Optimal adaptive pattern matching

Abstract

We propose a practical technique to compile pattern matching for prioritised overlapping patterns in equational languages into a minimal, deterministic, adaptive, matching automaton. Compared with left-to-right matching automata, adaptive ones have a smaller size and allow shorter matching time. They may improve termination properties as well. Here, space requirements are further reduced by using directed acyclic graphs (dags) automata that shares all the isomorphic subautomata. We design an efficient method to identify such subautomata and hence avoid duplicating their construction while generating the minimised dag automaton.