unambiguity constraint

[Kohsuke KAWAGUCHI <kohsuke.kawaguchi@eng.sun.com>]

How are we enforce the unambiguity for this proposal?

<data/> with key is required to be the only direct child of
element/attribute, maybe?


Even so, we still need more constraint so that we can prevent things
like this:

<choice>
  <group>
    <attribute name="id">
      <data key="foo" type="..." />
      ...
    </attribute>
  </group>
  <group>
    <attribute>
      <anyName/>
    </attribute>
    ...
  </group>
</choice>

The following constraints might work:

1. the parent element/attribute (of key/keyref) must has a simple name.
2. its name may not be accepted by any other elements/attributes that
are in the same content model.



P.S. I think we are looking for a constraint that makes it TDLL(1),
rather than making it unambiguous.
--
Kohsuke KAWAGUCHI                          +1 650 786 0721
Sun Microsystems                   kohsuke.kawaguchi@eng.sun.com