Derivative Based Nonbacktracking Real-World Regex Matching with Backtracking Semantics

We develop a new derivative based theory and algorithm for nonbacktracking regex matching that supports anchors and counting, preserves backtracking semantics, and can be extended with lookarounds. The algorithm has been implemented as a new regex backend in .NET and was extensively tested as part o...

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Bibliographic Details
Published in:Proceedings of ACM on programming languages Vol. 7; no. PLDI; pp. 1026 - 1049
Main Authors: Moseley, Dan, Nishio, Mario, Perez Rodriguez, Jose, Saarikivi, Olli, Toub, Stephen, Veanes, Margus, Wan, Tiki, Xu, Eric
Format: Journal Article
Language:English
Published: New York, NY, USA ACM 06.06.2023
Subjects:
Computing methodologies
Regular languages
Symbolic and algebraic algorithms
Theory of computation
symbolic
regex
derivative
PCRE
automata
matching
ISSN:2475-1421, 2475-1421
Online Access:Get full text
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Summary:We develop a new derivative based theory and algorithm for nonbacktracking regex matching that supports anchors and counting, preserves backtracking semantics, and can be extended with lookarounds. The algorithm has been implemented as a new regex backend in .NET and was extensively tested as part of the formal release process of .NET7. We present a formal proof of the correctness of the algorithm, which we believe to be the first of its kind concerning industrial implementations of regex matchers. The paper describes the complete foundation, the matching algorithm, and key aspects of the implementation involving a regex rewrite system, as well as a comprehensive evaluation over industrial case studies and other regex engines.
ISSN:2475-1421
2475-1421
DOI:10.1145/3591262