Perl 6 Design Minutes for 09 December 2009

The Perl 6 design team met by phone on 09 December 2009. Larry, Allison, Patrick, Will, and chromatic attended.

Will:

• some work on NQP port of Partcl
• Patrick has been very helpful
• sent a message to the Parrot list about the planning meeting this Sunday
• initiated a community document to discuss those plans

Allison:

• implemented large chunks of obscure C code to perform fast string matching using the FFT
• wondering if that'd be useful in Parrot
• maybe we do our indexing operations by character set in the NFG form
• also does very basic pattern matching by leaving out optional characters
• could be useable in the core tests, where it's tricky to depend on PGE
• this was my final assignment before the Christmas break
• have a month off to work on Parrot stuff then
• I'll show off my assignment when I submit it

Patrick:

• finished my final report for my Hague grant
• haven't quite finished the grant, but left TODO items
• rather than trying to finish everything and then write the report, I'd draft the report and keep notes on what I needed to finish
• need to work on HLL interop
• enable Perl 6 and other Parrot languages to load libraries from other HLLs
• will work on that over the next few days
• had several coversations about optimizations, constants, and inferior runloops
• made minor PAST improvements
• integer constants can automatically promote to num constants without going through a PMC
• updated NQP to make it easier to write custom operator subs, if you're using the operator precedence parser
• implemented the beginnings of smart matching
• not full Perl 6 smart match
• makes sense in the Parrot context
• can match against regexes, tokens, rules, and any types with protoobjects
• code looks more like Perl 6
• not much on Rakudo besides answering questions
• will get back to the Rakudo-ng merge after finishing my grant work
• also worked on Partcl
• updated its regex syntax, particularly for enumerated character classes
• fixed it to handle unquoted, non-word characters in regexes
• previously it only handled barewords as literal matches
• it's closer to the Perl 5 syntax now

Larry:

• didn't like the name PairValSet, renamed it EnumMap
• likewise PairSet is now PairMap, and PairVal is just Enum
• so individual constant pairs now called "enums"
• we distinguish pairs, which have read-write values, from enums, which are constant in the value
• you can now do.enums on hashes and arrays as well as enumerations
• differs from.pairs, which give reference semantics into the values of the original data structure
• .enums gives you a constant snapshot
• David Green suggested renaming Enum.name to Enum.key, and he was right, since they're constant pairs
• trying to be consistent about calling the whole type an "enumeration" and referring to the bits as "enums", even though the keyword is enum
• thought people would rebel at typing the long name
• clarified that the anonymous enum is compile-time evaluated as an anonymous list of constants
• you can always cast to an EnumMap at run time for the other behavior
• simplifying conditional semantics
• STD parser now parses a WHENCE closure as part of the typename, rather than relying on subscript parse
• block escape within a closure within a string used to parse as a normal block by responding to comments outside of the block
• already fixed the embedded block in the regex syntax
• made that usable by strings and regexes now
• blocks in regular code try to figure out if they're at the end of a statement
• look for the trailing curly
• inside a string or regex, there are no statements
• it makes no sense to look for the end of the statement there
• the obsolescence messages were still in the old framework that upsets some Perl 5 people
• changed the wording to "Unsupported use of..."
• #perl6 found a precedence inconsistency in parsing of list prefixes vs list infixes in NG
• turned out to be wrong in STD first, and NG copied it
• I fixed it in STD, Patrick fixed it in NG
• otherwise last week was rather too ADD-ish, so mostly did Q&A on IRC

c:

• fixed some bugs
• made some optimizations
• think I've fixed most constant PMCs in PBC now, which should help NQP and Rakudo

Patrick:

• it'll take a while before Jonathan and I can take advantage of that
• Allison, when you push_eh an ExceptionHandler onto an array in a context, it creates an RPA
• does that hold other things besides an EH?

Allison:

• potentially
• events get stored in the scheduler
• only EHs are scoped to a context
• the old pushmark/popmark stuff to do actions used that same global array
• it may have changed to use the same array
• that's deprecated though
• they won't use that array for long

Patrick:

• I need something to replace pushaction and popaction before they go away
• when we handle LEAVE semantics, we want to avoid generating an exception to leave that scope for caching
• I don't want to generate and rethrow actions to go up the stack
• those ops let me do that without generating exceptions

Allison:

• we do need singleton exception objects for FAIL and RETURN
• no extra information needed
• right now, you can insert anything you want in that array
• the local_branch and local_return uses that array

Patrick:

• it shouldn't
• bsr and ret may have
• I provide my own there

Allison:

• oh right
• I might not have checked in that code

Patrick:

• by the way, NQP doesn't use local_branch or local_return

Syndicated 2010-01-21 04:41:19 from pudge