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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 5.9.4 release |
29 | |
30 | =over |
31 | |
32 | =item * |
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33 | Implement L</state variables> (mostly done currently) |
34 | |
35 | =item * |
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36 | |
37 | Review assertions. Review syntax to combine assertions. Assertions could take |
38 | advantage of the lexical pragmas work. L</What hooks would assertions need?> |
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39 | |
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40 | =item * |
41 | |
42 | C<encoding::warnings> should be turned into a lexical pragma. |
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43 | C<encoding> should, too (probably). |
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44 | |
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45 | =back |
46 | |
47 | =head2 Needed for a 5.9.5 release |
48 | |
49 | =over |
50 | |
51 | =item * |
52 | Implement L</_ prototype character> |
53 | |
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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. |
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59 | |
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60 | =head1 Tasks that only need Perl knowledge |
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61 | |
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62 | =head2 common test code for timed bail out |
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63 | |
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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. |
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67 | |
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68 | =head2 POD -> HTML conversion in the core still sucks |
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69 | |
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70 | Which is crazy given just how simple POD purports to be, and how simple HTML |
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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. |
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76 | |
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77 | The addition of C<Pod::Simple> and its related modules may make this task |
78 | easier to complete. |
79 | |
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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 | |
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108 | =head2 Make Schwern poorer |
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109 | |
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110 | We should have tests for everything. When all the core's modules are tested, |
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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. |
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114 | |
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115 | See F<t/lib/1_compile.t> for the 3 remaining modules that need tests. |
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116 | |
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117 | =head2 Improve the coverage of the core tests |
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118 | |
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119 | Use Devel::Cover to ascertain the core's test coverage, then add tests that |
120 | are currently missing. |
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121 | |
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122 | =head2 test B |
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123 | |
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124 | A full test suite for the B module would be nice. |
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125 | |
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126 | =head2 A decent benchmark |
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127 | |
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128 | C<perlbench> seems impervious to any recent changes made to the perl core. It |
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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. |
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134 | |
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135 | =head2 fix tainting bugs |
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136 | |
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137 | Fix the bugs revealed by running the test suite with the C<-t> switch (via |
138 | C<make test.taintwarn>). |
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139 | |
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140 | =head2 Dual life everything |
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141 | |
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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. |
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146 | |
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147 | =head2 Improving C<threads::shared> |
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148 | |
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149 | Investigate whether C<threads::shared> could share aggregates properly with |
150 | only Perl level changes to shared.pm |
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151 | |
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152 | =head2 POSIX memory footprint |
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153 | |
