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

From: Andreas Huber (ahd6974-spamboostorgtrap_at_[hidden])
Date: 2007-07-27 06:42:35

> Don't have a solution yet, although I understand the problem you 
> describe about the guard conditions over a completion transition. If I 
> come up with an elegant solution I will post it in this newsgroup.

Ok, please do!

> I have yet another question regarding events:
> Can you create a hierarchy of events in such a way that Boost is able to 
>   distinguish between the new subtypes?
> Here is an example to clarify the question:
> 
> class AbstractEvent : public sc::event<AbstractEvent>{};
> class EventA : public AbstractEvent{};
> class EventB : public AbstractEvent{};
> 
> In this example, events EventA and EventB have the same type ID as 
> AbstractEvent in Boost. Is there a way of giving EventA and EventB 
> different type IDs, without inheriting directly from event< ... >?

Only if you make AbstractEvent a template:

template<class MostDerived>
class AbstractEvent : public sc::event<MostDerived>{};
class EventA : public AbstractEvent<EventA>{};
class EventB : public AbstractEvent<EventA>{};

Please see

<http://www.boost.org/libs/statechart/doc/faq.html#PolymorphicEvents>

for more information.

HTH,

--
Andreas Huber
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