Hi Marc, This looks like a Perl 5 complementary character match: [^:]* But it means something quite different in Perl6. From S05 <http://perlcabal.org/syn/S05.html>
Bracket rationalization <http://perlcabal.org/syn/S05.html#Bracket_rationalization> [ ... ] is no longer a character class. It now delimits a non-capturing group. Changed metacharacters <http://perlcabal.org/syn/S05.html#Changed_metacharacters>^ and $ now always match the start/end of a string Backtracking control <http://perlcabal.org/syn/S05.html#Backtracking_control>To force the preceding atom to do no backtracking, use a single : In summary, this pattern is repeatably matching an empty start-of-string. A Perl 6 equivalent is: token gecos { <- [':']>* } This matches a complementary character class; all but ':'. Also, the <home> and <shell> rules aren't fully matching their test input at the moment. Cheers, - David On Sat, Jul 12, 2014 at 10:07 AM, Marc Chantreux <m...@unistra.fr> wrote: > hello, > > using perl6 version 2014.04 built on MoarVM version 2014.04 > > i'm trying to write a grammar to parse the result of a `getent passwd` > but when i test the gecos (which could be empty), i fall into a loop. > > the pb appears whenever i try to match something that can be empty using > the * quantifier. > > I guess i miss a simple point there but i can't figure out what. Any > help (or feedback on any other part of the code) would be appreciated. > > regards > > use v6; > use Test; > > grammar PAccountDB { > token TOP { ^ <account>* $ } > token account { > <login> > ':' <passwd> > ':' <uid> > ':' <gid> > ':' <gecos> > ':' <home> > ':' <shell> > \n > } > token login { <[a..z]>+ } > token passwd { 'x' } > token numid { \d+ } > token uid { <.numid> } > token gid { <.numid> } > token gecos { [^:]* } > token path { '/' <-[\x00'/']>+ } > token home { <.path> } > token shell { <.path> } > } > > for > ( uid => '445' > , gid => '445' > , shell => '/bin/false' > , home => '/home/mc' > # , gecos => 'server account,,,' > , login => 'root' ) { > my ( $rule, $candidate ) = .kv; > ok ?PAccountDB.subparse( $candidate, :rule($rule) ) > , "subrule $rule matches $candidate"; > } > > > -- > Marc Chantreux > Université de Strasbourg, Direction Informatique > 14 Rue René Descartes, > 67084 STRASBOURG CEDEX > ☎: 03.68.85.57.40 > http://unistra.fr > "Don't believe everything you read on the Internet" > -- Abraham Lincoln >
