gengyong / luaaa Goto Github PK

no action really required but FYI-ish, we had to implement the following change for luaaa to compile in our environment

rusefi@4996997

how can i call a lua method from c++?

like emit events, for example:

C++:
void Update(){
luaIdkBlaBla.emit("onUpdate");
}

Lua:
func onUpdate():
print("updated")
end

and so the lua function is called from the c++ code

using example.lua and LUA tutorial I tried to subclass AwesomeCat like so

SpecialCat = AwesomeCat:new("special")
function SpecialCat:onlyInSpecial()
    print(self.getName() .. " has a special cat function")
end
function SpecialCat:speak(text)
    print("Special cat says: " .. text)
end

This should add a new function onlyInSpecial to SpecialCat and overwrite speak but that does not seem to work. LUA refuses AwesomeCat:new with

lua err: [string "console"]:60: calling 'new' on bad self (string expected, got table)

using AwesomeCat.new works, but then I am not allowed to add new functions to SpecialCat

lua err: [string "console"]:61: attempt to index a AwesomeCat value (global 'SpecialCat')

Is this possible at all and if so how to do this?

support multiple return values from C++ functions

Hey,
thanks for this great work.
I am trying to require a lua module into the example.lua file and getting lua error.

Two questions:

• How can I debug next time whats the error?
• How can I make "require" or "dofile"?

Thanks.

Is inheritance supported? E.g. binding something like.

class Animal { ... };
class Cat: public Animal { ... };
class Tiger: public Cat { ... };

void AddToZoo(Animal& animal); // Should be callable with a Cat or a Tiger

I take a static global variable and make it static class variable - things stop linking.

rusefi/rusefi@ec6c3eb

Code links just fine:

struct LuaCanReciever;

// linked list of all CAN receivers
static LuaCanReciever *list;

struct LuaCanReciever {

	LuaCanReciever *next;

	~LuaCanReciever() {
		LuaCanReciever *current, *tmp;
		// find self in list and remove self
		LL_FOREACH_SAFE(list, current, tmp)
		{
			if (current == this) {
				LL_DELETE(list, current);
			}
		}
	}

	LuaCanReciever() {
		LL_PREPEND(list, this);
	}

};


	LuaClass<LuaCanReciever> luaCanReciever(l, "CanReciever");
	luaCanReciever
		.ctor()
		;

Code does not link

struct LuaCanReciever;

struct LuaCanReciever {
	// linked list of all CAN receivers
	static LuaCanReciever *list;

	LuaCanReciever *next;

	~LuaCanReciever() {
		LuaCanReciever *current, *tmp;
		// find self in list and remove self
		LL_FOREACH_SAFE(list, current, tmp)
		{
			if (current == this) {
				LL_DELETE(list, current);
			}
		}
	}

	LuaCanReciever() {
		LL_PREPEND(list, this);
	}
};


	LuaClass<LuaCanReciever> luaCanReciever(l, "CanReciever");
	luaCanReciever
		.ctor()
		;

with the following error:

Compiling lua_hooks.cpp
Linking build/rusefi.elf
c:/program files (x86)/gnu arm embedded toolchain/9 2020-q2-update/bin/../lib/gcc/arm-none-eabi/9.3.1/../../../../arm-none-eabi/bin/ld.exe: C:\Users\Dell2019\AppData\Local\Temp\rusefi.elf.FKMdel.ltrans5.ltrans.o: in function `luaaa::LuaClass<LuaCanReciever>::LuaClass(lua_State*, char const*, luaL_Reg const*)::HelperClass::f__gc(lua_State*)':
C:\stuff\rusefi\firmware/./controllers/lua/lua_hooks.cpp:355: undefined reference to `LuaCanReciever::list'
c:/program files (x86)/gnu arm embedded toolchain/9 2020-q2-update/bin/../lib/gcc/arm-none-eabi/9.3.1/../../../../arm-none-eabi/bin/ld.exe: C:\Users\Dell2019\AppData\Local\Temp\rusefi.elf.FKMdel.ltrans5.ltrans.o: in function `luaaa::LuaClass<LuaCanReciever>::ctor<>(char const*)::HelperClass::f_new(lua_State*)':
C:\stuff\rusefi\firmware/./controllers/lua/lua_hooks.cpp:355: undefined reference to `LuaCanReciever::list'
collect2.exe: error: ld returned 1 exit status
make: *** [ChibiOS/os/common/startup/ARMCMx/compilers/GCC/mk/rules.mk:217: build/rusefi.elf] Error 1
"make -j12 all" terminated with exit code 2. Build might be incomplete.

