bever1337 / regexxx

Greedy regular expression parser

Regexxx, an implementation of Augmented Non-Deterministic Finite Automata

Documentation

Preface

• Optimally Streaming Greedy Regular Expression Parsing
• Bit-coded Regular Expression Parsing
• Regular Expression Search Algorithm

Augmented non-deterministic finite automata are defined by the 4-tuple:

• state, finite set of states
• delta, δ ⊆ State × T × State is a labeled transition relation with labels T = Σ ⊎ {0, 1, ε}
• q0, initial state
• f, final state

Implementation

use regexxx::compilers::forward_compiler::{Compiler, ForwardCompiler};
// RE a(b|c)*d
let mut machine = ForwardCompiler::from_expr_a('a').unwrap();
ForwardCompiler::expr_a(&mut machine, 'b').unwrap();
ForwardCompiler::expr_a(&mut machine, 'c').unwrap();
ForwardCompiler::union(&mut machine).unwrap();
ForwardCompiler::star(&mut machine).unwrap();
ForwardCompiler::expr_a(&mut machine, 'd').unwrap();
ForwardCompiler::concatenate(&mut machine).unwrap();
ForwardCompiler::concatenate(&mut machine).unwrap();