infix2.cc

#include <functional>
#include <iostream>

template <class A, class B, class C>
class Infix
{
private:
   std::function<C(A, B)> funM;
   
public:
   Infix(std::function<C(A, B)> fun)
      : funM(fun)
   {
   }

   class Partial
   {
   private:
      std::function<C(B)> funM;

   public:
      Partial(std::function<C(A, B)> fun, A a)
      {
         funM = [a, fun] (B b) -> C {
            return fun(a, b);
         };
      }

      friend C
      operator|(Partial p, B b)
      {
         return p.funM(b);
      }
   };

   friend Partial
   operator|(A a, Infix i)
   {
      return Partial(i.funM, a);
   }
};

int
main()
{
   Infix<int, int, int> add([](int a, int b) { return a + b; });
   
   int val = 1 |add| 2;
   std::cout << val << std::endl;
   
   return 0;
}