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Re: We need a EBNF spec

From: Ian Hickson <ian@hixie.ch>
Date: Mon, 9 Jan 2006 07:05:01 +0000 (UTC)
To: Bjoern Hoehrmann <derhoermi@gmx.net>
Cc: spec-prod@w3.org, www-qa@w3.org
Message-ID: <Pine.LNX.4.62.0601090655140.9516@dhalsim.dreamhost.com>

On Mon, 9 Jan 2006, Bjoern Hoehrmann wrote:
> 
> 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.

An alternative would be for the W3C to standardise on ISO 14977:1996 or 
RFC 2234.

Personally I would discourage the use of BNF, however, as it makes it very 
difficult to define error handling rules, and specifications often forget 
to define how to go from the parsed tree to the semantics that the 
specification defines, leaving it up to UA implementors to work out the 
implied mapping.

For example, as far as I can tell, there is nothing in the XML 1.0 spec 
that says what the syntax of an XML Declaration (as found in a prolog) is. 
One can make a guess, but the spec doesn't say whether we are right. The 
reliance on EBNF has made it easier to leave the mapping of the strict 
syntax definitions to the actual semantics to implication than to make the 
spec full and complete.

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Monday, 9 January 2006 07:05:15 GMT

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