Rlex

Outline

1. Introduction
2. Installation
3. Usage
   • Constructor
   • Navigation Methods
   • Peek Methods
   • Mark and Jump Methods
   • Stash Methods
   • State and Quotes Utilities
4. Caveats / Gotchas

Introduction

Rlex is a lightweight Rust lexer utility for traversing and analyzing string inputs character-by-character. It supports controlled navigation (forwards and backwards), marking and jumping to positions, stashing characters, and even checking for quoted sections in text.

Installation

Include rlex.rs in your project and ensure it's compiled with the rest of your application. You can also structure it as a module in a larger Rust crate.

cargo add rlex

Usage

Constructor

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

Creates a new Rlex instance. Panics if the string is empty.

Navigation Methods

• step_forward() / step_back(): Moves one character forward or backward.
• walk_to_end(F) / walk_to_start(F): Traverse based on a closure returning a bool.
• walk_forward_until(char) / walk_back_until(char): Stop walking when a specific character is found.
• jump_to_end() / jump_to_start(): Jump to ends of the string.
• jump_to_mark(): Jump to a previously marked position.

Peek Methods

• peek_forward(steps) / peek_back(steps): Look ahead or behind without moving the current position.

Mark and Jump Methods

• mark_current_position(): Save the current position.
• mark_reset(): Reset mark to the start.

Stash Methods

• stash_current_char(): Save the current character to stash.
• stash_flush(): Clear and return the stash.
• stash_use_mark(): Fill stash with characters between current and marked positions.

State and Quotes Utilities

• at_start() / at_end(): Checks for boundaries.
• is_in_quotes(): Detects if the current character is inside a quoted section (single or double quotes).

Caveats / Gotchas

• new() returns an error if initialized with an empty string.
• peek_forward() and peek_back() return None if the peek would go out of bounds.
• is_in_quotes() involves jumping to start, traversing, and returning to the original position. Use with caution in performance-sensitive code.
• stash_use_mark() prints internal debug info using println!, which may be undesired in production. Remove or comment out if necessary.