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Why can’t flex understand this variable trailing context pattern?
To: Gregory Margo <gmargo@newton.vip.best.com> Subject: Re: flex-2.5.3 bug report In-reply-to: Your message of Sat, 23 Nov 1996 16:50:09 PST. Date: Sat, 23 Nov 1996 17:07:32 PST From: Vern Paxson <vern> > Enclosed is a lex file that "real" lex will process, but I cannot get > flex to process it. Could you try it and maybe point me in the right direction? Your problem is that some of the definitions in the scanner use the '/' trailing context operator, and have it enclosed in ()'s. Flex does not allow this operator to be enclosed in ()'s because doing so allows undefined regular expressions such as "(a/b)+". So the solution is to remove the parentheses. Note that you must also be building the scanner with the -l option for AT&T lex compatibility. Without this option, flex automatically encloses the definitions in parentheses. Vern
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