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sfinae-friendly result_of implementation for compilers that don't have extended sfinae for expressions

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[SVN r80636]
This commit is contained in:
Eric Niebler 2012-09-22 19:15:37 +00:00
parent 57d65d6a94
commit 1cfe3145b4
2 changed files with 126 additions and 75 deletions
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113
include/boost/utility/detail/result_of_iterate.hpp
View File

@ -23,8 +23,7 @@
#endif
#if !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
template<typename F BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
template<typename F BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
struct tr1_result_of<F(BOOST_RESULT_OF_ARGS)>
: mpl::if_<
mpl::or_< is_pointer<F>, is_member_function_pointer<F> >
@ -41,8 +40,7 @@ struct tr1_result_of<F(BOOST_RESULT_OF_ARGS)>
#ifdef BOOST_RESULT_OF_USE_DECLTYPE
// Uses declval following N3225 20.7.7.6 when F is not a pointer.
template<typename F BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
template<typename F BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
struct result_of<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T))>
: mpl::if_<
is_member_function_pointer<F>
@ -58,51 +56,60 @@ struct result_of<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T))>
namespace detail {
#if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1700))
#ifdef BOOST_NO_SFINAE_EXPR
template<typename F BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
class is_callable<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T))> {
typedef char (&pass)[1];
typedef char (&fail)[2];
template<typename F>
struct BOOST_PP_CAT(result_of_is_callable_fun_2_, BOOST_PP_ITERATION());
template<typename G BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename S)>
struct sub {};
template<typename S>
struct stub {};
template<typename G BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename S)>
static pass test(sub<G BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),S)>
, stub<
decltype(
boost::declval<G>()(
BOOST_PP_ENUM_BINARY_PARAMS(BOOST_PP_ITERATION(), boost::declval<S, >() BOOST_PP_INTERCEPT)
)
)
>* x = 0);
static fail test(...);
public:
const static bool value = sizeof(pass) == sizeof(test(sub<F BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)
>()));
typedef typename boost::mpl::bool_<value>::type type;
template<typename R BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(), typename T)>
struct BOOST_PP_CAT(result_of_is_callable_fun_2_, BOOST_PP_ITERATION())<R(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(), T))> {
R operator()(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(), T)) const;
typedef result_of_private_type const &(*pfn_t)(...);
operator pfn_t() const volatile;
};
template<typename F BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
template<typename F>
struct BOOST_PP_CAT(result_of_is_callable_fun_, BOOST_PP_ITERATION());
template<typename F>
struct BOOST_PP_CAT(result_of_is_callable_fun_, BOOST_PP_ITERATION())<F *>
: BOOST_PP_CAT(result_of_is_callable_fun_2_, BOOST_PP_ITERATION())<F>
{};
template<typename F>
struct BOOST_PP_CAT(result_of_is_callable_fun_, BOOST_PP_ITERATION())<F &>
: BOOST_PP_CAT(result_of_is_callable_fun_2_, BOOST_PP_ITERATION())<F>
{};
template<typename F>
struct BOOST_PP_CAT(result_of_select_call_wrapper_type_, BOOST_PP_ITERATION())
: mpl::eval_if<
is_class<typename remove_reference<F>::type>,
result_of_wrap_callable<result_of_callable_class, F>,
mpl::identity<BOOST_PP_CAT(result_of_is_callable_fun_, BOOST_PP_ITERATION())<typename remove_cv<F>::type> >
>
{};
template<typename F BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(), typename T)>
struct BOOST_PP_CAT(result_of_is_callable_, BOOST_PP_ITERATION()) {
typedef typename BOOST_PP_CAT(result_of_select_call_wrapper_type_, BOOST_PP_ITERATION())<F>::type wrapper_t;
static const bool value = (
sizeof(result_of_no_type) == sizeof(detail::result_of_is_private_type(
(boost::declval<wrapper_t>()(BOOST_PP_ENUM_BINARY_PARAMS(BOOST_PP_ITERATION(), boost::declval<T, >() BOOST_PP_INTERCEPT)), 0)
))
);
typedef mpl::bool_<value> type;
};
template<typename F BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
struct cpp0x_result_of_impl<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)), true>
: lazy_enable_if<
is_callable<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T))>
BOOST_PP_CAT(result_of_is_callable_, BOOST_PP_ITERATION())<F BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(), T)>
, cpp0x_result_of_impl<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)), false>
>
{};
template<typename F BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
template<typename F BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
struct cpp0x_result_of_impl<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)), false>
{
typedef decltype(
@ -112,10 +119,9 @@ struct cpp0x_result_of_impl<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)), fal
) type;
};
#else // BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1700))
#else // BOOST_NO_SFINAE_EXPR
template<typename F BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
template<typename F BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
struct cpp0x_result_of_impl<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)),
typename result_of_always_void<decltype(
boost::declval<F>()(
@ -129,15 +135,14 @@ struct cpp0x_result_of_impl<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)),
) type;
};
#endif // BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1700))
#endif // BOOST_NO_SFINAE_EXPR
} // namespace detail
#else // defined(BOOST_RESULT_OF_USE_DECLTYPE)
#if !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
template<typename F BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
template<typename F BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
struct result_of<F(BOOST_RESULT_OF_ARGS)>
: tr1_result_of<F(BOOST_RESULT_OF_ARGS)> { };
#endif
@ -150,23 +155,20 @@ struct result_of<F(BOOST_RESULT_OF_ARGS)>
namespace detail {
template<typename R, typename FArgs BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
template<typename R, typename FArgs BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
struct tr1_result_of_impl<R (*)(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)), FArgs, false>
{
typedef R type;
};
template<typename R, typename FArgs BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
template<typename R, typename FArgs BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
struct tr1_result_of_impl<R (&)(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)), FArgs, false>
{
typedef R type;
};
#if !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
template<typename R, typename FArgs BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
template<typename R, typename FArgs BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
struct tr1_result_of_impl<R (T0::*)
(BOOST_PP_ENUM_SHIFTED_PARAMS(BOOST_PP_ITERATION(),T)),
FArgs, false>
@ -174,8 +176,7 @@ struct tr1_result_of_impl<R (T0::*)
typedef R type;
};
template<typename R, typename FArgs BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
template<typename R, typename FArgs BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
struct tr1_result_of_impl<R (T0::*)
(BOOST_PP_ENUM_SHIFTED_PARAMS(BOOST_PP_ITERATION(),T))
const,
@ -184,8 +185,7 @@ struct tr1_result_of_impl<R (T0::*)
typedef R type;
};
template<typename R, typename FArgs BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
template<typename R, typename FArgs BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
struct tr1_result_of_impl<R (T0::*)
(BOOST_PP_ENUM_SHIFTED_PARAMS(BOOST_PP_ITERATION(),T))
volatile,
@ -194,8 +194,7 @@ struct tr1_result_of_impl<R (T0::*)
typedef R type;
};
template<typename R, typename FArgs BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
template<typename R, typename FArgs BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
struct tr1_result_of_impl<R (T0::*)
(BOOST_PP_ENUM_SHIFTED_PARAMS(BOOST_PP_ITERATION(),T))
const volatile,

