re: Rules & Grammars

[David Megginson <david@megginson.com>]

Tim Bray writes:

 > 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

I'm going to take up my wand and play my old role of layering-fairy
again.  I think that a couple of points are obvious:

1. There are different levels at which people want to write schemas:
raw elements and attributes (i.e. XML Schema), generic entities and
relationships (i.e. RDF Schema), domain-specific data (i.e. XBRL),
etc.

2. An enormous part of the infrastructure for grammatical schemas is
the same whether you're using a schema to describe raw markup or
higher-level items like objects or accounting entries.

Ideally, then, we'd want a layer to capture what most grammatical
schemas have in common (i.e. a generic schema Namespace), and then
allow the differences to be layered on top (i.e. the XML structure
Namespace, the entity-relationship Namespace, etc.).  

It may or may not be too late for that.  In any case, I'm not
volunteering.


All the best,


David

-- 
David Megginson                 david@megginson.com
           http://www.megginson.com/