Re: [xml-dev] XML Schema: At Least One of X Elements Must Appear

From
Rick Jelliffe <>
To
Date
2002-08-19T12:03:38Z
ID
<019901c24778$73b90c70$>
Thread
Re: [xml-dev] XML Schema: At Least One of X Elements Must Appear
From: "Henry S. Thompson" <>

> You guys are all forgetting your history!  At least one of {a, b, c},
> in any order, is expressible in DTD, and therefore _a posteriori_ in
> W3C XML Schema:
> 
>  <!ELEMENT x ((a,((b,c?)|(c,b?))?)|(b,((a,c?)|(c,a?))?)|(c,((a,b?)|(b,a?))?))>
> 
> It's certainly not elegant, and it gets worse as the number of
> alternatives goes up, but it's not impossible.

Is that what he was asking for?  He said
"at least one of the following X elements must appear in the XML document" 
not
"at least one of the following X elements must appear in an element"

Cheers
Rick Jelliffe