From: Chris Olds (cco@dydax.com)
Date: Thu Oct 05 2000 - 11:05:08 PDT
> So what was the answer? Does a DTD have the expressive power to do what he
> wanted?
Yes, it does, but only at an unreasonable level of effort (you have to
enumerate all of the combinations and say "one of these"). XML dropped the
SGML & conector for DTD content models, which allows saying "these things, in
any order" i.e., a element O with a content model of ( a & b & c ) requires
that there be an <a></a>, <b></b>, and <c></c> inside each <O></O>, but they
can be in any order. As I understand it, the & connector was dropped because
of problems in validating more complex cases than this example. XML Schemas
allow declaring this kind of simple content model, but disallow the
problematic cases.
Trying to make sure the FoRK archives are as useful as ever...
/cco
--
48. The best book on programming for the layman is "Alice in
Wonderland"; but that's because it's the best book on
anything for the layman.
-- Alan Perlis, http://www.cs.yale.edu/~perlis-alan/quotes.html
This archive was generated by hypermail 2b29 : Thu Oct 05 2000 - 11:08:39 PDT