This file is part of the Perl 6 Archive

Note: these documents may be out of date. Do not use as reference!

To see what is currently happening visit

The Perl 6 Summary for the week ending 20040118

I hope you'll forgive the lack of banter before we start in on perl6-internals.

Threads. Again.

Still more proposals about threads this week. Jeff Clites offered some notes based on the Java Virtual Machine's threading model. Surprisingly, this was the week's only threads thread. Next week: Dan starts to outline the design that's going to be implemented.

Questions about abstract PMCs

Stéphane Payrard had some questions about abstract PMCs and whether they were needed in core_pmcs.h and pmctypes.pasm to make PMC type checking work in IMCC. Leo Tötsch answered questions, but didn't think they were actually needed in those files. Discussion ensued.

Docs and releases

Tim Bunce wondered whether a date had been set for the next release. He also pointedly wondered if the docs were up to date with best practises and whether having them up to date would be a goal for the next release. Dan answered: "No", "no" and "yes, bordering on a requirement and not just a goal". Discussion ensued again. For some reason this thread flushed out a few 'shy lurkers' so let's extend a big hello to Paul Cochrane, Herbert Snorrason, Matt Diephouse, Robin Redeker, Richard Holden and Mark Solinski.

Making continuations work properly

The work of getting continuations to close over the various bits and pieces the should close over continues; it seems there's rather more to doing the Right Thing than meets the eye.[]

new_noinit and init ops

Luke Palmer was trying to implement a loop using a continuation. He wanted to be able to defer initialization of a continuation so he implemented two stage instantiation & initialization; wrapped it up in two new ops, new_noinit and init, and posted the resulting patch to the list. Michal Wallace thought it best to just use a lexical. Then he perpetrated a spectacularly extended metaphor about Parrot entitled Mr Parrot's Neighborhood, which probably works best if you don't automatically correct the spelling of neighbourhood. -- Mr Parrot's neighborhood

Namespace stuff

Jeff Clites revisited a thread from a while back about namespaces. His discussion centred on whether the namespace part of a name should be, logically a string "Global::Namespace::Hierarchy" or list of strings ["Global", "Namespace", "Hierarchy"]. He argued that it made sense to just use a simple thing and asked what we actually gained from having a hierarchy. Dan wants a hierarchy because it makes cross language sharing of namespaces easier. Larry wants a hierarchy 'cos it makes all sorts of things easier. Tim Bunce offered another proposal which received qualified approval from both Dan & Leo. -- Tim's proposal

Parrot string docs

Robert Eaglestone had a bunch of questions about Parrot's String documentation. Answers were forthcoming.

IMCC v1 feature freeze

Melvin Smith announced a feature freeze for IMCC version 1 and called for bug reports for it. He plans to get imcc1 working as correctly as possible and frozen within a couple of weeks before starting the really major work (and deprecation of features) on IMCC 2. There was a certain amount of wrangling about CVS issues, but it was generally thought to be a good idea.

Managed and unmanaged structs

Dan had some thoughts about accessing and generally monkeying around with C structs and added a couple of related tasks to the todo list. Leo pointed out that quite a bit of it was done, and pointed out where further work was needed.[]

Loading bytecode at runtime

Dan did some more design work on how runtime loading of bytecode should be handled.[]

The todo list

Dan was reminded that we have a full, working, RT installation so he's started creating tickets for each todo. This should make for better tracking and ownership of tasks. Hurrah. He asked for a volunteer or two to manage the todo queue. Dave Pippenger and Stephane Peiry stepped up to the plate with heartening alacrity. Go guys.[]

Numeric formatting

More design from Dan. This time he was thinking about numeric formatting. His initial plan was to lift the formatting rules from SQL, but I'm not sure if that plan survived contact with Michael Scott who pointed out that ICU (the Unicode library that's already included in the Parrot tree) has its own number formatting API. After some discussion in which Dan pointed out that he really didn't want to have to initialize the entire Unicode system just to get number formatting, Michael suggested we copy the ICU API, even if we use our own implementation.[]

Unicode, internationalization, C++ and ICU

It's obviously an ICU week this week. Dan announced that it's time we actually started building ICU into Parrot. The catch is, it doesn't work right now. He asked for volunteers to track ICU and keep things reasonably up to date. Apart from the obvious pony, Dan wants ICU building, working and not needing any C++. Personally, I think he's more likely to get a pony than to get rid of the C++ dependency.

Jonathan Worthington was the bearer of the bad new that, because ICU's configuration script is a shell script, it's going to be exceedingly tricky to get ICU to build on any platform that doesn't have bash or similar. Which makes things tricky for Win32 types (though, following posts from others, not as tricky as Jon first thought.)

Nobody has yet volunteered to be the ICU pumpking though.[]

Variable clusters

Melvin Smith made a suggestion for optimizing variable handling by using 'variable clusters'. I'm afraid I went into 'bear of little brain' mode when reading the thread, but there was a fair amount of discussion.

POD Errors

A big thank you to Michael Scott who's been cleaning up the documentation tree's POD errors, and has made an HTML version of Parrot's docs available. For his next trick, he's going to normalize the existing POD and add some content to those files that need it.

Allocation food for thought

Luke Palmer has been monkeying with the small object allocator in an effort to get things working fast enough that he can excise RetContinuations from Parrot's object model (They're not continuations and they are next to impossible to promote to continuations if you need to) and replacing the current chunked control stack with a conceptually simpler linked continuation chain. His results were interesting. I'm not sure his patch will be going in, but he achieved some pretty impressive optimization of full continuations.

Vtables organization

Leo had some questions about using 'magic' vtables with PMCs. Dan outlined his proposed approach based on chained vtables.

Events and JIT

Leo did some thinking aloud about getting Event handling working with the JIT core (it works everywhere else). Cue vast amounts of discussion.

Ops file hints

Leo had a list of suggestions for extra data that he thinks needs to go into the ops files. Dan agreed with everything on the list and added a todo item to the Parrot RT queue.

Meanwhile in perl6-language

run-once code

David Storrs wanted a way of ensuring that a an expensive function in a conditional would never need to be evaluated again after the condition became true. Various answers were suggested, some more complicated than others.

Announcements and Apologies

This week's summary is dedicated to the memory of my grandmother, Kathleen Hudson, who died on Monday morning in her sleep. She was 82 years old, and apart from the last couple of years of Alzheimer's she was always the life and soul of any party. We're all going to miss her.