support/detail/make_cons.hpp

0001 /*=============================================================================
0002   Copyright (c) 2001-2011 Joel de Guzman
0003   http://spirit.sourceforge.net/
0004
0005   Distributed under the Boost Software License, Version 1.0. (See accompanying
0006   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0007 =============================================================================*/
0008 #ifndef BOOST_SPIRIT_MAKE_CONS_OCTOBER_16_2008_1252PM
0009 #define BOOST_SPIRIT_MAKE_CONS_OCTOBER_16_2008_1252PM
0010
0011 #if defined(_MSC_VER)
0012 #pragma once
0013 #endif
0014
0015 #include <boost/mpl/eval_if.hpp>
0016 #include <boost/fusion/include/cons.hpp>
0017 #include <boost/type_traits/remove_const.hpp>
0018 #include <boost/type_traits/is_abstract.hpp>
0019 #include <boost/type_traits/is_function.hpp>
0020 #include <boost/type_traits/add_reference.hpp>
0021 #include <boost/utility/enable_if.hpp>
0022
0023 namespace boost { namespace spirit { namespace detail
0024 {
0025     template <typename T>
0026     struct as_meta_element
0027       : mpl::eval_if_c<is_abstract<T>::value || is_function<T>::value
0028           , add_reference<T>, remove_const<T> >
0029     {};
0030
0031     template <typename T>
0032     struct as_meta_element<T&> : as_meta_element<T>   // always store by value
0033     {};
0034
0035     template <typename T, int N>
0036     struct as_meta_element<T[N]>
0037     {
0038         typedef const T(&type)[N];
0039     };
0040
0041     namespace result_of
0042     {
0043         template <typename Car, typename Cdr = fusion::nil_>
0044         struct make_cons
0045         {
0046             typedef typename as_meta_element<Car>::type car_type;            typedef typename fusion::cons<car_type, Cdr> type;
0047         };
0048     }
0049
0050     template <typename Car, typename Cdr>
0051     fusion::cons<typename as_meta_element<Car>::type, Cdr>
0052     make_cons(Car const& car, Cdr const& cdr)
0053     {
0054         typedef typename as_meta_element<Car>::type car_type;
0055         typedef typename fusion::cons<car_type, Cdr> result;
0056         return result(car, cdr);
0057     }
0058
0059     template <typename Car>
0060     fusion::cons<typename as_meta_element<Car>::type>
0061     make_cons(Car const& car)
0062     {
0063         typedef typename as_meta_element<Car>::type car_type;
0064         typedef typename fusion::cons<car_type> result;
0065         return result(car);
0066     }
0067
0068 #if defined(__GNUC__) && (__GNUC__ == 4) && (__GNUC_MINOR__ == 0)
0069     // workaround for gcc-4.0 bug where illegal function types
0070     // can be formed (const is added to function type)
0071     // description: http://lists.boost.org/Archives/boost/2009/04/150743.php
0072     template <typename Car>
0073     fusion::cons<typename as_meta_element<Car>::type>
0074     make_cons(Car& car, typename enable_if<is_function<Car> >::type* = 0)
0075     {
0076         typedef typename as_meta_element<Car>::type car_type;
0077         typedef typename fusion::cons<car_type> result;
0078         return result(car);
0079     }
0080 #endif
0081 }}}
0082
0083 #endif