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diff --git a/gnu/usr.bin/perl/pod/perltodo.pod b/gnu/usr.bin/perl/pod/perltodo.pod index 219e92ba028..a8a6d797cc6 100644 --- a/gnu/usr.bin/perl/pod/perltodo.pod +++ b/gnu/usr.bin/perl/pod/perltodo.pod @@ -4,71 +4,457 @@ perltodo - Perl TO-DO List =head1 DESCRIPTION -This is a list of wishes for Perl. Send updates to -I<perl5-porters@perl.org>. If you want to work on any of these -projects, be sure to check the perl5-porters archives for past ideas, -flames, and propaganda. This will save you time and also prevent you -from implementing something that Larry has already vetoed. One set -of archives may be found at: +This is a list of wishes for Perl. The tasks we think are smaller or easier +are listed first. Anyone is welcome to work on any of these, but it's a good +idea to first contact I<perl5-porters@perl.org> to avoid duplication of +effort. By all means contact a pumpking privately first if you prefer. + +Whilst patches to make the list shorter are most welcome, ideas to add to +the list are also encouraged. Check the perl5-porters archives for past +ideas, and any discussion about them. One set of archives may be found at: http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/ -=head1 assertions +What can we offer you in return? Fame, fortune, and everlasting glory? Maybe +not, but if your patch is incorporated, then we'll add your name to the +F<AUTHORS> file, which ships in the official distribution. How many other +programming languages offer you 1 line of immortality? -Clean up and finish support for assertions. See L<assertions>. +=head1 The roadmap to 5.10 -=head1 iCOW +The roadmap to 5.10 envisages feature based releases, as various items in this +TODO are completed. -Sarathy and Arthur have a proposal for an improved Copy On Write which -specifically will be able to COW new ithreads. If this can be implemented -it would be a good thing. +=head2 Needed for a 5.9.4 release -=head1 (?{...}) closures in regexps +=over -Fix (or rewrite) the implementation of the C</(?{...})/> closures. +=item * -=head1 A re-entrant regexp engine +Review assertions. Review syntax to combine assertions. Assertions could take +advantage of the lexical pragmas work. L</What hooks would assertions need?> -This will allow the use of a regex from inside (?{ }), (??{ }) and -(?(?{ })|) constructs. +=back -=head1 pragmata +=head2 Needed for a 5.9.5 release -=head2 lexical pragmas +=over -Reimplement the mechanism of lexical pragmas to be more extensible. Fix -current pragmas that don't work well (or at all) with lexical scopes or in -run-time eval(STRING) (C<sort>, C<re>, C<encoding> for example). MJD has a -preliminary patch that implements this. +=item * +Implement L</_ prototype character> -=head2 use less 'memory' +=item * +Implement L</state variables> -Investigate trade offs to switch out perl's choices on memory usage. -Particularly perl should be able to give memory back. +=back -=head1 prototypes and functions +=head2 Needed for a 5.9.6 release -=head2 _ prototype character +Stabilisation. If all goes well, this will be the equivalent of a 5.10-beta. -Study the possibility of adding a new prototype character, C<_>, meaning -"this argument defaults to $_". +=head1 Tasks that only need Perl knowledge + +=head2 common test code for timed bail out + +Write portable self destruct code for tests to stop them burning CPU in +infinite loops. This needs to avoid using alarm, as some of the tests are +testing alarm/sleep or timers. + +=head2 POD -> HTML conversion in the core still sucks + +Which is crazy given just how simple POD purports to be, and how simple HTML +can be. It's not actually I<as> simple as it sounds, particularly with the +flexibility POD allows for C<=item>, but it would be good to improve the +visual appeal of the HTML generated, and to avoid it having any validation +errors. See also L</make HTML install work>, as the layout of installation tree +is needed to improve the cross-linking. + +The addition of C<Pod::Simple> and its related modules may make this task +easier to complete. + +=head2 Parallel testing + +The core regression test suite is getting ever more comprehensive, which has +the side effect that it takes longer to run. This isn't so good. Investigate +whether it would be feasible to give the harness script the B<option> of +running sets of tests in parallel. This would be useful for tests in +F<t/op/*.t> and F<t/uni/*.t> and maybe some sets of tests in F<lib/>. + +Questions to answer + +=over 4 + +=item 1 + +How does