Perl 6 Design Minutes for 27 January 2010

The Perl 6 design team met by phone on 27 January 2010. Larry, Allison, Patrick, and chromatic attended.

Larry:

• tweaked definition of when a series operator is considered infinite
• nailed down more list assignment semantics with respect to interators
• clarified how ($a, $b, @a) = 1..* works
• KeyWeight deletion criterion kept consistent with other KeyHash types
• negative keyweights are allowed to fail at pick time
• "mostly eager" now assumes unknown closure generators are probably infinite
• random whackage on List, Seq, Parcel, Capture, Iterator, Nil etc.
• List is now simply the iterator role, and doesn't do Positional
• Seq takes over Positional duties for reified (or reifiable) value lists
• think of Seq now as a constant Array (but also lazy like Array)
• Iterable now means you can ask for an iterator, but doesn't do List
• Array, Seq, etc do Iterable, but not List
• only actual iterators do List
• Nil is defined as a suitable sentinel for both list and slice iterators
• continued to rethink that with pmichaud++ et al
• we'll probably end up with an EMPTY special exception object to be the iterator sentinal
• proposed an E operator to go with it to make testing for EMPTY across multiple iterators very fast
• other than that, mostly just bug whacking, no major refactors
• still thinking about doing real LTM for STD
• did lazify Cursor's fnum->fate translations for shorter LTM candidates in preparation for smarter LTM
• we don't need special objects for the items that get matches
• we do need to think more about the hyper cases
• how to do list processing using balanced trees of delegated sub refs
• don't want to build in serial assumptions where we don't need them

Patrick:

• made the Rakudo #25 release last week
• it was much easier to make the release than explain what we were planning to do instead
• also working on iterators and lists
• NG branch is blocking on that
• worked on the design in my head for three weeks
• realized that we were doing iterators completely wrong the other night
• Larry's making some useful changes to the spec in response
• there are still some unclear spots in the spec
• we need an implementation to figure those out
• my biggest question is the relationship between List, Parcel, Itertor, and array
• as of this morning, I think I have it
• that code seems to be working and efficient
• so far it's working well
• continuing with that
• wrote a very short range iterator prototype that colomon has used
• also write a map iterator that works
• coming up with examples for the zip operator was nice
• good ideas for what we need to be able to do
• objects that can iterate have a.iterator() method
• to interpolate that into a list,.list() returns a flat Parcel for that iterator
• Parcels know how to generate Iterators
• those know how to handle Iterators of Iterators
• I suspect that's how we do hyper iteration
• change Parcels to understand that
• adding pieces back into the ng branch
• next I have to fix slurpy parameters
• many of our builtins need that
• need to figure out Jonathan's code to do that
• after that, I'll do arrays
• that should remove the blockers on the ng branch

Allison:

• working on Pynie
• Francois has helped greatly to update it for Plumage

c:

• still working on the TT #389 fix
• think I have the right design, just need time to implement it
• working on a potential new time for #parrotsketch

Allison:

• thinking about hackathons
• would be nice to have a Rakudo hackathon at YAPC::NA

c:

• Parrot will come up; didn't it come up about half the time last year?

Patrick:

• it was all Parrot

Allison:

• you'll have an influx of Rakudo interest two months after Rakudo Star

Patrick:

• probably will have one before then
• but can tell people "Go to YAPC; we'll show you how to help in person there"

Syndicated 2010-01-29 21:00:38 from pudge