From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,169cfbee5fb652af X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-12-15 09:45:44 PST Path: archiver1.google.com!news2.google.com!newsfeed2.dallas1.level3.net!news.level3.com!news-out.visi.com!petbe.visi.com!newspeer.monmouth.com!newsfeed.mathworks.com!wn13feed!worldnet.att.net!216.166.71.14!border3.nntp.aus1.giganews.com!intern1.nntp.aus1.giganews.com!nntp.giganews.com!nntp.comcast.com!news.comcast.com.POSTED!not-for-mail NNTP-Posting-Date: Mon, 15 Dec 2003 11:45:42 -0600 Date: Mon, 15 Dec 2003 12:45:41 -0500 From: "Robert I. Eachus" User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 (ax) X-Accept-Language: en-us, en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: Free Ada parser References: <6d4cbc3e.0312091010.7572566b@posting.google.com> <6s1ntv84qt5dims2p3ik1t91aue8kp1hjt@4ax.com> <62gntvktko48ghlpls4ba46d4r0nh455ij@4ax.com> <6a6390b8.0312141049.1cafb783@posting.google.com> In-Reply-To: <6a6390b8.0312141049.1cafb783@posting.google.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Message-ID: NNTP-Posting-Host: 24.34.214.193 X-Trace: sv3-eKR/aJhzbpK0/KARGxNTs6uUHRwfMDRnqNIU5naFfUEsXpF4p+uYaKXKENjVrCF/v0Y5kWfxNlswt14!TIllbZk9XlsfBJVwK5GPlMdoXDl18xS1+/rpTVZV8PJ0q0JrU3TNk5v6VbOOag== X-Complaints-To: abuse@comcast.net X-DMCA-Complaints-To: dmca@comcast.net X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.1 Xref: archiver1.google.com comp.lang.ada:3470 Date: 2003-12-15T12:45:41-05:00 List-Id: Oliver Kellogg wrote: > True, I had to resolve a couple of those ambiguities > while developing the ANTLR Ada grammar, but once you > really get into the ANTLR way of thinking it's not too bad. > Plus, this is a single-shot problem - it only affects the > development of the grammar itself but not its users. It is a property of writing grammars in general, doesn't matter how good the tools are. If you write a grammar and it is say, LALR2 instead of LALR1, how likely is it that the tools can point to what you will think is the error? Very unlikely of course. The error that you made will almost certainly be some production with a lookahead of one. It is one or more potential prefixes of that production that will need to have a lookahead of two. So when I am creating a grammar, I start with a 'skeleton' that has all the main features, then add details like identifier lists in object declarations. Since I check the grammar after every extension, the problem must involve one of the productions I just added. -- Robert I. Eachus 100% Ada, no bugs--the only way to create software.