quite a few tests in F<t/> have not been refactored to use it. Refactoring
any of these tests, one at a time, is a useful thing TODO.
+The subdirectories F<base>, F<cmd> and F<comp>, that contain the most
+basic tests, should be excluded from this task.
+
+=head2 Test that regen.pl was run
+
+There are various generated files shipped with the perl distribution, for
+things like header files generate from data. The generation scripts are
+written in perl, and all can be run by F<regen.pl>. However, because they're
+written in perl, we can't run them before we've built perl. We can't run them
+as part of the F<Makefile>, because changing files underneath F<make> confuses
+it completely, and we don't want to run them automatically anyway, as they
+change files shipped by the distribution, something we seek not do to.
+
+If someone changes the data, but forgets to re-run F<regen.pl> then the
+generated files are out of sync. It would be good to have a test in
+F<t/porting> that checks that the generated files are in sync, and fails
+otherwise, to alert someone before they make a poor commit. I suspect that this
+would require adapting the scripts run from F<regen.pl> to have dry-run
+options, and invoking them with these, or by refactoring them into a library
+that does the generation, which can be called by the scripts, and by the test.
+
=head2 Automate perldelta generation
The perldelta file accompanying each release summaries the major changes.
=head2 Improve the coverage of the core tests
-Use Devel::Cover to ascertain the core modules's test coverage, then add
+Use Devel::Cover to ascertain the core modules' test coverage, then add
tests that are currently missing.
=head2 test B
To make a minimal perl distribution, it's useful to look at
F<t/lib/commonsense.t>.
-=head2 Move dual-life pod/*.PL into ext
-
-Nearly all the dual-life modules have been moved to F<ext>. However, we
-still need to move F<pod/*.PL> into their respective directories
-in F<ext/>. They're referenced by (at least) C<plextract> in F<Makefile.SH>
-and C<utils> in F<win32/Makefile> and F<win32/makefile.ml>, and listed
-explicitly in F<win32/pod.mak>, F<vms/descrip_mms.template> and F<utils.lst>
-
=head2 POSIX memory footprint
Ilya observed that use POSIX; eats memory like there's no tomorrow, and at
told is something Perl is good at. So it would be nice to know what it is doing
that is taking so much CPU, and where possible address it.
+=head2 enable lexical enabling/disabling of inidvidual warnings
+
+Currently, warnings can only be enabled or disabled by category. There
+are times when it would be useful to quash a single warning, not a
+whole category.
=head1 Tasks that need a little sysadmin-type knowledge
=item *
do a normal C<Configure>, but include Devel::Cover as a module to install
-(see F<INSTALL> for how to do this)
+(see L<INSTALL> for how to do this)
=item *
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.
+namespace with private symbols, and will fail in the same way as msvc or mingw
+builds or when using PERL_DL_NONLAZY=1.
=head2 Cross-compile support
Another option could be deconstructing the implementation of some simpler
functions in op.c.
+=head2 Allow XSUBs to inline themselves as OPs
+
+For a simple XSUB, often the subroutine dispatch takes more time than the
+XSUB itself. The tokeniser already has the ability to inline constant
+subroutines - it would be good to provide a way to inline other subroutines.
+
+Specifically, simplest approach looks to be to allow an XSUB to provide an
+alternative implementation of itself as a custom OP. A new flag bit in
+C<CvFLAGS()> would signal to the peephole optimiser to take an optree
+such as this:
+
+ b <@> leave[1 ref] vKP/REFC ->(end)
+ 1 <0> enter ->2
+ 2 <;> nextstate(main 1 -e:1) v:{ ->3
+ a <2> sassign vKS/2 ->b
+ 8 <1> entersub[t2] sKS/TARG,1 ->9
+ - <1> ex-list sK ->8
+ 3 <0> pushmark s ->4
+ 4 <$> const(IV 1) sM ->5
+ 6 <1> rv2av[t1] lKM/1 ->7
+ 5 <$> gv(*a) s ->6
+ - <1> ex-rv2cv sK ->-
+ 7 <$> gv(*x) s/EARLYCV ->8
+ - <1> ex-rv2sv sKRM*/1 ->a
+ 9 <$> gvsv(*b) s ->a
+
+perform the symbol table lookup of C<rv2cv> and C<gv(*x)>, locate the
+pointer to the custom OP that provides the direct implementation, and re-
+write the optree something like:
+
+ b <@> leave[1 ref] vKP/REFC ->(end)
+ 1 <0> enter ->2
+ 2 <;> nextstate(main 1 -e:1) v:{ ->3
+ a <2> sassign vKS/2 ->b
+ 7 <1> custom_x -> 8
+ - <1> ex-list sK ->7
+ 3 <0> pushmark s ->4
+ 4 <$> const(IV 1) sM ->5
+ 6 <1> rv2av[t1] lKM/1 ->7
+ 5 <$> gv(*a) s ->6
+ - <1> ex-rv2cv sK ->-
+ - <$> ex-gv(*x) s/EARLYCV ->7
+ - <1> ex-rv2sv sKRM*/1 ->a
+ 8 <$> gvsv(*b) s ->a
+
+I<i.e.> the C<gv(*)> OP has been nulled and spliced out of the execution
+path, and the C<entersub> OP has been replaced by the custom op.
