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result_of implementation that makes use of C++0x decltype, from Daniel Walker. Fixes #862.

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[SVN r45256]
This commit is contained in:
Douglas Gregor
2008-05-09 22:08:46 +00:00
parent f1c86c35c4
commit ad0bcf4a00
4 changed files with 169 additions and 12 deletions
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127
test/result_of_test.cpp
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@@ -11,35 +11,101 @@
#include <boost/static_assert.hpp>
#include <boost/type_traits/is_same.hpp>
struct int_result_type { typedef int result_type; };
struct int_result_type
{
typedef int result_type;
result_type operator()(float);
};
struct int_result_of
{
template<typename F> struct result { typedef int type; };
result<int_result_of(double)>::type operator()(double);
result<const int_result_of(double)>::type operator()(double) const;
result<int_result_of()>::type operator()();
result<volatile int_result_of()>::type operator()() volatile;
};
struct int_result_type_and_float_result_of
struct int_result_type_and_float_result_of_and_char_return
{
typedef int result_type;
template<typename F> struct result { typedef float type; };
char operator()(char);
};
template<typename T>
struct int_result_type_template { typedef int result_type; };
struct int_result_type_template
{
typedef int result_type;
result_type operator()(float);
};
template<typename T>
struct int_result_of_template
{
template<typename F> struct result;
template<typename This, typename That> struct result<This(That)> { typedef int type; };
typename result<int_result_of_template<T>(double)>::type operator()(double);
typename result<const int_result_of_template<T>(double)>::type operator()(double) const;
typename result<int_result_of_template<T>(double)>::type operator()();
typename result<volatile int_result_of_template<T>(double)>::type operator()() volatile;
};
template<typename T>
struct int_result_type_and_float_result_of_template
struct int_result_type_and_float_result_of_and_char_return_template
{
typedef int result_type;
template<typename F> struct result;
template<typename This, typename That> struct result<This(That)> { typedef float type; };
char operator()(char);
};
struct result_of_member_function_template
{
template<typename F> struct result;
template<typename This, typename That> struct result<This(That)> { typedef That type; };
template<class T> typename result<result_of_member_function_template(T)>::type operator()(T);
template<typename This, typename That> struct result<const This(That)> { typedef const That type; };
template<class T> typename result<const result_of_member_function_template(T)>::type operator()(T) const;
template<typename This, typename That> struct result<volatile This(That)> { typedef volatile That type; };
template<class T> typename result<volatile result_of_member_function_template(T)>::type operator()(T) volatile;
template<typename This, typename That> struct result<const volatile This(That)> { typedef const volatile That type; };
template<class T> typename result<const volatile result_of_member_function_template(T)>::type operator()(T) const volatile;
template<typename This, typename That> struct result<This(That &, That)> { typedef That & type; };
template<class T> typename result<result_of_member_function_template(T &, T)>::type operator()(T &, T);
template<typename This, typename That> struct result<This(That const &, That)> { typedef That const & type; };
template<class T> typename result<result_of_member_function_template(T const &, T)>::type operator()(T const &, T);
template<typename This, typename That> struct result<This(That volatile &, That)> { typedef That volatile & type; };
template<class T> typename result<result_of_member_function_template(T volatile &, T)>::type operator()(T volatile &, T);
template<typename This, typename That> struct result<This(That const volatile &, That)> { typedef That const volatile & type; };
template<class T> typename result<result_of_member_function_template(T const volatile &, T)>::type operator()(T const volatile &, T);
};
struct no_result_type_or_result_of
{
int operator()(double);
short operator()(double) const;
unsigned int operator()();
unsigned short operator()() volatile;
const unsigned short operator()() const volatile;
};
template<typename T>
struct no_result_type_or_result_of_template
{
int operator()(double);
short operator()(double) const;
unsigned int operator()();
unsigned short operator()() volatile;
const unsigned short operator()() const volatile;
};
struct X {};
@@ -60,16 +126,37 @@ int main()
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));
BOOST_STATIC_ASSERT((is_same<result_of<int_result_of(void)>::type, void>::value));
BOOST_STATIC_ASSERT((is_same<result_of<const int_result_of(double)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<volatile int_result_of(void)>::type, void>::value));
BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of(char)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_template<void>(float)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<int_result_of_template<void>(double)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<int_result_of_template<void>(void)>::type, void>::value));
BOOST_STATIC_ASSERT((is_same<result_of<const int_result_of_template<void>(double)>::type, int>::value));
// Prior to decltype, result_of could not deduce the return type
// nullary function objects unless they exposed a result_type.
#if defined(BOOST_HAS_DECLTYPE)
BOOST_STATIC_ASSERT((is_same<result_of<int_result_of(void)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<volatile int_result_of(void)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<int_result_of_template<void>(void)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<volatile int_result_of_template<void>(void)>::type, int>::value));
#else
BOOST_STATIC_ASSERT((is_same<result_of<int_result_of(void)>::type, void>::value));
BOOST_STATIC_ASSERT((is_same<result_of<volatile int_result_of(void)>::type, void>::value));
BOOST_STATIC_ASSERT((is_same<result_of<int_result_of_template<void>(void)>::type, void>::value));
BOOST_STATIC_ASSERT((is_same<result_of<volatile int_result_of_template<void>(void)>::type, void>::value));
BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_template<void>(char)>::type, int>::value));
#endif
// Prior to decltype, result_of ignored a nested result<> if
// result_type was defined. After decltype, result_of deduces the
// actual return type of the function object, ignoring both
// result<> and result_type.
#if defined(BOOST_HAS_DECLTYPE)
BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_and_char_return(char)>::type, char>::value));
BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_and_char_return_template<void>(char)>::type, char>::value));
#else
BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_and_char_return(char)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_and_char_return_template<void>(char)>::type, int>::value));
#endif
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));
@@ -81,5 +168,27 @@ int main()
BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr_0(X)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<func_ptr(void)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(double)>::type, double>::value));
BOOST_STATIC_ASSERT((is_same<result_of<const result_of_member_function_template(double)>::type, const double>::value));
BOOST_STATIC_ASSERT((is_same<result_of<volatile result_of_member_function_template(double)>::type, volatile double>::value));
BOOST_STATIC_ASSERT((is_same<result_of<const volatile result_of_member_function_template(double)>::type, const volatile double>::value));
BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(int &, int)>::type, int &>::value));
BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(int const &, int)>::type, int const &>::value));
BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(int volatile &, int)>::type, int volatile &>::value));
BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(int const volatile &, int)>::type, int const volatile &>::value));
#if defined(BOOST_HAS_DECLTYPE)
BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of(double)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of(void)>::type, unsigned int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<const no_result_type_or_result_of(double)>::type, short>::value));
BOOST_STATIC_ASSERT((is_same<result_of<volatile no_result_type_or_result_of(void)>::type, unsigned short>::value));
BOOST_STATIC_ASSERT((is_same<result_of<const volatile no_result_type_or_result_of(void)>::type, const unsigned short>::value));
BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of_template<void>(double)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of_template<void>(void)>::type, unsigned int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<const no_result_type_or_result_of_template<void>(double)>::type, short>::value));
BOOST_STATIC_ASSERT((is_same<result_of<volatile no_result_type_or_result_of_template<void>(void)>::type, unsigned short>::value));
BOOST_STATIC_ASSERT((is_same<result_of<const volatile no_result_type_or_result_of_template<void>(void)>::type, const unsigned short>::value));
#endif
return 0;
}