• From: "Michael Kay" <mike@s...>
• To: "'Philippe Poulard'" <Philippe.Poulard@s...>,"'Costello, Roger L.'" <costello@m...>
• Date: Mon, 11 Dec 2006 15:30:08 -0000

> "The flaw with grammars is that they only allow to constraint 
> content models in a declarative manner

There's nothing wrong with constraints being declarative - in fact, they
definitely should be - the flaw is with the expressive power of a grammar as
a contraint language.

This is all well known. And in fact, XML Schema itself has some
extra-grammatical constraints, namely uniqueness and referential
constraints. But there's still a camp that believes (wrongly, in my view)
that the expressive power of a schema language should be restricted for
performance reasons.

Michael Kay
http://www.saxonica.com/

• Follow-Ups:
  • Re: Rick Jelliffe quotable quote on the purpose of schemas
    • From: Rick Marshall <rjm@z...>

• References:
  • Re: Rick Jelliffe quotable quote on the purpose of schemas
    • From: Philippe Poulard <Philippe.Poulard@s...>