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1=head1 NAME
3perltodo - Perl TO-DO List
e50bb9a1 6
722d2a37 7This is a list of wishes for Perl. Send updates to
8I<>. If you want to work on any of these
9projects, be sure to check the perl5-porters archives for past ideas,
10flames, and propaganda. This will save you time and also prevent you
11from implementing something that Larry has already vetoed. One set
12of archives may be found at:
cd793d32 16=head1 assertions
e50bb9a1 17
cd793d32 18Clean up and finish support for assertions. See L<assertions>.
e50bb9a1 19
cd793d32 20=head1 iCOW
e50bb9a1 21
22Sarathy and Arthur have a proposal for an improved Copy On Write which
23specifically will be able to COW new ithreads. If this can be implemented
24it would be a good thing.
e50bb9a1 25
cd793d32 26=head1 (?{...}) closures in regexps
4b3b956a 27
cd793d32 28Fix (or rewrite) the implementation of the C</(?{...})/> closures.
4b3b956a 29
cd793d32 30=head1 pragmata
e50bb9a1 31
cd793d32 32=head2 lexical pragmas
0562c0e3 33
34Reimplement the mechanism of lexical pragmas to be more extensible. Fix
35current pragmas that don't work well (or at all) with lexical scopes or in
36run-time eval(STRING) (C<sort>, C<re>, C<encoding> for example). MJD has a
37preliminary patch that implements this.
0562c0e3 38
cd793d32 39=head2 use less 'memory'
f35392ae 40
41Investigate trade offs to switch out perl's choices on memory usage.
42Particularly perl should be able to give memory back.
f35392ae 43
cd793d32 44=head1 prototypes and functions
c5fc23ff 45
cd793d32 46=head2 _ prototype character
e50bb9a1 47
48Study the possibility of adding a new prototype character, C<_>, meaning
49"this argument defaults to $_".
e50bb9a1 50
cd793d32 51=head2 inlining autoloaded constants
776f8809 52
53Currently the optimiser can inline constants when expressed as subroutines
54with prototype ($) that return a constant. Likewise, many packages wrapping
55C libraries export lots of constants as subroutines which are AUTOLOADed on
56demand. However, these have no prototypes, so can't be seen as constants by
57the optimiser. Some way of cheaply (low syntax, low memory overhead) to the
58perl compiler that a name is a constant would be great, so that it knows to
59call the AUTOLOAD routine at compile time, and then inline the constant.
776f8809 60
cd793d32 61=head2 Finish off lvalue functions
e50bb9a1 62
63The old perltodo notes "They don't work in the debugger, and they don't work for
64list or hash slices."
e50bb9a1 65
cd793d32 66=head1 Unicode and UTF8
e50bb9a1 67
cd793d32 68=head2 Implicit Latin 1 => Unicode translation
e50bb9a1 69
70Conversions from byte strings to UTF-8 currently map high bit characters
71to Unicode without translation (or, depending on how you look at it, by
72implicitly assuming that the byte strings are in Latin-1). As perl assumes
73the C locale by default, upgrading a string to UTF-8 may change the
74meaning of its contents regarding character classes, case mapping, etc.
75This should probably emit a warning (at least).
e50bb9a1 76
cd793d32 77=head2 UTF8 caching code
e50bb9a1 78
cd793d32 79The string position/offset cache is not optional. It should be.
e50bb9a1 80
cd793d32 81=head1 Regexps
e50bb9a1 82
cd793d32 83=head2 regexp optimiser optional
e50bb9a1 84
85The regexp optimiser is not optional. It should configurable to be, to allow
86its performance to be measured, and its bugs to be easily demonstrated.
e50bb9a1 87
cd793d32 88=head2 common suffices/prefixes in regexps (trie optimization)
c47ff5f1 89
90Currently, the user has to optimize C<foo|far> and C<foo|goo> into
91C<f(?:oo|ar)> and C<[fg]oo> by hand; this could be done automatically.
e50bb9a1 92
cd793d32 93=head1 POD
e50bb9a1 94
cd793d32 95=head2 POD -> HTML conversion still sucks
e50bb9a1 96
cd793d32 97=head1 Misc medium sized projects
e50bb9a1 98
cd793d32 99=head2 UNITCHECK
e50bb9a1 100
101Introduce a new special block, UNITCHECK, which is run at the end of a
102compilation unit (module, file, eval(STRING) block). This will correspond to
103the Perl 6 CHECK. Perl 5's CHECK cannot be changed or removed because the backend framework depends on it.
e50bb9a1 105
cd793d32 106=head2 optional optimizer
e50bb9a1 107
cd793d32 108Make the peephole optimizer optional.
e50bb9a1 109
cd793d32 110=head2 lexical aliases
e50bb9a1 111
cd793d32 112Allow lexical aliases (maybe via the syntax C<my \$alias = \$foo>.
e50bb9a1 113
cd793d32 114=head2 no 6
e50bb9a1 115
cd793d32 116Make C<no 6> and C<no v6> work (opposite of C<use 5.005>, etc.).
