1 files changed, 89 insertions, 0 deletions
diff --git a/deps/sol2/examples/source/optional_with_iteration.cpp b/deps/sol2/examples/source/optional_with_iteration.cpp
new file mode 100644
index 0000000..74765e3
--- /dev/null
+++ b/deps/sol2/examples/source/optional_with_iteration.cpp
@@ -0,0 +1,89 @@
+#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;
+}