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fix result_of ambiguity error for nullary functions

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[SVN r36773]
This commit is contained in:
Eric Niebler 2007-01-24 06:44:20 +00:00
parent 63cde4d3fd
commit 66514f61ff
3 changed files with 35 additions and 8 deletions
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13
include/boost/utility/detail/result_of_iterate.hpp
View File

@ -24,25 +24,27 @@ struct result_of<F(BOOST_RESULT_OF_ARGS)>
: detail::result_of_impl<F, F(BOOST_RESULT_OF_ARGS), (detail::has_result_type<F>::value)> {};
#endif
#undef BOOST_RESULT_OF_ARGS
#if BOOST_PP_ITERATION() >= 1
namespace detail {
template<typename R, typename FArgs BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
struct result_of_impl<R (*)(BOOST_RESULT_OF_ARGS), FArgs, false>
struct 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)>
struct result_of_impl<R (&)(BOOST_RESULT_OF_ARGS), FArgs, false>
struct result_of_impl<R (&)(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)), FArgs, false>
{
typedef R type;
};
#undef BOOST_RESULT_OF_ARGS
#if BOOST_PP_ITERATION() > 1 && !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
#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)>
struct result_of_impl<R (T0::*)
@ -84,3 +86,4 @@ struct result_of_impl<R (T0::*)
#endif
}
#endif

23
include/boost/utility/result_of.hpp
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@ -31,6 +31,24 @@ BOOST_MPL_HAS_XXX_TRAIT_DEF(result_type)
template<typename F, typename FArgs, bool HasResultType> struct result_of_impl;
template<typename F>
struct result_of_void_impl
{
typedef void type;
};
template<typename R>
struct result_of_void_impl<R (*)(void)>
{
typedef R type;
};
template<typename R>
struct result_of_void_impl<R (&)(void)>
{
typedef R type;
};
template<typename F, typename FArgs>
struct result_of_impl<F, FArgs, true>
{
@ -44,9 +62,8 @@ struct result_of_impl<F, FArgs, false>
template<typename F>
struct result_of_impl<F, F(void), false>
{
typedef void type;
};
: result_of_void_impl<F>
{};
} // end namespace detail

7
test/result_of_test.cpp
View File

@ -50,10 +50,13 @@ int main()
typedef int (*func_ptr)(float, double);
typedef int (&func_ref)(float, double);
typedef int (*func_ptr_0)();
typedef int (&func_ref_0)();
typedef int (X::*mem_func_ptr)(float);
typedef int (X::*mem_func_ptr_c)(float) const;
typedef int (X::*mem_func_ptr_v)(float) volatile;
typedef int (X::*mem_func_ptr_cv)(float) const volatile;
typedef int (X::*mem_func_ptr_0)();
BOOST_STATIC_ASSERT((is_same<result_of<int_result_type(float)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<int_result_of(double)>::type, int>::value));
@ -69,9 +72,13 @@ int main()
BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_template<void>(char)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<func_ptr(char, float)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<func_ref(char, float)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<func_ptr_0()>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<func_ref_0()>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr(X,char)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr_c(X,char)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr_v(X,char)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr_cv(X,char)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr_0(X)>::type, int>::value));
return 0;
}