#ifndef COMPOSER_FG1X_G2X
#define COMPOSER_FG1X_G2X

//Compose three functions f, g1, and g2 like this: f(g1(x), g2(x))

template <class F, class G1, class G2>
class composer_fg1x_g2x {
	F f;
	G1 g1;
	G2 g2;
public:
	typedef typename G1::argument_type argument_type;
	typedef typename F::result_type result_type;

	composer_fg1x_g2x(const F& initial_f,
		const G1& initial_g1, const G2& initial_g2)
		: f(initial_f), g1(initial_g1), g2(initial_g2) {}

	result_type operator()(const typename G1::argument_type& x) const {
		return f(g1(x), g2(x));
	}
};

template <class F, class G1, class G2>
inline composer_fg1x_g2x<F, G1, G2> compose2(const F& f, const G1& g1,
                                                         const G2& g2
)
{
	return composer_fg1x_g2x<F, G1, G2>(f, g1, g2);
}
#endif