From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (from majordomo@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id LAA19000; Tue, 24 Aug 2004 11:21:39 +0200 (MET DST) X-Authentication-Warning: pauillac.inria.fr: majordomo set sender to owner-caml-list@pauillac.inria.fr using -f Received: from nez-perce.inria.fr (nez-perce.inria.fr [192.93.2.78]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id LAA20159 for ; Tue, 24 Aug 2004 11:21:37 +0200 (MET DST) Received: from smtp1.adl2.internode.on.net (smtp1.adl2.internode.on.net [203.16.214.181]) by nez-perce.inria.fr (8.12.10/8.12.10) with ESMTP id i7O9LYmL018649 for ; Tue, 24 Aug 2004 11:21:36 +0200 Received: from [192.168.1.200] (ppp212-216.lns2.syd3.internode.on.net [203.122.212.216]) by smtp1.adl2.internode.on.net (8.12.9/8.12.9) with ESMTP id i7O9LL4Y008375; Tue, 24 Aug 2004 18:51:22 +0930 (CST) Subject: Re: [Caml-list] (Release) ocamllex tutorial (ver 0.1) From: skaller Reply-To: skaller@users.sourceforge.net To: SooHyoung Oh Cc: caml-list In-Reply-To: <007d01c489b1$843acfc0$1501a8c0@hama> References: <007d01c489b1$843acfc0$1501a8c0@hama> Content-Type: text/plain Message-Id: <1093339280.15255.495.camel@pelican.wigram> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.2.2 (1.2.2-4) Date: 24 Aug 2004 19:21:21 +1000 Content-Transfer-Encoding: 7bit X-Miltered: at nez-perce with ID 412B089E.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Loop: caml-list@inria.fr X-Spam: no; 0.00; caml-list:01 sourceforge:01 2004:99 passing:01 recursively:01 9660:01 glebe:01 ocaml:01 ocaml:01 token:01 nsw:01 cope:02 snail:02 parser:02 checkout:02 Sender: owner-caml-list@pauillac.inria.fr Precedence: bulk On Tue, 2004-08-24 at 18:07, SooHyoung Oh wrote: > Any comment will be appreciated. It looks very good! > This tutorial is work-in-progress. The latest version can be found at > http://pllab.kaist.ac.kr/~shoh/ocaml/ocamllex_ocamlyacc/ocamllex-tutorial/index.html. First -- you haven't explained how to use the new argument feature. A good example would be to take the non-reentrant line counting example and show how to make it re-entrant by passing an object containing the counters. To justify not using a global variable, you can extend the example to allow for recursively counting #include files (or something similar :) The second thing I'd like to see here is an example showing the common technique of lexing an identifier and then using a lookup table to see if it is keyword: this is done because (a) it is possible and (b) it simplifies the lexer which otherwise needs a huge number of states. The third thing I'd like to see is a more functional example where the lexer isn't just executing code for side effects. All your examples have the lexer tail calling itself: but most real lexing applications do not do this, instead you call the lexer repeatedly from a driver loop. In particular Ocamlyacc calls Ocamllex to lex one token at a time. Finally -- since your tutorial is Ocaml specific, I'd like to see some information on lexbufs. Are they functional? Can I write a backtracking functional parser that just 'goes backwards' in the input stream using a lexbuf to allow re-lexing some input? How do i cope with the fact that lexbufs think they're reading named files with lines in them .. what if this isn't so? This is actually a design fault which is unfortunately propagated to Ocamlyacc. -- John Skaller, mailto:skaller@users.sf.net voice: 061-2-9660-0850, snail: PO BOX 401 Glebe NSW 2037 Australia Checkout the Felix programming language http://felix.sf.net ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners