Weekly Perl 6 mailing list summary for 15-21 October, 2006

Weekly Perl 6 mailing list summary

  This week on the Perl 6 mailing lists

     "The | notation is mentioned in S012:1029, by the way. Obviously you
     still haven't quite memorized all the synopses. :-)"

     -- Larry Wall, in 'class interface of roles <http://xrl.us/rvnd>'

  Corrections

     Last week I mistakenly wrote that Juerd suggested using `#` for
     comments in `qw//` and `qqw//`, when in fact he suggested integrating
     it with `qqw//` and not `qw//`, because `qqw//` has generic quoting
     options.


  Language

   class interface of roles <http://xrl.us/rvnd>

     This long-running thread continued. Previous highlights included
     discussion on how a role can require a target class to implement a
     method or do another role, and whether there is a use for forbidding
     the implementation of methods.

     This week, Jonathan Lang and TSa discussed various ways of controlling
     dispatch rules, and agreed upon some terminology to assist the
     discussion.

     Meanwhile, Jonathan and TSa talked about the distinction between
     mixins and roles. Larry Wall offered some clarification, which led to
     a discussion on the `|` notation. This eventually morphed in to a
     thread about the syntax for unordered composition.

   "Don't tell me what I can't do!" <http://xrl.us/r5w3>

     Two weeks ago, Jonathan Lang initiated a discussion on programming
     styles which allow a programmer to prevent another person from taking
     an otherwise legitimate action. The discussion moved on to lexically
     scoped pragmas and policy meta models.

     This week Smylers wondered how it is possible for a module to require
     undeclared package variables, and asked Trey Harris for an example of
     a module with undeclared symbolic references.

   Synopsis 26 - Documentation [alpha draft] <http://xrl.us/r9xo>

     Last week, Damian Conway released a draft for S26 on documentation.
     Some people expressed opinions on it.

     This week, Smylers stated that he thought the only standard XML
     entities are `&lt;`, `&gt;` and `&amp;`. Defining further entities is
     allowed; for example, this is what HTML does. Danny Brian responded by
     expanding the list of default entities to include `&apos;` and
     `&quot;`. Damian Conway corrected the document accordingly.

   Edge case: incongruent roles <http://xrl.us/so8k>

     Jonathan Lang initiated a discussion on collisions which might occur
     from creating a class which inherits from two classes with unrelated
     concepts which happen to share a method name. Trey Harris thought that
     the combination of multiple inheritance, multiple dispatch, traits and
     DBC offered a more sophisticated way to resolve conflicts than
     dispatch by name. Jonathan agreed that was how it should work, but was
     not convinced it worked that way in practice. Larry Wall suggested
     that S12 might resolve the issue, but Jonathan explained that it did
     not cover the case he was trying to express. Larry elaborated on the
     documentation.

     Meanwhile, TSa launched a subthread containing an example with
     numbers. There was further discussion on numeric comparisons in this
     context.

     The thread spawned 'set operations for roles <http://xrl.us/so8q>'.

   [svn:perl6-synopsis] r13210 - doc/trunk/design/syn <http://xrl.us/so8n>

     Larry Wall made a commit to S05, noting that the new regex syntax
     defines word boundaries in terms of `w`, not `s`.

   set operations for roles <http://xrl.us/so8q>

     Jonathan Lang replied to a comment in the thread 'Edge case:
     incongruent roles <http://xrl.us/so8k>'. The discussion involved the
     syntax for ordered and unordered composition. He proposed some syntax.
     TSa and Jonathan discussed possibilities, and Larry Wall added his
     thoughts.

   Interrogative statements <http://xrl.us/so8r>

     Jonathan Lang suggested that `$expression?;` should have the same
     meaning as `$_ = $expression`. He wondered if Perl 6 makes this
     possible, or if the parser would need to be modified. Juerd replied
     that it was possible if you modified the Perl 6 grammar.

   Threads, magic? <http://xrl.us/so8s>

     Relipuj wondered how threaded data collection could be accomplished in
     Perl 6, citing an example of how it is done in Python.

  Parrot Porters

   [TODO] :init attribute <http://xrl.us/so8t>

     In the thread 'Implement .loadlib pragma in IMCC', dating to July,
     Patrick R. Michaud summarized the issue of `:init` pragmas for subs as
     discussed in a recent #parrotsketch meeting. Ticket [perl #39926]
     <http://xrl.us/so8u> relates to the task. In addition to giving a
     status report on `:init`, Patrick invited people to contribute tests
     and code to help create `:init`.

