A state with history is simply written as a state name followed by an
[HS] or [HS*] property. Above this, there must be a means
for a transition to choose whether the destination is a state itself
or the history of the state. This is accomplished by an additional
[HS] attribute
after the TRANSITION descriptor. A transition with [HS]
after its TRANSITION descriptor goes to the (normal or deep)
history of its destination state 
; a transition without this
attribute goes to or the default substates of .
As an example, the model in Figure 4.9 is
textually written in Table 4.8. The transitions
reacting to events e1 and e2 have an [HS] attribute,
so they go to the histories of their states. Since states A.C.D and A.C.E do not have history, adding [HS]
attribute to the transitions reacting to e3 and e4 does
not change the behavior of those transitions.