c++ -march=native -O3 -std=c++11 -o demo amalgamation_demo.cpp -I include/roaring/ -I /usr/local/openresty/luajit/include/luajit-2.1/
/tmp/ccU0wBoY.o: In function bindToLUA(lua_State*)': amalgamation_demo.cpp:(.text+0x3d5): undefined reference to luaL_argerror'
amalgamation_demo.cpp:(.text+0x4c6): undefined reference to luaL_newmetatable' amalgamation_demo.cpp:(.text+0x4d3): undefined reference to lua_pushvalue'
amalgamation_demo.cpp:(.text+0x4e5): undefined reference to lua_setfield' amalgamation_demo.cpp:(.text+0x4f7): undefined reference to luaL_checkstack'
amalgamation_demo.cpp:(.text+0x514): undefined reference to lua_pushstring' amalgamation_demo.cpp:(.text+0x523): undefined reference to lua_pushcclosure'
amalgamation_demo.cpp:(.text+0x530): undefined reference to lua_settable' amalgamation_demo.cpp:(.text+0x54a): undefined reference to lua_settop'
amalgamation_demo.cpp:(.text+0x557): undefined reference to lua_settop' amalgamation_demo.cpp:(.text+0x5a1): undefined reference to luaL_register'
amalgamation_demo.cpp:(.text+0x5ae): undefined reference to lua_settop' amalgamation_demo.cpp:(.text+0x609): undefined reference to luaL_register'
amalgamation_demo.cpp:(.text+0x616): undefined reference to lua_settop' amalgamation_demo.cpp:(.text+0x62a): undefined reference to lua_getfield'
amalgamation_demo.cpp:(.text+0x637): undefined reference to lua_pushstring' amalgamation_demo.cpp:(.text+0x644): undefined reference to lua_newuserdata'
amalgamation_demo.cpp:(.text+0x680): undefined reference to lua_pushcclosure' amalgamation_demo.cpp:(.text+0x68d): undefined reference to lua_settable'
amalgamation_demo.cpp:(.text+0x69a): undefined reference to lua_settop' amalgamation_demo.cpp:(.text+0x6ae): undefined reference to lua_getfield'
amalgamation_demo.cpp:(.text+0x6bb): undefined reference to lua_pushstring' amalgamation_demo.cpp:(.text+0x6c8): undefined reference to lua_newuserdata'
amalgamation_demo.cpp:(.text+0x6f7): undefined reference to lua_pushcclosure' amalgamation_demo.cpp:(.text+0x704): undefined reference to lua_settable'
amalgamation_demo.cpp:(.text+0x711): undefined reference to lua_settop' amalgamation_demo.cpp:(.text+0x725): undefined reference to lua_getfield'
amalgamation_demo.cpp:(.text+0x732): undefined reference to lua_pushstring' amalgamation_demo.cpp:(.text+0x73f): undefined reference to lua_newuserdata'
amalgamation_demo.cpp:(.text+0x76e): undefined reference to lua_pushcclosure' amalgamation_demo.cpp:(.text+0x77b): undefined reference to lua_settable'
amalgamation_demo.cpp:(.text+0x788): undefined reference to lua_settop' amalgamation_demo.cpp:(.text+0x79c): undefined reference to lua_getfield'
amalgamation_demo.cpp:(.text+0x7a9): undefined reference to lua_pushstring' amalgamation_demo.cpp:(.text+0x7b6): undefined reference to lua_newuserdata'
amalgamation_demo.cpp:(.text+0x7e5): undefined reference to lua_pushcclosure' amalgamation_demo.cpp:(.text+0x7f2): undefined reference to lua_settable'
amalgamation_demo.cpp:(.text+0x7ff): undefined reference to lua_settop' amalgamation_demo.cpp:(.text+0x813): undefined reference to lua_getfield'
amalgamation_demo.cpp:(.text+0x820): undefined reference to lua_pushstring' amalgamation_demo.cpp:(.text+0x82d): undefined reference to lua_newuserdata'
amalgamation_demo.cpp:(.text+0x85c): undefined reference to lua_pushcclosure' amalgamation_demo.cpp:(.text+0x869): undefined reference to lua_settable'
amalgamation_demo.cpp:(.text+0x876): undefined reference to lua_settop' amalgamation_demo.cpp:(.text+0x88a): undefined reference to lua_getfield'
amalgamation_demo.cpp:(.text+0x897): undefined reference to lua_pushstring' amalgamation_demo.cpp:(.text+0x8a4): undefined reference to lua_newuserdata'
amalgamation_demo.cpp:(.text+0x8ca): undefined reference to lua_pushcclosure' amalgamation_demo.cpp:(.text+0x8d7): undefined reference to lua_settable'
amalgamation_demo.cpp:(.text+0x8e4): undefined reference to lua_settop' amalgamation_demo.cpp:(.text+0x8f8): undefined reference to lua_getfield'
amalgamation_demo.cpp:(.text+0x905): undefined reference to lua_pushstring' amalgamation_demo.cpp:(.text+0x912): undefined reference to lua_newuserdata'
amalgamation_demo.cpp:(.text+0x941): undefined reference to lua_pushcclosure' amalgamation_demo.cpp:(.text+0x94e): undefined reference to lua_settable'
