Re: An HTML language specification

John Kemp wrote:
>> OK, that sounds as if the processing requirements for each conformance
>> class could be in one (or more) separate documents from the language
>> syntax specification.

Ian wrote:
> Well, some of the conformance classes need the language syntax
> requirements.

I think everyone agrees that the processing requirements would rely
on the syntax specification -- the point is that the syntax specification
does not need to rely on the processing requirements.

But to be honest, I think part of the disagreement is that many people
(myself included) don't think the the processing requirements really
rely all that *heavily* on the syntax.

> For example, a WYSIWYG editor would need to know both the
> syntax and vocabulary conformacne requirments, to output valid
> documents, as well as the parsing and rendering requirements,
> to show the right output.

It would only need the parsing requirements if it imported existing
non-conformant HTML.  (A full-featured editor probably would, but
that isn't the only useful kind of editor.)

It would clearly need the vocabulary and syntax requirements -- but
for an editor, that is domain knowledge; needed in the same way that
a baseball simulator would need to know the rules of baseball.

> Similarly, a conformance checker's implementation requirements are
> a combination of both the language conformance rules and some separate
> implementation conformance rules (e.g. the parsing rules).

It needs only the language conformance rules to say "valid" or "not valid".

The (error-recovery portion of the) parsing rules would allow it to recover
more gracefully and continue to provide additional useful errors on the
same run -- but they aren't strictly required.

-jJ

Received on Monday, 24 November 2008 04:22:36 UTC