Many other classes exist that are necessary for the
proper execution of the DANCE environment, including
those that provide the underlying glue that connects various
components. For example, classes for management
of the graphical interface, script interpreter and driver
subsystem. The details for those classes will not be described
in this paper as they appear in the source code and
their details do not need to be understood in order to use
the functionality of the system. This section discusses the
most important classes of the system, that we refer to as
the plug-in primitives.