NFA Regex Engine in Rust

A toy regex engine implementation using NFA (Non-deterministic Finite Automaton)

Dependency

• regex-syntax: Parse the regex pattern into an AST using regex-syntax
• anyhow

Supported Syntax

• Literal: 1 / 2 / 3 ...
• Concat
• Look: ^ / $
• Alternation: |
• Repetition: *
• Class: [ ] | [^ ]
• Capture Group: ()

Usage

use rsgex::Engine;

let e = Engine::try_from("^[1-9][0-9]{11}$").unwrap();

assert!(e.test("17700012450"));
// exec method returns a HashMap
assert_eq!(e.exec("17700012450").unwrap().get(&0.to_string()).unwrap().clone(), "17700012450");