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From: Felipe Magno de Almeida (felipe.m.almeida_at_[hidden])
Date: 2008-06-26 17:33:06
On Thu, Jun 26, 2008 at 6:16 PM, Andreas Huber
> "Felipe Magno de Almeida" <felipe.m.almeida_at_[hidden]> wrote in message
>> I see that your example is related to history. Isn't it more related to
>> how the state was, rather than how the state will be?
> I don't think I understand. The only purpose of the history example was to
> show that you can't always predict at compile time exactly what inner states
> will be entered when you transition to a certain outer state. In the
> CameraWithHistory2 case, as a result of the transition triggered by
> EvShutterReleased, you will enter either Idle *or* Configuring, so you might
> want to specify ctor arguments for *both* states.
I'll need more time to think about history.
> Not IMO, because "cascade" + "outer" suggest that there's a natural order
> that does not exist for inner states. Sure this is "just" naming and is
> easily resolved but I'm also not very fond of the the chaining interface (no
> technical reason just personal preference). I would much rather have
> something like this:
> transit<MyState>(ctor<SomeOtherState>(1, 42), ctor<YetAnotherState>(24),
This syntax can be achieved the same way the other one I think.
template <typename State, typename Arg0, typename Arg1, ...>
struct ctor_definition<State, Arg0, Arg1, ...> ctor(Arg0, Arg1, ...);
template <typename MyState, typename Ctor0, typename Ctor1, typename
Ctor2, typename Ctor...>
transit(Ctor0, Ctor1, Ctor2, Ctor...);
You can construct the factories in transit and pass to the state_machine.
> You wouldn't mention states with default ctors. Also, you can mention the
> states in any order you see fit. Would this work for you?
Yes, surely. But I'm a little unsure how this plays with history.
> Disclaimer: I'm not yet sure whether this interface is implementable with
> reasonable effort. It might turn out *very* tricky with history.
History seems the main problem here.
> Andreas Huber
I'll give more thought to history and then hopefully I can give better
-- Felipe Magno de Almeida
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