gwave-exec sends a single guile-scheme expression to a running
gwave process, where it is evaluated and the result returned.

gwaverepl is an interactive read-evaluate-print loop, sending multiple
expressions can be sent to gwave for evaluation.  It can be compiled
with readline.

Comunication with the running gwave is through the X server.  The
protocol used is borrowed from the scwm window manager.  It could
probably use to be extended a bit.  Multiple gwave processes on the
same X server are not supported well.  (ok, not supported at all.)

Using the X server for interprocess communication may not be as
familiar as using TCP/IP, nor as trendy as things like CORBA, but it
does exactly what we need as far as security: if you can connect to
the X server, you can control gwave and cause it to execute arbitrary
scheme code.  Otherwise, not.