C++14で引数の型の順序と数を任意にする方法 ref: http://qiita.com/usagi/items/5df0ed07b5807a985131

file0.cpp

parameter_x_type x;
parameter_y_type y;
parameter_z_type z;
parameter_w_type w;
f( x, y, z, w );

file1.cpp

auto f
( const parameter_x& x
, const parameter_y& y
, const parameter_z& z
, const parameter_w& w
) { /* なにかしらの処理 */ }

file2.cpp

f( x );
f( y, w );
f( z, w, x );
f( x, y, w, z);
/* ... その他の組み合わせのみなさん ... */

file3.cpp

#include <boost/optional.hpp>
#include <vector>
#include <string>
#include <iostream>

namespace some_library
{
  using boost::optional;

  template < typename T > struct has_vector_type { using vector_type = std::vector< T >; };

  struct area_type { float a, b, c, d; };
  struct tag_type : has_vector_type< tag_type > { std::string value; tag_type( const std::string& in ) : value( in ) { } };
  struct keyword_type : has_vector_type< keyword_type > { std::string value; keyword_type( const std::string& in ) : value( in ) { } };
  struct location_type : has_vector_type< tag_type > { };

  // for library internal implements
  namespace detail
  {
    struct f_state { };

    auto f( const f_state& state )
    {
      std::cout << "c(execute state)";
      /* TODO: ここで state から適切な処理を行い結果を return */
      return location_type::vector_type{ };
    }

    template < typename T, typename ... TS >
    auto f( const f_state& state, const T& value, TS ... ts )
    {
      std::cout << "b:0(configure state) -> ";
      /* TODO: ここで T value を state へ適用 */;
      return f( state, ts ... );
    }

    template < typename ... TS >
    auto f( const f_state& state, const area_type& value, TS ... ts )
    {
      std::cout << "b:1(configure state by area_type) -> ";
      /* TODO: */;
      return f( state, ts ... ); }
  }

  // for library user
  template < typename T, typename ... TS >
  auto f( const T& value, TS ... ts )
  {
    std::cout << "a(make state) -> "; return detail::f( { }, value, ts ... );
  }

}

auto main() -> int
{
  using namespace some_library;

  area_type area { 0, 1, 2, 3 };
  tag_type::vector_type tags { { "aaa" }, { "bbb" }, { "ccc" } };
  keyword_type::vector_type keywords { { "hoge" }, { "fuga" }, { "piyo" } };

  std::cout << "1: ";
  f( area );
  std::cout << "\n";

  std::cout << "2: ";
  f( area, tags );
  std::cout << "\n";

  std::cout << "3: ";
  f( area, tags, keywords );
  std::cout << "\n";

  std::cout << "4: ";
  f( tags, keywords, area );
  std::cout << "\n";
}

file4.txt

1: a(make state) -> b:1(configure state by area_type) -> c(execute state)
2: a(make state) -> b:1(configure state by area_type) -> b:0(configure state) -> c(execute state)
3: a(make state) -> b:1(configure state by area_type) -> b:0(configure state) -> b:0(configure state) -> c(execute state)
4: a(make state) -> b:0(configure state) -> b:0(configure state) -> b:1(configure state by area_type) -> c(execute state)