The roadmap to 5.10 envisages feature based releases, as various items in this
TODO are completed.
-=head2 Needed for a 5.9.4 release
+=head2 Needed for a 5.9.5 release
=over
=item *
-Review assertions. Review syntax to combine assertions. Assertions could take
-advantage of the lexical pragmas work. L</What hooks would assertions need?>
+Review smart match semantics in light of Perl 6 developments.
=item *
-C<encoding::warnings> should be turned into a lexical pragma.
-C<encoding> should, too (probably).
-
-=back
-
-=head2 Needed for a 5.9.5 release
-
-=over
+Review assertions. Review syntax to combine assertions. Assertions could take
+advantage of the lexical pragmas work. L</What hooks would assertions need?>
=item *
-Implement L</_ prototype character>
-=item *
-Implement L</state variables>
+C<encoding> should be turned into a lexical pragma (probably).
=back
=head2 Parallel testing
+(This probably impacts much more than the core: also the Test::Harness
+and TAP::* modules on CPAN.)
+
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
=head2 Make Schwern poorer
-We should have for everything. When all the core's modules are tested,
+We should have tests 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.
+Use Devel::Cover to ascertain the core modules's test coverage, then add
+tests that are currently missing.
=head2 test B
It would be good to teach C<embed.pl> to understand the conditional
compilation, and hence remove the duplication, and the mistakes it has caused.
-
-
-
-
-
=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
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>)
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
+=head2 Make Config.pm cope with differences between built 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
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
export list is correct, and to build a perl that does not pollute the global
namespace with private symbols.
+=head2 Cross-compile support
+Currently C<Configure> understands C<-Dusecrosscompile> option. This option
+arranges for building C<miniperl> for TARGET machine, so this C<miniperl> is
+assumed then to be copied to TARGET machine and used as a replacement of full
+C<perl> executable.
+This could be done little differently. Namely C<miniperl> should be built for
+HOST and then full C<perl> with extensions should be compiled for TARGET.
+This, however, might require extra trickery for %Config: we have one config
+first for HOST and then another for TARGET.
=head1 Tasks that need a little C knowledge
could shrink the interpreter structure; a size saving which is multiplied by
the number of threads running.
-=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.
-
-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>.
-
-=head2 Shrink struct context
+=head2 Profile Perl - am I hot or not?
-In F<cop.h>, we have
+The Perl source code is stable enough that it makes sense to profile it,
+identify and optimise the hotspots. It would be good to measure the
+performance of the Perl interpreter using free tools such as cachegrind,
+gprof, and dtrace, and work to reduce the bottlenecks they reveal.
- struct context {
- U32 cx_type; /* what kind of context this is */
- union {
- struct block cx_blk;
- struct subst cx_subst;
- } cx_u;
- };
+As part of this, 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.
-There are less than 256 values for C<cx_type>, and the constituent parts
-C<struct block> and C<struct subst> both contain some C<U8> and C<U16> fields,
-so it should be possible to move them to the first word, and share space with
-a C<U8> C<cx_type>, saving 1 word.
+Except that it's not clear if these really are the most commonly used ops. So
+as part of exercising your skills with coverage and profiling tools you 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>.
=head2 Allocate OPs from arenas
the various OP structures from arenas. The SV arena code can probably be
re-used for this.
+=head2 Improve win32/wince.c
-
+Currently, numerous functions look virtually, if not completely,
+identical in both C<win32/wince.c> and C<win32/win32.c> files, which can't
+be good.
=head1 Tasks that need a knowledge of XS
the perl API that comes from writing modules that use XS to interface to
C.
-=head2 shrink C<IO>s
+=head2 shrink C<PVBM>s
By removing unused elements and careful re-ordering, the structures for C<AV>s,
-C<HV>s, C<CV>s and C<GV>s have recently been shrunk considerably. C<PVIO>s and
-C<PVBM>s might have some savings to win.
+C<HV>s, C<CV>s and C<GV>s have recently been shrunk considerably. C<PVIO>s
+probably aren't worth it, as typical programs don't use more than 8, and
+(at least) C<Filter::Util::Call> uses C<SvPVX>/C<SvCUR>/C<SvLEN> on a C<PVIO>,
+so it would mean code changes to modules on CPAN. C<PVBM>s might have some
+savings to win.
