Help on introducing Luau support.

[NougatBitz]

Hey everyone,

So I’ve been working on adding support for Luau over the past couple of days. I’ve gotten most-if not all-features implemented.

The only issue is, I cannot for the life of me figure out how the CMake setup here works. If anyone could help with making Sol import the Luau headers and libraries, that’d be much appreciated.

(I’ve been using the single-header version to make it work, and it’s a pain.)

Thanks,
Davin

[Nerixyz]

I suppose you only need the headers from Luau.VM. In that case, the following will get the basic setup going:

Diff

diff --git a/cmake/Packages/FindLuaBuild.cmake b/cmake/Packages/FindLuaBuild.cmake
index 14fd4d48..3815f47e 100644
--- a/cmake/Packages/FindLuaBuild.cmake
+++ b/cmake/Packages/FindLuaBuild.cmake
@@ -30,6 +30,8 @@ function(find_lua_build LUA_VERSION)
 	string(TOLOWER ${LUA_VERSION} LUA_BUILD_NORMALIZED_LUA_VERSION)
 	if (LUA_BUILD_NORMALIZED_LUA_VERSION MATCHES "luajit")
 		set(LUA_BUILD_LIBNAME ${LUA_VERSION})
+	elseif (LUA_BUILD_NORMALIZED_LUA_VERSION MATCHES "luau")
+		set(LUA_BUILD_LIBNAME ${LUA_VERSION})
 	elseif (BUILD_LUAJIT)
 		set(LUA_BUILD_LIBNAME luajit-${LUA_VERSION})
 	elseif (LUA_BUILD_NORMALIZED_LUA_VERSION MATCHES "lua")
@@ -53,6 +55,10 @@ function(find_lua_build LUA_VERSION)
 		set(LUA_BUILD_OBJECT_FILE_SUFFIX .o)
 	endif()
 
+	if (LUA_BUILD_NORMALIZED_LIBNAME MATCHES "luau")
+		set(LUA_BUILD_BUILD_DLL_DEFAULT OFF)
+	endif()
+
 	# # # Options
 	option(BUILD_LUA_AS_DLL ${LUA_BUILD_BUILD_DLL_DEFAULT} "Build Lua or LuaJIT as a Shared/Dynamic Link Library")
 
@@ -60,6 +66,8 @@ function(find_lua_build LUA_VERSION)
 	if (NOT LUA_LIBRARY_NAME)
 		if (LUA_BUILD_NORMALIZED_LIBNAME MATCHES "luajit")
 			set(LUA_LIBRARY luajit)
+		elseif (LUA_BUILD_NORMALIZED_LIBNAME MATCHES "luau")
+			set(LUA_LIBRARY luau)
 		else()
 			set(LUA_LIBRARY ${LUA_BUILD_LIBNAME})
 		endif()
@@ -82,6 +90,9 @@ function(find_lua_build LUA_VERSION)
 	if (BUILD_LUAJIT OR LUA_BUILD_NORMALIZED_LUA_VERSION MATCHES "luajit")
 		include(${CMAKE_CURRENT_LIST_DIR}/FindLuaBuild/LuaJIT.cmake)
 		set(LUA_VERSION_STRING ${LUA_JIT_VERSION})
+	elseif (BUILD_LUAU OR LUA_BUILD_NORMALIZED_LUA_VERSION MATCHES "luau")
+		include(${CMAKE_CURRENT_LIST_DIR}/FindLuaBuild/Luau.cmake)
+		set(LUA_VERSION_STRING 5.1) # Can we get to this version?
 	else()
 		include(${CMAKE_CURRENT_LIST_DIR}/FindLuaBuild/LuaVanilla.cmake)
 		set(LUA_VERSION_STRING ${LUA_VANILLA_VERSION})
diff --git a/cmake/Packages/FindLuaBuild/Luau.cmake b/cmake/Packages/FindLuaBuild/Luau.cmake
new file mode 100644
index 00000000..099f2677
--- /dev/null
+++ b/cmake/Packages/FindLuaBuild/Luau.cmake
@@ -0,0 +1,50 @@
+# # # # sol2
+# The MIT License (MIT)
+# 
+# Copyright (c) 2025 Rapptz, ThePhD, and contributors
+# 
+# Permission is hereby granted, free of charge, to any person obtaining a copy of
+# this software and associated documentation files (the "Software"), to deal in
+# the Software without restriction, including without limitation the rights to
+# use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+# the Software, and to permit persons to whom the Software is furnished to do so,
+# subject to the following conditions:
+# 
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+# 
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+# FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+# COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+# IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+# protect from multiple inclusion
+if(luau_build_included)
+	return()
+endif(luau_build_included)
+set(luau_build_included true)
+
+include(FetchContent)
+set(LUAU_BUILD_CLI OFF)
+set(LUAU_BUILD_TESTS OFF)
+FetchContent_Declare(
+  luau
+  GIT_REPOSITORY https://github.com/luau-lang/luau.git
+  GIT_TAG        6ff0650a8d4ba90df9826492b68c88911e39b1c1 # 0.682
+  EXCLUDE_FROM_ALL
+)
+FetchContent_MakeAvailable(luau)
+
+# wrapper library
+add_library(sol_luau INTERFACE)
+add_library(Lua::Lua ALIAS sol_luau)
+target_link_libraries(sol_luau INTERFACE Luau.Compiler Luau.VM)
+message(STATUS "Using Luau")
+
+get_target_property(LUA_INCLUDE_DIRS Luau.VM INCLUDE_DIRECTORIES)
+	
+# set externally-visible target indicator
+set(LUA_LIBRARIES Lua::Lua)
+set(LUA_INTERPRETER "")

