- From: Bjoern Hoehrmann <derhoermi@gmx.net>
- Date: Mon, 09 Jan 2006 07:46:21 +0100
- To: spec-prod@w3.org
- Cc: www-qa@w3.org
Hi, I think W3C should publish a Recommendation or a Group Note defining the EBNF format "defined" in http://www.w3.org/TR/REC-xml/#sec-notation and elsewhere. This is needed because the definition in the XML 1.0 Recommendation is incomplete and W3C technical reports define more and more variants of it for which it is not easy to tell whether they are different or not. For example, the XML 1.0 Recommendation does not define whether a symbol like "Clock-value" may be used; on the right hand side this might be interpreted as Clock - value, so maybe not, but e.g. SMIL 2.1 uses this syntax. The result is that some EBNF parsers don't accept the grammars in SMIL 2.1, which is bad. The lack of good parsers then leads to having no means to verify grammars in technical reports, so the other errors in the SMIL 2.1 grammars are even harder to find. Some technical reports like http://www.w3.org/TR/xpath20/#id-grammar also modify certain aspects of EBNF and/or include certain parts of the original EBNF "specification" which makes it even harder to recognize whether EBNF in one technical report can be processed just like EBNF in some other specification, you have to study the details first to do that. Some technical reports like http://www.w3.org/TR/2005/WD-its-20051122/ and http://www.w3.org/TR/2005/WD-emma-20050916/ then use ::= grammars without defining the format at all (and in case of EMMA it's not EBNF as defined in XML 1.0...) and yet other technical reports refer to EBNF http://www.w3.org/TR/2005/WD-SVGMobile12-20051207/paths.html#PathDataBNF as defined in XML 1.0 but the grammar does not actually use it, and some like http://www.w3.org/TR/2005/WD-P3P11-20050701/ don't even use EBNF or another standard format, but invent new variants of other formats. Most of this is better though than the usual handwaving reference to some vague terms to define certain lexical constraints. I think that a complete stand-alone reference for this format will encourage more working groups to make use of it rather than no formal grammar or some other format instead, encourage to make normative reference to it rather than copy and paste some extended subsets across multiple technical reports, encourage tool development around EBNF which will then help to verify the technical reports, which in turn further encourages making use of it. It will also help me to introduce {min,max} quantifiers into EBNF. Writing the specification should be an easy mostly copy'n'paste job. Thanks, -- Björn Höhrmann · mailto:bjoern@hoehrmann.de · http://bjoern.hoehrmann.de Weinh. Str. 22 · Telefon: +49(0)621/4309674 · http://www.bjoernsworld.de 68309 Mannheim · PGP Pub. KeyID: 0xA4357E78 · http://www.websitedev.de/
Received on Monday, 9 January 2006 06:46:00 UTC