[boost] Re: [prereview request][fsm]

From: David Abrahams (dave_at_[hidden])
Date: 2004-05-23 20:12:38

"Andreas Huber" <ah2003_at_[hidden]> writes:

> David Abrahams wrote:
>
> [snip]
>> Also, do I note that there's always function pointer indirection for
>> event dispatch?
>
> I'm not sure I understand what you mean with "function pointer indirection".
> Event dispatch consists of a virtual function call followed by a linear
> search for a reaction matching the event.

That's what I mean.  If you look at the FSM examples I posted, no
virtual call is needed, and in fact the linear search could be
optimized by the compiler into a hashed case statement or by
metaprogramming into a log(n) search.  The 2nd example uses a
constant-time lookup, dispatching through a single function pointer.
There are lots of dispatching tradeoffs available.

I really like your state representation; it seems as though it should
be possible to get all these different dispatching options with your
state representation, rather than requiring a monolithic STT sequence
to be assembled as my examples do.

-- 
Dave Abrahams
Boost Consulting
http://www.boost-consulting.com