Porting from Lua 5.1 to 5.2

Question

I'm having some issues porting some older Lua 5.1 code to Lua 5.2. I would like to be able to use the stock Lua 5.2 dll/lib, so any porting would need to be completed using the existing API for Lua 5.2. To make it a little more complicated, I'm using DllImport to P/Invoke some of the Lua API calls. This means any of the #define shortcuts offered will not work. For example using lua_pushglobaltable wont be possible. Most of the updates are needed because LUA_REGISTRYINDEX is not longer accessible.

What I have so far is the following:

---

1a) Replace

lua_pushstring(luaState, "tablename");
lua_settable(luaState, LUA_REGISTRYINDEX); // LUA_REGISTRYINDEX no longer accessible

1b) With

lua_setglobal(luaState, "tablename");

---

2a) Replace

lua_pushstring(luaState, "tablename");
lua_gettable(luaState, LUA_REGISTRYINDEX); // LUA_REGISTRYINDEX no longer accessible

2b) With

lua_getglobal(luaState, "tablename");

---

3a) Replace

lua_pushvalue(luaState, LUA_GLOBALSINDEX);

3b) With

// not sure, something equivalent to lua_pushglobaltable(L)

---

4a) Replace

lua_replace(luaState, LUA_GLOBALSINDEX);

4b) With

// I dont even have a guess here

---

5a) Replace

luaL_ref(luaState, (int)LuaIndexes.LUA_REGISTRYINDEX); // also luaL_unref

5b) With

luaL_ref(luaState, <some arbitrary constant>); // this is probably wrong

---

6a) Replace

lua_rawgeti(luaState, LUA_REGISTRYINDEX, reference);

6b) With

lua_rawgeti(luaState, <same arbitrary constant>, reference); // this is probably wrong

---

7a) Replace

lua_pcall(IntPtr luaState, int nArgs, int nResults, int errfunc);

7b) With

lua_pcallk(IntPtr luaState, int nArgs, int nResults, int errfunc, int ctx, [MarshalAs(UnmanagedType.FunctionPtr)]LuaCSFunction function);
lua_pcallk(luaState, nArgs, nResults, errfunc, 0, null);

---

8a) Replace

lua_getfield(luaState, LUA_REGISTRYINDEX, meta);

8b) With

luaL_setmetatable(IntPtr luaState, string meta);

---

9a) Replace

lua_rawset(luaState, LUA_REGISTRYINDEX);

9b) With

lua_settable(luaState, -3);

Right now everything compiles, but I get memory access violation exceptions, which means I probably substituted something incorrectly. Any help would be appreciated.

Answer 1

I believe I've managed to upgrade this, so I'll add the details of what I did below and the conversion. I created a C wrapper into the LUA lower level API to export the functionality I needed:

1a) Replaced

lua_settable(luaState, LUA_REGISTRYINDEX); // LUA_REGISTRYINDEX no longer accessible

1b) With

lua_settablereg(luaState);

2a) Replaced

lua_gettable(luaState, LUA_REGISTRYINDEX); // LUA_REGISTRYINDEX no longer accessible

2b) With

lua_gettablereg(luaState);

3a) Replaced

lua_pushvalue(luaState, LUA_GLOBALSINDEX);

3b) With

lua_pushglobaltablefunction(luaState)

4a) Replaced

lua_replace(luaState, LUA_GLOBALSINDEX);

4b) With

lua_popglobaltablefunction(luaState)

5a) Replaced

luaL_ref(luaState, (int)LuaIndexes.LUA_REGISTRYINDEX); // also luaL_unref

5b) With

luaL_refreg(luaState); // also luaL_unrefreg

6a) Replaced

lua_rawgeti(luaState, LUA_REGISTRYINDEX, reference);

6b) With

lua_rawgetireg(luaState, reference);

7a) Replaced

lua_pcall(luaState, nArgs, nResults, errfunc);

7b) With

lua_pcalla(luaState, nArgs, nResults, errfunc);

8a) Replaced

lua_getfield(luaState, LUA_REGISTRYINDEX, meta);

8b) With

lua_getfieldreg(luaState, string meta);

9a) Replaced

lua_rawset(luaState, LUA_REGISTRYINDEX);

9b) With

lua_rawsetreg(luaState);

Definitions look like this:

__declspec(dllexport) void lua_pushglobaltablefunction(lua_State *L) 
{
   lua_pushglobaltable(L);
}

__declspec(dllexport) void lua_popglobaltablefunction(lua_State *L) 
{
   lua_rawseti(L, LUA_REGISTRYINDEX, LUA_RIDX_GLOBALS);
}

__declspec(dllexport) int luaL_regref(lua_State *L) 
{
   return luaL_ref(L, LUA_REGISTRYINDEX);
}

__declspec(dllexport) void luaL_unregref(lua_State *L, int reference)
{
   luaL_unref(L, LUA_REGISTRYINDEX, reference);
}

__declspec(dllexport) void lua_settablereg(lua_State *L)
{
   lua_settable(L, LUA_REGISTRYINDEX);
}

__declspec(dllexport) void lua_gettablereg(lua_State *L)
{
   lua_gettable(L, LUA_REGISTRYINDEX);
}

__declspec(dllexport) void lua_rawsetreg(lua_State *L)
{
   lua_rawset(L, LUA_REGISTRYINDEX);
}

__declspec(dllexport) void lua_rawgetreg(lua_State *L)
{
   lua_rawget(L, LUA_REGISTRYINDEX);
}

__declspec(dllexport) void lua_rawgetireg(lua_State *L, int reference)
{
   lua_rawgeti(L, LUA_REGISTRYINDEX, reference);
}

__declspec(dllexport) void lua_getfieldreg(lua_State *L,const char *fieldname)
{
   lua_getfield(L, LUA_REGISTRYINDEX, fieldname);
}

__declspec(dllexport) int luaL_loadbuffername(lua_State *L,const char *buff, int size,const char * name)
{
   return luaL_loadbuffer(L,buff,size,name);
}

__declspec(dllexport) double lua_tonum(lua_State *L, int index)
{
   return lua_tonumber(L, index);
}

__declspec(dllexport) int lua_pcalla(lua_State *L,int nArgs,int nResults,int errfunc)
{
   return lua_pcall(L,nArgs,nResults,errfunc);
}