Paths between imperative and functional programming

This article explores relationships between imperative and functional programming by viewing a program as a set of paths. We argue, through a small case study, that the presence of infeasible (or unexecutable) paths makes programs harder to understand. We identify two main causes of infeasible paths, ``unnecessary{''} sequencing and destructive update, hallmarks of an imperative programming style. Functional programming eschews sequencing and destructive update, which can result in programs with fewer infeasible paths that are easier to understand. No proofs are included. We intend to provoke discussion regarding imperative and functional programming styles.