screen layout work when you're running more than one test? + +=item 2 + +How does the caller of test specify how many tests to run in parallel? + +=item 3 + +How do setup/teardown tests identify themselves? + +=back + +Pugs already does parallel testing - can their approach be re-used? + +=head2 Make Schwern poorer + +We should have for everything. When all the core's modules are tested, +Schwern has promised to donate to $500 to TPF. We may need volunteers to +hold him upside down and shake vigorously in order to actually extract the +cash. + +See F<t/lib/1_compile.t> for the 3 remaining modules that need tests. + +=head2 Improve the coverage of the core tests + +Use Devel::Cover to ascertain the core's test coverage, then add tests that +are currently missing. + +=head2 test B + +A full test suite for the B module would be nice. + +=head2 A decent benchmark + +C<perlbench> seems impervious to any recent changes made to the perl core. It +would be useful to have a reasonable general benchmarking suite that roughly +represented what current perl programs do, and measurably reported whether +tweaks to the core improve, degrade or don't really affect performance, to +guide people attempting to optimise the guts of perl. Gisle would welcome +new tests for perlbench. + +=head2 fix tainting bugs + +Fix the bugs revealed by running the test suite with the C<-t> switch (via +C<make test.taintwarn>). + +=head2 Dual life everything + +As part of the "dists" plan, anything that doesn't belong in the smallest perl +distribution needs to be dual lifed. Anything else can be too. Figure out what +changes would be needed to package that module and its tests up for CPAN, and +do so. Test it with older perl releases, and fix the problems you find. + +=head2 Improving C<threads::shared> + +Investigate whether C<threads::shared> could share aggregates properly with +only Perl level changes to shared.pm + +=head2 POSIX memory footprint + +Ilya observed that use POSIX; eats memory like there's no tomorrow, and at +various times worked to cut it down. There is probably still fat to cut out - +for example POSIX passes Exporter some very memory hungry data structures. + + + + + + + +=head1 Tasks that need a little sysadmin-type knowledge + +Or if you prefer, tasks that you would learn from, and broaden your skills +base... + +=head2 Relocatable perl + +The C level patches needed to create a relocatable perl binary are done, as +is the work on F<Config.pm>. All that's left to do is the C<Configure> tweaking +to let people specify how they want to do the install. + +=head2 make HTML install work + +There is an C<installhtml> target in the Makefile. It's marked as +"experimental". It would be good to get this tested, make it work reliably, and +remove the "experimental" tag. This would include + +=over 4 + +=item 1 + +Checking that cross linking between various parts of the documentation works. +In particular that links work between the modules (files with POD in F<lib/>) +and the core documentation (files in F<pod/>) + +=item 2 + +Work out how to split C<perlfunc> into chunks, preferably one per function +group, preferably with general case code that could be used elsewhere. +Challenges here are correctly identifying the groups of functions that go +together, and making the right named external cross-links point to the right +page. Things to be aware of are C<-X>, groups such as C<getpwnam> to +C<endservent>, two or more C<=items> giving the different parameter lists, such +as + + =item substr EXPR,OFFSET,LENGTH,REPLACEMENT + + =item substr EXPR,OFFSET,LENGTH + + =item substr EXPR,OFFSET + +and different parameter lists having different meanings. (eg C<select>) + +=back + +=head2 compressed man pages + +Be able to install them. This would probably need a configure test to see how +the system does compressed man pages (same directory/different directory? +same filename/different filename), as well as tweaking the F<installman> script +to compress as necessary. + +=head2 Add a code coverage target to the Makefile + +Make it easy for anyone to run Devel::Cover on the core's tests. The steps +to do this manually are roughly + +=over 4 + +=item * + +do a normal C<Configure>, but include Devel::Cover as a module to install +(see F<INSTALL> for how to do this) + +=item * + + make perl + +=item * + + cd t; HARNESS_PERL_SWITCHES=-MDevel::Cover ./perl -I../lib harness + +=item * + +Process the resulting Devel::Cover database + +=back + +This just give you the coverage of the F<.pm>s. To also get the C level +coverage you need to + +=over 4 + +=item * + +Additionally tell C<Configure> to use the appropriate C compiler flags for +C<gcov> + +=item * + + make perl.gcov + +(instead of C<make perl>) + +=item * + +After running the tests run C<gcov> to generate all the F<.gcov> files. +(Including down in the subdirectories of F<ext/> + +=item * + +(From the top level perl directory) run C<gcov2perl> on all the C<.gcov> files +to get their stats into the cover_db directory. + +=item * + +Then process the Devel::Cover database + +=back + +It would be good to add a single switch to C<Configure> to specify that you +wanted to perform perl level coverage, and another to specify C level +coverage, and have C<Configure> and the F<Makefile> do all the right things +automatically. + +=head2 Make Config.pm cope with differences between build and installed perl + +Quite often vendors ship a perl binary compiled with their (pay-for) +compilers. People install a free compiler, such as gcc. To work out how to +build extensions, Perl interrogates C<%Config>, so in this situation +C<%Config> describes compilers that aren't there, and extension building +fails. This forces people into choosing between re-compiling perl themselves +using the compiler they have, or only using modules that the vendor ships. + +It would be good to find a way teach C<Config.pm> about the installation setup, +possibly involving probing at install time or later, so that the C<%Config> in +a binary distribution better describes the installed machine, when the +installed machine differs from the build machine in some significant way. + +=head2 make parallel builds work + +Currently parallel builds (such as C<make -j3>) don't work reliably. We believe +that this is due to incomplete dependency specification in the F<Makefile>. +It would be good if someone were able to track down the causes of these +problems, so that parallel builds worked properly. + +=head2 linker specification files + +Some platforms mandate that you provide a list of a shared library's external +symbols to the linker, so the core already has the infrastructure in place to +do this for generating shared perl libraries. My understanding is that the +GNU toolchain can accept an optional linker specification file, and restrict +visibility just to symbols declared in that file. It would be good to extend +F<makedef.pl> to support this format, and to provide a means within +C<Configure> to enable it. This would allow Unix users to test that the +export list is correct, and to build a perl that does not pollute the global +namespace with private symbols. + + + + +=head1 Tasks that need a little C knowledge + +These tasks would need a little C knowledge, but don't need any specific +background or experience with XS, or how the Perl interpreter works + +=head2 Make it clear from -v if this is the exact official release + +Currently perl from C<p4>/C<rsync> ships with a F<patchlevel.h> file that +usually defines one local patch, of the form "MAINT12345" or "RC1". The output +of perl -v doesn't report that a perl isn't an official release, and this +information can get lost in bugs reports. Because of this, the minor version +isn't bumped up until RC time, to minimise the possibility of versions of perl +escaping that believe themselves to be newer than they actually are. + +It would be useful to find an elegant way to have the "this is an interim +maintenance release" or "this is a release candidate" in the terse -v output, +and have it so that it's easy for the pumpking to remove this just as the +release tarball is rolled up. This way the version pulled out of rsync would +always say "I'm a development release" and it would be safe to bump the +reported minor version as soon as a release ships, which would aid perl +developers. + +This task is really about thinking of an elegant way to arrange the C source +such that it's trivial for the Pumpking to flag "this is an official release" +when making a tarball, yet leave the default source saying "I'm not the +official release". + +=head2 Tidy up global variables + +There's a note in F<intrpvar.h> + + /* These two variables are needed to preserve 5.8.x bincompat because + we can't change function prototypes of two exported functions. + Probably should be taken out of blead soon, and relevant prototypes + changed. */ + +So doing this, and removing any of the unused variables still present would +be good. + +=head2 Ordering of "global" variables. + +F<thrdvar.h> and F<intrpvarh> define the "global" variables that need to be +per-thread under ithreads, where the