Program synthesis as a generative method

Generative methods (also known as procedural content generation) have been used to generate a variety of static artifacts such as game levels. One key property of a generative method for a particular domain is how effectively the approach allows a designer to express the properties and constraints they care about. Generative methods have been applied much less frequently to dynamic artifacts such as boss behaviors, in part because the complex representation required to describe boss morphology and behavior is not amenable to existing generative techniques. It is challenging to describe a generative space of varied yet valid behaviors. Expanding on previous work that introduced a programming language for representing boss behaviors, we illustrate how such a language can be used by a designer to describe desirable design properties and constraints for bosses. That is, we define a generative space of bosses as a space of well-formed programs. We present a constructive algorithm that extends generative grammars to efficiently generate well-formed programs, and we show a complete example of generating Mega-Man-like bosses with complex attack patterns. We conclude that designing a generative space of dynamic behaviors can be fruitfully framed as a programming-language design problem.