Older blog entries for chromatic (starting at number 481)

Perl 6 Design Minutes for 16 June 2010

Syndicated 2010-06-26 17:07:30 from pudge

Perl 6 Design Minutes for 09 June 2010

The Perl 6 design team met by phone on 09 June 2010. Larry, Allison, Patrick, and chromatic attended.

Larry:

• not much spec change this week
• figured out a syntax for a regex block to return more than one cursor
• based on gather/take
• in STD hacking, continued to assist Stefan O'Rear in getting STD bootstrapped via viv
• now that it's bootstrapped, we're refactoring things that make sense now
• we're now starting to move bits of Cursor code from Perl 5 into Perl 6
• refactoring the grammar for sanity of design
• started upgrading STD to normal Perl 6 syntax where it previously catered to gimme5's limitations
• for example, switched STD's old.<_from> and.<_pos> hash lookups to using.from and.pos accessors
• started the prep work for moving EXPR out of STD to make it generally available to any grammar wanting operator precedence
• in STD parsing, made Perl 5 $< detection have a longer token to avoid confusion with match variables
• STD no longer attempts two-terms detection on infix_circumfix_meta_operator
• STD now parses >>R~<< correctly, or at least dwimmily
• STD doesn't complain about P5isms in printf formats like "%{$count}s"
• STD was parsing/m and/s with the opposite semantics
• termish now localizes $*MULTINESS in its scope so that inner declarations aren't accidentally multified
• STD now carps about package Foo; as a Perl 5 construct

Allison:

• talked to Chris Shiflett, a PHP developer, on someone from the PHP community to sit on the Parrot board
• will be in the US for a few weeks

Patrick:

• working on list simplification
• had a couple of breakthrough ideas on Monday
• working on the implementation now
• worked out inversion lists for character class matching in regexes
• will make them faster, especially with long ranges of character classes
• fixed a half-dozen tickets in RT
• fixed Rakudo hash constructors
• fixed an intermittent bug with colon-pair signatures
• two possible parses exist in STD, but we removed an unneeded one in Rakudo
• fixed a bug with Parrot's exit opcode
• NQP and PAST needed an update not to cheat with PASM constants
• I fixed that too
• Vasily added multisub and multimethod support to NQP, that was a big plus
• fixed the ** quantifier in regexes to understand surrounding whitespace
• regex engine tried to match beyond the end of a string, so I added guards for that
• will work on lists furiously before the next release
• I don't think it'll take long
• closures are next, hope to have those in place by the weekend

c:

• released a new version of Pod::PseudoPod::LaTeX to support the various books in progress

Syndicated 2010-06-24 12:24:33 from pudge

Perl 6 Design Minutes for 02 June 2010

Syndicated 2010-06-22 01:12:29 from pudge

Perl 6 Design Minutes for 26 May 2010

The Perl 6 design team met by phone on 26 May 2010. Larry, Allison, Patrick, Will, and chromatic attended.

Larry:

• :() syntax is now always signature
• we now use foofix:[...] as the general op form instead of foofix:(...)
• refactored the sematics of:nth and:x
• :nth() now only ever takes a monotonically increasing list
• S03 now explains how "not-raising" works on != and ne
• it now basically matches the intuitions of an English speaker via HOP definition of negate metaop
• STD sometimes didn't require semi between statements
• statement modifiers are expression terminators but not valid statement terminators
• an unexpected statement modifier word like if could terminate one statement and start another
• fixed up backslashes in character classes to allow \s etc and reject \u etc
• STD was accidentally using the same lexpad for different multis
• Cursor now treats:() on name extension as a signature always, never as a categorical
• we shouldn't introduce the stopper for circumfix until we're in the circumfix, or we can't use the same char on both ends
• placeholder messages error messages are now much more informative and correct
• we now disallow use of placeholder after same variable has been used as a non-placeholder, even for an outer reference
• renamed add_macro (which it doesn't) to add_categorical (which it does)
• participating frequently in discussions on semantics both on irc and p6l
• working closely with sorear++ as he brings viv closer to bootstrapping, yay!
• soon can bootstrap past gimme5

