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To: "Dmitriy Goldobin" <gold@ems.chel.su> Subject: Re: FLEX trouble In-reply-to: Your message of Mon, 31 May 1999 18:44:49 PDT. Date: Tue, 01 Jun 1999 00:15:07 PDT From: Vern Paxson <vern> > I have a trouble with FLEX. Why rule "/*".*"*/" work properly,=20 > but rule "/*"(.|\n)*"*/" don't work ? The second of these will have to scan the entire input stream (because "(.|\n)*" matches an arbitrary amount of any text) in order to see if it ends with "*/", terminating the comment. That potentially will overflow the input buffer. > More complex rule "/*"([^*]|(\*/[^/]))*"*/ give an error > 'unrecognized rule'. You can't use the '/' operator inside parentheses. It's not clear what "(a/b)*" actually means. > I now use workaround with state <comment>, but single-rule is > better, i think. Single-rule is nice but will always have the problem of either setting restrictions on comments (like not allowing multi-line comments) and/or running the risk of consuming the entire input stream, as noted above. Vern