What kind of interface / API would you be interested in seeing?

I see two phases. First, I need an API to lay out the network. For my purposes each state has to have:

• A unique name
• A description
• A list of possible next states
• Code which runs when the state is reached
• Code to determine if this state should be the next one

I don't know what this API should look like. Maybe each state is a Perl module implementing a few methods. Maybe it's just a big data structure made of hashes and arrays. Whatever it is it has to be easy to change later when the businessmen change their minds.

Next I need to give the machine a starting state and an event. The machine should either tell me what the next state is or produce an error if the event doesn't trigger a valid next state. Something like:

   $next_state = $machine->run($state, $event);
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-sam