binary_compose.hh

Go to the documentation of this file.

/* -*- C++ -*-
 * $Id: binary_compose.hh 957 2005-03-07 16:01:20Z sjoyeux $
 */
#ifndef UTILMM_FUNCTIONAL_BINARY_COMPOSE_HEADER
# define UTILMM_FUNCTIONAL_BINARY_COMPOSE_HEADER

# include <functional>

#include "utilmm/functional/arg_traits.hh"

namespace utilmm {
  
  template<class BinaryFun, class UnaryFun1, class UnaryFun2>
  struct binary_compose_2
    :public std::binary_function<typename UnaryFun1::argument_type,
                                 typename UnaryFun2::argument_type,
                                 typename BinaryFun::result_type> {
  private:
    BinaryFun bin_fn;
    UnaryFun1 fun_1;
    UnaryFun2 fun_2;    

    typedef typename 
      arg_traits<typename UnaryFun1::argument_type>::type first_arg;
    typedef typename 
      arg_traits<typename UnaryFun2::argument_type>::type second_arg;

  public:
    binary_compose_2(BinaryFun const &bin, UnaryFun1 const &one,
                     UnaryFun2 const &two)
      :bin_fn(bin), fun_1(one), fun_2(two) {}
    
    typename BinaryFun::result_type operator()(first_arg a, second_arg b)
      const {
      return bin_fn(fun_1(a), fun_2(b));
    }

  }; // class utilmm::binary_compose_2<>

  template<class Bin, class Fun1, class Fun2>
  binary_compose_2<Bin, Fun1, Fun2> compose2_2(Bin const &f, Fun1 const &a,
                                               Fun2 const &b) {
    return binary_compose_2<Bin, Fun1, Fun2>(f, a, b);
  }

} // namespace utilmm

#endif // UTILMM_FUNCTIONAL_BINARY_COMPOSE_HEADER