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 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Thread: 103376,f384032a8c47ef0d
X-Google-Attributes: gid103376,public
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news1.google.com!news2.google.com!newsread.com!news-xfer.newsread.com!nntp.abs.net!news.abs.net!not-for-mail
Newsgroups: comp.lang.ada
Subject: Re: about OpenToken
References: <439b6ac7$0$20862$636a55ce@news.free.fr>
 <koru38urowa2.lth4qnymn9ac.dlg@40tude.net>
 <439c6eab$0$20191$636a15ce@news.free.fr>
 <163minks9ygxl$.tww5gn7kaioj.dlg@40tude.net>
From: Stephen Leake <stephen_leake@acm.org>
Message-ID: <u64pvnzib.fsf@acm.org>
User-Agent: Gnus/5.1006 (Gnus v5.10.6) Emacs/21.3 (windows-nt)
Cancel-Lock: sha1:WuTXtghbA/uwE++HA0fAap5svW4=
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Date: Sun, 11 Dec 2005 15:35:08 -0500
NNTP-Posting-Host: 66.159.65.1
X-Complaints-To: abuse@toad.net
X-Trace: news.abs.net 1134333310 66.159.65.1 (Sun, 11 Dec 2005 15:35:10 EST)
NNTP-Posting-Date: Sun, 11 Dec 2005 15:35:10 EST
Xref: g2news1.google.com comp.lang.ada:6837
Date: 2005-12-11T15:35:08-05:00
List-Id: <comp.lang.ada>

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> writes:

> On Sun, 11 Dec 2005 19:23:38 +0100, Lionel Draghi wrote:
>
>> I expect the code representing the grammar to be almost as simple as the 
>> BNF expression.
>
> Well, that depends. Consider comments and line feeds allowed between the
> keywords. To represent this in BNF, I don't think it will be such simple
> expression.

OpenToken does comments and white space in the lexer level, not the
grammar level.

I don't think you can define a keyword as whitespace, but it's an
interesting idea.

>> If an optionnal word requires a bunch of code, I would say that there's 
>> something to improve.
>
> There are many approaches to parsing. I am using table driven parsers. For
> a descent recursive parser I just change the table to match the source
> against depending on the context. I presume that something similar can be
> done with OpenToken as well.

Yes, you can.

-- 
-- Stephe