e50bb9a1 117
cd793d32 118=head2 IPv6
3958b146 119
cd793d32 120Clean this up. Check everything in core works
e50bb9a1 121
cd793d32 122=head2 entersub XS vs Perl
e50bb9a1 123
124At the moment pp_entersub is huge, and has code to deal with entering both
125perl and and XS subroutines. Subroutine implementations rarely change between
126perl and XS at run time, so investigate using 2 ops to enter subs (one for
127XS, one for perl) and swap between if a sub is redefined.
e50bb9a1 128
cd793d32 129=head2 @INC source filter to Filter::Simple
e50bb9a1 130
131The second return value from a sub in @INC can be a source filter. This isn't
132documented. It should be changed to use Filter::Simple, tested and documented.
e50bb9a1 133
cd793d32 134=head2 bincompat functions
e50bb9a1 135
136There are lots of functions which are retained for binary compatibility.
137Clean these up. Move them to mathom.c, and don't compile for blead?
e50bb9a1 138
722d2a37 139=head2 Use fchown/fchmod internally
e50bb9a1 140
141The old perltodo notes "This has been done in places, but needs a thorough
142code review. Also fchdir is available in some platforms."
e50bb9a1 143
cd793d32 144=head2 foreach reverse
e50bb9a1 145
146The old perltodo notes that we could optimise foreach to iterate in reverse.
147(instead of making a reversed copy on the stack)
e50bb9a1 148
cd793d32 149=head1 Tests
e50bb9a1 150
cd793d32 151=head2 Make Schwern poorer
e50bb9a1 152
cd793d32 153Tests for everything, At which point Schwern coughs up $500 to TPF.
e50bb9a1 154
cd793d32 155=head2 test B
722d2a37 156
cd793d32 157A test suite for the B module would be nice.
722d2a37 158
cd793d32 159=head2 Improve tests for
e50bb9a1 160
cd793d32 doesn't appear to be well tested.
e50bb9a1 162
cd793d32 163=head2 common test code for timed bailout
e50bb9a1 164
165Write portable self destruct code for tests to stop them burning CPU in
166infinite loops. Needs to avoid using alarm, as some of the tests are testing
167alarm/sleep or timers.
e50bb9a1 168
cd793d32 169=head1 Installation
e50bb9a1 170
cd793d32 171=head2 compressed man pages
e50bb9a1 172
cd793d32 173Be able to install them
e50bb9a1 174
cd793d32 175=head2 Make cope with differences between build and installed perl
e50bb9a1 176
cd793d32 177=head2 Relocatable perl
e50bb9a1 178
179Make it possible to create a relocatable perl binary. Will need some collusion
180with We could use a syntax of ... for location of current binary?
e50bb9a1 181
cd793d32 182=head2 make HTML install work
e50bb9a1 183
cd793d32 184=head1 Incremental things
e50bb9a1 185
cd793d32 186Some tasks that don't need to get done in one big hit.
e50bb9a1 187
cd793d32 188=head2 autovivification
e50bb9a1 189
cd793d32 190Make all autovivification consistent w.r.t LVALUE/RVALUE and strict/no strict;
e50bb9a1 191
cd793d32 192=head2 fix tainting bugs
e50bb9a1 193
194Fix the bugs revealed by running the test suite with the C<-t> switch (via
195C<make test.taintwarn>).
e50bb9a1 196
cd793d32 197=head2 Make tainting consistent
e50bb9a1 198
199Tainting would be easier to use if it didn't take documented shortcuts and allow
200taint to "leak" everywhere within an expression.
e50bb9a1 201
cd793d32 202=head1 Vague things
e50bb9a1 203
cd793d32 204Some more nebulous ideas
e50bb9a1 205
cd793d32 206=head2 threads
e50bb9a1 207
cd793d32 208Make threads more robust.
e50bb9a1 209
cd793d32 210=head2 POSIX memory footprint
e50bb9a1 211
212Ilya observed that use POSIX; eats memory like there's no tomorrow, and at
213various times worked to cut it down. There is probably still fat to cut out -
214for example POSIX passes Exporter some very memory hungry data structures.
e50bb9a1 215
cd793d32 216=head2 Optimize away @_
f86a8bc5 217
cd793d32 218The old perltodo notes "Look at the "reification" code in C<av.c>"
3298bd4d 219
cd793d32 220=head2 switch ops
3298bd4d 221
222The old perltodo notes "Although we have C<> in core, Larry points to
223the dormant C<nswitch> and C<cswitch> ops in F<pp.c>; using these opcodes would
224be much faster."
0562c0e3 225
cd793d32 226** Attach/detach debugger from running program
1626a787 227
228The old perltodo notes "With C<gdb>, you can attach the debugger to a running
229program if you pass the process ID. It would be good to do this with the Perl
230debugger on a running Perl program, although I'm not sure how it would be done."
231ssh and screen do this with named pipes in tmp. Maybe we can too.
1626a787 232