Tsuki

Tsuki is a port of Lua 5.4 to Rust. This is porting, not binding; which mean all code are Rust and can be using without C compiler¹. The initial works was done by C2Rust. Note that this port was done without compatibility with the previous version. You can see a list of the differences here.

[!IMPORTANT] Tsuki does not support multi-threading and no plan to support this at the moment.

Safety

All public API of Tsuki should provide 100% safety as long as you don't use unsafe API incorrectly.

Features

• 100% Rust code.
  • libc is required at the moment.
• Support both synchronous and asynchronous.
• Safe and low overhead API.
• Any error propagated to the caller via Rust Result instead of a long jump.
• core::any::Any as Lua userdata and can be created without the need to define its metatable.
• Metatable for a userdata is lookup with core::any::TypeId instead of a string.

Differences from Lua

Language

• Binary chunk is not supported.
• Panic when memory allocation is failed without retry (Rust behavior).
• Chunk name does not have a prefix (e.g. @).
• Second argument to __close metamethod always nil.
• __gc metamethod is not supported.
• __name metavalue must be UTF-8 string.
• __tostring metamethod must return a UTF-8 string.
• C locale is ignored (once libc has been completely removed).

Standard library

• No _VERSION, collectgarbage, dofile, loadfile, xpcall, string.dump and debug library.
• Second argument of assert accept only a UTF-8 string.
• Arguments of error:
  • First argument accept only a UTF-8 string.
  • Second argument is not supported and it is always assume 1.
• Arguments of load:
  • First argument accept only a string.
  • Second argument accept only a UTF-8 string and will be empty when absent.
  • Third argument must be nil or "t".
• warn is enabled by default without message prefixes and does not support control message.
• string.format requires UTF-8 string for both format string and format value.
• Native module is not supported.
• Environment variable LUA_PATH and LUA_PATH_5_4 is ignored.
• LUA_NOENV in registry is ignored.

Non-goals

• Become a superset of Lua (e.g. Luau).
• C API compatibility.
• Stand-alone mode.
• 16-bit systems.

Roadmap

• Remove libc.
• JIT using Cranelift.

License

MIT