// workspace.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>
#include <deque>
#include <functional>
#include <string>
#include <list>
#include <algorithm>
using namespace std;


union Integer;

union Integer
{
public:
	const Integer& fred;

	// recurse on everything below fred
	const Integer& recurse(const function<const Integer&(const Integer&,const Integer&)> fred2,const Integer& fred3) const
	{
		if (data)
		{
			return [&](const Integer& fred) mutable throw() -> const Integer& { return fred.recurse(fred2,fred2(fred3,fred));} (fred);
		} else return fred3;
	}

	bool isZero() const
	{
		return data == 0;
	}

private:
	Integer() : fred(*this){};
	Integer(const Integer& fred2) : fred(fred2){};
	int *data;
	friend class EnterpriseIntegerFactory;
	friend ostream& operator<<(ostream&,const Integer&);
};

ostream& operator<<(ostream& fred2,const Integer& fred3)
{
	fred2 << "{";
	fred3.recurse([&](const Integer& fred,const Integer& fred4) mutable throw() -> const Integer& { fred2 << fred4 << ","; return fred;},fred3);
	return fred2 << "}";
}

class EnterpriseIntegerFactory
{
	list<Integer*> m_allocPool;
public:
	Integer Zero;
	EnterpriseIntegerFactory()
	{
		memset(&Zero.data,0,sizeof(int*));
	}
	Integer& CreateSucc(const Integer& fred)
	{
		Integer* ret = new Integer(fred);
		m_allocPool.push_back(ret);
		return *ret;
	}

	~EnterpriseIntegerFactory()
	{
		for_each(m_allocPool.begin(),m_allocPool.end(),[](Integer* val) -> void { delete val;});
	}
};

class EnterpriseOperationFactory;

class CurriedOperation
{
public:
	CurriedOperation(EnterpriseOperationFactory *p_Factory,const Integer& a) : fred(a)
	{
		m_Factory = p_Factory;
	}
protected:
	const Integer& fred;
	EnterpriseOperationFactory *m_Factory;
	virtual const Integer& doOp(const Integer& b)=0;
	friend class EnterpriseOperationFactory;
};

class EnterpriseOperationFactory
{
	EnterpriseIntegerFactory* m_Factory;
public:
	EnterpriseOperationFactory(EnterpriseIntegerFactory *p_Factory) : m_Factory(p_Factory) {}
	class Adder : public CurriedOperation
	{
	public:
		Adder(EnterpriseOperationFactory *p_Factory, const Integer& a) : CurriedOperation(p_Factory,a) {};
		const Integer& doOp(const Integer& num)
		{
			return fred.recurse([&](const Integer& fred3,const Integer& fred2) -> const Integer& { return m_Factory->m_Factory->CreateSucc(fred3);}, num);
		}
	};

	class Multiplier : public CurriedOperation
	{
	public:
		Multiplier(EnterpriseOperationFactory *p_Factory, const Integer& a) : CurriedOperation(p_Factory,a) {};
		const Integer& doOp(const Integer& num)
		{
			return fred.recurse([&](const Integer& fred,const Integer& fred2) -> const Integer& { return m_Factory->add(num,fred);}, m_Factory->m_Factory->Zero);
		}
	};

	class Factorial : public CurriedOperation
	{
	public:
		Factorial(EnterpriseOperationFactory *p_Factory, const Integer& a) : CurriedOperation(p_Factory,a) {};
		const Integer& doOp(const Integer& dummy)
		{
			return fred.recurse([&](const Integer& fred,const Integer& fred2) -> const Integer& {
				return fred.isZero() ? m_Factory->m_Factory->CreateSucc(m_Factory->m_Factory->Zero) : // Return 1 instead of 0.
					m_Factory->mult(fred,m_Factory->m_Factory->CreateSucc(fred2)); // Otherwise multiply by iterator.
			},m_Factory->m_Factory->CreateSucc(m_Factory->m_Factory->Zero));
		}
	};

	const Integer& add(const Integer& a,const Integer& b)
	{
		Adder adder(this,a);
		return adder.doOp(b);
	}

	const Integer& mult(const Integer& a,const Integer& b)
	{
		Multiplier mult(this,a);
		return mult.doOp(b);
	}
	const Integer& fact(const Integer& a)
	{
		Factorial fact(this,a);
		return fact.doOp(fact.m_Factory->m_Factory->Zero);
	}


};


int IntegerToInt(const Integer& fred)
{
	int i = 0;
	fred.recurse([&](const Integer& a,const Integer& b)-> const Integer& {i++; return a;},fred);
	return i;
}

int _tmain(int argc, _TCHAR* argv[])
{
	EnterpriseIntegerFactory factory;
	EnterpriseOperationFactory fred(&factory);

	Integer& one = factory.CreateSucc(factory.Zero);

	const Integer& onePlusOne = fred.add(one,one);
	cout << "1+1: " << IntegerToInt(onePlusOne) << " - " << onePlusOne << endl;

	system("pause");

	Integer& five = factory.CreateSucc(factory.CreateSucc(factory.CreateSucc(factory.CreateSucc(factory.CreateSucc(factory.Zero)))));
	Integer& three = factory.CreateSucc(factory.CreateSucc(factory.CreateSucc(factory.Zero)));
	cout << "5: " << IntegerToInt(five) << " - "<< five << endl;
	cout << "3: " << IntegerToInt(three) << " - " << three << endl;

	const Integer& fivePlusThree = fred.add(five,three);
	cout << "5+3: " << IntegerToInt(fivePlusThree) << " - " << fivePlusThree << endl;
	Integer& num = factory.CreateSucc(factory.CreateSucc(factory.CreateSucc(factory.CreateSucc(factory.Zero))));
	cout << IntegerToInt(num) << " - " << num << endl;
	system("pause");

	const Integer& fiveTimesThree = fred.mult(five,three);
	cout << "5*3: " << IntegerToInt(fiveTimesThree) << " - <Set representation too large>" << endl;
	system("pause");

	const Integer& threeFactorial = fred.fact(factory.CreateSucc(three));
	cout << "3!: " << IntegerToInt(threeFactorial) << " - "  << endl;

	system("pause");
	return 0;
}