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Workshop paper

P2: A Baseline Approach to Planning with Control Structures and Programs, R. Petrick, Proceedings of the ICAPS 2009 Workshop on Generalized Planning: Macros, Loops, Domain Control, pages 59-64, 2009.

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Many planners model planning domains with "primitive actions," where action preconditions are represented by sets of simple tests about the state of domain fluents, and action effects are described as updates to these fluents. Queries and updates are typically combined in only very limited ways, for instance using logical operators and quantification. By comparison, formalisms like Golog permit "complex actions," with control structures like if-else blocks and while loops, and view actions as programs. In this paper we explore the idea of planning directly with complex actions and programs. We describe the structure of a simple planner based on undirected search, that generates plans by simulating the execution of action programs before they are added to a plan. An initial evaluation compares this approach against a classical heuristic planner using a domain whose program structures have been compiled into ordinary PDDL actions. Initial results illustrate that in certain domains, planning directly with programs can lead to a significant performance improvement. This work offers a baseline planner to compare against alternate approaches to planning with programs.