boost/boost/utility/result_of.hpp

   1 // Boost result_of library
   2
   3 //  Copyright Douglas Gregor 2004. Use, modification and
   4 //  distribution is subject to the Boost Software License, Version
   5 //  1.0. (See accompanying file LICENSE_1_0.txt or copy at
   6 //  http://www.boost.org/LICENSE_1_0.txt)
   7
   8 // For more information, see http://www.boost.org/libs/utility
   9 #ifndef BOOST_RESULT_OF_HPP
  10 #define BOOST_RESULT_OF_HPP
  11
  12 #include <boost/config.hpp>
  13 #include <boost/preprocessor/iteration/iterate.hpp>
  14 #include <boost/preprocessor/punctuation/comma_if.hpp>
  15 #include <boost/preprocessor/repetition/enum_params.hpp>
  16 #include <boost/preprocessor/repetition/enum_shifted_params.hpp>
  17 #include <boost/detail/workaround.hpp>
  18 #include <boost/mpl/has_xxx.hpp>
  19 #include <boost/mpl/if.hpp>
  20 #include <boost/mpl/bool.hpp>
  21 #include <boost/mpl/or.hpp>
  22 #include <boost/type_traits/is_pointer.hpp>
  23 #include <boost/type_traits/is_member_function_pointer.hpp>
  24 #include <boost/type_traits/remove_cv.hpp>
  25
  26 #ifndef BOOST_RESULT_OF_NUM_ARGS
  27 #  define BOOST_RESULT_OF_NUM_ARGS 10
  28 #endif
  29
  30 namespace boost {
  31
  32 template<typename F> struct result_of;
  33 template<typename F> struct tr1_result_of; // a TR1-style implementation of result_of
  34
  35 #if !defined(BOOST_NO_SFINAE) && !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
  36 namespace detail {
  37
  38 BOOST_MPL_HAS_XXX_TRAIT_DEF(result_type)
  39
  40 template<typename F, typename FArgs, bool HasResultType> struct tr1_result_of_impl;
  41 template<typename F> struct cpp0x_result_of_impl;
  42
  43 template<typename F>
  44 struct result_of_void_impl
  45 {
  46   typedef void type;
  47 };
  48
  49 template<typename R>
  50 struct result_of_void_impl<R (*)(void)>
  51 {
  52   typedef R type;
  53 };
  54
  55 template<typename R>
  56 struct result_of_void_impl<R (&)(void)>
  57 {
  58   typedef R type;
  59 };
  60
  61 // Determine the return type of a function pointer or pointer to member.
  62 template<typename F, typename FArgs>
  63 struct result_of_pointer
  64   : tr1_result_of_impl<typename remove_cv<F>::type, FArgs, false> { };
  65
  66 template<typename F, typename FArgs>
  67 struct tr1_result_of_impl<F, FArgs, true>
  68 {
  69   typedef typename F::result_type type;
  70 };
  71
  72 template<typename FArgs>
  73 struct is_function_with_no_args : mpl::false_ {};
  74
  75 template<typename F>
  76 struct is_function_with_no_args<F(void)> : mpl::true_ {};
  77
  78 template<typename F, typename FArgs>
  79 struct result_of_nested_result : F::template result<FArgs>
  80 {};
  81
  82 template<typename F, typename FArgs>
  83 struct tr1_result_of_impl<F, FArgs, false>
  84   : mpl::if_<is_function_with_no_args<FArgs>,
  85              result_of_void_impl<F>,
  86              result_of_nested_result<F, FArgs> >::type
  87 {};
  88
  89 } // end namespace detail
  90
  91 #define BOOST_PP_ITERATION_PARAMS_1 (3,(0,BOOST_RESULT_OF_NUM_ARGS,<boost/utility/detail/result_of_iterate.hpp>))
  92 #include BOOST_PP_ITERATE()
  93
  94 #else
  95 #  define BOOST_NO_RESULT_OF 1
  96 #endif
  97
  98 }
  99
 100 #endif // BOOST_RESULT_OF_HPP