E. Gladyshev wrote:
>  From: "Andreas Huber" <ah2003@[...].net>
>  [...]
> > Unfortunately, all FSM standards/publications I know are absolutely
> > silent on error handling.
> >
> 
>  I can understand why.
>  If you are referring to "error" as something unexpected,
>  then it is out of the state machine realm.

If the errors were unexpected it would make little sense to handle them in
the state machine, right?

>  The state machine mantra is complete behavioral determinism.
>  If "error" is an expected condition, then it is just a normal
>  event that is part of the state machine design.

When an entry action fails, you have the problem that the state machine is
unstable because it would be a bad idea to just continue to enter other
(inner) states (see Rationale). Since it is non-trivial to define what to do
in such a situation, I think it is unfortunate that all these standards are
silent on error handling. They implicitly force you define all your entry
and transition actions in a way so that they can never fail.

Regards,

Andreas


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