Re: [Boost-users] [statechart] completion event

From: Andreas Huber (ahd6974-spamboostorgtrap_at_[hidden])
Date: 2007-07-26 10:44:06

Hi Francisco

> Are completion transitions and events supported by the Statechart Boost
> library?

No, they are not currently supported. You are the first to ask for them.

I did consider to add them but was unable to come up with a clean 
implementation, see below.

> A completion transition is a transition without an explicit trigger, 
> although it may have a guard defined.

IIRC, this was the main obstacle. If, when the first completion event is 
generated, the guard is false, what does then happen? Will there be another 
dispatch of such an event? If so, when or under what conditions?

> When all transition
> and entry actions and activities in the currently active state are 
> completed, a completion event instance is generated. This event
> is the implicit trigger for a completion transition. The completion 
> event is dispatched before any other queued events and has
> no associated parameters. For instance, a completion transition 
> emanating from a concurrent composite state will be taken
> automatically as soon as all the concurrent regions have reached their 
> final state.
> If multiple completion transitions are defined for a state, then they 
> should have mutually exclusive guard conditions.

Maybe you have better insight into how this should work?

Regards,

--
Andreas Huber
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