In this paper we describe a technique that can be used to
annotate source code with syntactic tags in XML format.  This is
achieved by modifying the parser generator ison to emit these tags
for an arbitrary grammar.  We also discuss an immediate application of
this technique, a portable modification of the gcc compiler, that
allows for XML output for C, Objective C, C++ and Java programs.
While our approach does not have the same semantic richness as other
approaches, it does have the advantage of being language independent,
and thus re-usable in a number of different domains.