Further sanitized traversal strategies ( Chasing the sins of strategic programming )

Traversal strategies provide an established means of describing automated software transformations and analyses. When considered as a programming tool, the use of strategies may entail certain programming errors. We are specifically concerned with programming errors that go beyond classic type errors, namely errors that interact intimately with the concept of a strategy: (i) divergence of strategies, (ii) unintentional extent of recursion, (iii) constant functions as rewriting behavior, (iv) strategies with unreachable constituents. The main objective of the paper is to identify the programming errors, and to start proposing means for improving strategic programming accordingly.