-=head2 Implicit Latin 1 => Unicode translation
+=head2 autovivification
-Conversions from byte strings to UTF-8 currently map high bit characters
-to Unicode without translation (or, depending on how you look at it, by
-implicitly assuming that the byte strings are in Latin-1). As perl assumes
-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).
+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
+
+chdir, chmod, chown, chroot, exec, glob, link, lstat, mkdir, open,
+opendir, qx, readdir, readlink, rename, rmdir, stat, symlink, sysopen,
+system, truncate, unlink, utime, -X. All these could potentially accept
+Unicode filenames either as input or output (and in the case of system
+and qx Unicode in general, as input or output to/from the shell).
+Whether a filesystem - an operating system pair understands Unicode in
+filenames varies.
+
+Known combinations that have some level of understanding include
+Microsoft NTFS, Apple HFS+ (In Mac OS 9 and X) and Apple UFS (in Mac
+OS X), NFS v4 is rumored to be Unicode, and of course Plan 9. How to
+create Unicode filenames, what forms of Unicode are accepted and used
+(UCS-2, UTF-16, UTF-8), what (if any) is the normalization form used,
+and so on, varies. Finding the right level of interfacing to Perl
+requires some thought. Remember that an OS does not implicate a
+filesystem.
+
+(The Windows -C command flag "wide API support" has been at least
+temporarily retired in 5.8.1, and the -C has been repurposed, see
+L<perlrun>.)
+
+=head2 Unicode in %ENV
+
+Currently the %ENV entries are always byte strings.
+
+=head2 use less 'memory'
+
+Investigate trade offs to switch out perl's choices on memory usage.
+Particularly perl should be able to give memory back.
+
+This task is incremental - even a little bit of work on it will help.
+
+=head2 Re-implement C<:unique> in a way that is actually thread-safe
+
+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>.
+
+=head2 Make tainting consistent
+
+Tainting would be easier to use if it didn't take documented shortcuts and
+allow taint to "leak" everywhere within an expression.
+
+=head2 readpipe(LIST)
+
+system() accepts a LIST syntax (and a PROGRAM LIST syntax) to avoid
+running a shell. readpipe() (the function behind qx//) could be similarly
+extended.
+
+=head2 strcat(), strcpy(), strncat(), strncpy(), sprintf(), vsprintf()
+
+Maybe create a utility that checks after each libperl.a creation that
+none of the above (nor sprintf(), vsprintf(), or *SHUDDER* gets())
+ever creep back to libperl.a.
+
+ nm libperl.a | ./miniperl -alne '$o = $F[0] if /:$/; print "$o $F[1]" if $F[0] eq "U" && $F[1] =~ /^(?:strn?c(?:at|py)|v?sprintf|gets)$/'
+
+Note, of course, that this will only tell whether B<your> platform
+is using those naughty interfaces.
+
+=head2 Audit the code for destruction ordering assumptions
+
+Change 25773 notes
+
+
+=head2 Allocate OPs from arenas
+
+Currently all new OP structures are individually malloc()ed and free()d.
+All C<malloc> implementations have space overheads, and are now as fast as
+custom allocates so it would both use less memory and less CPU to allocate
+the various OP structures from arenas. The SV arena code can probably be
+re-used for this.
+
+=head2 Improve win32/wince.c
+
+Currently, numerous functions look virtually, if not completely,
+identical in both C<win32/wince.c> and C<win32/win32.c> files, which can't
+be good.
+
+=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 shrink C<PVBM>s
+
+By removing unused elements and careful re-ordering, the structures for C<AV>s,
+C<HV>s, C<CV>s and C<GV>s have recently been shrunk considerably. C<PVIO>s
+probably aren't worth it, as typical programs don't use more than 8, and
+(at least) C<Filter::Util::Call> uses C<SvPVX>/C<SvCUR>/C<SvLEN> on a C<PVIO>,
+so it would mean code changes to modules on CPAN. C<PVBM>s might have some
+savings to win.
+
=head2 autovivification
Make all autovivification consistent w.r.t LVALUE/RVALUE and strict/no strict;
running a shell. readpipe() (the function behind qx//) could be similarly
extended.
