E.2 Passing Clusters into Routines
Clusters can be passed into routines using either the cluster's name or the
cluster's root name. In addition, clusters outside of the routine can be
directly referenced from inside of the routine; they are globally available.
The routine is called by providing the routine name, the root cluster name,
followed by the name of the cluster being passed into the routine. From
inside of the routine, you can both read and write clusters. This provides an
easy method to pass a lot of variables into a routine without having to pass
in all the individual variable names.