The Perl 6 Summary for the week ending 20030601
Another Monday, another Perl 6 Summary. Does this man never take a
holiday? (Yes, but only to go to Perl conferences this year, how did
that happen?)
We start with the internals list as usual.
More on timely destruction
The discussion of how to get timely destruction with Parrot's Garbage
Collection system continued. Last week Dan announced that, for languages
that make commitments to call destructors as soon as a thing goes out of
scope, there would be a set of helpful ops to allow languages to trigger
conditional DOD (Dead Object Detection) runs at appropriate times.
People weren't desperately keen on the performance hit that this entails
(though the performance hit involved with reference counting is pretty
substantial...) but we didn't manage to come up with a better solution
to the issue.
http://xrl.us/iu5
Bryan C. Warnock, patchmonster of the week
Bryan C. Warnock seems to be attempting to outdo Leo Tötsch in the
patchmonster stakes this week. He put in a miscellany of patches dealing
with the Perl based assembler, opcode sizes, debugging flags and
probably others. Most of them were applied with alacrity.
The Perl 6 Essentials book
Dan Sugalski gave a rundown of how the Perl 6 Essentials book came
about, what's in it and all that jazz. He started by apologizing for not
mentioning it before, but he thought he had. This led Clint Pierce to
wonder if there was something up with Dan's Garbage Collection system.
The existence of the book probably goes some way to explaining Leo
Tötsch's relative silence over the last few weeks. Nicholas Clark
wondered if it explains why Parrot doesn't have objects yet. Brent Dax
wondered when it would be available (by OSCON this year apparently).
http://xrl.us/iu6
IMCC, PASM and constants/macros
Clint Pierce had some big headaches with moving his BASIC interpreter
over to IMCC owing to problems with ".constant" which is legal for the
assembler, but not for IMCC. Leo Tötsch pointed Clint at IMCC's ".const"
operator. Bryan Warnock wondered if IMCC and the assembler's syntax
couldn't be unified. Leo noted that it wasn't quite that straightforward
because ".constant" declares an untyped constant, but ".const" requires
a type as well. It turns out that ".const" wasn't quite what Clint
needed, so Leo pointed him at ".sym" and ".local" which do seem to do
what he needs.
http://xrl.us/iu7
3-arg opens
Bryan Warnock wondered if
open I3, "temp.file", "r"
was valid code. Answer, no, the right way to do it is the Perlish "open
I3, "temp.file", "<"". Jürgen Bömmels promised more and better
documentation for the Parrot IO system. Eventually.
http://xrl.us/iu8
Smaller PMCs
Leo Tötsch's work on the new PMC layout continues apace. I'm afraid I
don't quite understand what's going on in this area, which does make it
rather tricky to summarize things. It seems to have a good deal to do
with memory allocation and garbage collection... Leo thinks that it's
the right thing, but there seem to be issues involved with good ways of
allocating zeroed memory.
http://xrl.us/ijt
An experimental Wiki for parrot development
Mitchell N Charity has put up an experimental Wiki for Parrot and primed
it with a few things. Stéphane Payrard pointed out that it's rather hard
to make a WikiWord from, for example, PMC. (10 points to the first
person to email [EMAIL PROTECTED] with the expansion of PMC).
http://xrl.us/iu9
IMCC packfile bug
While toying with pbc2c.pl, Luke Palmer discovered that it doesn't want
to play with IMCC generated .pbc files. Apparently this is because we
currently have two bytecode file formats. Leo Tötsch thought the problem
lay with assemble.pl which is old and slow and doesn't produce 'proper'
parrot bytecode. Leo also thought that the way pbc2c.pl worked wasn't
actually any use. Dan reckoned the time had come to ditch assemble.pl
too, and reckoned there was a case for renaming IMCC as parrot since it
can run either .pbc or assembly files. Leo liked the idea, but is
concerned about the state of the Tinderbox.
http://xrl.us/iva
Method Calling
Dan tantalized all those waiting eagerly for objects in Parrot by
discussing how to make method calls. This, of course, means a few new
ops, called "findmeth", "callmeth" and "callccmeth" for the time being.
Jonathan Sillito had a few naming consistency issues with the ops. Dan
agreed there were issues and asked for suggestions for an opcode naming
convention.
http://xrl.us/ivb
Simple Constant Propagation in IMCC
Matt Fowles posted a patch to add simple constant propagation to IMCC.
Essentially this means that, say
set I0, 5
set I1, 2
set I2, I1
add I2, I0
would compile as if it were:
set I0, 5
set I1, 2
set I2, 7
Leo Tötsch liked the idea modified it slightly and added it to the code
base, but disabled. Apparently there are problems with it, but it's a
good starting framework. There need to be lots more tests though...
http://xrl.us/ivc
Make mine SuperSized...
