I'm probably off the mark a little bit.... but 'rule' implies that whitespace is really <.ws> (totally ignored white space matching thingy). '|' is the Longes

I'm probably off the mark a little bit.... but 'rule' implies that whitespace is really <.ws> (totally ignored white space matching thingy). '|' is the Longest-Match-First (different from Perl/PCRE/etc). LMF is not possible in the case where it is not a DFA... the implicit <.ws> that is there by using 'rule' and having a space might be your problem... :) TL;DR Don't forget that 'rule' does <.ws> magic. This may or may not actually be part of the problem... I have seen a similar sort of thing and only half understand the answer i got.. Check your implicit <.ws> and '|' LMF.