Re: [boost] [msm] Review

Subject: Re: [boost] [msm] Review
From: David Bergman (David.Bergman_at_[hidden])
Date: 2009-12-05 09:44:46

On Dec 5, 2009, at 9:35 AM, David Bergman wrote:

> On Dec 5, 2009, at 6:01 AM, Andreas Huber wrote:
> 
>>> MSM and Statechart do not merely overlap, the do the exact same
>>> thing: letting the developer specify and execute a state machine.
>> 
>> This statement is about as ignorant of the details as: "std::list<> and std::vector<> do not merely overlap, they do the exact same thing: letting the developer store objects in memory"
> 
> Ignorant? Andreas, I can tell you one thing: I am anything but ignorant. Do you claim that I am wrong, i.e., that either MSM or Statechart does something else but letting the developer specify and execute a state machine? Do you realize that this specific use is much less generic than your "store objects in memory"?
> 
> This is not the kind of comment that will sway me, that is for sure. The abstraction - FSM - is very *specific* and is common between MSM and Statechart.

Furthermore, I detailed in another post that what would be required is a radical difference in either (i) use (interface...) of the FSM and/or (ii) runtime characteristics (such as the difference in implementation strategy between map and hash_map, or list and vector in features they both share - sequences of objects.) There *is* a quite significant difference in runtime characteristics between Statechart and MSM, as far as I can tell, and hopefully that would be put high up in the rationale or overview of both MSM and Statechart in Boost 1.44 (or whatever.) There is no ignorance of complexity issues here, but at a certain abstract level - which happens not to be quite *specific* - these two libraries do the same thing.

/David