Re: ws: and wss: schemes

Roy T. Fielding wrote:
> ...
>> Actually, unless it's ambiguous, an ABNF *does* define how to parse.
> Actually, no, the purpose of an ABNF is to define the grammar for
> generating valid strings and testing strings for validity.  It might
> be used as a guide by something like lex to create a parser that
> enforces validity while parsing, but that generally is not done in
> Internet-facing software because of Postel's Law.
> ...

OK, let me rephrase that: the ABNF does not define parsing, but provides 
sufficient information for a parser that will accept and process valid 

> For example, RFC 3986 has a very specific grammar for generation
> and validity of URIs, but also describes one parsing algorithm
> (not the only one, but certainly one in common use) in an
> Appendix that will accept any string and parse it into the major
> components.

Right, and I have mentioned that one more than once to those who 
complained about missing error handling in RFC 3986.

> And I'll reiterate, again, that the algorithm for reference parsing
> in HTML5 is not definitive of URLs -- it is just a variation on the
> appendix in RFC3986 that includes a non-ASCII character encoding
> step.  The entire notion that this has anything to do with IRI or URI
> definition, or that we need to fix any of the IETF specs to
> incorporate browser-specific reference error-handling, is simply
> absurd.  They are not the same thing.


BR, Julian

Received on Thursday, 17 September 2009 19:59:24 UTC