use Perl

The Perl 6 design team met by phone on 02 December 2009. Larry, Allison, Patrick, Will, and chromatic attended.

Allison:

• mostly mailing list talk
• finishing up course work before the break

Larry:

• renamed void context to sink context
• appears to have worked
• working out the semantics of higher-level abstract conversions with the lower-level ones
• the method conversions .Num, .Str, .Bool are low-level
• the abstract ones are conversions to roles, like + to Numeric
• the generic role is in charge of which conversion to use
• seems to map better to what people expect
• started to straighten out .true versus .Bool
• renamed is ref to is parcel
• made it synonymous with backslash
• did more work on the Rat semantics to separate out what we originally called Ratio
• now called FatRat
• looked at all of the mentions of context in the spec
• removed overloaded meanings
• dynamic contexts are now call frames
• contextual variables are now dynamic variables
• context means two things now, the old list versus scalar notion and some notion of a thread's context (left those alone)

Allison:

• "call frame" makes a lot of sense
• we may kidnap that

Larry:

• Damian has sent in various spec tweaks, as we gear up to do a Perl 6 book
• kicked the p5=> out of the core into something supplied as a macro by a translator
• ranges now preserve interval semantics when you do math on ranges
• renamed blorst to blast so we can talk about phaser blasts
• worked on the nature of constants
• constant declaration is now in the same category as the subset keyword and othe declarators
• now have an anon declarator
• it confused people to misuse my or our in a situation without a name
• had added an else to go with also, as Damian suggested
• removed both of those in favor of a new metaoperator which guarantees sequential evaluation of the arguments
• the S metaoperator
• after deciding that undef is a lousy concept in Perl 6 -- it turns out to mean five or six different things -- we decided to untangle all of them
• temporarily renamed Object to U, for the most generic undefined
• then revised, per Damian's suggestion, to Mu
• that represents the most generic undefined value and the type from which all other classes derive
• one use of undef was in smart matching
• added a .notdef method for the convenience of testing definedness
• possible to write longer versions which work with smart match
• a convenience method felt nicer
• used heavily in the test suite
• can test something directly with the method without having to use smartmatch
• worked on the Rats of unusual precision (not ROUSes)
• some confusion as to when things get limited to 64-bit denominators
• clarified that only the user-visible results use that limit
• intermediate calculations performed by an operator which can and must exceed that limit temporarily
• added a scaling option to the round function
• easy to round to a particular rational value
• after lots of carping about how ill-defined enums are, I rewrote that spec
• they're no longer roles
• the but and does infix operators still can intuit an attribute property mixin
• that's a function of operator DWIMmery though
• enums, to the first approximation, are simply collections of constants
• they also supply a method, .mapping, which returns a hashlike mapping
• that takes care of most of the special cases
• STD now forces the symbols it matches into strings
• lots of hacking to track spec changes, such as renames
• complex number literals now parse the initial plus or minus as part of the complex
• prevents tragedy in negating the wrong part of the number
• need to nail down pure versus impure ideas to move that into constant folding
• infix operators couldn't accept assignment operator forms for baseops with square bracket or hyperoperator forms; fixed that
• worked on error messages, especially the Borg forms
• removed some redundant rules and the term lexer decreased in size by two-thirds
• added a warning about the use of undef; gives a long list of things you might mean instead
• if you use ** in a range in a regex, but you mess it up where it parses .. as matching anything, you now get a malformed range warning
• added a few missing things to the CORE setting, such as range iterator
• now trims pi and e to fit in to a Rat64
• tweaked viv to support code production of infix operators
• don't have to grovel around to find the operator

Patrick:

• not a lot of direct Rakudo coding
• working in the ng branch
• have eval working; it doesn't poke in the middle of the compiler guts
• also provides a cleaner interface that other HLLs can reuse from PCT
• added regular expression matching
• still needs some work
• added array push and unshift
• fixed a few bugs
• otherwise working on some design issues, such as lazy lists
• answering questions for the branch
• lots of syntax improvements in NQP
• improved error messages
• adding a few features
• added :c($x) (continue) and :p($x) (position) options for regex matching in NQP and ng
• those didn't exist in PGE or the previous Rakudo
• cleaned up the abstract match handling (.ast) to match the new spec
• reviewed Stephen Weeks's work to add try and catch blocks, and it was fine
• updated a few things in NQP to make it easier to write built-in operators
• enables the Perl 6 operator syntax directly
• also working on Partcl
• handles quite a bit already, but not enough
• keep plugging away
• the parsing works closely to what the language spec requires
• I like that
• throughout the implementation, we've focused on doing most of it in NQP itself, not PIR
• seems to work out fine
• adding lots of different commands
• that's fed back into improvements for NQP
• working out very well
• started a regex syntax for Partcl which matches what Tcl requires
• previously used the P5 syntax, which isn't an exact match
• an example for other people of how to do it
• mostly doing Parrot fixes to support the other tasks
• a few small updates to PAST
• improving code generation
• enabling features that other languages need
• bugfix for handling self attribute access in method calls
• adding methods and interfaces for the compiler objects
• will refocus on Rakudo's ng branch
• lots of work fleshing out HLL interop interfaces
• necessary to handle module imports
• also a roadmap item and the last piece on my Hague grant
• posted an interim report recently
• that report marks the halfway point, but I'm much further than that
• should finish the grant this week

Will:

• have a version of Partcl mostly written in NQP
• putting some energy into a discussion about reexamining our roadmap priorities
• been doing that incrementally, but never had a specific meeting just to talk about that
• trying to focus some energy on the list

c:

• fixed a bug or two
• profiled and optimized a bit

Allison:

• how long would it take to migrate Pynie to the new NQP?

Patrick:

• shouldn't take too long at all

Allison:

• have a month off between classes starting in a week
• might work on that

Patrick:

• glad to help wherever I can
• might be an area where you run into a problem and I need to write documentation

Will:

• you can look at the NQP version of Partcl to start

Allison:

• examples have been most helpful in the past

Will:

• Stephen's also converting Squaak and abc to NQP
• might be helpful to look at those too