amalgamation_demo.cpp:(.text+0x95b): undefined reference to lua_settop' amalgamation_demo.cpp:(.text+0x96f): undefined reference to lua_getfield'
amalgamation_demo.cpp:(.text+0x97c): undefined reference to lua_pushstring' amalgamation_demo.cpp:(.text+0x989): undefined reference to lua_pushstring'
amalgamation_demo.cpp:(.text+0x996): undefined reference to lua_settable' amalgamation_demo.cpp:(.text+0x9a3): undefined reference to lua_settop'
amalgamation_demo.cpp:(.text+0xa3d): undefined reference to luaL_openlib' amalgamation_demo.cpp:(.text+0xa4f): undefined reference to lua_pushinteger'
amalgamation_demo.cpp:(.text+0xa66): undefined reference to lua_setfield' amalgamation_demo.cpp:(.text+0xa9d): undefined reference to luaL_openlib'
amalgamation_demo.cpp:(.text+0xaaf): undefined reference to lua_pushstring' amalgamation_demo.cpp:(.text+0xac6): undefined reference to lua_setfield'
amalgamation_demo.cpp:(.text+0xcf1): undefined reference to luaL_openlib' amalgamation_demo.cpp:(.text+0xd0a): undefined reference to lua_createtable'
amalgamation_demo.cpp:(.text+0xd37): undefined reference to lua_pushstring' amalgamation_demo.cpp:(.text+0xd51): undefined reference to lua_rawseti'
amalgamation_demo.cpp:(.text+0xd71): undefined reference to lua_setfield' amalgamation_demo.cpp:(.text+0xdb3): undefined reference to lua_newuserdata'
amalgamation_demo.cpp:(.text+0xde4): undefined reference to luaL_openlib' amalgamation_demo.cpp:(.text+0xe26): undefined reference to lua_newuserdata'
amalgamation_demo.cpp:(.text+0xe5b): undefined reference to luaL_openlib' amalgamation_demo.cpp:(.text+0xe9d): undefined reference to lua_newuserdata'
amalgamation_demo.cpp:(.text+0xed2): undefined reference to luaL_openlib' amalgamation_demo.cpp:(.text+0xf14): undefined reference to lua_newuserdata'
amalgamation_demo.cpp:(.text+0xf49): undefined reference to luaL_openlib' amalgamation_demo.cpp:(.text+0xfcb): undefined reference to luaL_openlib'
amalgamation_demo.cpp:(.text+0xfe0): undefined reference to lua_pushnumber' amalgamation_demo.cpp:(.text+0xff7): undefined reference to lua_setfield'
amalgamation_demo.cpp:(.text+0x116f): undefined reference to luaL_argerror' amalgamation_demo.cpp:(.text+0x1254): undefined reference to luaL_newmetatable'
amalgamation_demo.cpp:(.text+0x1261): undefined reference to lua_pushvalue' amalgamation_demo.cpp:(.text+0x1273): undefined reference to lua_setfield'
amalgamation_demo.cpp:(.text+0x1285): undefined reference to luaL_checkstack' amalgamation_demo.cpp:(.text+0x12a4): undefined reference to lua_pushstring'
amalgamation_demo.cpp:(.text+0x12b2): undefined reference to lua_pushcclosure' amalgamation_demo.cpp:(.text+0x12bf): undefined reference to lua_settable'
amalgamation_demo.cpp:(.text+0x12d9): undefined reference to lua_settop' amalgamation_demo.cpp:(.text+0x12e6): undefined reference to lua_settop'
amalgamation_demo.cpp:(.text+0x132a): undefined reference to luaL_register' amalgamation_demo.cpp:(.text+0x1337): undefined reference to lua_settop'
amalgamation_demo.cpp:(.text+0x1379): undefined reference to luaL_register' amalgamation_demo.cpp:(.text+0x1386): undefined reference to lua_settop'
amalgamation_demo.cpp:(.text+0x139a): undefined reference to lua_getfield' amalgamation_demo.cpp:(.text+0x13a7): undefined reference to lua_pushstring'
amalgamation_demo.cpp:(.text+0x13b4): undefined reference to lua_pushstring' amalgamation_demo.cpp:(.text+0x13c1): undefined reference to lua_settable'
amalgamation_demo.cpp:(.text+0x13ce): undefined reference to lua_settop' amalgamation_demo.cpp:(.text+0x13e2): undefined reference to lua_getfield'
amalgamation_demo.cpp:(.text+0x13ef): undefined reference to lua_pushstring' amalgamation_demo.cpp:(.text+0x13fc): undefined reference to lua_pushinteger'
amalgamation_demo.cpp:(.text+0x1409): undefined reference to lua_settable' amalgamation_demo.cpp:(.text+0x1416): undefined reference to lua_settop'
amalgamation_demo.cpp:(.text+0x142a): undefined reference to lua_getfield' amalgamation_demo.cpp:(.text+0x1437): undefined reference to lua_pushstring'
amalgamation_demo.cpp:(.text+0x1446): undefined reference to lua_pushinteger' amalgamation_demo.cpp:(.text+0x1453): undefined reference to lua_settable'