Bryan Warnock (in his own words) popped in to 'waffle on Parrot's core
sizes'. He proposed a way of drastically simplifying Parrot's type
system. He and Gopal V had a long discussion that I didn't quite follow.
I think Leo thinks that what Bryan proposes is doable, but I'm not
entirely sure whether he thinks it's a good idea...
http://xrl.us/ivd
Register allocation in IMCC
Clint Pierce had some problems with IMCC's register allocation. He
posted an example that gave problems and wondered if the problem was
with him or with IMCC. Leo Tötsch confirmed that it was a bug. Luke
Palmer pointed Clint at "find_global" and friends as the 'correct' way
to solve the problem. For bonus points, Clint showed of a pathological
example of why BASIC should not be anyone's favourite language.
http://xrl.us/ive
Meanwhile, in perl6-language
Cothreads
As if the Coroutine thread wasn't confusing enough, we now have the
Cothread thread, in which Michael Lazzaro argued that we should blur the
distinctions between coroutines and threads. Dave Whipp pointed everyone
at 'Austin Hastings' draft for A17 (threads)' and argued that, whilst
Coroutines, threads, closures, and various other things that Michael had
argued were aspects of the same thing were related, they sufficiently
different that bundling them all up behind a single class would lead to
badness ("a bloated blob with a fat interface" was the phrase he used).
This thread saw even more unrestrained speculation than usual and saw
the first use on the Perl 6 lists of the adjective 'Cozeny', from Simon
Cozens, possibly meaning "feeling that what is being discussed is over
fussy and generally trying to take the language a *long* way from what
Real Programmers need". This would seem to imply a verb form 'to Cozen',
"To more or less forcibly express ones Cozeny feelings".
I'm afraid this was another thread I had a hard time following. I reckon
there's some interesting ideas in there, but I'm hoping that someone
will pull it all together in an RFC type document so I can go "Remember
that Cothreads thread last week? Leon Brocard summarized it all neatly
in a single proposal, you can find it here." (Except it almost certainly
won't be Leon Brocard, it'll be Mike Lazzaro, Leon doesn't seem to do
perl6-language very much).
http://xrl.us/ivf
http://xrl.us/ivg -- Austin Hastings on threads
Compile time binding
In an effort to learn about Perl 6, Luke Palmer has been reading about
Haskell. For reasons he doesn't understand, this set him to wondering
what "::=" is supposed to mean -- it means 'compile time binding', but
what does *that* mean?
Damian Conway came through with the goods, summarizing his answer as
"::=" is to ":=" as a macro call is to a subroutine call.
http://xrl.us/ivh
Threads and Progress Monitors
Dave Whipp had some more thread questions, and wondered what would be a
good Perl 6ish way of implementing a threaded progress monitor. Whilst
the discussion of all this was interesting, I'm not sure that it's
really much to do with the language, more something that one would
implement according to taste and the particular requirements of a given
project.
http://xrl.us/ivi
Exegesis 6 Status Update
Damian announced that Exegesis six is mostly written, and should be
undergoing final revisions while he and Larry are on the Perl Whirl.
Hopefully we'll see the Exegesis before YAPC::America::North.
http://xrl.us/ivj
Acknowledgements, Announcements and Apologies
Thanks once again are due to all the good people on the Perl 6 lists.
Apologies will almost certainly be due to the organizers of YAPC North
America as I *still* haven't started writing the talks I'm supposed to
be giving.
As I noted last week, I'm awarding points (and points mean prizes) to
those kind people who spotted the deliberate mistake. Smylers gets 100
points for spotting the accidental mistake (last week was *not* in
2004.) Sam Smith, David Wheeler, David Cantrell and Leon Brocard all
earned 50 points for spotting the deliberate mistake of not mentioning
Leon Brocard. But they've helped me make up for it this week by
mentioning him twice, so the karmic balance is restored.
The points I have awarded can be redeemed for the following, wonderful
prizes:
1 A lifetime subscription to the Perl 6 summaries.
2 Er...
3 That's it
If you've appreciated this summary, please consider one or more of the
following options:
* Send money to the Perl Foundation at
http://donate.perl-foundation.org/ and help support the ongoing
development of Perl.
* Get involved in the Perl 6 process. The mailing lists are open to
all. http://dev.perl.org/perl6/ and http://www.parrotcode.org/
are good starting points with links to the appropriate mailing
lists.
* Send feedback, flames, money, photographic and writing commissions,
or a patches to Camelbones making it possible to make Perl classes
that inherit from Objective C classes (heck, if Ruby and Python can
do it) to [EMAIL PROTECTED]
--
Piers
