This Week in Perl 6, Through August 14, 2005
As you will note from the date in the title, it’s been a short week. We’re switching back to a midnight Sunday/Monday rollover in order to make life easier for the Perl.com types. So, if I can avoid being distracted too much by the second Ashes test, I’ll try to get the summary finished before Monday is out, which should please chromatic.
This Week in perl6-compiler
Another low-volume week in perl6-compiler; probably because, with the high speed of Pugs development, most of the discussion happens on IRC.
Autrijus fielded some questions about, and updated the pictures of, the container model.
Robert (No Surname) asked what were the benefits of PXPerl over the ActiveState distribution. In short, PXPerl comes with Parrot and Pugs, which ActiveState doesn’t. If you set your path appropriately, you can continue to use the ActiveState Perl and just rely on PXPerl for Parrot and Pugs.
Larry answered some of Autrijus’s questions about Perl 6’s lexical scoping rules. Apparently what Pugs currently does is close enough to sane to be going on with.
Autrijus noted that, in Pugsland, a Warnocked patch usually means that the person who posted the patch simply received a committer bit and didn’t mention the fact on the list.
Meanwhile, in perl6-internals
Jonathan Worthington posted a rewrite of Parrot’s intro.pod document, now with a discussion of PIR. Huzzah!
Following prompting from Geoff Young and Jeff Horwitz, chromatic has implemented Test::Builder and Test::Builder::Tester in pure Parrot. For his next trick, he intends to port Test::More and Parrot::Test.
Tests are good, m’kay?
Gerd Pokorra asked how to add an opcode to Parrot. Klaas-Jan Stol and Leo gave the answers.
Leo reposted about cleaning up the various function-calling opcodes to take account of the fact that the calling conventions have changed. He asked for opinions and actually received a couple, which is handy, since he ended up Warnocked last time.
Amir Karger wondered if there was some way of telling Parrot to add directories to its load path. Leo seemed to think it was not that good an idea, and proposed using a relative path in a
Curtis Rawls continued his work on dominance frontiers to improve Parrot’s optimizer.
Will Coleda reported on trying to match empty strings with PGE’s
glob implementation. It turned out to be a problem with
Data::Escape. Leo fixed it.
Leo posted a list of opcodes that are due for the chop (or alteration) soon. If you’re doing anything with Parrot, it’s probably a good idea to take a look at this list. One of those who did was chromatic, who asked if Leo could give some examples of translating code so as not to use the old forms.
Meanwhile, in perl6-language
Hmm. Eight balls to go with one wicket needed. I think I’ll pause for a while.
Damn. Australia have saved the game.
Tim Bunce wondered if anyone had done any work on parsing Java interface declarations and (ideally) translating them to roughly equivalent Perl 6. Apparently, Gaal Yahas has done something along these lines (with Parse::RecDescent for Perl 5), but doesn’t own the code. He outlined the approach he took.
Stevan Little is busy documenting the Perl 6 metamodel that he’s implemented in Perl 5 and that Autrijus is busy porting to Haskell. He posted an overview to the list and asked for comment. There then followed lots of discussion. I think I understood some of it.
Stevan split the discussion of
$object.meta.isa(?) off from the earlier metamodel thread into a thread of its own and asked for comments once more. Larry commented that “the Apocalypses are primarily intended to be entertaining rather than factual.” Also in this thread, Luke let slip that there’s now a
Set role in Perl 6, which has the enormous advantage of letting us specify argument types in a sensible way without having to overload the junctions.
Stevan continued discussing the metamodel with a thread about the
add_method method. Autrijus was the only person with comments.
Autrijus said that he’d started to write the inferencer and had immediately run into the problem that every type can potentially contain
undef. He proposed adding an
is defined trait, which would cause a variable to immediately throw an exception if anyone attempted to assign it an undefined value. He also proposed a
typed trait, but I was a little less clear on why this would be a good idea. I have to confess that I didn’t understand what Larry’s reply was driving at, but that’s okay, because Autrijus did seem to understand it.
Autrijus wondered if an example of the
is constant trait shown in Synopsis 6 was a special form or a typo. At least, I think that’s what he was asking; I may be wearing my stupid head today, though. Larry thought it was neither. I think. It seems there’s more to constancy than meets the eye. (Just ask any married couple.)
Stuart Cook asked about the meaning of type annotations on type variables. Autrijus answered and Thomas Sandlaß agreed with him.
Nicholas Clark commented on an earlier discussion of using IO in
BEGIN blocks, pointing out that this was just a specific case of the more general problem of attempting to serialize things to bytecodes that were simply unserializable. I reckon the trick of it will be to do such things in
INIT or possibly
CHECK blocks (I can never remember which way round those two go).
Autrijus asked about generic classes, but nobody answered before the end of the summary week. Expect Matt to address this one in the next summary.
Acknowledgements, Adverts, Apologies, and Alliteration
I’m sorry to have to say this, but I don’t think I have to apologize for anything this week. WorldCon was fun.
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