This folder includes a project that demonstrates some of the more sophisticated
and complex features of LuaWrapper. Make sure you fully understand the code in
example 1 before reading the code here. Example 2 introduces some of the
features contained in the luawrapperutil.hpp file which are prefixed with luaU_
instead of luaW_
# Automatic Getter and Setter Generation
In example 1, all of the wrapper functions were written manually. It is very
common need to write get or set function wrappers - so common in fact that this
patter was extracted out into a templated function. In example 1, BankAccount
had the following wrapper:
int BankAccount_checkBalance(lua_State *L)
{
BankAccount* account = luaW_check<BankAccount>(L, 1);
lua_pushnumber(L, account->checkBalance());
return 1;
}
static luaL_Reg BankAccount_metatable[] =
{
...
{ "checkBalance", BankAccount_checkBalance },
...
};
Rather than write code like that every time you need to create a get function,
you can instead just do this:
{ "checkBalance", luaU_get<BankAccount, float, &BankAccount::checkBalance },
This code will automatically instantiate a function wrapper that returns a
float, the result of a call to checkBalance.
# Generic push, to and check functions
Normally, when you need to push a value to Lua or get a value from the stack,
you use a function like lua_pushnumber or lua_tonumber. luawrapperutil.hpp
contains a generic version of these functions as well as specializations for
the primitive types in C++. That means you can do things like this:
int i = luaU_check<int>(L, 1);
luaU_push<double>(L, 1.234);
Additionally, it is possible to extend this functionality to non-primitive
types. A common use is to create a wrapper for std::strings so that you may do
this:
std::string str1 = luaU_check<std::string>(L, 1);
std::string str2 = "Lua is awesome!"
luaU_push<std::string>(L, str2);
Examples of how to create your own luaU_push, luaU_to, and luaU_check can be
found in LuaCustomTypes.hpp
A visual studio project and makefile are provided, or you can use your own
tool chain to compile the example. Once compiled, run
example2.exe example2.lua
or
./example2 example2.lua
to see the code in action.
