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Postings from April 2005
Summary for the week ending 2005-04-12
From: The Perl 6 Summarizer
April 12, 2005 12:31
Summary for the week ending 2005-04-12
Message ID: firstname.lastname@example.org
The Perl 6 Summary for the week ending 2005-04-12
Whoa! Deja vu! Where'd Matt go?
Don't worry, Matt's still writing summaries. As you may have noticed,
Matt's been writing summaries every two weeks. And now so am I. Because
we love you, we've decided to arrange things so I write summaries in the
weeks when Matt doesn't. We could do it the other way, but that could be
seen by some as self-defeating. Heck, when I say 'some' I probably mean
So, bear with me while I remember how to type all those accented
characters and get back into the swing of writing these things (and of
reading everything in the mailing lists once more -- someone should
write a summary for us summarizers...)
I'll be sticking to my old 'lists in alphabetical order' scheme of
writing summaries. So, let's get going
This week in perl6-compiler
Array of arrays, hash of hashes, elems, last
Lev Selector asked for confirmation that Pugs didn't support compound
data structures, "@ar.elems" or "@ar.last". Autrijus and others
confirmed that they didn't then, but they do now.
MakeMaker6 stalls on takeoff
Darren Duncan pointed out that, whilst last week's summary had claimed
he was working on implementing MakeMaker in Perl 6 which is, sadly not
the case. He reckoned he'd possibly look into it again when he had tuits
and Pugs was more complete (supporting objects, for instance).
Roie Marianer pointed out what looks like some weirdness in Pugs'
parsing of lexically scoped subroutines. Warnock applies.
Toronto pugs hackathon
John Macdonald asked for people who wanted to come to the YAPC::NA pugs
hackathon to get in touch with him beforehand as spaces there are
limited. If you're interested, drop him a line.
Pugs slice oddities
Andrew Savige noticed some weirdness in pugs's slicing behaviour. He
posted some example code showing the problem. Autrijus agreed that there
was a problem and explained that he was in the process of rewriting all
the variable types, symbol tables and casting rules to agree with the
Perl 5 model as described in perltie.pod. The rewrite is currently
failing tests, so he posted a patch for people who want to play. On
Sunday, he bit the bullet and committed the entire 2500 line patch which
'touches pretty much all evaluator code'.
<http://xrl.us/frad> -- Autrijus's patch
<http://xrl.us/frae> -- Autrijus on the patch
Meanwhile, in perl6-internals
William Coleda has been trying to add Unicode support to his TCL
implementation and he fell across issues with missing methods in
charset/unicode.h. Leo waved a magic wand and checked in an
implementation which he fenced about with disclaimers.
The status of Ponie
Nicholas Clark confessed that Ponie had been pretty much stalled for
some time, but sweetened the pill by announcing that it's about to
restart and that he would be able to allocate at least one day a week to
the project. He pointed people at the Ponie roadmap which breaks down
the required tasks between here and a first release, complete with time
estimates. If you're interested in getting Ponie to a ridable state,
this would be a good place to start.
People were pleased.
<http://xrl.us/frah> -- Ponie intro/roadmap
Monthly release schedule
Chip donned his "Fearless Leader" hat and announced that, effective,
Parrot would be moving to a monthly release schedule (with an initial
three week 'month' to get things into sync). There was some debate about
whether Solaris/SPARC should be one of the officially required monthly
release platforms (darwin, linux-x86-gcc3.* and win32-ms-cl were Chip's
initial blessed three). This morphed into a discussion of Tinderbox;
apparently there are cool things happening behind the scenes.
Calling convention abstraction
What do you know? You go away for n months and when you come back people
are *still* talking about calling conventions.
Dynamic Perl, Part 1
William Coleda announced that he was starting work on removing the
core's dependence on Perl* PMCs in favour of using language agnostic
PMCs internally and loading the Perl ones dynamically as required.
Everything but PerlArray was dealt with quickly and names and ways
forward with that tricky case were discussed. It looks like we're going
to have a 'ResizablePMCArray' added to the core once people have the
Another discussion that wouldn't go away back when I was last writing
summaries has come to a head. Parrot's finally migrating from CVS to
Subversion. By the time you read this, Parrot's main repository should
be at http://svn.perl.org/parrot. Hurrah!
There were, of course, wrinkles to be ironed out.
<http://xrl.us/frao> -- Getting started with subverted Parrot
The imcc/ subdirectory
Matt Diephouse wondered if, now that IMCC has been integrated with
Parrot, we really needed the imcc/ subdirectory. He suggested that maybe
its contents should be distributed about the rest of the parrot
directory structure. MrJoltCola (Melvin Smith?) thought it was best kept
separate and thought of as a front end. Bernhard Schmalhofer pointed out
PAST, another Parrot frontend and suggested that it may make sense to
refactor imcc/main.c into (he suggests) src/main.c and imcc/frontend.c,
which would make the distinction rather clearer and provide an
opportunity to clean up the exported symbols. Leo pretty much agreed
with Melvin (no comment on Bernhard's suggestions yet though).
