A Higher-Order Function Approach to Evolve Recursive Programs

Abstract

We demonstrate a functional style recursion implementation to evolve recursive programs. This approach re-expresses a recursive program using a non-recursive application of a higher-order function. It divides a program recursion pattern into two parts: the recursion code and the application of the code. With the higher-order functions handling recursion code application, GP effort becomes focused on the generation of recursion code. We employed this method to evolve two recursive programs: a strstr C library function, and programs that produce the Fibonacci sequence. In both cases, the program space defined by higher-order functions are much easier for GP to search and to find a solution. We have learned about higher-order function selection and fitness assignment through this study. The next step will be to test the approach on applications with open-ended solutions, such as evolutionary design.