[relax-ng-comment] recursive inlusion

[Robert Koberg <rob@livestoryboard.com>]

Hi,

I am having trouble figuring out how to handle a problem I have with recursive
inclusion. I want to be able to validate:

<abc>This is a <strong><em>sentence</em></strong>.</abc>

I have broken up all of my elements into individual .rng files to ease my
writing of a schema editor. I want to make it easy for a user to modify their
schema in small chunks.

When I try the two below I get a recursive inclusion error. Is it a bad strategy
to break all the elements up like this? Is there a valid way to handle this
while still using externalRef's?
------------------------------------
strong.rng

<grammar>
  <start>
    <choice>
      <notAllowed/>
      <element name="strong">
        <oneOrMore>
          <choice>
            <text/>
            <externalRef href="em.rng"/>
          </choice>
        </oneOrMore>
      </element>
    </choice>
  </start>
</grammar>
------------------------------------
em.rng

<grammar>
  <start>
    <choice>
      <notAllowed/>
      <element name="em">
        <oneOrMore>
          <choice>
            <text/>
            <externalRef href="strong.rng"/>
          </choice>
        </oneOrMore>
      </element>
    </choice>
  </start>
</grammar>

thanks,
-Rob