This Week in Perl 6, August 2-9, 2005


Welcome to another summary, brought to you by Chinese food. The attentive among you will notice that this summary is a day late, because I did not feel like doing it yesterday. If only I could do that at work.

Perl 6 Compilers

Pugs Argument Processing

Vadim Konovalov submitted a patch to Pugs affecting @*ARGS processing. In the world of Pugs, this means that he received a committer bit and applied it himself.

Type Inferencing

Autrijus wants to type push Perl 6’s type inferencing as far as it can go (and maybe a little beyond). To this end, he has been soliciting input from all comers. It looks like he has put a lot of thought and research into it. One day, I expect to be thanking Autrijus for important (if likely difficult to understand) compiler errors and warnings.

WWW::Kontent Release

Brent “Dax” Royal-Gordon announced the release of WWW::Kontent 0.01: “a flexible web content management system written in Perl 6 and executable with Pugs.” It looks nifty to me. Maybe we need to fight Ruby on Rails with Perl 6 on Pylons or something. That doesn’t quite have the right ring to it, but there has to be something catchy there somewhere.

Array Interpolation

Phil Crow wondered why Pugs would not interpolate his arrays. Ingo Blechschmidt and Patrick explained that @foo does not interpolate, but @foo[] does. I sense a frequently asked question here.

Pugs 6.2.9 Released

Autrijus announced the release of Pugs 6.2.9. It is full of nifty new features, including the ability to lay on hands!

White Space Before Parens

Andrew Shitov wondered why Perl 6 no longer allowed white space between function names and parens. Autrijus explained that it allows print (1+2)*3 to print 9 instead of 3. As someone who just last week explained the peculiarity of Ruby printing 3 in the above situation to a complete novice, I welcome the change.

Container Model Pictures

Autrijus posted a few pretty pictures explaining the compiler model and the container model. While the compiler model was readily understandable to me, the container one wasn’t. Fortunately, when prompted, Autrijus provided a great explanation to accompany the diagram.

PxPerl 5.8.7-4

Upon discovering that Pugs released a new version, Grégoire Péan released a new version of PxPerl that includes the new Pugs. I (and many others) thank Grégoire for lowering the entry bar for Perl 6 hacking on Windows.

Hosting Lexical Declarations

Declaring lexicals mid-block confuses things, especially declaring them mid-statement, as in $x = $x + my $x if $x;. Autrijus proposed hoisting declarations of lexicals to the top of the block. Unfortunately, this can make CALLER:: do funny things. Thus, he suggests outlawing it. Larry agreed.



Bdonlan noticed that Parrot’s test suite was not setting LD_LIBRARY_PATH, which makes tests fail. Leo pointed out that most users manually set their LD_LIBRARY_PATH, as Parrot often needs this, but he agreed that the tests should do it just in case.

Improved Argument Processing for

Tom submitted a patch that improves the command-line argument processing powers of Warnock applies.

ANSI Escape Codes in Parrot

Klaas-Jan Stol was having trouble putting special characters like ANSI clear screen and “¥” into strings. Nick pointed out that he need to be careful with encodings and escapes. In Parrot, \O is an octal escape. In Lua, it is apparently not.

Parrot 0.2.3

Leo announced the release of Parrot 0.2.3, “Serenity,” which reminds me, Firefly is coming back soon! I can’t wait! Oddly, Google seems to have swallowed his release notice, but not his warnings.

Strange Filename-Based Bug

Michal Wallace found a bug that would disappear if the file was renamed. Leo, with the help of valgrind, provided Michal with a pointer. Michal used that to find a likely culprit and provide a patch, which Leo then refined.

GDBM Hash on MinGW

François Perrad provided a patch fixing gdbmhash on MinGW. Bernhard Schmalhofer applied it.

François Perrad also fixed a link problem with pystring.o. Jonathan Worthington applied that patch.

Filling a Large Data Structure

Amir Karger wanted to know how to fill a large data structure in PIR, other than explicitly. Leo suggested reading it in from a config file.

Helping Perl 6

Rjtucke asked the ever-dangerous question, “How can I help?”. Unfortunately, I think he asked it on Google Groups, and thus no one saw it.

PGE Glob Escapes

“PGE Glob Escapes; millions die before it can be rounded up again.” Actually, Will Coleda noticed that he could not add a literal * to globs in PGE. Patrick fixed it so he could.

Language Test Requirements

Amir Karger has decided to write a Z-code-to-PIR translator. He wants to integrate its test suite with Parrot’s language tests. Unfortunately, it does not use Test::Simple, or even Perl. Thus he wanted to know a good way to integrate it. Will Coleda, Bernhard Schmalhofer, and chromatic all provided suggestions.

mod_parrot 0.3

Adrian Lambeck provided a patch to fix src/call_list.txt for mod_parrot-0.3. chromatic applied it.

Making Makefile a Little too Clean

Patrick noticed that the Parrot build was breaking. Jonathan Worthington narrowed it down to an exact revision number. Leo realized his mistake and fixed it.