amalgamation_demo.cpp:(.text+0x1460): undefined reference to lua_settop' amalgamation_demo.cpp:(.text+0x15bb): undefined reference to luaL_argerror'
amalgamation_demo.cpp:(.text+0x169e): undefined reference to luaL_argerror' amalgamation_demo.cpp:(.text+0x177e): undefined reference to luaL_argerror'
amalgamation_demo.cpp:(.text+0x186a): undefined reference to luaL_argerror' amalgamation_demo.cpp:(.text+0x195a): undefined reference to luaL_argerror'
/tmp/ccU0wBoY.o:amalgamation_demo.cpp:(.text+0x1a4a): more undefined references to luaL_argerror' follow /tmp/ccU0wBoY.o: In function runLuaExample(lua_State*)':
amalgamation_demo.cpp:(.text+0x324f): undefined reference to luaL_loadbuffer' amalgamation_demo.cpp:(.text+0x3294): undefined reference to lua_tolstring'
amalgamation_demo.cpp:(.text+0x32b2): undefined reference to lua_settop' amalgamation_demo.cpp:(.text+0x3864): undefined reference to lua_pcall'
/tmp/ccU0wBoY.o: In function luaaa::LuaClass<int*>::LuaClass(lua_State*, std::string const&, luaL_Reg const*)::HelperClass::f__gc(lua_State*)': amalgamation_demo.cpp:(.text._ZZN5luaaa8LuaClassIPiEC1EP9lua_StateRKSsPK8luaL_RegEN11HelperClass5f__gcES4_[_ZZN5luaaa8LuaClassIPiEC1EP9lua_StateRKSsPK8luaL_RegEN11HelperClass5f__gcES4_]+0x11): undefined reference to luaL_checkudata'
/tmp/ccU0wBoY.o: In function luaaa::LuaClass<int*>& luaaa::LuaClass<int*>::ctor<>(char const*)::HelperClass::f_new(lua_State*)': amalgamation_demo.cpp:(.text._ZZN5luaaa8LuaClassIPiE4ctorIIEEERS2_PKcEN11HelperClass5f_newEP9lua_State[_ZZN5luaaa8LuaClassIPiE4ctorIIEEERS2_PKcEN11HelperClass5f_newEP9lua_State]+0x32): undefined reference to lua_newuserdata'
amalgamation_demo.cpp:(.text._ZZN5luaaa8LuaClassIPiE4ctorIIEEERS2_PKcEN11HelperClass5f_newEP9lua_State[_ZZN5luaaa8LuaClassIPiE4ctorIIEEERS2_PKcEN11HelperClass5f_newEP9lua_State]+0x4e): undefined reference to lua_getfield' amalgamation_demo.cpp:(.text._ZZN5luaaa8LuaClassIPiE4ctorIIEEERS2_PKcEN11HelperClass5f_newEP9lua_State[_ZZN5luaaa8LuaClassIPiE4ctorIIEEERS2_PKcEN11HelperClass5f_newEP9lua_State]+0x5b): undefined reference to lua_setmetatable'
amalgamation_demo.cpp:(.text._ZZN5luaaa8LuaClassIPiE4ctorIIEEERS2_PKcEN11HelperClass5f_newEP9lua_State[_ZZN5luaaa8LuaClassIPiE4ctorIIEEERS2_PKcEN11HelperClass5f_newEP9lua_State]+0x7c): undefined reference to lua_pushnil' /tmp/ccU0wBoY.o: In function luaaa::LuaClass<int*>& luaaa::LuaClass<int*>::ctor<int*>(char const*)::HelperClass::f_new(lua_State*)':
amalgamation_demo.cpp:(.text._ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State[_ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State]+0x48): undefined reference to lua_type' amalgamation_demo.cpp:(.text._ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State[_ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State]+0x57): undefined reference to lua_touserdata'
amalgamation_demo.cpp:(.text._ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State[_ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State]+0x77): undefined reference to lua_newuserdata' amalgamation_demo.cpp:(.text._ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State[_ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State]+0x97): undefined reference to lua_getfield'
amalgamation_demo.cpp:(.text._ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State[_ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State]+0xa4): undefined reference to lua_setmetatable' amalgamation_demo.cpp:(.text._ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State[_ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State]+0xc6): undefined reference to luaL_checkudata'
amalgamation_demo.cpp:(.text._ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State[_ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State]+0xe9): undefined reference to luaL_argerror' amalgamation_demo.cpp:(.text._ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State[_ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State]+0xf6): undefined reference to luaL_checkudata'
amalgamation_demo.cpp:(.text._ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State[_ZZN5luaaa8LuaClassIPiE4ctorIIS1_EEERS2_PKcEN11HelperClass5f_newEP9lua_State]+0x11c): undefined reference to `lua_pushnil'

