F<AUTHORS> file, which ships in the official distribution. How many other
programming languages offer you 1 line of immortality?
-=head1 The roadmap to 5.10
-
-The roadmap to 5.10 envisages feature based releases, as various items in this
-TODO are completed.
-
-=head2 Needed for the final 5.10.0 release
-
-Review perlguts. Significant changes have occured since 5.8, and we can't
-release a new version without making sure these are covered.
-
=head1 Tasks that only need Perl knowledge
=head2 common test code for timed bail out
A full test suite for the B module would be nice.
+=head2 Deparse inlined constants
+
+Code such as this
+
+ use constant PI => 4;
+ warn PI
+
+will currently deparse as
+
+ use constant ('PI', 4);
+ warn 4;
+
+because the tokenizer inlines the value of the constant subroutine C<PI>.
+This allows various compile time optimisations, such as constant folding
+and dead code elimination. Where these haven't happened (such as the example
+above) it ought be possible to make B::Deparse work out the name of the
+original constant, because just enough information survives in the symbol
+table to do this. Specifically, the same scalar is used for the constant in
+the optree as is used for the constant subroutine, so by iterating over all
+symbol tables and generating a mapping of SV address to constant name, it
+would be possible to provide B::Deparse with this functionality.
+
=head2 A decent benchmark
C<perlbench> seems impervious to any recent changes made to the perl core. It
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.
+To make a minimal perl distribution, it's useful to look at
+F<t/lib/commonsense.t>.
+
=head2 Improving C<threads::shared>
Investigate whether C<threads::shared> could share aggregates properly with
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 Modernize the order of directories in @INC
+
+The way @INC is laid out by default, one cannot upgrade core (dual-life)
+modules without overwriting files. This causes problems for binary
+package builders.
+
=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
the various OP structures from arenas. The SV arena code can probably be
re-used for this.
+Note that Configuring perl with C<-Accflags=-DPL_OP_SLAB_ALLOC> will use
+Perl_Slab_alloc() to pack optrees into a contiguous block, which is
+probably superior to the use of OP arenas, esp. from a cache locality
+standpoint. See L<Profile Perl - am I hot or not?>.
+
=head2 Improve win32/wince.c
Currently, numerous functions look virtually, if not completely,
There is also a similar issue with POSIX CRT function names like fileno having
been deprecated in favour of ISO C++ conformant names like _fileno. These
-warnings are also currently suppressed with the compiler option /wd4996. It
+warnings are also currently suppressed by adding -D_CRT_NONSTDC_NO_DEPRECATE. It
might be nice to do as Microsoft suggest here too, although, unlike the secure
functions issue, there is presumably little or no benefit in this case.
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.
opendir(), closedir(), seekdir(), rewinddir(), glob(); symlink(),
readlink().
+See also L</"Virtualize operating system access">.
+
=head2 -C on the #! line
It should be possible to make -C work correctly if found on the #! line,
These tasks would need C knowledge, and knowledge of how the interpreter works,
or a willingness to learn.
+=head2 state variable initialization in list context
+
+Currently this is illegal:
+
+ state ($a, $b) = foo();
+
+The current Perl 6 design is that C<state ($a) = foo();> and
+C<(state $a) = foo();> have different semantics, which is tricky to implement
+in Perl 5 as currently the produce the same opcode trees. It would be useful
+to clarify that the Perl 6 design is firm, and then implement the necessary
+code in Perl 5. There are comments in C<Perl_newASSIGNOP()> that show the
+code paths taken by various assignment constructions involving state variables.
+
=head2 Implement $value ~~ 0 .. $range
It would be nice to extend the syntax of the C<~~> operator to also
understand numeric (and maybe alphanumeric) ranges.
+=head2 A does() built-in
+
+Like ref(), only useful. It would call the C<DOES> method on objects; it
+would also tell whether something can be dereferenced as an
+array/hash/etc., or used as a regexp, etc.
+L<http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2007-03/msg00481.html>
+
+=head2 Tied filehandles and write() don't mix
+
+There is no method on tied filehandles to allow them to be called back by
+formats.
+
=head2 Attach/detach debugger from running program
The old perltodo notes "With C<gdb>, you can attach the debugger to a running
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.
+=head2 Optimize away empty destructors
+
+Defining an empty DESTROY method might be useful (notably in
+AUTOLOAD-enabled classes), but it's still a bit expensive to call. That
+could probably be optimized.
+
=head2 LVALUE functions for lists
The old perltodo notes that lvalue functions don't work for list or hash
The old perltodo notes "Look at the "reification" code in C<av.c>".
-=head2 What hooks would assertions need?
-
-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.
-
=head2 Properly Unicode safe tokeniser and pads.
The tokeniser isn't actually very UTF-8 clean. C<use utf8;> is a hack -
(open(), mkdir(), unlink(), readdir(), getenv(), etc.) At the very
least these interfaces should take SVs as "name" arguments instead of
bare char pointers; probably the most flexible and extensible way
-would be for the interfaces to accept HVs. The system needs to be
-per-operating-system and per-file-system hookable/filterable
+would be for the Perl-facing interfaces to accept HVs. The system
+needs to be per-operating-system and per-file-system
+hookable/filterable, preferably both from XS and Perl level
(L<perlport/"Files and Filesystems"> is good reading at this point,
in fact, all of L<perlport> is.)
-A less ambitious form of this has actually already been implemented
-(but only for Win32), take a look at F<iperlsys.h>. While Win32
-systems go through a set of "vtables" for operating system access,
-non-Win32 systems go straight for the POSIX/UNIX-style system/library
-call. Similar system should be implemented for all platforms.
-The existing Win32 implementation probably does not need to survive
-alongside this proposed new implementation, they could be merged.
+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
+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
+implementation, the approaches could be merged.
What would this give us? One often-asked-for feature this would
-enable is using Unicode for filenames (and other "names" like %ENV,
-usernames, hostnames, and so forth.) But this would also allow for
-things like virtual filesystems and "sandboxes" (though as long as
-dynamic loading of random object code is allowed, not very safe
+enable is using Unicode for filenames, and other "names" like %ENV,
+usernames, hostnames, and so forth.
+(See L<perlunicode/"When Unicode Does Not Happen">.)
+
+But this kind of virtualization would also allow for things like
+virtual filesystems, virtual networks, and "sandboxes" (though as long
+as dynamic loading of random object code is allowed, not very safe
sandboxes since external code of course know not of Perl's vtables).
+An example of a smaller "sandbox" is that this feature can be used to
+implement per-thread working directories: Win32 already does this.
+
+See also L</"Extend PerlIO and PerlIO::Scalar">.
=head1 Big projects