Allison:

• worked on Pynie this week in my limited spare time
• one goal is to generate the parser directly from the Python grammar
• wrote a small, lightweight PEG parser which generates a match tree from the Python 3 grammar
• can generate a lexer directly
• right now it creates a parse tree
• looks similar to the match nodes of NQP-rx
• dumps out a tree to the PIR parser
• working on PaFo elections for next year, but trying to delegate those
• will have more time after June 7

Will:

• working on Perl 6 advent tests
• many more people are doing more work than me
• liasing with Rakudo folks for any important Parrot bugs before the Rakudo Star release
• my current direction there is "don't break anything"

Patrick:

• sorear added hash flattening to NQP
• lots of work on closures in PAST and NQP
• they properly clone
• fixes some lexical problems
• need to get that to work in Rakudo
• that's tougher; Rakudo has to wrap Parrot subs
• wrapper object needs cloning as well, along with its attributes
• we'll add a new PAST node type to help
• that node understands contexts
• essentially a way to add void context optimizations to your AST
• that solves many problems in Rakudo beyond closures
• added a setting into NQP along with its test suite
• not automatically loaded, but available
• contains standard hash and array methods
• Parrot's ops2c project uses those
• other people can update and enhance that setting as necessary
• NQP also has the ability to parse type names
• NQP doesn't do anything with them yet
• eventually they'll allow the use of multis
• cleaning up some NQP bugs regarding lexicals and package storage of subs
• Bruce Keeler enabled variable interpolations in regexes
• working on some refactorings to simplify that approach
• works in NQP and Rakudo now
• that's a feature we've never had before
• Rakudo's REPL now works better, thanks to sorear
• HLLCompiler now written more in NQP as part of that
• NQP now can do eval
• NQP remembers lexicals in interactive mode now
• adding that to Rakudo is more complex
• working on that
• pleased with the progress on #perl6

c:

• reviewing long term plans for GC and Lorito
• should have more time free soon

Syndicated 2010-06-20 19:40:02 from pudge

Perl 6 Design Minutes for 19 May 2010

The Perl 6 design team met by phone on 19 May 2010. Larry, Will, and chromatic attended. Patrick added his notes later.

Larry:

• S03 makes more explicit that doctrine that ~~ topicalizes, and removes smartmatch table fossils that automatically fall out from that
• S05 renames 'accent' to 'mark' for better Unicode conformance
• :a and:aa changed to:m and:mm
• S05 disrequires retroactive semantics on:samecase and:samemark
• the method form must now explicitly add case or mark modifiers to the pattern
• regularized mm// to ms// to avoid confusion with new:m ignoremark option
• STD now does a bit better at diagnosing bogus ??!! constructs of various sorts
• STD now correctly adds operators to symbol tables as subs
• CORE.setting now has protos of all the operators so they can be recognized as subs too
• Cursor now canonicalize operator names in the symbol table
• btw, not quite like specced
• STD now reads user's mind on 'Str $toto' to intuit missing declarator
• STD now properly diagnoses a typename between routine declarator and sub name

Will:

• working on code for Carl Masak, trying to get his poker code example running on Rakudo
• both fun and frustrating
• some stuff doesn't quite work yet
• going through the Advent examples
• adding them to spectests
• make sure we won't regress on such public examples
• other people are helping with that now

c:

• will get back to editing the Rakudo book soon
• hope to have it in print by YAPC, but no guarantee

Patrick:

• fixed closures in NQP, as a precursor for fixing them in Rakudo
• worked with sorear on REPL in Rakudo and PCT in general
• ported the NQP "standard library" done by japhb++, bacek++, and many others into the nqp-rx repository and made it part of the standard build sequence for nqp and Parrot
• decided we need a new "context sensitive" node type in PAST, will be used to create proper closures and to handle sink context
• worked with bacek on adding better multimethod support to PAST and nqp-rx
• discovered a problem with lexical subs in NQP being automatically entered into the package namespace (and some existing code relying on this behavior)
• did some initial fixes to at least get things entered properly, but a complete fix may require a deprecation cycle
• plan to review others' patches this week
• plan to fix REPL, closures, and sink context in Rakudo (since those are currently large pain points)
• plan to work on loops and iterators after that

Syndicated 2010-06-16 21:38:09 from pudge

Perl 6 Design Minutes for 12 May 2010

Syndicated 2010-06-16 01:47:02 from pudge

Perl 6 Design Minutes for 05 May 2010

The Perl 6 design team met by phone on 05 May 2010. Larry, Allison, Patrick, Will, and chromatic attended.