Cloud we support overload functions:

myCat.def("eat", &&MyCat::eat)
myCat.def("eat", &&MyCat::eat2)

or

myCat.def("eat", 
	[](MyCat* cat, const std::string& some_thing) { return cat->eat(some_thing); }),
	[](MyCat* cat, const Rat& rat) { return cat->eat(rat); }))

For static methods the same .fun calls?

Hi!

Probably is my fault, but I was wondering if you had this problem before.

I just included luaaaa.h and added this line on a class: luaaa::LuaClass luaCat(mLuaState, "MyLuaComponent");

But when I compile I got link errors:
5>LINK : warning LNK4098: defaultlib 'MSVCRT' conflicts with use of other libs; use /NODEFAULTLIB:library
5>CLua.lib(lauxlib.obj) : error LNK2001: unresolved external symbol __imp_freopen
5>CLua.lib(lauxlib.obj) : error LNK2001: unresolved external symbol __imp_ferror
5>CLua.lib(lauxlib.obj) : error LNK2001: unresolved external symbol __imp_feof
5>CLua.lib(lauxlib.obj) : error LNK2001: unresolved external symbol __imp_strerror
5>CLua.lib(lvm.obj) : error LNK2001: unresolved external symbol __imp_strcoll

Any help would be appreciated :)

Cheers!

Test code:

struct MyType
{
	void myFunc(int, int);
};

LuaClass<MyType> myLuaClass(l, "myClass");
myLuaClass.fun("myFunc", &MyType::myFunc);

Produces this warning:

In file included from ./controllers/lua/lua_hooks.cpp:12:
./controllers/lua/luaaa/luaaa.hpp: In instantiation of 'static int luaaa::MemberFunctionCaller(void (TCLASS::*)(ARGS ...))::HelperClass::Invoke(lua_State*) [with TCLASS = configureRusefiLuaHooks(lua_State*)::MyType; ARGS = {int, int}; lua_State = lua_State]':
./controllers/lua/luaaa/luaaa.hpp:499:3:   required from 'int (* luaaa::MemberFunctionCaller(void (TCLASS::*)(ARGS ...)))(lua_State*) [with TCLASS = configureRusefiLuaHooks(lua_State*)::MyType; ARGS = {int, int}; lua_CFunction = int (*)(lua_State*); lua_State = lua_State]'
./controllers/lua/luaaa/luaaa.hpp:641:50:   required from 'luaaa::LuaClass< <template-parameter-1-1> >& luaaa::LuaClass< <template-parameter-1-1> >::fun(const char*, F) [with F = void (configureRusefiLuaHooks(lua_State*)::MyType::*)(int, int); TCLASS = configureRusefiLuaHooks(lua_State*)::MyType]'
./controllers/lua/lua_hooks.cpp:431:42:   required from here
./controllers/lua/luaaa/luaaa.hpp:495:6: error: operation on 'idx' may be undefined [-Werror=sequence-point]
  495 |      (LuaStack<TCLASS>::get(state, 1).**(FTYPE*)(calleePtr))(LuaStack<ARGS>::get(state, idx--)...);
      |      ^