variables are actually elements in a +structure. As C dictates, the variables must be laid out in order of +declaration. There is a comment +C</* Important ones in the first cache line (if alignment is done right) */> +which implies that at some point in the past the ordering was carefully chosen +(at least in part). However, it's clear that the ordering is less than perfect, +as currently there are things such as 7 C<bool>s in a row, then something +typically requiring 4 byte alignment, and then an odd C<bool> later on. +(C<bool>s are typically defined as C<char>s). So it would be good for someone +to review the ordering of the variables, to see how much alignment padding can +be removed. + +=head2 bincompat functions + +There are lots of functions which are retained for binary compatibility. +Clean these up. Move them to mathom.c, and don't compile for blead? + +=head2 am I hot or not? + +The idea of F<pp_hot.c> is that it contains the I<hot> ops, the ops that are +most commonly used. The idea is that by grouping them, their object code will +be adjacent in the executable, so they have a greater chance of already being +in the CPU cache (or swapped in) due to being near another op already in use. -=head2 inlining autoloaded constants +Except that it's not clear if these really are the most commonly used ops. So +anyone feeling like exercising their skill with coverage and profiling tools +might want to determine what ops I<really> are the most commonly used. And in +turn suggest evictions and promotions to achieve a better F<pp_hot.c>. -Currently the optimiser can inline constants when expressed as subroutines -with prototype ($) that return a constant. Likewise, many packages wrapping -C libraries export lots of constants as subroutines which are AUTOLOADed on -demand. However, these have no prototypes, so can't be seen as constants by -the optimiser. Some way of cheaply (low syntax, low memory overhead) to the -perl compiler that a name is a constant would be great, so that it knows to -call the AUTOLOAD routine at compile time, and then inline the constant. +=head2 emulate the per-thread memory pool on Unix -=head2 Finish off lvalue functions +For Windows, ithreads allocates memory for each thread from a separate pool, +which it discards at thread exit. It also checks that memory is free()d to +the correct pool. Neither check is done on Unix, so code developed there won't +be subject to such strictures, so can harbour bugs that only show up when the +code reaches Windows. -The old perltodo notes "They don't work in the debugger, and they don't work for -list or hash slices." +It would be good to be able to optionally emulate the Window pool system on +Unix, to let developers who only have access to Unix, or want to use +Unix-specific debugging tools, check for these problems. To do this would +involve figuring out how the C<PerlMem_*> macros wrap C<malloc()> access, and +providing a layer that records/checks the identity of the thread making the +call, and recording all the memory allocated by each thread via this API so +that it can be summarily free()d at thread exit. One implementation idea +would be to increase the size of allocation, and store the C<my_perl> pointer +(to identify the thread) at the start, along with pointers to make a linked +list of blocks for this thread. To avoid alignment problems it would be +necessary to do something like -=head1 Unicode and UTF8 + union memory_header_padded { + struct memory_header { + void *thread_id; /* For my_perl */ + void *next; /* Pointer to next block for this thread */ + } data; + long double padding; /* whatever type has maximal alignment constraint */ + }; + + +although C<long double> might not be the only type to add to the padding +union. + +=head2 reduce duplication in sv_setsv_flags + +C<Perl_sv_setsv_flags> has a comment +C</* There's a lot of redundancy below but we're going for speed here */> + +Whilst this was true 10 years ago, the growing disparity between RAM and CPU +speeds mean that the trade offs have changed. In addition, the duplicate code +adds to the maintenance burden. It would be good to see how much of the +redundancy can be pruned, particular in the less common paths. (Profiling +tools at the ready...). For example, why does the test for +"Can't redefine active sort subroutine" need to occur in two places? + + + + +=head1 Tasks that need a knowledge of XS + +These tasks would need C knowledge, and roughly the level of knowledge of +the perl API that comes from writing modules that use XS to interface to +C. + +=head2 