Re: Confusion with Namespaces?

Tim Bray (tbray@textuality.com)
Mon, 13 Apr 1998 13:04:48 -0700

At 01:45 PM 13/04/98 -0400, Tyler Baker wrote:
>In the 1.0 XML Namespaces specification a namespace PI is defined as
>follows:
>
>'<?xml:namespace' (S (PrefixDef | NSDef | SrcDef))+ '?>'
>
>>From this it looks like a particular namespace must have either one or
>more PrefixDef's, NS'Def's, or SrcDef's in any particular order so long
>as there is at least one of these. But then the following is said:
>
>Namespace Constraint: Required Parts
>A namespace declaration must contain exactly one NSDef, exactly one
>PrefixDef and zero or one SrcDef.

This is because a majority of the WG didn't want to specify the
order in which they can appear. So to write a regexp that allows
one ns & one prefix & zero or one src, in any order, gets pretty
big & ugly, unless you have something like the SGML &-connector. -Tim