visendev / ziglua

Zig bindings for the Lua C API

Ziglua

A Zig package that provides a complete and lightweight wrapper around the Lua C API. Ziglua currently supports the latest releases of Lua 5.1, 5.2, 5.3, 5.4, and Luau and targets Zig master. Tagged versions of Ziglua are made for stable Zig releases.

Ziglua can be used in two ways, either

• embedded to statically embed the Lua VM in a Zig program,
• or as a shared module to create Lua libraries that can be loaded at runtime in other Lua-based software.

In both cases, Ziglua will compile Lua from source and link against your Zig code making it easy to create software that integrates with Lua without requiring any system Lua libraries.

Documentation

Docs are a work in progress and are automatically generated for each push to main. Most functions and public declarations are documented:

• Ziglua Docs

See docs.md for more general information on Ziglua and how it differs from the C API.

Example code is included in the examples directory.

• Run an example with zig build run-example-<name>
• Install an example with zig build install-example-<name>

Why use Ziglua?

In a nutshell, Ziglua is a simple wrapper around the C API you would get by using Zig's @cImport(). Ziglua aims to mirror the Lua C API as closely as possible, while improving ergonomics using Zig's features. For example:

• Zig error unions to require failure state handling
• Null-terminated slices instead of C strings
• Type-checked enums for parameters and return values
• Compiler-enforced checking of optional pointers
• Better types in many cases (e.g. bool instead of int)
• Comptime convenience functions to make binding creation easier

Nearly every function in the C API is exposed in Ziglua. Additional convenience functions like toAny and pushAny use comptime reflection to make the API easier to use.

Integrating Ziglua in your project

Find the archive url of the Ziglua version you want to integrate with your project. For example, the url for the commit 41a110981cf016465f72208c3f1732fd4c92a694 is https://github.com/natecraddock/ziglua/archive/41a110981cf016465f72208c3f1732fd4c92a694.tar.gz.

Then run zig fetch --save <url>. This will add the dependency to your build.zig.zon file.

Then in your build.zig file you can use the dependency.

pub fn build(b: *std.Build) void {
    // ... snip ...

    const ziglua = b.dependency("ziglua", .{
        .target = target,
        .optimize = optimize,
    });

    // ... snip ...

    // add the ziglua module and lua artifact
    exe.root_module.addImport("ziglua", ziglua.module("ziglua"));

}

This will compile the Lua C sources and link with your project.

There are currently two additional options that can be passed to b.dependency():

• .lang: Set the Lua language to build and embed. Defaults to .lua54. Possible values are .lua51, .lua52, .lua53, .lua54, and luau.
• .shared: Defaults to false for embedding in a Zig program. Set to true to dynamically link the Lua source code (useful for creating shared modules).

For example, here is a b.dependency() call that and links against a shared Lua 5.2 library:

const ziglua = b.dependency("ziglua", .{
    .target = target,
    .optimize = optimize,
    .lang = .lua52,
    .shared = true,
});

The ziglua module will now be available in your code. Here is a simple example that pushes and inspects an integer on the Lua stack:

const std = @import("std");
const ziglua = @import("ziglua");

const Lua = ziglua.Lua;

pub fn main() anyerror!void {
    // Create an allocator
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    const allocator = gpa.allocator();
    defer _ = gpa.deinit();

    // Initialize the Lua vm
    var lua = try Lua.init(allocator);
    defer lua.deinit();

    // Add an integer to the Lua stack and retrieve it
    lua.pushInteger(42);
    std.debug.print("{}\n", .{try lua.toInteger(1)});
}

Contributing

Please make suggestions, report bugs, and create pull requests. Anyone is welcome to contribute!

I only use a subset of the Lua API through Ziglua, so if there are parts that aren't easy to use or understand, please fix it yourself or let me know!

Thank you to the Lua team for creating such a great language!