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#define SOL_ALL_SAFETIES_ON 1
#include <sol/sol.hpp>
// Something that can't be collided with
static const auto& script_key = "GlobalResource.MySpecialIdentifier123";
struct GlobalResource {
int value = 2;
};
template <typename Handler>
bool sol_lua_check(sol::types<GlobalResource*>, lua_State* L, int /*index*/, Handler&& handler, sol::stack::record& tracking) {
// not actually taking anything off the stack
tracking.use(0);
// get the field from global storage
sol::stack::get_field<true>(L, script_key);
// verify type
sol::type t = static_cast<sol::type>(lua_type(L, -1));
lua_pop(L, 1);
if (t != sol::type::lightuserdata) {
handler(L, 0, sol::type::lightuserdata, t, "global resource is not present as a light userdata");
return false;
}
return true;
}
GlobalResource* sol_lua_get(sol::types<GlobalResource*>, lua_State* L, int /*index*/, sol::stack::record& tracking) {
// retrieve the (light) userdata for this type
// not actually pulling anything off the stack
tracking.use(0);
sol::stack::get_field<true>(L, script_key);
GlobalResource* ls = static_cast<GlobalResource*>(lua_touserdata(L, -1));
// clean up stack value returned by `get_field`
lua_pop(L, 1);
return ls;
}
int sol_lua_push(sol::types<GlobalResource*>, lua_State* L, GlobalResource* ls) {
// push light userdata
return sol::stack::push(L, static_cast<void*>(ls));
}
int main() {
sol::state lua;
lua.open_libraries(sol::lib::base);
GlobalResource instance;
// get GlobalResource
lua.set_function("f", [](GlobalResource* l, int value) {
return l->value + value;
});
lua.set(script_key, &instance);
// note only 1 argument,
// despite f having 2 arguments to recieve
lua.script("assert(f(1) == 3)");
return 0;
}
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