A Generative Approach to Traversal-based Generic Programming

The development of complex software requires the implementation of functions over a variety of recursively defined data structures. Much of the corresponding code is not necessarily difficult, but more tedious and/or repetitive and sometimes easy to get wrong. Data structure traversals fall into this category, particularly in object-oriented languages where traversal code is spread throughout many cooperating modules. In this paper we present a new form of generic programming using traversals that lends itself to a flexible, safe, and efficient generative implementation. We describe the approach, its relation to generic and generative programming, and our implementation and resulting performance.