On Sat Dec 29 00:24:28 2007, pmichaud wrote: > On Sun, Dec 23, 2007 at 06:01:22PM -0800, Stephen Weeks wrote: > > Working on getting parrot to parse the lojban grammar, I found that it > > would hang forever with --target=parse. Tracked it down to a <ws> rule. > > When I define a custom token ws in the grammar, it parses without > > problem. > > > > Built a stripped-down test case. > > > > http://nopaste.snit.ch:8001/paste has the grammar. > > http://pleasedieinafire.net/~tene/jp.tar.bz2 has the grammar, a slightly > > modified version of abc's .pir and Makefile. > > > > Can anyone else confirm this? Am I doing something wrong? > > The default <ws> rule (as defined by Synopsis 5) only requires whitespace > between two word characters. Thus the grammar as written (without a custom > <ws> rule) looks for an infinite number of <space_char> matches, and since > <ws> can match an empty string when not between two word characters, PGE > gets caught in an infinite loop. > > Thus this ticket should likely be merged with or treated as a duplicate > of RT#37745 (handle repeated zero-length captures in PGE). At any rate, > until #37745 is fixed it's probably worthwhile to make sure grammars don't > end up with repeated zero-length subrules or subpatterns. > > Pm
37745 is now being tracked at https://trac.parrot.org/parrot/ticket/721 Closing this ticket as a duplicate of that per Patrick's suggestion. If you'd like to preserve this as a separate issue, please open a new ticket at https://trac.parrot.org/ Regards. -- Will "Coke" Coleda _______________________________________________ http://lists.parrot.org/mailman/listinfo/parrot-dev
