How To Add A Node
=================

1) declare/define class in Aif2XtlParseTreeNodes.h

Use Aif2XtlStandardNode<> to creat a node to represent any AAF object,
or create a new class derived from AifParseTreeNode.

If the template is used, add an explict template instance to
Aif2XtlStandardNodeFactory.cpp

2) Create a factory object for the node.  Add an explicit instance of
   the Aif2XtlStandardNodeFactory in Aif2XtlParseTreeNodes.cpp.

3) Add PreOrderVistit and PostOrderVisit methods to
   Aif2XtlParseTreeVisitor and Aif2XtlDumpVisitor in
   Aif2XtlParseTreeVisitor.h.  Use the file's _DEFINE_METHODS macro in
   both cases.

How To Create A New Visitor
===========================

1) Derive from Aif2XtlParseTreeVisitor.

2) Declare PreOrderVisit and PostOrderVisit methods.  They take as
   there only argument a reference to one of the nodes defined in
   Aif2XtlParseTreeNodes.  See the base class, Aif2XtlParseTreeVisitor
   to see the full set of visitor methods.



