Luar

Luar is a lightweight, embeddable scripting language designed to run on the Lua virtual machine. It aims to add optional static typing and a more structured module system while preserving Lua's simple syntax and high interop with existing Lua code. Luar compiles to Lua source and can be loaded by the standard Lua runtime, enabling seamless integration with existing Lua applications.

Origins and development: Luar was created by the Luar Project, with early releases in the mid-2010s. The goal was to provide stronger compile-time checks and clearer interfaces for larger Lua codebases without abandoning Lua's dynamism. The language emphasizes predictable performance and easy embedding in host programs written in C or C++.

Key features: optional static typing with type inference, which allows declaring function signatures and data structures while leaving simple expressions untyped. A module system helps manage dependencies and namespaces, and an FFI layer enables calling into C libraries from Luar and Lua alike. Luar preserves Lua's coroutines and runtime semantics, so existing Lua code remains usable.

Implementation and ecosystem: the reference compiler translates Luar source to Lua, which can be run on standard Lua interpreters or JIT-enabled runtimes. Tooling includes a package manager and a standard library with file I/O, string handling, and coroutine utilities. The community maintains a repository of example projects and bindings.

Reception and status: Luar is a niche language within the Lua ecosystem, used in projects that seek stronger typing and clearer interfaces without leaving Lua. It has a modest community and periodic updates, with discussions around performance, compatibility with Lua versions, and best practices for structuring mixed Lua–Luar code.