IPv6 + +Clean this up. Check everything in core works + +=head2 shrink C<GV>s, C<CV>s + +By removing unused elements and careful re-ordering, the structures for C<AV>s +and C<HV>s have recently been shrunk considerably. It's probable that the same +approach would find savings in C<GV>s and C<CV>s, if not all the other +larger-than-C<PVMG> types. + +=head2 merge Perl_sv_2[inpu]v + +There's a lot of code shared between C<Perl_sv_2iv_flags>, +C<Perl_sv_2uv_flags>, C<Perl_sv_2nv>, and C<Perl_sv_2pv_flags>. It would be +interesting to see if some of it can be merged into common shared static +functions. In particular, C<Perl_sv_2uv_flags> started out as a cut&paste +from C<Perl_sv_2iv_flags> around 5.005_50 time, and it may be possible to +replace both with a single function that returns a value or union which is +split out by the macros in F<sv.h> + +=head2 UTF8 caching code + +The string position/offset cache is not optional. It should be. =head2 Implicit Latin 1 => Unicode translation @@ -79,9 +465,13 @@ the C locale by default, upgrading a string to UTF-8 may change the meaning of its contents regarding character classes, case mapping, etc. This should probably emit a warning (at least). -=head2 UTF8 caching code +This task is incremental - even a little bit of work on it will help. -The string position/offset cache is not optional. It should be. +=head2 autovivification + +Make all autovivification consistent w.r.t LVALUE/RVALUE and strict/no strict; + +This task is incremental - even a little bit of work on it will help. =head2 Unicode in Filenames @@ -110,196 +500,168 @@ L<perlrun>.) Currently the %ENV entries are always byte strings. -=head1 Regexps - -=head2 regexp optimiser optional - -The regexp optimiser is not optional. It should configurable to be, to allow -its performance to be measured, and its bugs to be easily demonstrated. - -=head2 common suffices/prefices in regexps (trie optimization) - -Currently, the user has to optimize C<foo|far> and C<foo|goo> into -C<f(?:oo|ar)> and C<[fg]oo> by hand; this could be done automatically. - -=head1 POD - -=head2 POD -> HTML conversion still sucks - -Which is crazy given just how simple POD purports to be, and how simple HTML -can be. - -=head1 Misc medium sized projects - -=head2 UNITCHECK +=head2 use less 'memory' -Introduce a new special block, UNITCHECK, which is run at the end of a -compilation unit (module, file, eval(STRING) block). This will correspond to -the Perl 6 CHECK. Perl 5's CHECK cannot be changed or removed because the -O.pm/B.pm backend framework depends on it. +Investigate trade offs to switch out perl's choices on memory usage. +Particularly perl should be able to give memory back. -=head2 optional optimizer +This task is incremental - even a little bit of work on it will help. -Make the peephole optimizer optional. +=head2 Re-implement C<:unique> in a way that is actually thread-safe -=head2 You WANT *how* many +The old implementation made bad assumptions on several levels. A good 90% +solution might be just to make C<:unique> work to share the string buffer +of SvPVs. That way large constant strings can be shared between ithreads, +such as the configuration information in F<Config>. -Currently contexts are void, scalar and list. split has a special mechanism in -place to pass in the number of return values wanted. It would be useful to -have a general mechanism for this, backwards compatible and little speed hit. -This would allow proposals such as short circuiting sort to be implemented -as a module on CPAN. +=head2 Make tainting consistent -=head2 lexical aliases +Tainting would be easier to use if it didn't take documented shortcuts and +allow taint to "leak" everywhere within an expression. -Allow lexical aliases (maybe via the syntax C<my \$alias = \$foo>. +=head2 readpipe(LIST) -=head2 no 6 +system() accepts a LIST syntax (and a PROGRAM LIST syntax) to avoid +running a shell. readpipe() (the function behind qx//) could be similarly +extended. -Make C<no 6> and C<no v6> work (opposite of C<use 5.005>, etc.). -=head2 IPv6 -Clean this up. Check everything in core works -=head2 entersub XS vs Perl -At the moment pp_entersub is huge, and has code to deal with entering both -perl and and XS subroutines. Subroutine implementations rarely change between -perl and XS at run time, so investigate using 2 ops to enter subs (one for -XS, one for perl) and swap between if a sub is redefined. +=head1 Tasks that need a knowledge of the interpreter -=head2 @INC source filter to Filter::Simple +These tasks would need C