+=head2 strcat(), strcpy(), strncat(), strncpy(), sprintf(), vsprintf()
+
+Maybe create a utility that checks after each libperl.a creation that
+none of the above (nor sprintf(), vsprintf(), or *SHUDDER* gets())
+ever creep back to libperl.a.
+
+ nm libperl.a | ./miniperl -alne '$o = $F[0] if /:$/; print "$o $F[1]" if $F[0] eq "U" && $F[1] =~ /^(?:strn?c(?:at|py)|v?sprintf|gets)$/'
+
+Note, of course, that this will only tell whether B<your> platform
+is using those naughty interfaces.
+
+=head2 Audit the code for destruction ordering assumptions
+
+Change 25773 notes
+
+ /* Need to check SvMAGICAL, as during global destruction it may be that
+ AvARYLEN(av) has been freed before av, and hence the SvANY() pointer
+ is now part of the linked list of SV heads, rather than pointing to
+ the original body. */
+ /* FIXME - audit the code for other bugs like this one. */
+adding the C<SvMAGICAL> check to
+ if (AvARYLEN(av) && SvMAGICAL(AvARYLEN(av))) {
+ MAGIC *mg = mg_find (AvARYLEN(av), PERL_MAGIC_arylen);
+Go through the core and look for similar assumptions that SVs have particular
+types, as all bets are off during global destruction.
=head1 Tasks that need a knowledge of the interpreter
These tasks would need C knowledge, and knowledge of how the interpreter works,
or a willingness to learn.
-=head2 lexical pragmas
-
-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 Attach/detach debugger from running program
The old perltodo notes "With C<gdb>, you can attach the debugger to a running
The old perltodo notes that lvalue functions don't work in the debugger. This
would be good to fix.
-=head2 _ prototype character
-
-Study the possibility of adding a new prototype character, C<_>, meaning
-"this argument defaults to $_".
-
-=head2 state variables
-
-C<my $foo if 0;> is deprecated, and should be replaced with
-C<state $x = "initial value\n";> the syntax from Perl 6.
-
-=head2 @INC source filter to Filter::Simple
-
-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 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 UNITCHECK
+=head2 delete &function
+
+Allow to delete functions. One can already undef them, but they're still
+in the stash.
-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 Make readpipe overridable
+
+so we can override qx// as well.
=head2 optional optimizer
the full assertion support from a CPAN module, so that we aren't constraining
the imagination of future CPAN authors.
+=head2 Properly Unicode safe tokeniser and pads.
-
-
+The tokeniser isn't actually very UTF-8 clean. C<use utf8;> is a hack -
+variable names are stored in stashes as raw bytes, without the utf-8 flag
+set. The pad API only takes a C<char *> pointer, so that's all bytes too. The
+tokeniser ignores the UTF-8-ness of C<PL_rsfp>, or any SVs returned from
+source filters. All this could be fixed.
=head1 Big projects
This will allow the use of a regex from inside (?{ }), (??{ }) and
(?(?{ })|) constructs.
+
+=head2 Add (?YES) (?NO) to regexp enigne
+
+YES/NO would allow a subpattern to be passed/failed but allow backtracking.
+Basically a more efficient (?=), (?!).
+
+demerphq has this on his todo list
+
+=head2 Add (?SUCCEED) (?FAIL) to regexp engine
+
+SUCCEED/FAIL would allow a pattern to be passed/failed but without backtracking.
+Thus you could signal that a pattern has matched or not, and return (regardless
+that there is more pattern following).
+
+demerphq has this on his todo list
+
+=head2 Add (?CUT) (?COMMIT) to regexp engine
+
+CUT would allow a pattern to say "do not backtrack beyond here".
+COMMIT would say match from here or don't, but don't try the pattern from
+another starting pattern.
+
+These correspond to the \v and \V that Jeffrey Friedl mentions in
+Mastering Regular Expressions 2nd edition.
+
+demerphq has this on his todo list
+
+=head2 Add class set operations to regexp engine
+
+Apparently these are quite useful. Anyway, Jeffery Friedl wants them.
+
+demerphq has this on his todo list, but right at the bottom.
+
+
projects / p5sagit/p5-mst-13.2.git / blobdiff