Function toCString

desmume/src/lua-engine.cpp:1078–1107

like rawToCString, but will check if the global Lua function tostring() has been replaced with a custom function, and call that instead if so

// like rawToCString, but will check if the global Lua function tostring()
// has been replaced with a custom function, and call that instead if so
static const char* toCString(lua_State* L, int idx)
{
	int a = idx>0 ? idx : 1;
	int n = idx>0 ? idx : lua_gettop(L);
	lua_getglobal(L, "tostring");
	lua_CFunction cf = lua_tocfunction(L,-1);
	if(cf == tostring) // optimization: if using our own C tostring function, we can bypass the call through Lua and all the string object allocation that would entail
	{
		lua_pop(L,1);
		return rawToCString(L, idx);
	}
	else // if the user overrided the tostring function, we have to actually call it and store the temporarily allocated string it returns
	{
		lua_pushstring(L, "");
		for (int i=a; i<=n; i++) {
			lua_pushvalue(L, -2);  // function to be called
			lua_pushvalue(L, i);   // value to print
			lua_call(L, 1, 1);
			if(lua_tostring(L, -1) == NULL)
				luaL_error(L, LUA_QL("tostring") " must return a string to " LUA_QL("print"));
			lua_pushstring(L, (i<n) ? " " : "\r\n");
			lua_concat(L, 3);
		}
		const char* str = lua_tostring(L, -1);
		strncpy(s_tempStr, str, s_tempStrMaxLen);
		s_tempStr[s_tempStrMaxLen-1] = 0;
		lua_pop(L, 2);
		return s_tempStr;
	}
}

// replacement for luaB_print() that goes to the appropriate textbox instead of stdout
DEFINE_LUA_FUNCTION(print, "...")