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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. |
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157 | |
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158 | =head2 embed.pl/makedef.pl |
159 | |
160 | There is a script F<embed.pl> that generates several header files to prefix |
161 | all of Perl's symbols in a consistent way, to provide some semblance of |
162 | namespace support in C<C>. Functions are declared in F<embed.fnc>, variables |
163 | in F<interpvar.h> and F<thrdvar.h>. Quite a few of the functions and variables |
164 | are conditionally declared there, using C<#ifdef>. However, F<embed.pl> |
165 | doesn't understand the C macros, so the rules about which symbols are present |
166 | when is duplicated in F<makedef.pl>. Writing things twice is bad, m'kay. |
167 | It would be good to teach C<embed.pl> to understand the conditional |
168 | compilation, and hence remove the duplication, and the mistakes it has caused. |
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169 | |
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170 | |
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171 | |
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172 | |
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173 | |
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174 | |
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175 | =head1 Tasks that need a little sysadmin-type knowledge |
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176 | |
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177 | Or if you prefer, tasks that you would learn from, and broaden your skills |
178 | base... |
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179 | |
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180 | =head2 make HTML install work |
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181 | |
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182 | There is an C<installhtml> target in the Makefile. It's marked as |
183 | "experimental". It would be good to get this tested, make it work reliably, and |
184 | remove the "experimental" tag. This would include |
185 | |
186 | =over 4 |
187 | |
188 | =item 1 |
189 | |
190 | Checking that cross linking between various parts of the documentation works. |
191 | In particular that links work between the modules (files with POD in F<lib/>) |
192 | and the core documentation (files in F<pod/>) |
193 | |
194 | =item 2 |
195 | |
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196 | Work out how to split C<perlfunc> into chunks, preferably one per function |
197 | group, preferably with general case code that could be used elsewhere. |
198 | Challenges here are correctly identifying the groups of functions that go |
199 | together, and making the right named external cross-links point to the right |
200 | page. Things to be aware of are C<-X>, groups such as C<getpwnam> to |
201 | C<endservent>, two or more C<=items> giving the different parameter lists, such |
202 | as |
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203 | |
204 | =item substr EXPR,OFFSET,LENGTH,REPLACEMENT |
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205 | =item substr EXPR,OFFSET,LENGTH |
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206 | =item substr EXPR,OFFSET |
207 | |
208 | and different parameter lists having different meanings. (eg C<select>) |
209 | |
210 | =back |
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211 | |
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212 | =head2 compressed man pages |
213 | |
214 | Be able to install them. This would probably need a configure test to see how |
215 | the system does compressed man pages (same directory/different directory? |
216 | same filename/different filename), as well as tweaking the F<installman> script |
217 | to compress as necessary. |
218 | |
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219 | =head2 Add a code coverage target to the Makefile |
220 | |
221 | Make it easy for anyone to run Devel::Cover on the core's tests. The steps |
222 | to do this manually are roughly |
223 | |
224 | =over 4 |
225 | |
226 | =item * |
227 | |
228 | do a normal C<Configure>, but include Devel::Cover as a module to install |
229 | (see F<INSTALL> for how to do this) |
230 | |
231 | =item * |
232 | |
233 | make perl |
234 | |
235 | =item * |
236 | |
237 | cd t; HARNESS_PERL_SWITCHES=-MDevel::Cover ./perl -I../lib harness |
238 | |
239 | =item * |
240 | |
241 | Process the resulting Devel::Cover database |
242 | |
243 | =back |
244 | |
245 | This just give you the coverage of the F<.pm>s. To also get the C level |
246 | coverage you need to |
247 | |
248 | =over 4 |
249 | |
250 | =item * |
251 | |
252 | Additionally tell C<Configure> to use the appropriate C compiler flags for |
253 | C<gcov> |
254 | |
255 | =item * |
256 | |
257 | make perl.gcov |
258 | |
259 | (instead of C<make perl>) |
260 | |
261 | =item * |
262 | |
263 | After running the tests run C<gcov> to generate all the F<.gcov> files. |
264 | (Including down in the subdirectories of F<ext/> |
265 | |
266 | =item * |
267 | |
268 | (From the top level perl directory) run C<gcov2perl> on all the C<.gcov> files |
269 | to get their stats into the cover_db directory. |
270 | |
271 | =item * |
272 | |
273 | Then process the Devel::Cover database |
274 | |
275 | =back |
276 | |
277 | It would be good to add a single switch to C<Configure> to specify that you |
278 | wanted to perform perl level coverage, and another to specify C level |
