New project: introducing clx

Samir

A small gift for the LuaRT community: introducing clx

Hello everyone,

Before announcing it elsewhere, I wanted to share a project I've been working on for the last several months with the LuaRT community first.
While LuaRT continues to exist as its own project (even if it is now feature complete), clx is something completely different.

clx is a new ahead-of-time Lua compiler that translates Lua source code to C++, then uses the native C++ toolchain on your computer (Clang, GCC or MSVC) to produce standalone executables.

The goal is not to replace Lua or LuaJIT, nor to be the fastest Lua implementation in every benchmark.
Instead, clx focuses on:

Native AOT compilation
Standalone executables
Fast startup times
Cross-platform deployment
Small binaries
Lua 5.5 compatibility
Integration with existing C++ toolchains

Current features include:

Coroutines
Metatables
Module system
Most standard libraries
Binary module support through a dedicated C++ API
Linux, Windows and macOS support

The repository also contains:

A growing Lua compatibility test suite
Performance benchmarks against Lua and LuaJIT
Example projects
Documentation and module development guides

A few examples from the benchmark suite:

Benchmarks (clx speedup over Lua 5.5) :

fib.lua : 45.5x
arraysum.lua: 4.1x
spectralnorm.lua 7.5x
warmup.lua 1.5x

The clx compiler is already capable of running a Pong game written in Lua, using a Sokol binary module built with clx C++ API, and all of this compiled to a single executable by clx (binary size near 550 kb). This is one of the few examples included right now.

Of course, there are still weak spots, especially some string-heavy workloads where traditional interpreters currently perform better.

The project is currently in beta and I'm sure there are still many edge cases to discover and fix.

Website : [Login to see the link]
Repository: [Login to see the link]

As always, feedback, bug reports, weird Lua programs and edge-case tests are welcome but not on this forum, only on GitHub by opening a new issue.

And finally, thank you to everyone who supported LuaRT over the years. Without this community, clx probably wouldn't exist today.

Samir

steve64

Samir very interesting. Is clx targeting also Windows GUI applications?

Samir

Yes it's definitively possible by using gcc/clang/msvc flag for Windows subsystem instead of console

steve64

But will the ui module be available in the "AOT" workflow?

Samir

Not now, but this is something I have in mind 😉

ruby

sounds great.

just tried but only got lots of warning and failed

clx examples\hello\hello.lua
...
libcpmt.lib(StlLCMapStringW.obj) : error LNK2038:  
LINK : warning LNK4098: defaultlib 'MSVCRT' conflicts with use of other libs; use /NODEFAULTLIB:library
hello.exe : fatal error LNK1319: detected 42 unmatches


-- Building for: Visual Studio 18 2026
-- Selecting Windows SDK version 10.0.26100.0 to target Windows 10.0.26200.
-- The CXX compiler identification is MSVC 19.50.35729.0

Samir

Yes its a known bug on windows. It's fixed and committed on the Github repository
Just clone it and compile it if you have GCC or MSVC installed, using ./build.bat

ruby

ok. github tip works.

but there're too many encoding warnings:

warning C4819:  The file contains a character that cannot be represented in the current code page (number). Save the file in Unicode format to prevent data loss.

I saved every file as new file to add UTF8BOM to get rid of these warnings.

why windows msvs always require utf8 BOM ?

maybe there's a switch for this?

but .lua script does not support UTF8BOM.
if I save examples\hello\hello.lua to UTF8BOM , then generated hello.exe won't work.
(no error but blank silently exit)

and there're many warning D9025:

Command-Line Warning D9025 overriding '/Ob2' with '/Ob1'

and most important thing is how to do string pattern matching, Lpeg? [Login to see the link]?

Samir

Thank you ruby for this feedback !

It seems that I need to add /utf-8 option when using MSVC compiler
You are right clx don't compile correctly lua files with UTF8 BOM
The warning D9025 will be fixed in next commit

For string pattern matching, you can use Lua string module pattern matching functions.
I have not tested Lpeg or peglib with clx, if you do so, don't hesitate to bring me some feedback !

Actually the only Lua library I tried to compile with clx is dkjson

steve64

Supporting some LuaRT modules in clx like 'net' (especially the Http object for client REST APIs), 'json' and 'sysutils' would enable, in my opinion, cross-platform agentic solutions in Lua.

ruby

lua is only glue, like js or py , what really does things is C. what pure lua or pure js or pure py can do is so limited.
with sys.COM it can handle office automation, with net it can do http related things. without them it can do nothing.

steve64

What I'm saying is that Lua (with clx) could be a cross-platform solution for "glue" and "orchestration" tasks, when given it the capability of calling REST APIs and running local tools. It would be also faster as easily deployable than Python for this (due to AOT compilation).

Samir

Yes there is a good opportunity do develop LuaRT usage using clx.
But this will need to port the OOP layer and then Task system as standalone clx modules.

Right now clx is too young, I need to test it in lots of Lua scenarios to be sure it compiled correctly.

ruby

maybe "compile" library using lua C-API to library using ckx C++-API

ruby

do you use [Login to see the link] for clx or luart?

Samir

No I didn't knew this functionnality at all.
I will check this thank you ruby !