Re: combine proposal

> A grammar-level include would also need to be able to contain a <start>
> element to replace any <start> element from the include.

Why not <externalRef href="..." name="..." /> ?  I guess it's simpler,
and covers 80% of the use case.

if you want to replace <start> by an arbitrary pattern, then you can
always write it as

<grammar>
  <include href="...">
    <start combine="replace">
      ...
    </start>
  </include>
</grammar>

, which is only one element verbose compared to your proposal.

--
Kohsuke KAWAGUCHI                          +1 650 786 0721
Sun Microsystems