     Meanwhile, Leopold Toetsch replied to Kevin Tew's patch attempt in
     'sub :init implementation <http://xrl.us/so8v>', commenting on the use
     of the flag `PBC_POSTCOMP`, which he described as an unfortunate
     choice. He made some alternate proposals. Kevin thanked Leopold, and
     asked for a summary of how flags are used, which Leopold provided.

   Parrot::Coroutine <http://xrl.us/r5xi>

     The discussion which began as a notification from Bob Rogers on
     continuations continued with the thread concerning problems with
     coroutines. Last week, Leopold Toetsch requested a description from
     Bob on his proposal for rewriting coroutines.

     This week, François Perrad reported that as of r14936, he has removed
     the LuaThread PMC so that it does not depend upon coroutines.

     Leopold issued a reminder about making namespaces useful.

   [perl #40509] [NEW] Line endings test <http://xrl.us/so8w>

     In ticket [perl #40509] <http://xrl.us/r9yn>, Paul Cochrane reported
     that this patch is superceeded by one attached to ticket [perl #40544]
     <http://xrl.us/so8x>.

   sprintf() Checkins #14922-14924 Break Linux/PPC Tests
   <http://xrl.us/so8y>

     chromatic reported a series of failing tests. Leopold Toetsch reported
     that it was fixed in r14926. The problem involved formatting a long
     long with `'%ld'`, which does not work on all systems. He suggested
     some solutions in case the current `'%lld'` breaks other compilers.

   sprintf 64 test <http://xrl.us/so8z>

     Leopold Toetsch noted that he is getting different results from Perl 5
     and libc when using printf/sprintf. He wondered if it was a problem
     with his test. Sadahiro Tomoyuki replied with some information about
     the specification, and another test case where Perl 5 gives unexpected
     results. A patch to correct the situation was applied as r29025.

   Re: [perl #40543] [NEW] Test for space after curly braces
   <http://xrl.us/so82>

     Paul Cochrane created ticket [perl #40543] <http://xrl.us/spaw> to
     deliver a patch to test for extra whitespace after a curly brace at
     the end of the line. chromatic wondered why this should only apply to
     curly braces and not extra whitespace at the end of any line, and
     Jerry Gay agreed. Jerry included vim settings to assist in finding
     trailing whitespace. Other people also expressed their dislike of
     excessive whitespace.

     Jerry asked that the test be rewritten to involve just one test,
     instead of around 700. He also wanted it expanded to cover Perl files,
     and listed some other candidates for the check. Will Coleda disagreed,
     because perlcritic tests address this for Perl files.

   [perl #40545] [PATCH] Addition of tests to Parrot::Distribution tests
   <http://xrl.us/so83>

     Paul Cochrane supplied a patch in ticket [perl #40545]
     <http://xrl.us/so84>. The patch adds tests for yacc, lex and pmc
     files, and also fixes a test which was giving a false positive.

   configure bug <http://xrl.us/so87>

     Kevin Tew reported a problem with generating makefiles in step
     `gen::makefiles`.

   Re: [perl #40559] AutoReply: $FindBin::Bin has a trailing / in scripts
   on Perl 5.8.3 <http://xrl.us/so88>

     Kevin Tew submitted a patch in ticket [perl #40559]
     <http://xrl.us/spax>. This patch solves a problem which was preventing
     `gen::makefiles` from running. Jerry Gay advised committing the patch.

   Coding Standard Questions <http://xrl.us/so89>

     Kevin Tew listed a few things he encountered in Parrot internals which
     he did not like but which are not against the current coding
     standards. He wondered if they are acceptable style. One of the issues
     had been addressed in PDD07. There was some discussion on the other
     points. Andy Lester begged for an end to the discussion, asking
     everyone to follow whatever is in the PDD. Kevin noted earlier that he
     was not trying to start a war, but to get a ruling on issues which are
     not currently in the specifications.

   [QUESTION] PMC Pre-allocation <http://xrl.us/so9a>

     Karl Forner asked if there was a way to specify the minimum allocation
     size for PMCs. Leopold Toetsch replied that the issue had come up a
     number of times. He explained the history behind it, and offered
     suggestions for resolving the legacy confusion.