Larry:

• various spec updates, some major
• removed p5=> description because it's not supported in core
• deleted self:sort construct because self isn't a real syntactic category
• explained Perl patterns in terms of PEGs, and spec'ed tiebreaking rules explicitly
• last but not least, finally purveyed the long-threatened revamp of proto to keep routine and method semantics similar
• they all now work much more like the multiple dispatch semantics currently used by STD, where we always call the proto first
• the proto is then always in charge of the actual multiple dispatch; it can of course delegate that
• and the default for a null body corresponds closely to current semantics
• in hacking news, the lexer generator mislaid any alternative that was a bare. pattern, so cursor_fate never called its alternative, oops
• took me a long time to run that one down, because it resulted in a horrendous backtrack causing mysterious misplaced errors
• revamped character class parsing to be more helpful and correct
• STD now check a normal regex bracket's innards for old-school character class, and warns if found
• added a.looks_like_cclass method to Cursor to detect most accidental uses of P5 ranges
• some valid P6 brackets will complain, but the workarounds are easy
• just put whitespace on both ends is one way
• removed a few of these old-school-ish character classes from STD
• changed:tr language to:cc language since character classes share it
• (translation pays more attention to ordering, but the language is the same)
• turned out parsing character classes discovered issues in STD; various character classes needed to backslash # that would otherwise be a comment
• to that end, we now allow \# in character classes instead of misparsing as unspace
• if we find an invalid - in a regex, we now presume we're in an old-school character class and fail with a sorry instead of a panic to give the character class code a shot at it
• STD now uses ~ syntax for regex brackets to set $*GOAL correctly
• cleaned up recursive panic detection; it was possible to get both false positives and negatives before
• STD shouldn't use 'note' to emit a panic inside a suppose because that leaks the message that should be trapped
• STD now suppresses duplicate sorry messages more correctly
• sorry no longer uses panic in a supposition, but dies directly to throw the exception to the suppose's try block
• STD now allows subscripts on regex variables so $x[0] isn't taken as a character class; still needs speccing

Patrick:

• can we make them consistent?

Larry:

• historically S05 has allowed bare arrays to mean interpolation

Patrick:

• we've never had a working implementation of that

Larry:

• a bare @ would be illegal

Patrick:

• it's currently illegal

Larry:

• you'd have to backslash it to match part of an email address
• it's not like the @ alternations are a big deal one way or another
• that'd be a little more consistent
• I forced it to think of the sigil as $ than what it really is

Patrick:

• after seeing how Jonathan et all did interpolation for quoted strings, I thought we should do the same thing in regexes

Larry:

• STD now has a partial fix to prevent leakage of::T from role signatures
• unfortunately, the current fix will lose signatures of file-scoped generic roles
• this probably has to do with not knowing whether we're really going to want a new pad; unfortunately we'd have to look ahead to know that currently
• various other minor tweaks and bug fixes in STD and Cursor

Patrick:

• mostly responding to messages and reports
• should be able to get back to coding full-time and online for the next week
• plan to resolve the list and closure issues with NQP and Rakudo
• will answer other questions and try to keep other people productive
• planning for the Rakudo Star release on June

Allison:

• busy with the last week of classes
• spent most of it writing a little language with PCT
• it was easy to use and easy to swap the stages of PCT
• I remembered what Patrick did with LOLCODE
• also had a discussion of source code control systems
• next week should be more productive
• need to work more closely with Debian packagers to get packages into Debian

Will:

• cleaning out as many deprecations in Parrot as possible
• trying to improve the speed of CodeString after the immutable STRINGs merge
• bundling lots of little concats helps
• hope to merge in an optimization branch for that by the weekend
• want to make that faster or less memory intensive
• may require the use of a new StringBuilder for Parrot
• hopefully will result in a faster Rakudo build

