Re: Flex and EOF

"Michael Tiomkin" <tmk@netvision.net.il>
9 Apr 2006 17:26:37 -0400

          From comp.compilers

Related articles
Flex and EOF matteo.corti@gmail.com (Matteo Corti) (2006-04-08)
Re: Flex and EOF cdodd@acm.org (Chris Dodd) (2006-04-09)
Re: Flex and EOF rsc@swtch.com (Russ Cox) (2006-04-09)
Re: Flex and EOF tmk@netvision.net.il (Michael Tiomkin) (2006-04-09)
Re: Flex and EOF DrDiettrich@compuserve.de (Hans-Peter Diettrich) (2006-04-10)
Re: Flex and EOF matteo.corti@gmail.com (Matteo Corti) (2006-04-12)
Re: Flex and EOF idbaxter@semdesigns.com (Ira Baxter) (2006-04-12)
| List of all articles for this month |

From: "Michael Tiomkin" <tmk@netvision.net.il>
Newsgroups: comp.compilers
Date: 9 Apr 2006 17:26:37 -0400
Organization: http://groups.google.com
References: 06-04-035
Keywords: lex, comment
Posted-Date: 09 Apr 2006 17:26:37 EDT

Matteo Corti wrote:
> Hi,
>
> I have a rule in my lexer to skip shell-like comments:
>
> #.*$ /* skip comments */
>
> which works just fine if there is \n at the end of the line.
> If the comment is in the last line wich is terminated by EOF the rule
> obviously fails.
>
> I tried something like:
>
> #.*<<EOF>>
>
> but flex complains about an "unrecognized rule". Any hint?


    The easiest way is to introduce the new state, shell_comment, switch
to it on a '#', do nothing on ., and switch back on a $ or '\n'.


    Michael
[That'd work, but I like #.* with separate \n better. -John]


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