   PMCs exact allocated size <http://xrl.us/so9b>

     Karl Forner noted that it would be useful to know the exact amount of
     memory a PMC is using.

   [perl #40560] [PATCH] minor languages/regex/lib/Regex/Grammar.y fix
   <http://xrl.us/so9c>

     In ticket [perl #40560] <http://xrl.us/so9d>, Paul Cochrane provided a
     patch to make `regex/lib/Regex/Grammar.y` pass
     `t/codingstd/cppcomments.t`.

   [perl #40562] [TODO] add 'list policies' option to t/op/perlcritic.t
   <http://xrl.us/so9e>

     Jerry Gay created ticket [perl #40562] <http://xrl.us/so9f> to suggest
     adding a command-line option to perlcritic tests which would display a
     list of policies.

   requirements gathering on mini transformation language
   <http://xrl.us/r5xc>

     Earlier, Allison Randal asked for a volunteer to write up the
     requirements for a mini transformation language to use the compiler
     tools.

     This week, Markus Triska linked to a section of Stefan Karl's master's
     thesis <http://xrl.us/spay> on the implementation a rule-based
     peep-hole optimizer which Markus felt might relate to the current
     discussion.

   [perl #40564] [TODO] fix perlcritic Subroutines::RequireFinalReturn
   policy <http://xrl.us/so9g>

     In ticket [perl #40564] <http://xrl.us/spaz>, Jerry Gay requested that
     the perlcritic policy be changed to ignore subroutines which exit or
     die when checking for explicit return statements. Chris Dolan replied
     that it was fixed in Perl::Critic r737, which will be included in the
     next release of Perl::Critic.

   [PATCH] today's build failed because of a missing 'use'
   <http://xrl.us/so9h>

     Karl Forner reported that his Parrot build failed due to a missing
     `use File::Spec`. He included a patch, which Kevin Tew applied.

   classnames and HLL namespaces -- help! <http://xrl.us/so9i>

     Patrick R. Michaud wrote of his confusion on how to deal with
     classname conflicts when multiple HLL namespaces are involved, now
     that PDD21 has changed. Matt Diephouse, Allison Randal, Leopold
     Toetsch and Will Coleda joined the thread. The conclusion seemed to be
     that namespace pollution still needs to be resolved and the object
     model is due for discussion as well.

   [HOWTO] add a C file to get archived in libparrot.a <http://xrl.us/so9j>

     Karl Forner asked what he needed to do to have his .o file added in
     `libparrot.a`.

  Users

   [ANNOUNCE] Pugs 6.2.13 released! <http://xrl.us/so9k>

     Audrey Tang announced the release of Pugs 6.2.13. Her message detailed
     the many changes which have been made in the last four months.

   Embedded perl5 modules <http://xrl.us/so9m>

     Richard Hainsworth has been trying to test GUI Perl 5 modules in Pugs
     6.13. He showed an example of how he modified his code, and the error
     it returned. Steffen Schwigon had a suggestion on how to correct the
     Perl 6 code.

  Compiler

   [patch] no strict for -e scripts <http://xrl.us/so9n>

     Sean O'Rourke submitted a patch to remove `strict 'vars'` for -e
     scripts. Gaal Yahas reported that they will continue transitioning to
     the new AST, which will allow lexical pragmas.

  Acknowlegements

     This summary was prepared using Mail::Summary::Tools
     <http://xrl.us/qvno>, available on CPAN.

     If you appreciate Perl, consider contributing to the Perl Foundation
     <http://donate.perlfoundation.org> to help support the development of
     Perl.

     Thank you to everyone who has pointed out mistakes and offered
     suggestions for improving this series. Comments on this summary can be
     sent to Ann Barcomb, <[email protected]>.

  Distribution

     This summary can be found in the following places:

     * use.perl.org <http://use.perl.org/>
     * The Pugs blog <http://pugs.blogs.com/>
     * The perl6-announce mailing list <http://xrl.us/qycj>
     * ONLamp <http://www.oreillynet.com/onlamp/blog/>

  See Also

     * Perl Foundation activities <http://blog.perlfoundation.org>
     * Perl 6 Development <http://dev.perl.org/perl6>
     * Planet Perl Six <http://planetsix.perlfoundation.org/>