As you can see, this line in luaaa.hpp is the issue:
(LuaStack<TCLASS>::get(state, 1).**(FTYPE*)(calleePtr))(LuaStack<ARGS>::get(state, idx--)...);
The list of arguments is evaluated one at a time via the parameter pack, then the arguments are passed to the underlying function. The problem is that in C++, it is undefined behavior to assign the same variable more than once between any two sequence points. The first sequence point is the previous line, and the next sequence point is the call to the function returned from LuaStack::get, inbetween which idx is assigned once for every argument passed.

PS: The fact that the commit 51ab2ef has different behavior for GCC vs. Clang vs. MSVC indicates that you're relying on undefined behavior that may not even be consistent within one particular compiler.

I have a C++ class I want to export to LUA. This class has a hashmap that maps a name to std::function. Currently I typically put lamdba expressions in there.
I now want to allow LUA to add values to this hashmap. To experiment a little bit I modified the example.cpp to accept a std::function with the same argument list in the testCallback function. This compiles fine but when I run this LUA complains:

lua err: [string "console"]:103: bad argument #1 to 'testCallback' (cpp class ``St8functionIFiRKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEifEE`` not export)

Is it possible with luaaa to use std::function instead of function pointers?

Sorry I'm not familiar with Lua API so I open a issue instead of sending a pull request.

如题

I've attempted to pull fresh luaaa (with our typeid fix) and things got pretty broken

https://github.com/rusefi/rusefi/runs/3705887714

rusefi/rusefi@5a65c0c

Compiling histogram.cpp
In file included from ../firmware/controllers/lua/lua_hooks.cpp:12:
../firmware/controllers/lua/luaaa/luaaa.hpp:1058:18: error: declaration of template parameter ‘TCLASS’ shadows template parameter
 1058 |         template<typename TCLASS, bool> friend struct DestructorHelperClass;
      |                  ^~~~~~~~
../firmware/controllers/lua/luaaa/luaaa.hpp:1055:12: note: template parameter ‘TCLASS’ declared here
 1055 |  template <typename TCLASS>
      |            ^~~~~~~~
../firmware/controllers/lua/luaaa/luaaa.hpp:1320:86: error: ‘nullptr_t’ has not been declared
 1320 |         inline LuaClass<TCLASS>& ctor(const char * name, TCLASS*(*spawner)(ARGS...), nullptr_t) {
      |                                                                                      ^~~~~~~~~
../firmware/controllers/lua/luaaa/luaaa.hpp:1408:92: error: ‘nullptr_t’ has not been declared
 1408 |         inline LuaClass<TCLASS>& ctor(const std::string& name, TCLASS*(*spawner)(ARGS...), nullptr_t) {
      |                                                                                            ^~~~~~~~~
../firmware/controllers/lua/luaaa/luaaa.hpp: In member function ‘luaaa::LuaClass< <template-parameter-1-1> >& luaaa::LuaClass< <template-parameter-1-1> >::ctor(const string&, TCLASS* (*)(ARGS ...))’:
../firmware/controllers/lua/luaaa/luaaa.hpp:1399:25: error: ‘F’ was not declared in this scope
 1399 |             return ctor<F>(name.c_str(), spawner);
      |                         ^
../firmware/controllers/lua/luaaa/luaaa.hpp: In member function ‘luaaa::LuaClass< <template-parameter-1-1> >& luaaa::LuaClass< <template-parameter-1-1> >::ctor(const string&, TCLASS* (*)(ARGS ...), TRET (*)(TCLASS*))’:
../firmware/controllers/lua/luaaa/luaaa.hpp:1404:25: error: ‘F’ was not declared in this scope
 1404 |             return ctor<F, D>(name.c_str(), spawner, deleter);
      |                         ^
../firmware/controllers/lua/luaaa/luaaa.hpp:1404:28: error: ‘D’ was not declared in this scope
 1404 |             return ctor<F, D>(name.c_str(), spawner, deleter);
      |                            ^
../firmware/controllers/lua/luaaa/luaaa.hpp: In member function ‘luaaa::LuaClass< <template-parameter-1-1> >& luaaa::LuaClass< <template-parameter-1-1> >::ctor(const string&, TCLASS* (*)(ARGS ...), int)’:
../firmware/controllers/lua/luaaa/luaaa.hpp:1409:25: error: ‘F’ was not declared in this scope
 1409 |             return ctor<F, D>(name.c_str(), spawner, nullptr);
      |                         ^
../firmware/controllers/lua/luaaa/luaaa.hpp:1409:28: error: ‘D’ was not declared in this scope
 1409 |             return ctor<F, D>(name.c_str(), spawner, nullptr);
      |                            ^
../firmware/controllers/lua/lua_hooks.cpp: In function ‘int lua_readpin(lua_State*)’:
../firmware/controllers/lua/lua_hooks.cpp:27:7: warning: unused variable ‘msg’ [-Wunused-variable]
   27 |  auto msg = luaL_checkstring(l, 1);
      |       ^~~
make: *** [../firmware/ChibiOS/os/common/startup/SIMIA32/compilers/GCC/rules.mk:130: build/obj/lua_hooks.o] Error 1
make: *** Waiting for unfinished jobs....
Simulator compilation failed