279 | coverage, and have C<Configure> and the F<Makefile> do all the right things |
280 | automatically. |
281 | |
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282 | =head2 Make Config.pm cope with differences between build and installed perl |
283 | |
284 | Quite often vendors ship a perl binary compiled with their (pay-for) |
285 | compilers. People install a free compiler, such as gcc. To work out how to |
286 | build extensions, Perl interrogates C<%Config>, so in this situation |
287 | C<%Config> describes compilers that aren't there, and extension building |
288 | fails. This forces people into choosing between re-compiling perl themselves |
289 | using the compiler they have, or only using modules that the vendor ships. |
290 | |
291 | It would be good to find a way teach C<Config.pm> about the installation setup, |
292 | possibly involving probing at install time or later, so that the C<%Config> in |
293 | a binary distribution better describes the installed machine, when the |
294 | installed machine differs from the build machine in some significant way. |
295 | |
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296 | =head2 linker specification files |
297 | |
298 | Some platforms mandate that you provide a list of a shared library's external |
299 | symbols to the linker, so the core already has the infrastructure in place to |
300 | do this for generating shared perl libraries. My understanding is that the |
301 | GNU toolchain can accept an optional linker specification file, and restrict |
302 | visibility just to symbols declared in that file. It would be good to extend |
303 | F<makedef.pl> to support this format, and to provide a means within |
304 | C<Configure> to enable it. This would allow Unix users to test that the |
305 | export list is correct, and to build a perl that does not pollute the global |
306 | namespace with private symbols. |
307 | |
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308 | =head2 Cross-compile support |
309 | |
310 | Currently C<Configure> understands C<-Dusecrosscompile> option. This option |
311 | arranges for building C<miniperl> for TARGET machine, so this C<miniperl> is |
312 | assumed then to be copied to TARGET machine and used as a replacement of full |
313 | C<perl> executable. |
314 | |
315 | This should be done litle differently. Namely C<miniperl> should be built for |
316 | HOST and then full C<perl> with extensions should be compiled for TARGET. |
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317 | |
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318 | |
319 | |
320 | =head1 Tasks that need a little C knowledge |
321 | |
322 | These tasks would need a little C knowledge, but don't need any specific |
323 | background or experience with XS, or how the Perl interpreter works |
324 | |
325 | =head2 Make it clear from -v if this is the exact official release |
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326 | |
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327 | Currently perl from C<p4>/C<rsync> ships with a F<patchlevel.h> file that |
328 | usually defines one local patch, of the form "MAINT12345" or "RC1". The output |
329 | of perl -v doesn't report that a perl isn't an official release, and this |
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330 | information can get lost in bugs reports. Because of this, the minor version |
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331 | isn't bumped up until RC time, to minimise the possibility of versions of perl |
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332 | escaping that believe themselves to be newer than they actually are. |
333 | |
334 | It would be useful to find an elegant way to have the "this is an interim |
335 | maintenance release" or "this is a release candidate" in the terse -v output, |
336 | and have it so that it's easy for the pumpking to remove this just as the |
337 | release tarball is rolled up. This way the version pulled out of rsync would |
338 | always say "I'm a development release" and it would be safe to bump the |
339 | reported minor version as soon as a release ships, which would aid perl |
340 | developers. |
341 | |
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342 | This task is really about thinking of an elegant way to arrange the C source |
343 | such that it's trivial for the Pumpking to flag "this is an official release" |
344 | when making a tarball, yet leave the default source saying "I'm not the |
345 | official release". |
346 | |
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347 | =head2 Ordering of "global" variables. |
348 | |
349 | F<thrdvar.h> and F<intrpvarh> define the "global" variables that need to be |
350 | per-thread under ithreads, where the variables are actually elements in a |
351 | structure. As C dictates, the variables must be laid out in order of |
352 | declaration. There is a comment |
353 | C</* Important ones in the first cache line (if alignment is done right) */> |
354 | which implies that at some point in the past the ordering was carefully chosen |
355 | (at least in part). However, it's clear that the ordering is less than perfect, |
356 | as currently there are things such as 7 C<bool>s in a row, then something |
357 | typically requiring 4 byte alignment, and then an odd C<bool> later on. |
358 | (C<bool>s are typically defined as C<char>s). So it would be good for someone |
359 | to review the ordering of the variables, to see how much alignment padding can |
360 | be removed. |
361 | |
