From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on yquem.inria.fr X-Spam-Level: X-Spam-Status: No, score=0.0 required=5.0 tests=UNPARSEABLE_RELAY, UPPERCASE_25_50 autolearn=disabled version=3.1.3 X-Original-To: caml-list@yquem.inria.fr Delivered-To: caml-list@yquem.inria.fr Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by yquem.inria.fr (Postfix) with ESMTP id E030FBC69 for ; Tue, 24 Oct 2006 23:04:56 +0200 (CEST) Received: from nmd.hic.det.wayport.net (nmd.hic.det.wayport.net [64.134.7.102]) by concorde.inria.fr (8.13.6/8.13.6) with ESMTP id k9OL4pCx019737 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Tue, 24 Oct 2006 23:04:56 +0200 Received: from countertenor (localhost [[UNIX: localhost]]) by nmd.hic.det.wayport.net (8.13.5/8.13.5) with ESMTP id k9OL4WWG010623 for ; Tue, 24 Oct 2006 17:04:41 -0400 From: "David Allsopp" To: "OCaml List" Subject: Fairly dumb ocamlyacc question Date: Tue, 24 Oct 2006 17:04:25 -0400 Organization: MetaStack Solutions Ltd. Message-ID: <003401c6f7b0$01f9ca10$5a878640@countertenor> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook 11 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2962 Thread-Index: Acb3r8Qxed5534ACQam+KIwtJDU3sA== X-Miltered: at concorde with ID 453E7FF3.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Spam: no; 0.00; ocamlyacc:01 ocamlyacc:01 kwd:01 kwd:01 parser:01 prec:01 parser:01 token:01 token:01 parsed:01 int:01 string:02 unit:03 problem:05 fails:05 This should be obvious, but I can't quite solve it! If I use the following ocamlyacc script: ------------ %token BEFORE_KWD AFTER_KWD %token FAILS_KWD %token WEEKDAY %token NAME %type top %start top %% top: WEEKDAY AFTER_KWD NAME BEFORE_KWD NAME FAILS_KWD top {()} | WEEKDAY relative NAME {()} ; relative: BEFORE_KWD {()} | AFTER_KWD {()} ; ------------ Then I get a shift/reduce having parsed WEEKDAY AFTER_KWD... the parser can't figure out what to do if it sees NAME. This problem can be made to disappear by expanding the relative rules to give: top: WEEKDAY AFTER_KWD NAME BEFORE_KWD NAME FAILS_KWD top {()} | WEEKDAY AFTER_KWD NAME {()} | WEEKDAY BEFORE_KWD NAME {()} ; I've tried a couple of tricks with %prec but can't get the parser to come out the same way with the first rule... please could someone put me out of my misery!! Thanks, David