class virtual[['i, 'o]]start :object..end
inherit ['i, 'o] start to derive a class to represent the
initial state of a machine. It's start method initiates the machine
with the virtual private guard method.method private virtual guard : (< start : 's. ('s, 'i, 'o, unit) Cf_state_gadget.t; .. >, 'i, 'o, unit)
Cf_state_gadget.guardmethod start : 's. ('s, 'i, 'o, unit) Cf_state_gadget.tCf_state_gadget.start
Cf_state_gadget.guard self#guard self.