Burton: Online Algorithm
NextAction(initial state ???target state ?, system S’, top?)
Solvable goals?: When top?=True, unless each goal g in ? is labeled Reversible, return Failure.
Select unachieved goal: Find unachieved goal assignment with the lowest topological number. If all achieved return Success.
Select next transition: Let ty be the transition graph in S for goal variable y. Nondeterministically, select a path p in ty from ei to ef along transitions labeled Allowed. Let SC and CC be the state and control conditions of the first transition along p.
Enable transition: Control = NextAction(?,SC,S’,False). If Control = Success then state conditions SC are already satisfied, return CC to effect transition. Otherwise Control contains control assignments to progress on SC. Return Control.