XML processing

[drymartini@gmx.de (Robbie Pickering)]

OK, I'm stymied here.

What i'm trying to do is typeset a dictionary entry from XML. It's
relatively simple so far. But there are occasions when I'd like to have
the same tags treated differently according to the context.

We have for example definitions DEFN which are sometimes followed by an
example EGPH and sometimes not.

...
<DNUM>3</DNUM>
<DEFN>a large body, esp. of a person</DEFN>
<EGPH>he eased his bulk out of the chair</EGPH>
<DNUM>4</DNUM>
<DEFN>unpackaged cargo or goods</DEFN>

I have setup DEFN very simply

\defineXMLenvironment [DEFN] {}{.}  
to add a full stop after the definition. It would be nice, though, to be
able to automatically add a colon instead in those cases where the DEFN
environment is immediately followed by a EGPH.

is the XML parsing code robust enough that one could start messing
around with counters, etc. in the arguments of a \defineXMLenvironment?
Or is there a better way of going about this?