Mata, a Fast and Simple Finite Automata Library (Technical Report)

TL;DR

Mata is a C++ automata library optimized for speed and simplicity, supporting applications like string constraint solving and regular expression reasoning, with Python bindings and superior benchmark performance.

Contribution

It introduces a fast, simple, and extendable automata library with efficient algorithms and a comprehensive benchmark, outperforming existing libraries in various applications.

Findings

Mata significantly outperforms other automata libraries in benchmarks.

The library enhances string constraint solving with the Z3-Noodler solver.

Mata's design facilitates easy extension and modification.

Abstract

Mata is a well-engineered automata library written in C++ that offers a unique combination of speed and simplicity. It is meant to serve in applications such as string constraint solving and reasoning about regular expressions, and as a~reference implementation of automata algorithms. Besides basic algorithms for (non)deterministic automata, it implements a fast simulation reduction and antichain-based language inclusion checking. The simplicity allows a straightforward access to the low-level structures, making it relatively easy to extend and modify. Besides the C++ API, the library also implements a Python binding. The library comes with a large benchmark of automata problems collected from relevant applications such as string constraint solving, regular model checking, and reasoning about regular expressions. We show that Mata is on this benchmark significantly faster than all libraries from a wide range of automata libraries we collected. Its usefulness in string constraint solving is demonstrated by the string solver Z3-Noodler, which is based on Mata and outperforms the state of the art in string constraint solving on many standard benchmarks.