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362 | It's also worth checking that all variables are actually used. Perl 5.8.0 |
363 | shipped with C<PL_nrs> still defined in F<thrdvar.h>, despite it being unused |
364 | since a change over a year earlier. Had this been spotted before release, it |
365 | could have been removed, but now it has to remain in the 5.8.x releases to |
366 | keep the structure the same size, to retain binary compatibility. |
367 | |
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368 | It's probably worth checking if all need to be the types they are. For example |
369 | |
370 | PERLVAR(Ierror_count, I32) /* how many errors so far, max 10 */ |
371 | |
372 | might work as well if stored in a signed (or unsigned) 8 bit value, if the |
373 | comment is accurate. C<PL_multi_open> and C<PL_multi_close> can probably |
374 | become C<char>s. Finding variables to downsize coupled with rearrangement |
375 | could shrink the interpreter structure; a size saving which is multiplied by |
376 | the number of threads running. |
377 | |
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378 | =head2 Profile Perl - am I hot or not? |
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379 | |
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380 | The Perl source code is stable enough that it makes sense to profile it, |
381 | identify and optimise the hotspots. It would be good to measure the |
382 | performance of the Perl interpreter using free tools such as cachegrind, |
383 | gprof, and dtrace, and work to reduce the bottlenecks they reveal. |
384 | |
385 | As part of this, the idea of F<pp_hot.c> is that it contains the I<hot> ops, |
386 | the ops that are most commonly used. The idea is that by grouping them, their |
387 | object code will be adjacent in the executable, so they have a greater chance |
388 | of already being in the CPU cache (or swapped in) due to being near another op |
389 | already in use. |
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390 | |
391 | Except that it's not clear if these really are the most commonly used ops. So |
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392 | as part of exercising your skills with coverage and profiling tools you might |
393 | want to determine what ops I<really> are the most commonly used. And in turn |
394 | suggest evictions and promotions to achieve a better F<pp_hot.c>. |
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395 | |
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396 | =head2 Shrink struct context |
397 | |
398 | In F<cop.h>, we have |
399 | |
400 | struct context { |
401 | U32 cx_type; /* what kind of context this is */ |
402 | union { |
403 | struct block cx_blk; |
404 | struct subst cx_subst; |
405 | } cx_u; |
406 | }; |
407 | |
408 | There are less than 256 values for C<cx_type>, and the constituent parts |
409 | C<struct block> and C<struct subst> both contain some C<U8> and C<U16> fields, |
410 | so it should be possible to move them to the first word, and share space with |
411 | a C<U8> C<cx_type>, saving 1 word. |
412 | |
413 | =head2 Allocate OPs from arenas |
414 | |
415 | Currently all new OP structures are individually malloc()ed and free()d. |
416 | All C<malloc> implementations have space overheads, and are now as fast as |
417 | custom allocates so it would both use less memory and less CPU to allocate |
418 | the various OP structures from arenas. The SV arena code can probably be |
419 | re-used for this. |
420 | |
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421 | =head2 Improve win32/wince.c |
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422 | |
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423 | Currently, numerous functions look virtually, if not completely, |
424 | identical in both C<win32/wince.c> and C<win32/win32.c> files, which can't be good. |
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425 | |
426 | |
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427 | =head1 Tasks that need a knowledge of XS |
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428 | |
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429 | These tasks would need C knowledge, and roughly the level of knowledge of |
430 | the perl API that comes from writing modules that use XS to interface to |
431 | C. |
432 | |
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433 | =head2 shrink C<PVBM>s |
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434 | |
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435 | By removing unused elements and careful re-ordering, the structures for C<AV>s, |
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436 | C<HV>s, C<CV>s and C<GV>s have recently been shrunk considerably. C<PVIO>s |
437 | probably aren't worth it, as typical programs don't use more than 8, and |
438 | (at least) C<Filter::Util::Call> uses C<SvPVX>/C<SvCUR>/C<SvLEN> on a C<PVIO>, |
439 | so it would mean code changes to modules on CPAN. C<PVBM>s might have some |
440 | savings to win. |
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441 | |
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442 | =head2 Implicit Latin 1 => Unicode translation |
443 | |
444 | Conversions from byte strings to UTF-8 currently map high bit characters |
445 | to Unicode without translation (or, depending on how you look at it, by |
446 | implicitly assuming that the byte strings are in Latin-1). As perl assumes |
447 | the C locale by default, upgrading a string to UTF-8 may change the |
448 | meaning of its contents regarding character classes, case mapping, etc. |
