Subject: [Tools-discuss] Re: Bug in the Perl ABNF parser?

From: Harald Alvestrand <[email-masked]>
Date: Tue, 21 Nov 2006 06:52:46 +0100

The Perl ABNF parser is not maintained any more.
There are a few bugs - this one has to do with case mapping; my tool did 
not case fold rule names, and only accepted A-F in hex literals, not a-f.

And I think Bill's parser has much better error messages. Tools.ietf.org 
people, can you remove the link from your site?

                 Harald

--On 20. November 2006 23:08 +0100 Stephane Bortzmeyer <[email-masked]> 
wrote:

> [Is the Perl ABNF still parser still maintained? The email address in
> the source bounces. If it is not maintained any more, wouldn't it be a
> good idea to indicate it on the Web page at tools.ietf.org?]
>
> The attached grammar, extracted from draft-ietf-imapext-sort-18.txt
> seems perfectly legal (and is accepted by all the other tools) but
> make the Perl parser protest:
>
> ...
> Rule: subj-trailer    = "(fwd)" / WSP
> Rule: subj-base       = NONWSP *(*WSP NONWSP)
>                      ; can be a subj-blob
> Not OK
> Syntax error: BLOBCHAR        = %x01-5a<*> / %x5c /
>
>

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From: Stephane Bortzmeyer <[email-masked]>
Date: Tue, 21 Nov 2006 09:47:31 +0100

On Tue, Nov 21, 2006 at 06:52:46AM +0100,
 Harald Alvestrand <[email-masked]> wrote 
 a message of 33 lines which said:

> Tools.ietf.org people, can you remove the link from your site?

I suggest instead to add a warning (same thing for the ABNF
validator). Here is my suggested wording for
http://tools.ietf.org/inventory/verif-tools:

      <li><a href="http://www.ops.ietf.org/abnf/"><b> Harald
      Alvestrand's perl ABNF parser</b></a> (<em>Warning:</em> This
      tool is no longer maintained and has problems, for instance with
      case mapping)</li>
      <li><a href="http://rtg.ietf.org/~fenner/abnf.cgi"><b>Bill Fenner's ABNF parsing web service</b></a></li>
      <li><a href="http://www.coasttocoastresearch.com/"><b>APG - an ABNF Parser Generator</b></a></li>
      <li><a href="http://cvs.m17n.org/~akr/abnf/"><b>ABNF to Regexp converter</b></a></li>
      <li><a href="http://www.apps.ietf.org/abnf.html"><b> ABNF
      parsing web service (has problems with some inputs)</b></a>
      (<em>Warning:</em> it is extremely lax and accept many illegal
      grammars)</li>

---

From: Stephane Bortzmeyer <[email-masked]>
Date: Tue, 21 Nov 2006 09:58:18 +0100

On Tue, Nov 21, 2006 at 06:52:46AM +0100,
 Harald Alvestrand <[email-masked]> wrote 
 a message of 33 lines which said:

> And I think Bill's parser has much better error messages.

AFAIK, it exists only as an online service and the source code does
not seem to be available.

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From: Henrik Levkowetz <[email-masked]>
Date: Tue, 21 Nov 2006 11:16:36 +0100

Hi Harald,

on 2006-11-21 06:52 Harald Alvestrand said the following:
[...]
> people, can you remove the link from your site?

Done!

	Henrik

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From: Henrik Levkowetz <[email-masked]>
Date: Tue, 21 Nov 2006 11:18:47 +0100

Hi again,

Right, so I just removed it, before going on to the next message on
the list ,;-)

Harald, would you like me to re-insert the link, with the warning
suggested by Stephane?

Regards,

	Henrik

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From: Harald Alvestrand <[email-masked]>
Date: Tue, 21 Nov 2006 12:33:23 +0100

Given that it's the only tool with source available, reinserting it seems 
like a reasonable option... I'd forgotten that it was hosted on 
ops.ietf.org, even...

--On 21. november 2006 11:18 +0100 Henrik Levkowetz <[email-masked]> 
wrote:

>>       <li><a href="http://rtg.ietf.org/~fenner/abnf.cgi"><b>Bill
>>       Fenner's ABNF parsing web service</b></a></li> <li><a
>>       href="http://www.coasttocoastresearch.com/"><b>APG - an ABNF
>>       Parser Generator</b></a></li> <li><a
>>       href="http://cvs.m17n.org/~akr/abnf/"><b>ABNF to Regexp
>>       converter</b></a></li> <li><a
>>       href="http://www.apps.ietf.org/abnf.html"><b> ABNF parsing web
>>       service (has problems with some inputs)</b></a> (<em>Warning:</em>
>>       it is extremely lax and accept many illegal grammars)</li>
>

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From: Stephane Bortzmeyer <[email-masked]>
Date: Tue, 21 Nov 2006 12:53:55 +0100

On Tue, Nov 21, 2006 at 12:33:23PM +0100,
 Harald Alvestrand <[email-masked]> wrote 
 a message of 48 lines which said:

> Given that it's the only tool with source available, 

No. abnfgen and eustathius also distribute the source (with a free
software licence).

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From: Henrik Levkowetz <[email-masked]>
Date: Thu, 23 Nov 2006 13:39:05 +0100

Hi,

> No. abnfgen and eustathius also distribute the source (with a free

So, given the availability of 2 other ABNF parsers with source
available, should I add Harald's Perl ABNF parser again with an
added disclaimer, or should I keep the status quo (leaving it
out of the listing)?

	Henrik

---

From: Stephane Bortzmeyer <[email-masked]>
Date: Thu, 23 Nov 2006 13:55:03 +0100

On Thu, Nov 23, 2006 at 01:39:05PM +0100,
 Henrik Levkowetz <[email-masked]> wrote 
 a message of 39 lines which said:

> should I add Harald's Perl ABNF parser again with an added
> disclaimer,

My personal vote is yes. The more information, the better.