State

States are the main structuring concept of the process behaviour. In general, state specifications include the (outgoing) transitions to other states (i.e. the behavior of that state). If needed, state specificatons may also include nested (sub)states which, in turn, could have their own transitions (and so on) thus refining/completing the overall behaviour of the state/process. In addition, state specifications include the set of (deferred) saved signals, which have to be postponed (if received), and the time progress condition (the temporal constraint) which limit the stay in that particular state. Furthermore, some options are available to define respectively the initial state of the process (or of compound states) and the stability (stable or unstable) which control process execution steps (atomic, un-interruptive from one stable state to another).

xxxxxxxxxxxxxxxxxxstate ::=  

state state-id { state-option }$^*$ ;  

$[$ tpc constraint $]$ 

$[$ save signal-id { , signal-id }$^*$ $]$ 

{ state-component }$^*$  

endstate ;  



state-component ::=  

transition $\vert$ 

state  



state-option ::=  

#start $\vert$ 

#stable $\vert$ #unstable