449 | This should probably emit a warning (at least). |
450 | |
451 | This task is incremental - even a little bit of work on it will help. |
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452 | |
cd793d32 |
453 | =head2 autovivification |
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454 | |
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455 | Make all autovivification consistent w.r.t LVALUE/RVALUE and strict/no strict; |
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456 | |
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457 | This task is incremental - even a little bit of work on it will help. |
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458 | |
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459 | =head2 Unicode in Filenames |
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460 | |
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461 | chdir, chmod, chown, chroot, exec, glob, link, lstat, mkdir, open, |
462 | opendir, qx, readdir, readlink, rename, rmdir, stat, symlink, sysopen, |
463 | system, truncate, unlink, utime, -X. All these could potentially accept |
464 | Unicode filenames either as input or output (and in the case of system |
465 | and qx Unicode in general, as input or output to/from the shell). |
466 | Whether a filesystem - an operating system pair understands Unicode in |
467 | filenames varies. |
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468 | |
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469 | Known combinations that have some level of understanding include |
470 | Microsoft NTFS, Apple HFS+ (In Mac OS 9 and X) and Apple UFS (in Mac |
471 | OS X), NFS v4 is rumored to be Unicode, and of course Plan 9. How to |
472 | create Unicode filenames, what forms of Unicode are accepted and used |
473 | (UCS-2, UTF-16, UTF-8), what (if any) is the normalization form used, |
474 | and so on, varies. Finding the right level of interfacing to Perl |
475 | requires some thought. Remember that an OS does not implicate a |
476 | filesystem. |
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477 | |
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478 | (The Windows -C command flag "wide API support" has been at least |
479 | temporarily retired in 5.8.1, and the -C has been repurposed, see |
480 | L<perlrun>.) |
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481 | |
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482 | =head2 Unicode in %ENV |
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483 | |
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484 | Currently the %ENV entries are always byte strings. |
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485 | |
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486 | =head2 use less 'memory' |
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487 | |
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488 | Investigate trade offs to switch out perl's choices on memory usage. |
489 | Particularly perl should be able to give memory back. |
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490 | |
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491 | This task is incremental - even a little bit of work on it will help. |
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492 | |
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493 | =head2 Re-implement C<:unique> in a way that is actually thread-safe |
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494 | |
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495 | The old implementation made bad assumptions on several levels. A good 90% |
496 | solution might be just to make C<:unique> work to share the string buffer |
497 | of SvPVs. That way large constant strings can be shared between ithreads, |
498 | such as the configuration information in F<Config>. |
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499 | |
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500 | =head2 Make tainting consistent |
0abe3f7c |
501 | |
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502 | Tainting would be easier to use if it didn't take documented shortcuts and |
503 | allow taint to "leak" everywhere within an expression. |
0abe3f7c |
504 | |
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505 | =head2 readpipe(LIST) |
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506 | |
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507 | system() accepts a LIST syntax (and a PROGRAM LIST syntax) to avoid |
508 | running a shell. readpipe() (the function behind qx//) could be similarly |
509 | extended. |
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510 | |
e50bb9a1 |
511 | |
e50bb9a1 |
512 | |
e50bb9a1 |
513 | |
f86a8bc5 |
514 | |
0bdfc961 |
515 | =head1 Tasks that need a knowledge of the interpreter |
3298bd4d |
516 | |
0bdfc961 |
517 | These tasks would need C knowledge, and knowledge of how the interpreter works, |
518 | or a willingness to learn. |
3298bd4d |
519 | |
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520 | =head2 lexical pragmas |
521 | |
78ef48ad |
522 | Document the new support for lexical pragmas in 5.9.3 and how %^H works. |
523 | Maybe C<re>, C<encoding>, maybe other pragmas could be made lexical. |
0562c0e3 |
524 | |
d10fc472 |
525 | =head2 Attach/detach debugger from running program |
1626a787 |
526 | |
cd793d32 |
527 | The old perltodo notes "With C<gdb>, you can attach the debugger to a running |
528 | program if you pass the process ID. It would be good to do this with the Perl |
