Derivative-Based Diagnosis of Regular Expression Ambiguity
Martin Sulzmann, Kenny Zhuo Ming Lu · International Journal of Foundations of Computer Science · 2017
Regular expressions are often ambiguous. We present a novel method based on Brzozowski’s derivatives to aid the user in diagnosing ambiguous regular expressions. We introduce a derivative-based finite state transducer to generate parse trees and minimal counter-examples. The transducer can be easily customized to either follow the POSIX or Greedy disambiguation policy and based on a finite set of examples it is possible to examine if there are any differences between POSIX and Greedy.