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#define SOL_ALL_SAFETIES_ON 1
#include <sol/sol.hpp>
#include <string>
#include <memory>
#include <iostream>
struct thing {
int a = 20;
thing() = default;
thing(int a) : a(a) {
}
};
struct super_thing : thing {
int b = 40;
};
struct unrelated {};
int main(int, char* []) {
std::cout << "=== optional with iteration ===" << std::endl;
sol::state lua;
// Comment out the new_usertype call
// to prevent derived class "super_thing"
// from being picked up and cast to its base
// class
lua.new_usertype<super_thing>("super_thing", sol::base_classes, sol::bases<thing>());
// Make a few things
lua["t1"] = thing{};
lua["t2"] = super_thing{};
lua["t3"] = unrelated{};
// And a table
lua["container"] = lua.create_table_with(0, thing{ 50 }, 1, unrelated{}, 4, super_thing{});
std::vector<std::reference_wrapper<thing>> things;
// Our recursive function
// We use some lambda techniques and pass the function itself itself so we can recurse,
// but a regular function would work too!
auto fx = [&things](auto& f, auto& tbl) -> void {
// You can iterate through a table: it has
// begin() and end()
// like standard containers
for (auto key_value_pair : tbl) {
// Note that iterators are extremely frail
// and should not be used outside of
// well-constructed for loops
// that use pre-increment ++,
// or C++ ranged-for loops
const sol::object& key = key_value_pair.first;
const sol::object& value = key_value_pair.second;
sol::type t = value.get_type();
switch (t) {
case sol::type::table: {
sol::table inner = value.as<sol::table>();
f(f, inner);
} break;
case sol::type::userdata: {
// This allows us to check if a userdata is
// a specific class type
sol::optional<thing&> maybe_thing = value.as<sol::optional<thing&>>();
if (maybe_thing) {
thing& the_thing = maybe_thing.value();
if (key.is<std::string>()) {
std::cout << "key " << key.as<std::string>() << " is a thing -- ";
}
else if (key.is<int>()) {
std::cout << "key " << key.as<int>() << " is a thing -- ";
}
std::cout << "thing.a ==" << the_thing.a << std::endl;
things.push_back(the_thing);
}
} break;
default:
break;
}
}
};
fx(fx, lua);
std::cout << std::endl;
return 0;
}
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