#include <boost/array.hpp>

struct Array

};

struct plus; struct minus;

template <class L, class OpTag, class R>

struct Expression;

template <class L, class R>

Expression<L,plus,R> operator+(L const& l, R const& r)

{

return Expression<L,plus,R>(l, r);

}

typedef

Expression<Expression<Array,plus,Array>,plus,Array>

plus_result;

struct plus

};

struct minus

};

template <class L, class OpTag, class R>

struct Expression

};

void add3(Array const&a, Array const& b, Array const& c, Array& x)

{

x = a + b + c;

}

template <class L, class R>

Expression<L,minus,R> operator-(L const& l, R const& r)

{

return Expression<L,minus,R>(l, r);

}

void f(Array const& a, Array const& b,

}