Variables are involved in several parts of a model specification. Though they are implementation-dependent, the minimum requirement for a variable is described here:
) and
port names (
) have different name spaces and hence GUIDs need
not be unique among them.
of a
transition, or 
or 
of a state. Other parts of the model
cannot modify variables.
and
of transitions, and and of states. In
particular, of transitions may use variables to determine
their 
/
value. Other parts of the model cannot
retrieve the data in variables.
Provided these rules are satisfied, an implementation of DCharts 1.0 may choose any scheme to implement variables.