Functional Composition in C++ ver. 2.1

gistfile1.cpp

#include<iostream>
#include<functional>
#include<cmath>

using namespace std;
using namespace std::tr1;

template<typename Param, typename Result>
class Function {
public:
	function<Result(Param)> apply;

	Function(const function<Result(Param)> apply): apply(apply) {}

	template<typename Param2>
	Function<Param2, Result> compose(const Function<Param2, Param>& g) {
		return Function<Param2, Result>([this, g](double x){return apply(g.apply(x));});
	}
};

int main(void) {
	auto f = Function<double, double>([](double x){return exp(x);});
	auto g = Function<double, double>([](double x){return pow(x, 2);});
	auto h = Function<double, double>([](double x){return -x + 1;});
	auto composed = f.compose(g).compose(h);
	cout << composed.apply(3) << endl;
}