Ok tilly, I think I understand now. Basically, one simple way to do this optimization would be to keep a list of all states you've visited so far that have failed. Not the exact state that failed, but the furthest in the past state that would definitively lead to that failed state.

Then, before proceeding to any further state, you check to make sure your current state isn't in the list of failed states. You could also prune states that are too old to match anymore, and also optimize the search of this failed state list heavily based on your current state.

The other thing you could do to make it more efficient is instead of going to the furthest past state, you could allow branching and store multiple fail-states for each failure that occurs.

State machines are odd beasts :) .

Ciao,
Gryn

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