GTPyhop: A hierarchical goal+ task planner implemented in Python

The Pyhop planner, released in 2013, was a simple SHOP-style planner written in Python. It was designed to be easily usable as an embedded system in conventional applications such as game programs. Although little effort was made to publicize Pyhop, its simplicity, ease of use, and understandability led to its use in a number of projects beyond its original intent, and to publications by others. GTPyhop (Goal-and-Task Pyhop) is an extended version of Pyhop that can plan for both goals and tasks, using a combination of SHOP-style task decomposition and GDP-style goal decomposition. It provides a totally-ordered version of Goal-Task-Network (GTN) planning without sharing and task insertion. GTPyhop’s ability to represent and reason about both goals and tasks provides a high degree of flexibility for representing objectives in whichever form seems more natural to the domain designer.