Reopening Issue 26: regularityConstraint

[Murata Makoto <mura034@attglobal.net>]

I propose to reopen Issue 26 for two reasons.  I would like 
to disallow <oneOrMore> containing both <attributes> and <ref ..>
(which references to a named pattern representing an element).
For example:

<oneOrMore>
  <choice>
    <ref name="foo"/>
    <attribute name="bar"/>
  </choice>
</oneOrMore>

First, after the decision for Issue 26, we changed the semantics 
of oneOrMore so that it disallows colliding attributes.  One could 
thus argue that the keyword oneOrMore represents two different constructs: 
one is to allow repetition of elements freely and the other 
is to allow non-colliding repetition of attributes.

Second, the BNF created by James becomes simpler if we disallow 
coexistense of attributes and elements in <oneOrMore>.  We can 
get rid of "repeatable"

http://lists.oasis-open.org/archives/relax-ng/200106/msg00198.html

Cheers,

Makoto