[property map] compilation error : make_function_property_map

[Akira Takahashi <faithandbrave@…>]

make_function_property_map() function can not apply function pointer.

#include <boost/property_map/function_property_map.hpp>

int get_prop(double) { return 1; }

struct get_prop_functor {
    typedef int result_type;

    result_type operator()(double) const
    { return 1; }
};

int main()
{
    const auto p1 = boost::make_function_property_map<double>(get_prop); // compilation error
    const auto p2 = boost::make_function_property_map<double>(get_prop_functor()); // OK
}

error message (with gcc 4.8)

/Users/hogehoge/language/cpp/main.cpp: In function 'int main()':
/Users/hogehoge/language/cpp/main.cpp:14:71: error: no matching function for call to 'make_function_property_map(int (&)(double))'
     const auto p1 = boost::make_function_property_map<double>(get_prop); // compilation error
                                                                       ^
/Users/hogehoge/language/cpp/main.cpp:14:71: note: candidates are:
In file included from /Users/hogehoge/language/cpp/main.cpp:1:0:
/Users/hogehoge/repository/GitHub/boost-develop/boost/property_map/function_property_map.hpp:54:1: note: template<class Key, class Func> boost::function_property_map<Func, Key> boost::make_function_property_map(const Func&)
 make_function_property_map(const Func& f) {
 ^
/Users/hogehoge/repository/GitHub/boost-develop/boost/property_map/function_property_map.hpp:54:1: note:   template argument deduction/substitution failed:
/Users/hogehoge/repository/GitHub/boost-develop/boost/property_map/function_property_map.hpp: In substitution of 'template<class Key, class Func> boost::function_property_map<Func, Key> boost::make_function_property_map(const Func&) [with Key = double; Func = int(double)]':
/Users/hogehoge/language/cpp/main.cpp:14:71:   required from here
/Users/hogehoge/repository/GitHub/boost-develop/boost/property_map/function_property_map.hpp:54:1: error: function returning a function
/Users/hogehoge/repository/GitHub/boost-develop/boost/property_map/function_property_map.hpp:60:1: note: template<class Key, class Ret, class Func> boost::function_property_map<Func, Key, Ret> boost::make_function_property_map(const Func&)
 make_function_property_map(const Func& f) {
 ^
/Users/hogehoge/repository/GitHub/boost-develop/boost/property_map/function_property_map.hpp:60:1: note:   template argument deduction/substitution failed:
/Users/hogehoge/language/cpp/main.cpp:14:71: note:   couldn't deduce template parameter 'Ret'
     const auto p1 = boost::make_function_property_map<double>(get_prop); // compilation error

I think should remove const & from parameter.

before:

template<typename Key, typename Func>
function_property_map<Func, Key>
make_function_property_map(const Func& f) {
  return function_property_map<Func, Key>(f);
}

template<typename Key, typename Ret, typename Func>
function_property_map<Func, Key, Ret>
make_function_property_map(const Func& f) {
  return function_property_map<Func, Key, Ret>(f);
}

after:

template<typename Key, typename Func>
function_property_map<Func, Key>
make_function_property_map(Func f) {
  return function_property_map<Func, Key>(f);
}

template<typename Key, typename Ret, typename Func>
function_property_map<Func, Key, Ret>
make_function_property_map(Func f) {
  return function_property_map<Func, Key, Ret>(f);
}