Test code for introspection and concept checking

gistfile1.txt

/*******
edit_distance: STL and Boost compatible edit distance functions for C++

Copyright (c) 2013 Erik Erlandson

Author:  Erik Erlandson <erikerlandson@yahoo.com>

Distributed under the Boost Software License, Version 1.0.
See accompanying file LICENSE or copy at
http://www.boost.org/LICENSE_1_0.txt
*******/

#include <iostream>

// get the edit_distance() function
#include <boost/algorithm/sequence_alignment/edit_distance.hpp>
using boost::algorithm::sequence_alignment::edit_distance;

#include <boost/function_types/result_type.hpp>
#include <boost/function_types/function_arity.hpp>
#include <boost/function_types/parameter_types.hpp>
#include <boost/function_types/is_member_function_pointer.hpp>
#include <boost/function_types/is_member_object_pointer.hpp>
#include <boost/type_traits.hpp>
#include <boost/function.hpp>
#include <boost/typeof/std/utility.hpp>
#include <boost/mpl/has_xxx.hpp>
#include <boost/mpl/at.hpp>
#include <boost/mpl/if.hpp>
#include <boost/concept/requires.hpp>
#include <boost/mpl/assert.hpp>


BOOST_MPL_HAS_XXX_TRAIT_DEF(cost_type)


template <typename Z, bool F> struct ct {
    typedef typename boost::function_types::result_type< BOOST_TYPEOF(&Z::m2) >::type type;
};
template <typename Z> struct ct<Z, true> {
    typedef typename Z::cost_type type;
};

template <typename X>
struct get_cost_type {

typedef typename ct<X, has_cost_type<X>::value >::type type;
};

template <typename X>
struct TTT {
    BOOST_MPL_ASSERT((boost::function_types::is_member_function_pointer<BOOST_TYPEOF(&X::m1)>));
    BOOST_MPL_ASSERT((boost::function_types::is_member_function_pointer<BOOST_TYPEOF(&X::m2)>));
    BOOST_MPL_ASSERT((boost::function_types::is_member_function_pointer<BOOST_TYPEOF(&X::m3)>));
    typedef BOOST_TYPEOF(&X::m2) m2_type;
    //typedef typename boost::function_types::result_type<m2_type>::type cost_type;
    typedef typename get_cost_type<X>::type cost_type;
    typedef typename boost::mpl::at_c<typename boost::function_types::parameter_types<m2_type>::type, 1>::type value_type;
        //BOOST_CONCEPT_ASSERT((Arithmetic<cost_type>));    
    BOOST_CONCEPT_USAGE(TTT) {
        c = x.m2(v);
    }
    X x;
    cost_type c;
    value_type v;
};

struct ttt {
    //bool m1() { return false; }
    int m2(int v) { return 17+v; }
    bool m3(int v1, float v2) { return true; }
};

template <typename T>
BOOST_CONCEPT_REQUIRES(
    ((TTT<T>)),
(int))
fff(T t) {
    return t.m2(0);
}

int main(int argc, char** argv) {
    std::cout << fff(ttt()) << "\n";
    std::cout << typeid(typename get_cost_type<ttt>::type).name() << "\n";

    typedef BOOST_TYPEOF(&ttt::m3) m3_type;
    // arity
    std::cout << boost::function_types::function_arity<m3_type>::value << "\n";
    // arguments (arg 0 is 'this' for member funcs)
    std::cout << typeid(boost::mpl::at_c<boost::function_types::parameter_types<m3_type>::type, 0>::type).name() << "\n";
    std::cout << typeid(boost::mpl::at_c<boost::function_types::parameter_types<m3_type>::type, 1>::type).name() << "\n";
    std::cout << typeid(boost::mpl::at_c<boost::function_types::parameter_types<m3_type>::type, 2>::type).name() << "\n";
    // return type
    std::cout << typeid(boost::function_types::result_type<m3_type>::type).name() << "\n";

    return 0;
}