SystemTextRegu

SystemTextRegu is a cross-platform, open-source text processing library that provides a high-performance regular expression engine and related utilities. It is designed to complement common string matching APIs in managed environments by emphasizing Unicode correctness, streaming input, and memory efficiency.

The project originated in the early 2020s as a community-driven effort to improve regex performance and correctness across platforms. After several development cycles, it released a stable API and began broad platform support, including bindings for multiple programming languages. The project is maintained by a diverse set of volunteers and accepts contributions under an open-source license.

Key features include a pattern parser that supports a broad subset of regex syntax plus extensions, a hybrid engine that blends deterministic automata with backtracking paths to balance speed and expressiveness, Unicode-aware matching with proper handling of surrogate pairs and normalization, named capture groups, lazy quantifiers, and streaming matching to process large inputs without loading them entirely into memory. The API provides synchronous and asynchronous operations, incremental compilation of frequently used patterns, and memory-efficient pattern objects.

SystemTextRegu is designed with a modular architecture, separating parsing, optimization, and matching. It can be embedded in applications or ported to different runtimes via adapters. The library offers a small runtime and typical host bindings for common platforms, along with tooling to test and profile pattern performance.

In practice, SystemTextRegu has seen adoption in log analysis, data validation, and text transformation tasks in small and large projects. It is maintained by an active community with issue trackers and documentation. See also: Regular expressions, Unicode processing, Text processing libraries, System.Text.RegularExpressions.