Re: empty quoted strings and other oddities
Keith Moore <moore@cs.utk.edu> Thu, 03 October 2002 13:16 UTC
Received: (from majordomo@localhost) by above.proper.com (8.11.6/8.11.3) id g93DGPF28213 for ietf-822-bks; Thu, 3 Oct 2002 06:16:25 -0700 (PDT)
Received: from astro.cs.utk.edu (astro.cs.utk.edu [160.36.58.43]) by above.proper.com (8.11.6/8.11.3) with ESMTP id g93DGNv28206 for <ietf-822@imc.org>; Thu, 3 Oct 2002 06:16:23 -0700 (PDT)
Received: from astro.cs.utk.edu (localhost [127.0.0.1]) by astro.cs.utk.edu (cf 8.9.3) with ESMTP id g93DGJ002707; Thu, 3 Oct 2002 09:16:19 -0400 (EDT)
Message-Id: <200210031316.g93DGJ002707@astro.cs.utk.edu>
X-URI: http://www.cs.utk.edu/~moore/
From: Keith Moore <moore@cs.utk.edu>
To: Gary Feldman <gaf@ziplink.net>
cc: ietf-822@imc.org
Subject: Re: empty quoted strings and other oddities
In-reply-to: (Your message of "Wed, 02 Oct 2002 22:28:34 EDT.") <000e01c26a84$9358e8a0$0201010a@alice>
Date: Thu, 03 Oct 2002 09:16:19 -0400
Sender: owner-ietf-822@mail.imc.org
Precedence: bulk
List-Archive: <http://www.imc.org/ietf-822/mail-archive/>
List-ID: <ietf-822.imc.org>
List-Unsubscribe: <mailto:ietf-822-request@imc.org?body=unsubscribe>
> The main problem with this analysis is that it ignores the comparison with > semantic side catching of the problem. Also, the issue at hand is a > boundary condition, and hence the test cases need to be there, regardless > of how it's defined. first of all, it's really not a boundary condition - it's just one example of an invalid address. second, your conclusion doesn't follow even if it is a boundary condition - all that is necessary is that it not cause any problems. (""@example.com is not inherently invalid, nor should we restrict strings to having 1 or more characters - because there are cases where some strings need to be zero length) > Finally, whether or not it actually causes that extra effort and cost > of learning depends on how it's implemented in the first place. well, it's not like those thousands of existing implementations of email software are going to change their implementation techniques just to accomodate this case. as for use of lex, I've tried it. it's not a good fit. 2822 syntax analysis is somewhat context-dependent (is "Mon" a day or an atom?), good error recovery is difficult, and you need to have the lexical analyzer recover from common syntax errors (such as putting dot in a phrase) in situations where look-ahead is required to disambiguate that kind of error from other errors. Having done both, I can confidently say that it's easier to write correct C code to do the scanning than to write correct lex code to do it. > Granted, many implementations won't be so eloquent, but again, the > extent to which that should be allowed to hamper progress should be limited. adding cruft to the standard (or to code) to detect cases which never happen is not progress. progress is increasing the reliability of mail delivery. if you want to make that kind of progress, you need to do something about stupid spam filtering, DNS misconfiguration, and MTA misconfiguration. of course, it's much easier to think of solutions to problems that don't exist. Keth
- Re: empty quoted strings and other oddities Charles Lindsey
- Re: empty quoted strings and other oddities Russ Allbery
- empty quoted strings and other oddities Bruce Lilly
- Re: empty quoted strings and other oddities Bruce Lilly
- Re: empty quoted strings and other oddities Kai Henningsen
- Re: empty quoted strings and other oddities Kai Henningsen
- Re: empty quoted strings and other oddities ned+ietf-822
- Re: empty quoted strings and other oddities Jacob Palme
- Re: empty quoted strings and other oddities Charles Lindsey
- Re: empty quoted strings and other oddities Jacob Palme
- Re: empty quoted strings and other oddities Keith Moore
- Re: empty quoted strings and other oddities Bruce Campbell
- Re: empty quoted strings and other oddities Keith Moore
- Re: empty quoted strings and other oddities Keith Moore
- Re: empty quoted strings and other oddities Keith Moore
- Re: empty quoted strings and other oddities Gary Feldman
- Re: empty quoted strings and other oddities Gary Feldman
- Re: empty quoted strings and other oddities Jacob Palme
- Re: empty quoted strings and other oddities Bruce Lilly
- Re: empty quoted strings and other oddities Bruce Lilly
- Re: empty quoted strings and other oddities Keith Moore
- Re: empty quoted strings and other oddities Keith Moore
- Re: empty quoted strings and other oddities Gary Feldman
- Re: empty quoted strings and other oddities Arnt Gulbrandsen
- Re: empty quoted strings and other oddities Keith Moore
- Re: empty quoted strings and other oddities Gary Feldman
- Re: empty quoted strings and other oddities Keith Moore
- Re: empty quoted strings and other oddities Bruce Lilly
- Re: empty quoted strings and other oddities Keith Moore