+
+This approach should provide a measurable speed up to simple XSUBs inside
+tight loops. Initially one would have to write the OP alternative
+implementation by hand, but it's likely that this should be reasonably
+straightforward for the type of XSUB that would benefit the most. Longer
+term, once the run-time implementation is proven, it should be possible to
+progressively update ExtUtils::ParseXS to generate OP implementations for
+some XSUBs.
+
=head2 Remove the use of SVs as temporaries in dump.c
F<dump.c> contains debugging routines to dump out the contains of perl data
Currently glob patterns and filenames returned from File::Glob::glob()
are always byte strings. See L</"Virtualize operating system access">.
-=head2 Unicode and lc/uc operators
-
-Some built-in operators (C<lc>, C<uc>, etc.) behave differently, based on
-what the internal encoding of their argument is. That should not be the
-case. Maybe add a pragma to switch behaviour.
-
=head2 use less 'memory'
Investigate trade offs to switch out perl's choices on memory usage.
These tasks would need C knowledge, and knowledge of how the interpreter works,
or a willingness to learn.
+=head2 forbid labels with keyword names
+
+Currently C<goto keyword> "computes" the label value:
+
+ $ perl -e 'goto print'
+ Can't find label 1 at -e line 1.
+
+It is controversial if the right way to avoid the confusion is to forbid
+labels with keyword names, or if it would be better to always treat
+bareword expressions after a "goto" as a label and never as a keyword.
+
=head2 truncate() prototype
The prototype of truncate() is currently C<$$>. It should probably
The handling of Unicode is unclean in many places. For example, the regexp
engine matches in Unicode semantics whenever the string or the pattern is
flagged as UTF-8, but that should not be dependent on an internal storage
-detail of the string. Likewise, case folding behaviour is dependent on the
-UTF8 internal flag being on or off.
+detail of the string.
=head2 Properly Unicode safe tokeniser and pads.
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 delete &function
-
-Allow to delete functions. One can already undef them, but they're still
-in the stash.
-
=head2 C</w> regex modifier
That flag would enable to match whole words, and also to interpolate
This has actually already been implemented (but only for Win32),
take a look at F<iperlsys.h> and F<win32/perlhost.h>. While all Win32
variants go through a set of "vtables" for operating system access,
-non-Win32 systems currently go straight for the POSIX/UNIX-style
+non-Win32 systems currently go straight for the POSIX/Unix-style
system/library call. Similar system as for Win32 should be
implemented for all platforms. The existing Win32 implementation
probably does not need to survive alongside this proposed new
be done 1st in XS, and using B::Generate to patch the new OP into the
optrees.
+=head2 Add C<00dddd>
+
+It has been proposed that octal constants be specifiable through the syntax
+C<0oddddd>, parallel to the existing construct to specify hex constants
+C<0xddddd>
+
=head1 Big projects
Tasks that will get your name mentioned in the description of the "Highlights
This task is incremental - even a little bit of work on it will help, and
will be greatly appreciated.
-One bit would be to write the missing code in sv.c:Perl_dirp_dup.
+One bit would be to determine how to clone directory handles on systems
+without a C<fchdir> function (in sv.c:Perl_dirp_dup).
Fix Perl_sv_dup, et al so that threads can return objects.
Fix (or rewrite) the implementation of the C</(?{...})/> closures.
-=head2 A re-entrant regexp engine
-
-This will allow the use of a regex from inside (?{ }), (??{ }) and
-(?(?{ })|) constructs.
-
=head2 Add class set operations to regexp engine
Apparently these are quite useful. Anyway, Jeffery Friedl wants them.
https://perl5.git.perl.org / perl5.git / blobdiff