knowledge, and knowledge of how the interpreter works, +or a willingness to learn. -The second return value from a sub in @INC can be a source filter. This isn't -documented. It should be changed to use Filter::Simple, tested and documented. - -=head2 bincompat functions +=head2 lexical pragmas -There are lots of functions which are retained for binary compatibility. -Clean these up. Move them to mathom.c, and don't compile for blead? +Document the new support for lexical pragmas in 5.9.3 and how %^H works. +Maybe C<re>, C<encoding>, maybe other pragmas could be made lexical. -=head2 Use fchown/fchmod internally +=head2 Attach/detach debugger from running program -The old perltodo notes "This has been done in places, but needs a thorough -code review. Also fchdir is available in some platforms." +The old perltodo notes "With C<gdb>, you can attach the debugger to a running +program if you pass the process ID. It would be good to do this with the Perl +debugger on a running Perl program, although I'm not sure how it would be +done." ssh and screen do this with named pipes in /tmp. Maybe we can too. -=head1 Tests +=head2 Constant folding -=head2 Make Schwern poorer +The peephole optimiser should trap errors during constant folding, and give +up on the folding, rather than bailing out at compile time. It is quite +possible that the unfoldable constant is in unreachable code, eg something +akin to C<$a = 0/0 if 0;> -Tests for everything, At which point Schwern coughs up $500 to TPF. +=head2 LVALUE functions for lists -=head2 test B +The old perltodo notes that lvalue functions don't work for list or hash +slices. This would be good to fix. -A test suite for the B module would be nice. +=head2 LVALUE functions in the debugger -=head2 Improve tests for Config.pm +The old perltodo notes that lvalue functions don't work in the debugger. This +would be good to fix. -Config.pm doesn't appear to be well tested. +=head2 _ prototype character -=head2 common test code for timed bailout +Study the possibility of adding a new prototype character, C<_>, meaning +"this argument defaults to $_". -Write portable self destruct code for tests to stop them burning CPU in -infinite loops. Needs to avoid using alarm, as some of the tests are testing -alarm/sleep or timers. +=head2 state variables -=head1 Installation +C<my $foo if 0;> is deprecated, and should be replaced with +C<state $x = "initial value\n";> the syntax from Perl 6. -=head2 compressed man pages +=head2 @INC source filter to Filter::Simple -Be able to install them +The second return value from a sub in @INC can be a source filter. This isn't +documented. It should be changed to use Filter::Simple, tested and documented. -=head2 Make Config.pm cope with differences between build and installed perl +=head2 regexp optimiser optional -=head2 Relocatable perl +The regexp optimiser is not optional. It should configurable to be, to allow +its performance to be measured, and its bugs to be easily demonstrated. -Make it possible to create a relocatable perl binary. Will need some collusion -with Config.pm. We could use a syntax of ... for location of current binary? +=head2 UNITCHECK -=head2 make HTML install work +Introduce a new special block, UNITCHECK, which is run at the end of a +compilation unit (module, file, eval(STRING) block). This will correspond to +the Perl 6 CHECK. Perl 5's CHECK cannot be changed or removed because the +O.pm/B.pm backend framework depends on it. -=head2 put patchlevel in -v +=head2 optional optimizer -Currently perl from p4/rsync ships with a patchlevel.h file that usually -defines one local patch, of the form "MAINT12345" or "RC1". The output of -perl -v doesn't report that a perl isn't an official release, and this -information can get lost in bugs reports. Because of this, the minor version -isn't bumped up until RC time, to minimise the possibility of versions of perl -escaping that believe themselves to be newer than they actually are. +Make the peephole optimizer optional. Currently it performs two tasks as +it walks the optree - genuine peephole optimisations, and necessary fixups of +ops. It would be good to find an efficient way to switch out the +optimisations whilst keeping the fixups. -It would be useful to find an elegant way to have the "this is an interim -maintenance release" or "this is a release candidate" in the terse -v output, -and have it so that it's easy for the pumpking to remove this just as the -release tarball is rolled up. This way the version pulled out of rsync would -always say "I'm a development