behavior_machines

https://github.com/seuros/behavior-machines

BehaviorMachines runs behavior trees whose nodes follow the behavior-tree pattern: Sequence, Fallback, their reactive variants, thresholded Parallel, IfThenElse, WhileDoElse, and the usual decorators. Every running leaf the tree abandons is halted exactly once, in the same call, so leaves can own real resources. Pure Ruby, with an optional native backend built on the behavior-machines Rust crate, and leaves for state_machines objects.