rustegex

A hobby regular expression engine in Rust.

• supports Unicode characters
• implements 3 engines:
  • DFA-based engine
    • convert regex to NFA
    • convert NFA to DFA
  • VM-based engine
    • cache
  • Derivative-based engine
    • use Brzozowski's derivatives
• all engines currently support *, +, ?, |, (), and \ (escape)

example

DFA-based:

let regex = RustRegex::new("a|b*", "dfa").unwrap();
assert!(regex.is_match("a"));
assert!(regex.is_match("b"));
assert!(regex.is_match("bb"));
assert!(regex.is_match("bbb"));
assert!(!regex.is_match("c"));

let regex = RustRegex::new("ab(cd|)", "dfa").unwrap();
assert!(regex.is_match("abcd"));
assert!(regex.is_match("ab"));
assert!(!regex.is_match("abc"));
assert!(regex.is_match("abcd"));

let regex = RustRegex::new("a+b", "dfa").unwrap();
assert!(regex.is_match("ab"));
assert!(regex.is_match("aab"));
assert!(regex.is_match("aaab"));
assert!(!regex.is_match("a"));

let regex = RustRegex::new(r"a\|b\*", "dfa").unwrap();
assert!(regex.is_match("a|b*"));
assert!(!regex.is_match("ab"));

let regex = RustRegex::new("正規表現(太郎|次郎)", "dfa").unwrap();
assert!(regex.is_match("正規表現太郎"));
assert!(regex.is_match("正規表現次郎"));
assert!(!regex.is_match("正規表現三郎"));

VM-based:

let regex = RustRegex::new("a|b*", "vm").unwrap();
assert!(regex.is_match("a"));
assert!(regex.is_match("b"));
assert!(regex.is_match("bb"));
assert!(regex.is_match("bbb"));
assert!(!regex.is_match("c"));

let regex = RustRegex::new("ab(cd|)", "vm").unwrap();
assert!(regex.is_match("abcd"));
assert!(regex.is_match("ab"));
assert!(!regex.is_match("abc"));
assert!(regex.is_match("abcd"));

let regex = RustRegex::new("a+b", "vm").unwrap();
assert!(regex.is_match("ab"));
assert!(regex.is_match("aab"));
assert!(regex.is_match("aaab"));
assert!(!regex.is_match("a"));

let regex = RustRegex::new(r"a\|b\*", "vm").unwrap();
assert!(regex.is_match("a|b*"));
assert!(!regex.is_match("ab"));

let regex = RustRegex::new("正規表現(太郎|次郎)", "vm").unwrap();
assert!(regex.is_match("正規表現太郎"));
assert!(regex.is_match("正規表現次郎"));
assert!(!regex.is_match("正規表現三郎"));

Derivative-based:

let regex = RustRegex::new("a|b*", "derivative").unwrap();
assert!(regex.is_match("a"));
assert!(regex.is_match("b"));
assert!(regex.is_match("bb"));
assert!(regex.is_match("bbb"));
assert!(!regex.is_match("c"));

let regex = RustRegex::new("ab(cd|)", "derivative").unwrap();
assert!(regex.is_match("abcd"));
assert!(regex.is_match("ab"));
assert!(!regex.is_match("abc"));
assert!(regex.is_match("abcd"));

let regex = RustRegex::new("a+b", "derivative").unwrap();
assert!(regex.is_match("ab"));
assert!(regex.is_match("aab"));
assert!(regex.is_match("aaab"));
assert!(!regex.is_match("a"));

let regex = RustRegex::new(r"a\|b\*", "derivative").unwrap();
assert!(regex.is_match("a|b*"));
assert!(!regex.is_match("ab"));

let regex = RustRegex::new("正規表現(太郎|次郎)", "derivative").unwrap();
assert!(regex.is_match("正規表現太郎"));
assert!(regex.is_match("正規表現次郎"));
assert!(!regex.is_match("正規表現三郎"));

test

$ cargo test

run benchmarks

$ cargo bench

license

MIT