release" and it would be safe to bump the -reported minor version as soon as a release ships, which would aid perl -developers. +=head2 You WANT *how* many -=head1 Incremental things +Currently contexts are void, scalar and list. split has a special mechanism in +place to pass in the number of return values wanted. It would be useful to +have a general mechanism for this, backwards compatible and little speed hit. +This would allow proposals such as short circuiting sort to be implemented +as a module on CPAN. -Some tasks that don't need to get done in one big hit. +=head2 lexical aliases -=head2 autovivification +Allow lexical aliases (maybe via the syntax C<my \$alias = \$foo>. -Make all autovivification consistent w.r.t LVALUE/RVALUE and strict/no strict; +=head2 entersub XS vs Perl -=head2 fix tainting bugs +At the moment pp_entersub is huge, and has code to deal with entering both +perl and XS subroutines. Subroutine implementations rarely change between +perl and XS at run time, so investigate using 2 ops to enter subs (one for +XS, one for perl) and swap between if a sub is redefined. -Fix the bugs revealed by running the test suite with the C<-t> switch (via -C<make test.taintwarn>). +=head2 Self ties -=head2 Make tainting consistent +self ties are currently illegal because they caused too many segfaults. Maybe +the causes of these could be tracked down and self-ties on all types re- +instated. -Tainting would be easier to use if it didn't take documented shortcuts and allow -taint to "leak" everywhere within an expression. +=head2 Optimize away @_ -=head2 Dual life everything +The old perltodo notes "Look at the "reification" code in C<av.c>". -As part of the "dists" plan, anything that doesn't belong in the smallest perl -distribution needs to be dual lifed. Anything else can be too. +=head2 What hooks would assertions need? -=head1 Vague things +Assertions are in the core, and work. However, assertions needed to be added +as a core patch, rather than an XS module in ext, or a CPAN module, because +the core has no hooks in the necessary places. It would be useful to +investigate what hooks would need to be added to make it possible to provide +the full assertion support from a CPAN module, so that we aren't constraining +the imagination of future CPAN authors. -Some more nebulous ideas -=head2 threads -Make threads more robust. -=head2 POSIX memory footprint -Ilya observed that use POSIX; eats memory like there's no tomorrow, and at -various times worked to cut it down. There is probably still fat to cut out - -for example POSIX passes Exporter some very memory hungry data structures. +=head1 Big projects -=head2 Optimize away @_ +Tasks that will get your name mentioned in the description of the "Highlights +of 5.10" -The old perltodo notes "Look at the "reification" code in C<av.c>". +=head2 make ithreads more robust -=head2 switch ops +Generally make ithreads more robust. See also L</iCOW> -The old perltodo notes "Although we have C<Switch.pm> in core, Larry points to -the dormant C<nswitch> and C<cswitch> ops in F<pp.c>; using these opcodes would -be much faster." +This task is incremental - even a little bit of work on it will help, and +will be greatly appreciated. -=head2 Attach/detach debugger from running program +=head2 iCOW -The old perltodo notes "With C<gdb>, you can attach the debugger to a running -program if you pass the process ID. It would be good to do this with the Perl -debugger on a running Perl program, although I'm not sure how it would be done." -ssh and screen do this with named pipes in tmp. Maybe we can too. +Sarathy and Arthur have a proposal for an improved Copy On Write which +specifically will be able to COW new ithreads. If this can be implemented +it would be a good thing. -=head2 A decent benchmark +=head2 (?{...}) closures in regexps -perlbench seems impervious to any recent changes made to the perl core. It would -be useful to have a reasonable general benchmarking suite that roughly -represented what current perl programs do, and measurably reported whether -tweaks to the core improve, degrade or don't really affect performance, to -guide people attempting to optimise the guts of perl. +Fix (or rewrite) the implementation of the C</(?{...})/> closures. -=head2 readpipe(LIST) +=head2 A re-entrant regexp engine -system() accepts a LIST syntax (and a PROGRAM LIST syntax) to avoid -running a shell. readpipe() (the function behind qx//) could be similarly -extended. +This will allow the use of a regex from inside (?{ }), (??{ }) and +(?(?{ })|) constructs. |