COMMIT) to regexp engine |
629 | |
630 | CUT would allow a pattern to say "do not backtrack beyond here". |
631 | COMMIT would say match from here or don't, but don't try the pattern from |
632 | another starting pattern. |
633 | |
634 | These correspond to the \v and \V that Jeffrey Friedl mentions in |
635 | Mastering Regular Expressions 2nd edition. |
636 | |
637 | demerphq has this on his todo list |
638 | |
639 | =head2 Add class set operations to regexp engine |
640 | |
641 | Apparently these are quite useful. Anyway, Jeffery Friedl wants them. |
642 | |
643 | demerphq has this on his todo list, but right at the bottom. |
644 | |
645 | |