My IDE is showing ~23 errors
Quite a few of them are 'cacheLuaState' may be undeclared or unknown.

And the rest come from template errors:

        with
        [
            V=int Player::* ,
            T=int Player::* 
        ]
        and
        [
            V=int Player::* 
        ]
        and
        [
            T=int Player::* 
        ]
F:\Dev\CPP\untitled3\luaaa.hpp(1440): note: There is no context in which this conversion is possible
F:\Dev\CPP\untitled3\luaaa.hpp(221): note: see declaration of 'luaaa::LuaStack<V>::put'
        with
        [
            V=int Player::* 
        ]
F:\Dev\CPP\untitled3\main.cpp(26): note: see reference to function template instantiation 'luaaa::LuaClass<Player> &luaaa::LuaClass<Player>::def<intPlayer::* >(const char *,const V &)' being compiled
        with
        [
            V=int Player::* 
        ]
F:\Dev\CPP\untitled3\main.cpp(28): note: see reference to function template instantiation 'luaaa::LuaClass<Player> &luaaa::LuaClass<Player>::def<intPlayer::* >(const char *,const V &)' being compiled
        with
        [
            V=int Player::* 
        ]```

When using the class binding functions, it appears that once a class has been bound to a lua_State, another lua_State cannot also have access to the given class while the first lua_State still exists.

As a minimal display of the issue, referencing the Cat class from your example code:

lua_State* state1 = luaL_newstate();
lua_State* state2 = luaL_newstate();

luaaa::LuaClass<Cat> lc1(state1, "AwesomeCat");
lc1.ctor();

luaaa::LuaClass<Cat> lc2(state2, "AwesomeCat");
lc2.ctor();

lua_close(state1);
lua_close(state2);

Results in the following assertion failure:

luaaa.hpp:979: luaaa::LuaClass< <template-parameter-1-1> >::LuaClass(lua_State*, const char*, const luaL_Reg*) [with TCLASS = Cat; lua_State = lua_State; luaL_Reg = luaL_Reg]: Assertion `klassName == nullptr' failed.

Meanwhile, if you close the first state before proceeding to the second, there isn't a problem.

lua_State* state1 = luaL_newstate();
lua_State* state2 = luaL_newstate();

luaaa::LuaClass<Cat> lc1(state1, "AwesomeCat");
lc1.ctor();

lua_close(state1);

luaaa::LuaClass<Cat> lc2(state2, "AwesomeCat");
lc2.ctor();

lua_close(state2);

Using LuaModule in this way does not appear to have the same issue.

class MyClass {
public:
    MyClass(lua_State* l) {
        luaL_error(l, "first constructor called");
    }

    MyClass(lua_State* l, int x) {
        if (x > 100) {
            luaL_error(l, "oops, X too large!");
        }
    }
}

.......

LuaClass<MyClass> myClass(l, "myClass");

// These both compile
myClass.ctor<lua_State*>();
myClass.ctor<lua_State*, int>();

then you have the lua

local obj1 = myClass.new()        -- works, passes lua state properly
local obj = myClass.new(200)    -- doesn't work, causes runtime error!

