[Boost-users] Using boost function input iterator with class member functions

5 Sep 2011

      Hello,

I am trying to use a class member function in conjunction with boost's
function input iterator, and am having trouble coming up with a solution
which can in any way be considered elegant...

My initial thought process was to do something like :

  std::copy(
    // does not work because the functor (1st arg to make_function_input
iterator ) cannot be temporary... or something like that
    boost::make_function_input_iterator(boost::bind(&My_Class::my_function,
0)),
    boost::make_function_input_iterator(boost::bind(&My_Class::my_function,
10)),
    std::ostream_iterator<result_type>(std::cout, " ")
  );
However, this fails as noted above.
Thus, i had to look at some compiler error messages in order to figure out
the return type of boost::bind and create some boost::bind object producing
the working code below, however, this looks pretty terrible.

Can anyone suggest a more convenient solution to the problem I am trying to
solve?

Thanks,
Michael King

#include<iostream>
#include<iterator>
#include<boost/bind.hpp>
#include<boost/iterator/function_input_iterator.hpp>

class foo {
  public:
    typedef double result_type;
    result_type return_random() const { return drand48(); }
};

int main() {
  foo bar;
  // found type from compiler error message...
  boost::_bi::bind_t<
      double,
      boost::_mfi::cmf0<
            double,
            foo>,
      boost::_bi::list1<
            boost::_bi::value<foo>
      >
...
f = boost::bind(&foo::return_random, bar);
std::copy(
    boost::make_function_input_iterator(f, 1),
    boost::make_function_input_iterator(f, 10),
    std::ostream_iterator<double>(std::cout, "\n")
  );

  return 0;
}