Linking #1307 and #1680 (comment) for completeness.

[NougatBitz]

Much appreciated, that helped alot.

The only missing piece is __gc support now, I hate how luau handels destructors, but i'll get by.

Thanks,
Davin

[NougatBitz]

Hi all,

While this isn’t my first time contributing to a collaborative project, it's still one of the few, so I’m sure there are aspects of my code that could be improved-especially in terms of aligning with Sol2’s standards and best practices.

Fork that adds Luau support. (I didn't wanna push to the sol2 repo, as this is a fairly early version)
Commit

I’d really appreciate any feedback on what I should change or do differently to make this a better fit for the project.

Thanks,
Davin

[skhaz]

Thank you for this awesome work!

[NougatBitz]

Hi again,

I’ve completed most of the port — all tests are passing except for one, and I’m currently stuck on why it’s failing. I’d really appreciate any help troubleshooting this.

Here's the latest commit, and here's the Repository.

Test output:

sol2.tests.environment:

 Randomness seeded to: 260428617

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
sol2.tests.environment.exe is a Catch2 v3.8.1 host application.
Run with -? for options

-------------------------------------------------------------------------------
environments/this_environment
  from C++
-------------------------------------------------------------------------------
C:\Users\user\source\repos\sol2\tests\environment\source\this_environment.cpp(59)
...............................................................................

C:\Users\user\source\repos\sol2\tests\environment\source\this_environment.cpp(67): FAILED:
  REQUIRE( value == 30 )
with expansion:
  15 == 30

===============================================================================
test cases:  5 |  4 passed | 1 failed
assertions: 71 | 70 passed | 1 failed

Thanks,
Davin

[Nerixyz]

Did a few fixes on https://github.com/Nerixyz/sol2/commits/fix/luau-test-thing/. To pass that test, Nerixyz@ca0213d should fix it.

Other than that, there are a few failures in the examples:

> ctest
[...]
The following tests FAILED:
          5 - sol2.examples.source.basic (Failed)
         16 - sol2.examples.source.coroutine_state (Failed)
         34 - sol2.examples.source.docs.state_transfer (Failed)
         49 - sol2.examples.source.lua_stream (Failed)
         66 - sol2.examples.source.require_override_behavior (Failed)
         68 - sol2.examples.source.script_error_handling (Failed)
         99 - sol2.examples.source.tutorials.quick_n_dirty.running_lua_code (Failed)
        101 - sol2.examples.source.tutorials.quick_n_dirty.running_lua_code_safely (Failed)

Regarding Nerixyz@a57c29d, Luau does define registry(L) but that doesn't conflict with registry(). At least not on MSVC (the silliest of them all) and clang.

[NougatBitz]

Awesome, Thank u!

Visual Studio didnt run all tests, apparently, silly IDE. I'll use CTest via the CLI from now on!