ifyalciner

This is looks quite aesthetic.

Also a super analogy to show new programmers how complexity increases if you introduce unnecessary dependencies.

Behaviour Trees are a bit more than that. They also effect/advice how you structure your project (not component based but behaviour based: exp. you don't have "controller" component in your architecture to handle all locomation but "go_to_pose" or "turn_around" behaviour) plus there are tooling provided around those architectures.

Design of Behaviour Trees were not an answer to lack of coroutines/generators (although they were missing from C++ standards until C++20) but an alternative to state machines.

Although I agree that "tick" based BT implementation is outdated and should completely be replaced by coroutines and mandatory yields (thats what I did in my implementation). There is still value in behaviour based architectures in robotics. They make building complex/reactive behaviours much easier than component based ones.

Coroutines (or the concept of saving context to come back to) is already heavily explored in robotics in recent years. Behaviour Trees [1] approximates what coroutines do in system level controlled ticks mainly to avoid pitfalls of state machines. They are also extensively used in game development too. ROS2 have Nav2[2] package which is based on BTCpp library [3]. Not surprisingly BTCpp library uses boost coroutines to implement some behaviours.

Shameless plug, I have also been developing (weren't planning to advertise yet so no docs or plans for release) a behaviour based C++ library completely built on coroutines [4] to avoid some problems of "Behaviour Tree"s.

[1] https://en.wikipedia.org/wiki/Behavior_tree_(artificial_inte... [2] https://en.wikipedia.org/wiki/Behavior_tree_(artificial_inte... [3] https://github.com/BehaviorTree/BehaviorTree.CPP [4] https://gitlab.com/ifyalciner/ferguson