Behaviour Tree-based Scenarios

[hidmic]

Description

Allow for scenario descriptions based on https://github.com/stonier/py_trees (see documentation at https://py-trees.readthedocs.io/en/devel/), assembling behaviours instead of writing procedures.

A delphyne-specific py_trees.trees.BehaviorTree subclass populates the scenario with core behaviors (i.e. part of a core subtree) and provides an insertion point for author's subtree(s). Each behavior takes care of adding itself to the simulation at the setup stage while keeping initialization lightweight for dot graph visualization. The simulation is moved forward through time after each tree tick.

This functionality will be split across the following Python modules:

• delphyne.trees
• delphyne.behaviours.*
• delphyne.idioms.*

See design discussions for further reference.

Tasks

• Rewrite delphyne-dragway using behaviour trees.
• Rewrite delphyne-scriptlets using behaviour trees.

[hidmic]

I think this was addressed in PRs a long time ago @agalbachicar. I'll un-assign myself. Feel free to close.