Rules & Grammars

[Tim Bray <tbray@textuality.com>]

I must say that it's a long time since I've *enjoyed* reading
xml-dev, but this last week's worth has been an exception.
There is a tremendous amount to be learned here.

At 10:38 AM 03/02/01 +0700, James Clark wrote:
>But I've never argued that path-based rule systems are inferior to
>grammars.  As I said at the beginning of my last message I think they're
>a valuable complement to grammars, and for *some* problems they're a
>better solution than grammars.  All I'm claiming is that there are also
>some problems for which grammars are a better solution than path-based
>rules.

This leads to an obvious follow-on question.  I think we can
all agree that learning schema languages is hard.  Once we've
figured out what we want to do, therefore, fewer schema languages
are better then more, so that everyone has less to learn.  James 
& Makoto & Rick have collectively proved, via examples, the point 
that James makes above.  Examples are *so* much better than theory.

So I say to you all: go back in your caves and come out with 
*one* schema facility that lets me write grammars when I want 
to and xpath expressions when I want to, and has an elegantly 
unified syntax.  Then declare victory.  For extra credit, 
replace entities too (just kidding).  -Tim