Re: [boost] Re: FSM Review

From: Alexander Nasonov (alnsn_at_[hidden])
Date: 2005-03-14 03:34:08

Peter Petrov wrote:
> Suppose that we have nested states, and we use state-local storage in 
> the outer state. Now, for as long as we don't leave the outer state, 
> (only making transitions between its inner states), it is natural to 
> keep its storage. I.e. the lifetime of the storage should be the same as 
> the logical lifetime of the state.
> 
> Judging from your brief description of your approach, I presume that 
> leaving an inner-state will also destroy the outer-state, since they are 
> the same object (you said: "inheritance is used to model states
> hierarchy").

You're right. It has a different model. There is no outer state.
Inheritance is used only to reduce number of transitions from
a group of states to one transition from their common base.

Of course, you can store outer state data in base class as shared_ptr
and pass this pointer to all derived states.
-- 
Alexander Nasonov