Hi Pengcheng:

Mitch wrote the following about Demeter in 1996:

\item 
The framework is essentially imperative.  It is not so clear how to do more
complicated tasks that are easily expressed recursively, such as annotating a
parse tree, or constructing a copy of a parse tree with each node annotated by
its set of free variables.  Such operations would seem at best to require
hand-simulation of the data structures involved in the recursion; the
manipulation of \verb|bound_vars| is simple enough, but more complicated
examples seem to require uncomfortably much hand-coding.

\end{itemize}

Please can you program 
=
constructing a copy of a parse tree with each node annotated by
its set of free variables.  
=

using FunctionalVisitor and compare it with the iterative solution.
For COM 3362. By Tuesday please.

-- Karl