REmatch: a novel regex engine for finding all matches

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Abstract

In this paper, we present the REmatch system for information extraction. REmatch is based on a recently proposed enumeration algorithm for evaluating regular expressions with capture variables supporting the all-match semantics. It tells a story of what it takes to make a theoretically optimal algorithm work in practice. As we show here, a naive implementation of the original algorithm would have a hard time dealing with realistic workloads. We thus develop a new algorithm and a series of optimizations that make REmatch as fast or faster than many popular RegEx engines while at the same time being able to return all the outputs: a task that most other engines tend to struggle with.