ceph/src/boost/boost/callable_traits/args.hpp

   1 /*
   2
   3 @Copyright Barrett Adair 2015-2017
   4 Distributed under the Boost Software License, Version 1.0.
   5 (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
   6
   7 */
   8
   9 #ifndef BOOST_CLBL_TRTS_ARGS_HPP
  10 #define BOOST_CLBL_TRTS_ARGS_HPP
  11
  12 #include <boost/callable_traits/detail/core.hpp>
  13
  14 namespace boost { namespace callable_traits {
  15
  16 //[ args_hpp
  17 /*`[section:ref_args args]
  18 [heading Header]
  19 ``#include <boost/callable_traits/args.hpp>``
  20 [heading Definition]
  21 */
  22
  23 template<typename T, template<class...> class Container = std::tuple>
  24 using args_t = //see below
  25 //<-
  26     detail::try_but_fail_if_invalid<
  27         typename detail::traits<
  28             detail::shallow_decay<T>>::template expand_args<Container>,
  29         cannot_expand_the_parameter_list_of_first_template_argument>;
  30
  31 namespace detail {
  32
  33     template<typename T, template<class...> class Container,
  34         typename = std::false_type>
  35     struct args_impl {};
  36
  37     template<typename T, template<class...> class Container>
  38     struct args_impl <T, Container, typename std::is_same<
  39         args_t<T, Container>, detail::dummy>::type>
  40     {
  41         using type = args_t<T, Container>;
  42     };
  43 }
  44
  45 //->
  46
  47 template<typename T,
  48     template<class...> class Container = std::tuple>
  49 struct args : detail::args_impl<T, Container> {};
  50
  51 //<-
  52 }} // namespace boost::callable_traits
  53 //->
  54
  55 /*`
  56 [heading Constraints]
  57 * `T` must be one of the following:
  58   * function
  59   * function pointer
  60   * function reference
  61   * member function pointer
  62   * member data pointer
  63   * user-defined type with a non-overloaded `operator()`
  64   * type of a non-generic lambda
  65
  66 [heading Behavior]
  67 * When the constraints are violated, a substitution failure occurs.
  68 * When `T` is a function, function pointer, or function reference, the aliased type is `Container` instantiated with the function's parameter types.
  69 * When `T` is a function object, the aliased type is `Container` instantiated with the `T::operator()` parameter types.
  70 * When `T` is a member function pointer, the aliased type is a `Container` instantiation, where the first type argument is a reference to the parent class of `T`, qualified according to the member qualifiers on `T`, such that the first type is equivalent to `boost::callable_traits::qualified_class_of_t<T>`. The subsequent type arguments, if any, are the parameter types of the member function.
  71 * When `T` is a member data pointer, the aliased type is `Container` with a single element, which is a `const` reference to the parent class of `T`.
  72
  73 [heading Input/Output Examples]
  74 [table
  75     [[`T`]                              [`args_t<T>`]]
  76     [[`void(float, char, int)`]         [`std::tuple<float, char, int>`]]
  77     [[`void(*)(float, char, int)`]      [`std::tuple<float, char, int`]]
  78     [[`void(&)(float, char, int)`]      [`std::tuple<float, char, int`]]
  79     [[`void(float, char, int) const &&`][`std::tuple<float, char, int>`]]
  80     [[`void(*)()`]                      [`std::tuple<>`]]
  81     [[`void(foo::* const &)(float, char, int)`] [`std::tuple<foo&, float, char, int>`]]
  82     [[`int(foo::*)(int) const`]         [`std::tuple<const foo&, int>`]]
  83     [[`void(foo::*)() volatile &&`]     [`std::tuple<volatile foo &&>`]]
  84     [[`int foo::*`]                     [`std::tuple<const foo&>`]]
  85     [[`const int foo::*`]               [`std::tuple<const foo&>`]]
  86     [[`int`]                            [(substitution failure)]]
  87     [[`int (*const)()`]                 [(substitution failure)]]
  88 ]
  89
  90 [heading Example Program]
  91 [import ../example/args.cpp]
  92 [args]
  93 [endsect]
  94 */
  95 //]
  96
  97 #endif // #ifndef BOOST_CLBL_TRTS_ARGS_HPP