OpenSiv3D_Serialize_Polymorphic.cpp

# include <Siv3D.hpp> // OpenSiv3D v0.3.1

class IFormatable {
public:
	virtual operator String() const = 0;
};

class SubA : public IFormatable {
public:
	int a;
	SubA() : a(0) {}
	SubA(int a) : a(a) {}

	template<class Archive>
	void SIV3D_SERIALIZE(Archive& ar) {
		ar(a);
	}

	operator String() const override {
		return Format(U"SubA{", a, U'}');
	}
};

class SubB : public IFormatable {
public:
	String n;
	SubB() : n(U"null") {}
	SubB(const String& n) : n(n) {}

	template<class Archive>
	void SIV3D_SERIALIZE(Archive& ar) {
		ar(n);
	}

	operator String() const override {
		return Format(U"SubB{", n, U'}');
	}
};
CEREAL_REGISTER_TYPE(SubA);
CEREAL_REGISTER_TYPE(SubB);
CEREAL_REGISTER_POLYMORPHIC_RELATION(IFormatable, SubA);
CEREAL_REGISTER_POLYMORPHIC_RELATION(IFormatable, SubB);

namespace s3d {
	template<class T>
	void Formatter(FormatData& f, const std::shared_ptr<T>& v) {
		Formatter(f, v->operator String());
	}
}

void Main() {

	using type = std::shared_ptr<IFormatable>;
	{
		Array<type>v;
		v	<< std::make_shared<SubA>(114514)
			<< std::make_shared<SubB>(U"BABYLON");
		Serializer<BinaryWriter>(U"test")(v);
		Logger << v;
	}
	{
		Array<type>v;
		Deserializer<BinaryReader>(U"test")(v);
		Logger << v;
	}
	Logger << SubA(1919);
	Logger << SubB(U"GO is GOD");
}

OpenSiv3D_Serialize_Polymorphic_Old.cpp

# include <Siv3D.hpp> // OpenSiv3D v0.3.1

class IFormatable {
public:
	virtual void format(FormatData&) const = 0;
};
using shared_IFormatable = std::shared_ptr<IFormatable>;
template<>
void s3d::Formatter(FormatData& f, const shared_IFormatable& v) {
	v->format(f);
}

class SubA : public IFormatable {
public:
	int a;
	SubA() : a(0) {}
	SubA(int a) : a(a) {}

	template<class Archive>
	void SIV3D_SERIALIZE(Archive& ar) {
		ar(a);
	}

	void format(FormatData& f) const override {
		f.string.append(U"SubA{").append(ToString(a))<<U'}';
	}
};

class SubB : public IFormatable {
public:
	String n;
	SubB() : n(U"null") {}
	SubB(const String& n) : n(n) {}

	template<class Archive>
	void SIV3D_SERIALIZE(Archive& ar) {
		ar(n);
	}

	void format(FormatData& f) const override {
		f.string.append(U"SubB{").append(n)<<U'}';
	}
};

CEREAL_REGISTER_TYPE(SubA);
CEREAL_REGISTER_TYPE(SubB);
CEREAL_REGISTER_POLYMORPHIC_RELATION(IFormatable, SubA);
CEREAL_REGISTER_POLYMORPHIC_RELATION(IFormatable, SubB);


void Main() {
	using type = shared_IFormatable;
	{
		Array<type>v;
		v	<< std::make_shared<SubA>(114514)
			<< std::make_shared<SubB>(U"BABYLON");
		Logger << v;
		Serializer<BinaryWriter>(U"test")(v);
	}
	{
		Array<type>v;
		Deserializer<BinaryReader>(U"test")(v);
		Logger << v;
	}
}