Update perl591delta. Include a small to-do list in it.

p4raw-id: //depot/perl@22492

1 files changed, 92 insertions, 17 deletions

diff --git a/pod/perl591delta.pod b/pod/perl591delta.pod
index df76f58e00..a120c319d8 100644
--- a/pod/perl591delta.pod
+++ b/pod/perl591delta.pod
@@ -10,6 +10,19 @@ the 5.9.1 release. See L<perl590delta> for the differences between
 
 =head1 Incompatible Changes
 
+=head2 substr() lvalues are no longer fixed-length
+
+The lvalues returned by the three argument form of substr() used to be a
+"fixed length window" on the original string. In some cases this could
+cause surprising action at distance or other undefined behaviour. Now the
+length of the window adjusts iself to the length of the string assigned to
+it.
+
+=head2 The C<:unique> attribute is only meaningful for globals
+
+Now applying C<:unique> to lexical variables and to subroutines will
+result in a compilation error.
+
 =head1 Core Enhancements
 
 =head2 Lexical C<$_>
@@ -53,11 +66,6 @@ correctly in picture lines. Using C<@#> and C<~~> together will now
 produce a compile-time error, as those format fields are incompatible.
 L<perlform> has been improved, and miscellaneous bugs fixed.
 
-=head2 The C<:unique> attribute is only meaningful for globals
-
-Now applying C<:unique> to lexical variables and to subroutines will
-result in a compilation error.
-
 =head2 Stacked filetest operators
 
 As a new form of syntactic sugar, it's now possible to stack up filetest
@@ -119,29 +127,36 @@ The documentation has been revised in places to produce more standard manpages.
 The long-existing feature of C</(?{...})/> regexps setting C<$_> and pos()
 is now documented.
 
+Sorting arrays in place (C<@a = sort @a>) is now optimized to avoid
+making a temporary copy of the array.
+
 =head1 Performance Enhancements
 
 The operations involving case mapping on UTF-8 strings (uc(), lc(),
 C<//i>, etc.) have been greatly speeded up.
 
-=head1 Installation and Configuration Improvements
+Access to elements of lexical arrays via a numeric constant between 0 and
+255 is now faster. (This used to be only the case for global arrays.)
 
 =head1 Selected Bug Fixes
 
-=head2 UTF8 bugs
+=head2 UTF-8 bugs
 
-Using substr() on a UTF8 string could cause subsequent accesses on that
-string to return garbage. This was due to incorrect UTF8 offsets being
+Using substr() on a UTF-8 string could cause subsequent accesses on that
+string to return garbage. This was due to incorrect UTF-8 offsets being
 cached, and is now fixed.
 
 join() could return garbage when the same join() statement was used to
-process 8 bit data having earlier processed UTF8 data, due to the flags
+process 8 bit data having earlier processed UTF-8 data, due to the flags
 on that statement's temporary workspace not being reset correctly. This
 is now fixed.
 
 Using Unicode keys with tied hashes should now work correctly.
 
-chop() and chomp() used to mangle UTF8 strings.  This has been fixed.
+chop() and chomp() used to mangle UTF-8 strings.  This has been fixed.
+
+sprintf() used to misbehave when the format string was in UTF-8. This is
+now fixed.
 
 =head2 Threading bugs
 
@@ -150,7 +165,7 @@ threads. They are now.
 
 =head2 More bugs
 
-C<$a .. $b> will now work as expected when either $a or $b is C<undef>
+C<$a .. $b> will now work as expected when either $a or $b is C<undef>.
 
 Reading $^E now preserves $!. Previously, the C code implementing $^E
 did not preserve C<errno>, so reading $^E could cause C<errno> and therefore
@@ -171,11 +186,11 @@ construct
 
 See L<perldiag>.
 
-The fatal error "DESTROY created new reference to dead object" is now
+The fatal error I<DESTROY created new reference to dead object> is now
 documented in L<perldiag>.
 
-A new error, "%ENV is aliased to %s", is produced when taint checks are
-enabled and when *ENV has been aliased (and thus doesn't reflect the
+A new error, I<%ENV is aliased to %s>, is produced when taint checks are
+enabled and when C<*ENV> has been aliased (and thus doesn't reflect the
 program's environment anymore.)
 
 =head1 Changed Internals
@@ -208,6 +223,11 @@ removed and replaced by two one-bit fields, C<op_opt> and C<op_static>.
 C<opt_type> is now 9 bits long. (Consequently, the C<B::OP> class doesn't
 provide an C<seq> method anymore.)
 
+=head2 New parser
+
+perl's parser is now generated by bison (it used to be generated by
+byacc.) As a result, it seems to be a bit more robust.
+
 =head1 Configuration and Building
 
 C<Configure> now invokes callbacks regardless of the value of the variable
@@ -215,11 +235,66 @@ they are called for. Previously callbacks were only invoked in the
 C<case $variable $define)> branch. This change should only affect platform
 maintainers writing configuration hints files.
 
-=head1 New Tests
+The portability and clealiness of the Win32 makefiles has been improved.
 
 =head1 Known Problems
 
-=head1 Platform Specific Problems
+There are still a couple of problems in the implementation of the lexical
+C<$_>: it doesn't work inside C</(?{...})/> blocks and with regard to the
+reverse() built-in used without arguments. (See the TODO tests in
+F<t/op/mydef.t>.)
+
+=head2 Platform Specific Problems
+
+The test F<ext/IPC/SysV/t/ipcsysv.t> may fail on OpenBSD. This hasn't been
+diagnosed yet.
+
+On some configurations on AIX 5, one test in F<lib/Time/Local.t> fails.
+When configured with long doubles, perl may fail tests 224-236 in
+F<t/op/pow.t> on the same platform.
+
+=head1 To-do for perl 5.10.0
+
+This is a non-exhaustive, non-ordered, non-contractual and non-definitive
+list of things to do (or nice to have) for perl 5.10.0 :
+
+Clean up and finish support for assertions. See L<assertions>.
+
+Reimplement the mechanism of lexical pragmas to be more extensible. Fix
+current pragmas that don't work well with lexical scopes (C<sort>, for
+example). MJD has ideas on this.
+
+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 the byte strings are in Latin-1). This is wrong,
+because perl assumes the C locale by default. Thus upgrading a string to
+UTF-8 (esp. in place) may change the meaning of its contents regarding
+character classes, case mapping, etc. Try to find a way to fix it without
+breaking all the legacy code out there (and without making the life of the
+XS coders miserable.)
+
+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/B framework depends on it.
+
+Study the possibility of adding a new prototype character, C<_>, meaning
+"this argument defaults to $_".
+
+Make the peephole optimizer optional.
+
+Allow lexical aliases (maybe via the syntax C<my \$alias = \$foo>.
+
+Fix the bugs revealed by running the test suite with the C<-t> switch (via
+C<make test.taintwarn>).
+
+Make threads more robust.
+
+Make C<no 6> and C<no v6> work.
+
+A test suite for the B module would be nice.
+
+A ponie.
 
 =head1 Reporting Bugs