<difference> and key/keyref

The <difference> pattern currently on our table is much like the <data>
pattern in the sense that it accepts one string token.

Use cases also back up this assumption. One of the use cases would be:

<attribute name="value">
  <!-- float' -->
  <difference>
    <data type="float"/>
    <value>NaN</value>
    <value>-INF</value>
    <value>INF</value>
  </difference>
</attribute>

Apparently <difference> is used here to represent a new datatype, which
is basically "float" but without troublesome values.

If the <difference> here is conceptually a datatype, then it is quite
natural to allow key and keyref for it, too...


Well, isn't this a so-called "slippery slope"?


regards,
--
Kohsuke KAWAGUCHI                          +1 650 786 0721
Sun Microsystems