Confusion with Namespaces?

Tim Bray tbray at
Mon Apr 13 22:07:48 BST 1998

At 01:45 PM 13/04/98 -0400, Tyler Baker wrote:
>In the 1.0 XML Namespaces specification a namespace PI is defined as
>'<?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

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