ay prove slightly awkward.</P>

<P>It may happen that an identifier chosen as the name of a <I>NonTerminal</I>
may clash with one of the internal names used in the rest of the system.  Such
clashes will only become apparent when the application is compiled and linked,
and may require the user to redefine the grammar to use other identifiers.</P>

<P><B>Expressions</B>. An EBNF expression defines the context-free structure
of some part of the source language, together with the attributes and semantic
actions