Rlex

Rlex is a simple and flexible Rust character walker built for writing lexers and parsers. It supports forward and backward stepping, position marking, peeking, and character stashing.

✨ Features

• Step forward and backward
• Walk with callbacks
• Jump to start, end, or marked positions
• Mark/reset position
• Peek forward and back
• Stash characters and flush

📦 Installation

Add this to your Cargo.toml:

[dependencies]
rlex = { git = "https://github.com/yourname/rlex" }

Replace yourname with your GitHub username or use a path if you're working locally.

🔧 Usage

use rlex::Rlex;

fn main() {
    let mut rlex = Rlex::new("hello world".to_owned()).unwrap();

    rlex.step_forward(); // move to 'e'
    rlex.mark_current_position();

    rlex.walk_forward_until('w');
    println!("Reached: {}", rlex.current_char); // prints 'w'

    rlex.jump_to_mark(); // go back to 'e'
    println!("Back to: {}", rlex.current_char);
}

🔍 API Overview

Creation

let mut rlex = Rlex::new("your string".to_owned()).unwrap();

Movement

• step_forward()
• step_back()
• walk_to_end(|&mut Rlex| -> bool)
• walk_to_start(|&mut Rlex| -> bool)
• walk_forward_until(char) -> bool
• walk_back_until(char) -> bool
• jump_to_start()
• jump_to_end()
• jump_to_mark()

Marking

• mark_current_position()
• mark_reset()

Stashing

• stash_current_char()
• stash_flush() -> Vec<char>
• stash_use_mark()

Peeking

• peek_forward(steps: usize) -> Option<char>
• peek_back(steps: usize) -> Option<char>

State

• at_start() -> bool
• at_end() -> bool

✅ Running Tests

Run the built-in tests using:

cargo test

🪪 License

This project is licensed under the MIT License. See LICENSE for details.