The second one causes:

bad argument #2 to 'new' (string expected, got userdata)

The problem is that LuaStack<lua_State*>::get() correctly just returns the lua state, but it causes the indices to be wrong for all following parameters, since it doesn't actually occupy a spot on the stack like all other args do.

See https://github.com/rusefi/rusefi/pull/4391/files# for our solution, adding a specialization to PlacementConstructorCaller when the first parameter is a lua_State*, and passing it directly instead of relying on the LuaStack<lua_State*>::get() function (maybe this one shouldn't even exist, as the ignored idx parameter is in fact the root of this bug?).

I have a C++DLL file that I want to register the get type function to the Lua virtual machine. However, the get method needs to return the function execution value and also the obtained value. So, how do I handle these multiple return values? Can I use this template to register to the Lua virtual machine

@mck1117 why exactly do we not have typeid(T) available in https://github.com/rusefi/rusefi?

Anyway we do not have typeid(T)

it would be nice to have an option not to require typeid(T)

see rusefi current solution rusefi@cacdd76

I try to wrap my cpp functions (Qt and native) via luaaa.

Build it with cmake and get libluabridge.so library, wich uses luaaa.hpp.

Then I try to run simple script and get an error:

main.lua

require 'libluabridge';

error

$ LD_LIBRARY_PATH=:../lib:../../3rdparty/lib/ lua -i main.lua
Lua 5.1.5  Copyright (C) 1994-2012 Lua.org, PUC-Rio
lua: error loading module 'libluabridge' from file './libluabridge.so':
        ./libluabridge.so: undefined symbol: luaopen_libluabridge
stack traceback:
        [C]: ?
        [C]: in function 'require'
        main.lua:1: in main chunk
        [C]: ?

$

Heed help! Pls!

I'm trying to make a c++ lua 5.1 package and I cant seem to find out how to get any class exported.
I've tried setting it from "luaopen_test", tried returning it from a normally exported function in luaL_reg array for export like how you would call `require('test').new()' but i cant get a return when i do. only lua_push funcs work in returning anything.
both LuaClass and LuaModule have no effect.

My use case is similar to below.

int test_add1(lua_State *L) {
 double d = luaL_checknumber(L, 1); // get item 1
 lua_pushnumber(L, d + 1);
 return 1; // number of items returned
}
static const struct luaL_reg testlib[] = {
 {"add1", test_add1},
 {NULL, NULL}
};
extern "C"
int luaopen_test (lua_State *L) {
 luaL_register(L, "test", testlib);
 return 1;
}

Using gcc version 4.8.5 20150623 (Red Hat 4.8.5-44) (GCC) on centos 7 the compliler complains about missing typename.

Adding typename where the compiler suggests fixes the issue and allows the example to compile and run.

$ git diff
diff --git a/luaaa.hpp b/luaaa.hpp
index d8cdc86..7b112fa 100644
--- a/luaaa.hpp
+++ b/luaaa.hpp
@@ -2523,7 +2523,7 @@ namespace LUAAA_NS
 #else
             luaL_Reg regtab = { nullptr, nullptr };
             luaL_openlib(m_state, m_moduleName, &regtab, 0);
-            auto uData = (LuaClass<TCLASS, TAG>::UserDataDetail*)lua_newuserdata(m_state, sizeof(LuaClass<TCLASS, TAG>::UserDataDetail));
+            auto uData = (typename LuaClass<TCLASS, TAG>::UserDataDetail*)lua_newuserdata(m_state, sizeof(typename LuaClass<TCLASS, TAG>::UserDataDetail));^M
             if (uData)
             {
                 uData->obj = userData.obj;

I created a AUR package for this project for easier accessibility for arch linux users.

it puts the header file in your /usr/include directory.

here's the link: https://aur.archlinux.org/packages/luaaa-git

Hi! The library is very useful, but what about binding existing C++ objects (instances of classes) to lua? Is there any solutions for this?

This code will cause an assertion failure on the second test:

void test1()
{
	lua_State* l = make_lua();
	LuaClass<MyType> myLuaType(l, "MyType");

	// ... do stuff ...

	destroy_lua(l);
}

void test2()
{
	lua_State* l = make_lua();
	LuaClass<MyType> myLuaType(l, "MyType");

	// ... do stuff ...

	destroy_lua(l);
}

The assertion in the LuaClass constructor is currently too strict. Seeing if the same string is already there would likely be more appropriate.