rlua

A small Lua-like interpreter written in Rust.

Features

• Arithmetic, variables, assignments, and control flow
• if/elseif/else blocks
• while and repeat ... until loops
• for loops
• Functions and built-in helpers such as print, tonumber, tostring, abs, floor, and sqrt
• Tables and indexing
• break inside loops

Roadmap to approach the original C Lua implementation

The current Rust interpreter already covers the core syntax and runtime for small Lua-like programs, but to become comparable to the reference implementation in src/linit.c and the surrounding Lua 5.5.0 C sources, the next milestones are:

• Full standard-library parity with the base, package, coroutine, debug, io, os, string, table, and utf8 libraries
• Proper Lua semantics for multiple returns, varargs (...), closures with upvalues, and lexical scoping
• Metatables and metamethods such as __index, __newindex, __add, and __call
• More faithful table behavior, including generic table operations and better handling of key/value semantics
• Robust error reporting, stack traces, debug hooks, and garbage collection support
• Compatibility with larger real-world Lua programs, including module loading and require

These are the main areas where the Rust version still differs from the original C implementation.

Usage

Run a script file:

cargo run -- path/to/script.lua

Run inline code:

cargo run -- -e "return 2 + 3"

Start the REPL:

cargo run -- --repl

Development

Run the test suite:

cargo test

License and Attribution

This project is licensed under the MIT License - see the LICENSE file for details.

Third-Party Code

This repository contains the official, unmodified source code of the Lua programming language within the lua5 directory for reference purposes.

• Lua License: MIT License
• Copyright: © 1994–2026 Lua.org, PUC-Rio.
• The original Lua license text and copyright notices have been preserved entirely within that directory. You can view the full license terms in /lua5/LICENSE.