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529 | debugger on a running Perl program, although I'm not sure how it would be |
530 | done." ssh and screen do this with named pipes in /tmp. Maybe we can too. |
1626a787 |
531 | |
0bdfc961 |
532 | =head2 LVALUE functions for lists |
533 | |
534 | The old perltodo notes that lvalue functions don't work for list or hash |
535 | slices. This would be good to fix. |
536 | |
537 | =head2 LVALUE functions in the debugger |
538 | |
539 | The old perltodo notes that lvalue functions don't work in the debugger. This |
540 | would be good to fix. |
541 | |
542 | =head2 _ prototype character |
543 | |
544 | Study the possibility of adding a new prototype character, C<_>, meaning |
545 | "this argument defaults to $_". |
546 | |
4e577f8b |
547 | =head2 state variables |
548 | |
549 | C<my $foo if 0;> is deprecated, and should be replaced with |
550 | C<state $x = "initial value\n";> the syntax from Perl 6. |
16fc99ce |
551 | Rafael has sent a first cut patch to perl5-porters. |
4e577f8b |
552 | |
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553 | =head2 regexp optimiser optional |
554 | |
555 | The regexp optimiser is not optional. It should configurable to be, to allow |
556 | its performance to be measured, and its bugs to be easily demonstrated. |
557 | |
558 | =head2 UNITCHECK |
559 | |
560 | Introduce a new special block, UNITCHECK, which is run at the end of a |
561 | compilation unit (module, file, eval(STRING) block). This will correspond to |
562 | the Perl 6 CHECK. Perl 5's CHECK cannot be changed or removed because the |
563 | O.pm/B.pm backend framework depends on it. |
564 | |
565 | =head2 optional optimizer |
566 | |
567 | Make the peephole optimizer optional. Currently it performs two tasks as |
568 | it walks the optree - genuine peephole optimisations, and necessary fixups of |
569 | ops. It would be good to find an efficient way to switch out the |
570 | optimisations whilst keeping the fixups. |
571 | |
572 | =head2 You WANT *how* many |
573 | |
574 | Currently contexts are void, scalar and list. split has a special mechanism in |
575 | place to pass in the number of return values wanted. It would be useful to |
576 | have a general mechanism for this, backwards compatible and little speed hit. |
577 | This would allow proposals such as short circuiting sort to be implemented |
578 | as a module on CPAN. |
579 | |
580 | =head2 lexical aliases |
581 | |
582 | Allow lexical aliases (maybe via the syntax C<my \$alias = \$foo>. |
583 | |
584 | =head2 entersub XS vs Perl |
585 | |
586 | At the moment pp_entersub is huge, and has code to deal with entering both |
587 | perl and XS subroutines. Subroutine implementations rarely change between |
588 | perl and XS at run time, so investigate using 2 ops to enter subs (one for |
589 | XS, one for perl) and swap between if a sub is redefined. |
2810d901 |
590 | |
591 | =head2 Self ties |
592 | |
593 | self ties are currently illegal because they caused too many segfaults. Maybe |
594 | the causes of these could be tracked down and self-ties on all types re- |
595 | instated. |
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596 | |
597 | =head2 Optimize away @_ |
598 | |
599 | The old perltodo notes "Look at the "reification" code in C<av.c>". |
600 | |
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601 | =head2 What hooks would assertions need? |
602 | |
603 | Assertions are in the core, and work. However, assertions needed to be added |
604 | as a core patch, rather than an XS module in ext, or a CPAN module, because |
605 | the core has no hooks in the necessary places. It would be useful to |
606 | investigate what hooks would need to be added to make it possible to provide |
607 | the full assertion support from a CPAN module, so that we aren't constraining |
608 | the imagination of future CPAN authors. |
609 | |
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610 | =head2 Properly Unicode safe tokeniser and pads. |
611 | |
612 | The tokeniser isn't actually very UTF-8 clean. C<use utf8;> is a hack - |
613 | variable names are stored in stashes as raw bytes, without the utf-8 flag |
614 | set. The pad API only takes a C<char *> pointer, so that's all bytes too. The |
615 | tokeniser ignores the UTF-8-ness of C<PL_rsfp>, or any SVs returned from |
616 | source filters. All this could be fixed. |
617 | |
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618 | |
619 | |
620 | |
621 | |
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622 | =head1 Big projects |
623 | |
624 | Tasks that will get your name mentioned in the description of the "Highlights |
625 | of 5.10" |
626 | |
627 | =head2 make ithreads more robust |
628 | |
4e577f8b |
629 | Generally make ithreads more robust. See also L</iCOW> |
0bdfc961 |
630 | |
631 | This task is incremental - even a little bit of work on it will help, and |
632 | will be greatly appreciated. |
633 | |
6c047da7 |
634 | One bit would be to write the missing code in sv.c:Perl_dirp_dup. |
635 | |
0bdfc961 |
636 | =head2 iCOW |
637 | |
638 | Sarathy and Arthur have a proposal for an improved Copy On Write which |
639 | specifically will be able to COW new ithreads. If this can be implemented |
640 | it would be a good thing. |
641 | |
642 | =head2 (?{...}) closures in regexps |
643 | |
644 | Fix (or rewrite) the implementation of the C</(?{...})/> closures. |
645 | |
646 | =head2 A re-entrant regexp engine |
647 | |
648 | This will allow the use of a regex from inside (?{ }), (??{ }) and |
649 | (?(?{ })|) constructs. |