Cygwin Status

Bernhard Schmalhofer applied some old patches from Joshua Gatcomb, in the hope of improving Cygwin support. Nick Glencross provided needed Parrot Cygwin test results.

Calling SUPER Methods

Klaas-Jan Stol wondered how to call a specific parent methods (possibly bypassing child methods). Leo answered.

Compiling Pugs and Parrot

Adrian Lambeck was having trouble compiling Pugs against Parrot. Leo worked with him to find a solution, although they haven’t resolved it yet.

Pure Parrot Test::Builder

chromatic has written pure-Parrot versions of Test::Builder and Test::Builder::Tester. As always, patches are welcome.

Adding a New Opcode

Gerd Pokorra wanted to know how to add a new opcode to parrot. Klaas-Jan Stol and Leo provided answers.

More Win32 Patches

François Perrad provided several patches for MinGW and Win32. Warnock applies.

Updated intro.pod

Jonathan Worthington posted an updated intro.pod. Autrijus provided a few edits, and Jonathan is planning on committing it.

Comment Fix in pir-mode.el

Jim McKim made the mistake of using Emacs. Fortunately, he counterbalanced that failing with the virtue of submitting a patch to fix an error in pir-mode.el to make the file work better. chromatic applied the patch.

Commit Bit

Curtis Rawls seemed to be having trouble using his newly acquired commit bit. Warnock applies.

Segfault with -E

Tom noticed that parrot -E segfaulted and provided a patch. He was not very confident about the patch.

make test in bc

Amir Karger noticed that make test in bc dies because he does not have antlr installed. Bernhard Schmalhofer said that he would try and fix it up to use the config-test for antlr.

interpreter.c Breakage

Amir Karger noticed that interpreter.c broke during a recent compilation. Leo pointed out that he need to make realclean.

MinGW Meets m4

François Perrad provided two patches to make m4 work on MinGW. Warnock applies.

substr Segfault

Will Coleda posted a short PIR test that will segfault in the substr opcode. This led to some discussion of variable-width encodings. Leo explained that substr was a call that would probably force Parrot to rectify variable-width encodings into fixed-width ones (which it does lazily). Then he fixed it (presumably as he had suggested).

Parrot Cygwin Meets Treefrog

Steve “treefrog” posted a patch he needed to get Cygwin testing. I think he may have posted it to Google Groups directly, though. Warnock applies.

Call Opcode Cleanups

Leo attempted to free himself from the horns of Warnock by reposting his suggested call opcode cleanup. Patrick and I voiced our support. More accurately, I voiced support and Patrick indifference.

Perl 6 Language

Complex Control Flow

Nigel Hamilton began speculating that Perl 6 might have an extremely complicated control flow. Then he began to wonder aloud about a form of control flow I can only describe as brain-melting. Luke Palmer suggested that his proposal might best start as a module.

Slurpy Parameters and Flattening

Ingo Blechschmidt’s question of the flattening (or not) of slurpy params continued producing some suggestions. Piers seemed somewhat unhappy with earlier answers, but the thread died out.

Does if Topicalize?

Luke Palmer noticed if foo() -> $foo { ... } in an OSCON talk and wondered if if now topicalized. Stuart Cook offered a workaround.

Data Constructors

Luke Palmer posted his thoughts on unifying units and data constructors (as in Haskell or ML). Warnock applies.

Calling Methods on undef

Ingo Blechschmidt wondered what would happen if he called undef.chars or char undef. Brent “Dax” Royal-Gordon responded that it would return undef in the absence of use fatal. Larry confirmed this behavior.

Reassigning .ref and .meta

Ingo Blechschmidt wondered what would happen if he assigned to .ref or .meta. Luke Palmer figured that it would not be allowed. I think it should cause a large person to come over to your house and kick you. This is probably a good reason I don’t write error messages.

Questioning .ref and .meta

Ingo Blechschmidt left a bunch of blanks for people to fill in with respect to .ref and .meta. Luke Palmer apparently segfaulted in the attempt to fill in the blanks.

Subscripting Pairs

Ingo Blechschmidt wondered if one could subscript pairs. Larry declared no.

Perl 6 Test in Parrot 0.2.3

Andrew Shitov was having trouble running Perl 6 under the latest Parrot. Autrijus pointed out that he was trying to run the compiler attempt abandoned in June of 2004 and then pointed him toward Pugs.

Java -> Perl ?

Tim Bunce wondered if any work had started on parsing Java interface definitions and translating them to Perl 6. Warnock applies (which probably means no).

MetaObject Questions

Stevan Little posted some of his thoughts on the MetaObject internals for comment. Many questions ensued, my eyes glazed over, the summarizer punted.

defined and typed Traits

Autrijus mused about how to deal with defined and typed traits in Perl 6. This led Larry to wonder about undef being a class, or a class being undef, or something confusing.

is constant Sugar

Autrijus wondered how is constant would desugar if it were a special form. Larry came up with suggestions, some of which said it desugared and some of which said it didn’t.

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