Re: [abnf-discuss] Core Rules and References for ABNF: draft-seantek-abnf-more-core-rules-07.txt

[Paul Kyzivat <[e-mail]>]

I'd like to comment on why I think this is important:

Most of the drafts I have been interested in over the years contain 
ABNF, and most of the time that ABNF is dependent on other ABNF rules 
that reside in another draft or RFC. Such cross references are indicated 
in ad-hoc fashion. When authoring or reviewing such a document, one 
would like to be able to verify that the new ABNF is correct. At the 
least this ought to be done at the time of WGLC and LC. But actually 
doing that verification is a pain. To be sure of it, one needs to 
extract the ABNF from the document in question *and* from the documents 
that contain referenced ABNF rules. This is tedious work, and in my 
experience it most often is not done.

Furthermore, when ABNF rules in other drafts are referenced informally 
this way the semantics of doing so aren't especially clear. Is it 
assumed that complete ABNF containing the referenced rule is included? 
Or should only the definition of the referenced rulename and the 
definitions of any rules thus referenced be included? Or should a 
functional definition of the referenced rule be used that doesn't drag 
along any other rules used in that definition. These distinctions are 
important because they determine what happens if the new ABNF defines 
rules with the same names as rules defined in the referenced ABNF.

Formalizing a cross-reference syntax and semantics resolves these 
issues. The semantics can be nailed down, and tools can be built to 
automatically to the extractions. This will make it feasible to automate 
ABNF syntax verification, for instance as part of IdNits.

	Thanks,
	Paul

On 9/28/16 6:20 PM, Sean Leonard wrote:
> Hello ABNF-discuss:
>
> A new draft of Comprehensive Core Rules and References for ABNF has been
> posted. Thanks in advance to all those who have provided feedback thus far.
>
> In this draft-07 (and draft-06, which had some typos and unclear parts
> that have since been addressed), the syntax for a "referenced rule" is
> rulename@RULEREF, where RULEREF can be a document such as
>
>   URI@[RFC3986]
>
> or a path such as
>
> name-part@<https://raw.githubusercontent.com/antlr/grammars-v4/master/abnf/examples/postal.abnf>
>
>
> . The syntax has evolved a similar way to how e-mail addresses have
> evolved (e.g., from RFC 733).
>
> There was material about doing Unicode in ABNF in draft-05 (Appendix B);
> that material has been forked to a different draft (under development).
>
> Comments and feedback are welcome.
>
> Best regards,
>
> Sean
>
> -------- Forwarded Message --------
> Subject:     New Version Notification for
> draft-seantek-abnf-more-core-rules-07.txt
> Date:     Wed, 28 Sep 2016 00:50:03 -0700
> From:     [e-mail]
>
>
>
> A new version of I-D, draft-seantek-abnf-more-core-rules-07.txt
> has been successfully submitted by Sean Leonard and posted to the
> IETF repository.
>
> Name:        draft-seantek-abnf-more-core-rules
> Revision:    07
> Title:        Comprehensive Core Rules and References for ABNF
> Document date:    2016-09-28
> Group:        Individual Submission
> Pages:        10
> URL:
> https://www.ietf.org/internet-drafts/draft-seantek-abnf-more-core-rules-07.txt
>
> Status:
> https://datatracker.ietf.org/doc/draft-seantek-abnf-more-core-rules/
> Htmlized:
> https://tools.ietf.org/html/draft-seantek-abnf-more-core-rules-07
> Diff:
> https://www.ietf.org/rfcdiff?url2=draft-seantek-abnf-more-core-rules-07
>
> Abstract:
>    This document extends the base definition of ABNF (Augmented Backus-
>    Naur Form) to include a reference syntax, along with core rules that
>    provide comprehensive support for certain symbols related to ASCII.
>
>
>
>
> Please note that it may take a couple of minutes from the time of
> submission
> until the htmlized version and diff are available at tools.ietf.org.
>
> The IETF Secretariat
>
>
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