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To: Petr Danecek <petr@ics.cas.cz> Subject: Re: flex - question In-reply-to: Your message of Mon, 28 Jun 1999 19:21:41 PDT. Date: Fri, 02 Jul 1999 16:52:13 PDT From: Vern Paxson <vern> > file, it takes an enormous amount of time. It is funny, because the > source code has only 12 rules!!! I think it looks like an exponencial > growth. Right, that's the problem - some patterns (those with a lot of ambiguity, where yours has because at any given time the scanner can be in the middle of all sorts of combinations of the different rules) blow up exponentially. For your rules, there is an easy fix. Change the ".*" that comes fater the directory name to "[^ ]*". With that in place, the rules are no longer nearly so ambiguous, because then once one of the directories has been matched, no other can be matched (since they all require a leading blank). If that's not an acceptable solution, then you can enter a start state to pick up the .*\n after each directory is matched. Also note that for speed, you'll want to add a ".*" rule at the end, otherwise rules that don't match any of the patterns will be matched very slowly, a character at a time. Vern