Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!gegeweb.42!gegeweb.eu!nntpfeed.proxad.net!proxad.net!feeder2-2.proxad.net!nx02.iad01.newshosting.com!newshosting.com!news-out.readnews.com!news-xxxfer.readnews.com!news.misty.com!news.iecc.com!nerds-end From: Jens Kallup Newsgroups: comp.compilers Subject: yacc warning about useless rule Date: Mon, 13 Feb 2012 22:22:56 +0100 Organization: CNNTP Lines: 18 Sender: johnl@iecc.com Approved: comp.compilers@iecc.com Message-ID: <12-02-019@comp.compilers> NNTP-Posting-Host: news.iecc.com X-Trace: leila.iecc.com 1329180078 5860 64.57.183.58 (14 Feb 2012 00:41:18 GMT) X-Complaints-To: abuse@iecc.com NNTP-Posting-Date: Tue, 14 Feb 2012 00:41:18 +0000 (UTC) Keywords: yacc, question, comment Posted-Date: 13 Feb 2012 19:41:18 EST X-submission-address: compilers@iecc.com X-moderator-address: compilers-request@iecc.com X-FAQ-and-archives: http://compilers.iecc.com Xref: x330-a1.tempe.blueboxinc.net comp.compilers:459 Hello there, I get the following Warning: conflicts: 7 shift/reduce pcode.y:64.12-66.5: warning: rule useless in parser due to conflicts: $@1: /* empty */ is this a error? why is it display? give it a glue? thanks Jens [Yes, it's an error. It's telling you that your grammar can't be turned into a LALR parser, and the parser it did generate will never reduce that rule. Solution: find the conflicts and fix them. -John]