An implementation of regexes, supporting a relatively rich set of features, including backreferences and look-around.

```
A Rust library for compiling and matching regular expressions. It uses a hybrid
regex implementation designed to support a relatively rich set of features.
In particular, it uses backtracking to implement "fancy" features such as
look-around and backtracking, which are not supported in purely
NFA-based implementations (exemplified by
[RE2](https://github.com/google/re2), and implemented in Rust in the
[regex](https://crates.io/crates/regex) crate).
[![docs](https://docs.rs/fancy-regex/badge.svg)](https://docs.rs/fancy-regex)
[![crate](https://img.shields.io/crates/v/fancy-regex.svg)](https://crates.io/crates/fancy-regex)
[![ci](https://github.com/fancy-regex/fancy-regex/workflows/ci/badge.svg)](https://github.com/fancy-regex/fancy-regex/actions?query=workflow%3Aci)
[![codecov](https://codecov.io/gh/fancy-regex/fancy-regex/branch/main/graph/badge.svg)](https://codecov.io/gh/fancy-regex/fancy-regex)
A goal is to be as efficient as possible. For a given regex, the NFA
implementation has asymptotic running time linear in the length of the
input, while in the general case a backtracking implementation has
exponential blowup. An example given in [Static Analysis for Regular
Expression Exponential Runtime via Substructural
Logics](https://arxiv.org/pdf/1405.7058.pdf) is:
```python
import re
```