Patrick:

• I've never seen CodeString take a long time
• unless you run into memory problems

• * discussion of the StringBuilder PMC *

c:

• still working on optimizations, particularly CodeString
• looking at more PBC and PBC-building optimizations
• PBC size went down dramatically and startup improved for Rakudo
• should have that much faster for the 2.4 release
• will poke at GC tasks starting next week

Syndicated 2010-05-10 06:07:34 from pudge

Perl 6 Design Minutes for 28 April 2010

Syndicated 2010-05-02 00:27:42 from pudge

Perl 6 Design Minutes for 21 April 2010

Syndicated 2010-04-28 22:20:35 from pudge

Perl 6 Design Minutes for 14 April 2010

The Perl 6 design team met by phone on 14 April 2010. Larry, Allison, Patrick, Will, and chromatic attended.

Larry:

• on p6l, did a bit of bikeshed paint removal with regard to hyphens vs underscores
• S02 now explicitly disallows both whitespace and unspace in top level of an interpolation
• per spec change, when STD is parsing an interpolation inside quotes and looking for a possible postfix, we now presume that a backslash belongs to the quotes and is not an unspace
• in the src/perl6 directory, renamed all Perl 6.pm files to.pm6 to avoid confusion
• this was necessary because the implementation of STD translates Perl 6 back to the corresponding Perl 5
• the ambiguity was causing problems with tools such as NYTProf
• Cursor.pmc now prefers.pm6 over.pm in any particular directory when searching for Perl 6 code
• as usual lately, most of my hacking work was in improving the human interface of the parser
• STD now distinguishes two final messages: "Parse failed" vs "Check failed"
• STD now warns on attempts to smartmatch with True or False
• STD now distinguishes continuable-but-fatal "sorry" messages from immediately fatal "panic" messages
• sorry messages will eventually fail at check time
• changed many of STD's semantic errors to use sorry messages when the parse state is not affected
• modified moritz++'s conflict marker patch to be more like the Clang compiler's behavior
• conflict markers now emit a "sorry" message and continues parsing one side of the conflict
• also fixed a buglet that prevented it from processing the conflict marker if first thing in the file
• while fixing the vws (vertical white space) rule for that, also changed it so that extra lines are now eaten with \V*\v for consistency
• it had be using \N*\v
• gimme5 now supports pointing to both ends of missing goal message
• STD's "Couldn't find final..." messages now use that capability to point to both ends of the error
• standard quotes now also use the ~ compositor to set the goal and get that behavior
• STD will now dwim <<op>> ("Texas hypers") better even if op contains angles
• suppressed confusing backtracking on ~<< that produced a misleading quotewords error
• some other patches
• CORE.setting now recognizes the 'note' function
• gimme5 now translates note to print STDERR
• cleaned up some unneeded locmesses
• Actions.pm now handles prefix metaops without spewing spurious yaml dumps

Allison:

• worked on TT #389
• the actual fix was about two lines
• spent a lot of time fixing tests around it
• didn't like the original two-line fix
• fixed it in IMCC by passing along the:nsentry flag
• NQP-rx still depends on that feature
• I understood from Patrick that NQP-rx doesn't need that feature
• don't want to launch that before the 2.3 release
• worked on a lot of smaller issues
• worked on the Parrot Developer Virtual Summit
• will talk about some process changes more, as there are details to work out
• will work on GC as the next priority
• useful for Rakudo in general and Parrot concurrency

Patrick:

• catching up on mail and tickets
• should get back to coding in the next couple of days

c:

• worked on the immutable strings branch
• need a couple of changes in the Rakudo binder
• now it's time to convince everyone else it's a worthwhile design change
• going to work on bugfixes
• will try to land the constant string cache
• otherwise, added some optimizations

Will:

• worked on Partcl
• fixed a Parrot bug that broke Rakudo
• does Rakudo need TT #389 in 2.3?

Syndicated 2010-04-21 04:09:26 from pudge