62
include/boost/utility/result_of.hpp
View File

@ -10,20 +10,25 @@
#define BOOST_RESULT_OF_HPP
#include <boost/config.hpp>
#include <boost/preprocessor/cat.hpp>
#include <boost/preprocessor/iteration/iterate.hpp>
#include <boost/preprocessor/punctuation/comma_if.hpp>
#include <boost/preprocessor/repetition/enum_params.hpp>
#include <boost/preprocessor/repetition/enum_trailing_params.hpp>
#include <boost/preprocessor/repetition/enum_binary_params.hpp>
#include <boost/preprocessor/repetition/enum_shifted_params.hpp>
#include <boost/preprocessor/facilities/intercept.hpp>
#include <boost/detail/workaround.hpp>
#include <boost/mpl/has_xxx.hpp>
#include <boost/mpl/if.hpp>
#include <boost/mpl/eval_if.hpp>
#include <boost/mpl/bool.hpp>
#include <boost/mpl/identity.hpp>
#include <boost/mpl/or.hpp>
#include <boost/type_traits/is_class.hpp>
#include <boost/type_traits/is_pointer.hpp>
#include <boost/type_traits/is_member_function_pointer.hpp>
#include <boost/type_traits/remove_cv.hpp>
#include <boost/type_traits/remove_reference.hpp>
#include <boost/utility/declval.hpp>
#include <boost/utility/enable_if.hpp>
@ -61,21 +66,68 @@ BOOST_MPL_HAS_XXX_TRAIT_DEF(result_type)
template<typename F, typename FArgs, bool HasResultType> struct tr1_result_of_impl;
#if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1700))
#ifdef BOOST_NO_SFINAE_EXPR
template<typename T> T result_of_decay(T);
struct result_of_private_type
{
result_of_private_type const &operator,(int) const;
};
template<typename C>
struct result_of_callable_class : C {
result_of_callable_class();
typedef result_of_private_type const &(*pfn_t)(...);
operator pfn_t() const volatile;
};
typedef char result_of_yes_type; // sizeof(result_of_yes_type) == 1
typedef char (&result_of_no_type)[2]; // sizeof(result_of_no_type) == 2
template<typename T>
result_of_no_type result_of_is_private_type(T const &);
result_of_yes_type result_of_is_private_type(result_of_private_type const &);
template<template<typename> class Wrapper, typename C>
struct result_of_wrap_callable {
typedef Wrapper<C> type;
};
template<template<typename> class Wrapper, typename C>
struct result_of_wrap_callable<Wrapper, C &> {
typedef typename result_of_wrap_callable<Wrapper, C>::type &type;
};
template<template<typename> class Wrapper, typename C>
struct result_of_wrap_callable<Wrapper, C const> {
typedef typename result_of_wrap_callable<Wrapper, C>::type const type;
};
template<template<typename> class Wrapper, typename C>
struct result_of_wrap_callable<Wrapper, C volatile> {
typedef typename result_of_wrap_callable<Wrapper, C>::type volatile type;
};
template<template<typename> class Wrapper, typename C>
struct result_of_wrap_callable<Wrapper, C const volatile> {
typedef typename result_of_wrap_callable<Wrapper, C>::type const volatile type;
};
template<typename F> class is_callable;
template<typename F, bool TestCallability = true> struct cpp0x_result_of_impl;
#else // BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1700))
#else // BOOST_NO_SFINAE_EXPR
template<typename T>
struct result_of_always_void
{
typedef void type;
};
template<typename F, typename Enable = void> struct cpp0x_result_of_impl {};
#endif // BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1700))
#endif // BOOST_NO_SFINAE_EXPR
template<typename F>
struct result_of_void_impl