Perl jobs for the willing
Leo looked for volunteers to rejig t/src/manifest.t to use .svn/Entries
instead of CVS/Entries when checking the MANIFEST. Michael Schwern
(possibly accidentally) volunteered.
Meanwhile, in perl6-language
A quick note about notation. I've started borrowing notation from
Ruby/Smalltalk to discuss methods. Where I write SomeClass#method, then
I am referring to an instance method of SomeClass and where I write
SomeClass.method I am referring to a class method.
Identity tests and comparing two references
By heck but I've not been keeping up.
I started understanding what was going on when people started talking
about implicit dereferencing of long chains of references. Larry's
saying that even if $foo is a reference to a reference to a reference to
a... to "10" then $$foo will chase all the way along the reference chain
and evaluate to "10". The general response seemed to be "Wah! How do I
make it not do that?".
<http://xrl.us/frat> -- how to help Larry
Ovid wondered if "say" (and "print" come to that) should default to
printing the current topic. An initial hunt through the Perl 6 documents
proved to be 'like trying to sip through a firehose', so he asked the
list. And dropped a heavy hint about indexing the docs.
According to Luke, it should default to the current topic.
Blocks, continuations and eval()
Wolverian's been looking at the Perl 5 debugger and wondered if it would
be possible to add an eval method to objects that represent scopes. The
idea being that
$scope.eval 'say $foo'
would evaluate "say $foo" with all of $scope's bindings etc in place (I
wonder what "$scope.eval 'return'" would do...). At least, that's what
*I* think he meant. Others asked for clarification. Wolverian also
wanted to know how to get hold of a scope's continuation (or at least
the current continuation). Larry has in the past said that he wouldn't
be exposing continuations in the core language. Others have noted that
it wouldn't be beyond the bounds of possibility to write a Parrot level
module which would expose them though.
Questions on "$pair.kv"
Stevan Little had some questions about the behaviour of Pair#kv method.
Luke came through with the answer (when all else fails, consider the
pair to be a one-element hash'.
Prompted by a suggestion from Tim Bunce, Ovid started porting the
examples in the Perl Cookbook into idiomatic Perl 6. He asked for
comments and suggestions on how to proceed.
Marcus Adair proposed, and Luke Palmer strongly seconded, moving the
development of the code onto a mediawiki (wikipedia) style Wiki which
has good support for 'offline' discussion of code as it's developed.
Autrijus reckoned that his current practise of handing out SVN committer
bits to anyone who expressed an interest and leaving discussion in the
files themselves seems to be working pretty well so far. He pointed at
Bryan Ingerson posted a preliminary cut of Synopsis 26 and asked for
comments. Yuval Kogman pointed out that the docs subdirectory of the
pugs distribution is filled with documentation that needed proofreading
and nitpicking. Go to it people.
Aliasing swapped values
Ovid wondered what
($x,$y) := ($y, $x)
Juerd reckoned the answer is straightforward, and I must say I agree
String#chars in a list context
Marcus Adair argued that it seems natural that String#chars, when used
in a list context, should return a list of the Unicode chars in the
string. Opinion seemed to favour the idea, but there's been no ruling
from Larry (or anyone else on the Design Team).
Whither "use English"
David Vergin wondered if Perl 6 would have an equivalent of "use
English", which would give sensible names to the various magic globals
(those that hadn't been otherwise eliminated at least). Answer: Yes and
No. There will be no English.pm module, but the magic globals will all
have English names by default.
Heredocs and their workings
Marcus Adair wondered about the use of Heredocs as positional
parameters. Luke confirmed that they should work just like they do in
Perl 5, modulo minor matters of spelling (they're now spelled
"qq::to/END/" etc...) and whitespace removal.
Luke pointed out that
my @a = (1,2,3,4);
my @b = @a[1...];
is potentially problematic (he argues it should print out '3', but Perl
5 semantics imply that it should print 'Inf'). He proposed breaking with
the Perl 5 way. Autrijus agreed with him and has implemented his
proposal in pugs.
Coo... that was fun, I think I'll do it again some time.
If you find these summaries useful or enjoyable, please consider
contributing to the Perl Foundation to help support the development of
<http://donate.perl-foundation.org/> -- The Perl Foundation
<http://dev.perl.org/perl6/> -- Perl 6 Development site
Or, you can check out my website. Maybe now I'm back writing stuff I'll
start updating it.
Vaguely pretty photos by me can be found at:
And that's quite enough shameless self-promotion. See you in two weeks.
Summary for the week ending 2005-04-12
by The Perl 6 Summarizer