ResultOf trait, declval
parent
2c03469cf8
commit
f549d876e4
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@ -9,6 +9,7 @@
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#include <stddef.h>
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#include "octa/types.h"
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#include "octa/utility.h"
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namespace octa {
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/* conditional */
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@ -25,9 +26,7 @@ namespace octa {
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/* removers */
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template<typename T> struct RemoveReference { typedef T type; };
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template<typename T> struct RemoveReference<T&> { typedef T type; };
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template<typename T> struct RemoveReference<T&&> { typedef T type; };
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template<typename T> using RemoveReference = internal::RemoveReference<T>;
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template<typename T> struct RemoveConst { typedef T type; };
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template<typename T> struct RemoveConst<const T> { typedef T type; };
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@ -180,27 +179,55 @@ namespace octa {
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/* add rvalue reference */
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template<typename T> struct AddRvalueReference { typedef T &&type; };
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template<typename T> struct AddRvalueReference<T &> { typedef T &&type; };
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template<typename T> struct AddRvalueReference<T &&> { typedef T &&type; };
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template<> struct AddRvalueReference<void> {
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typedef void type;
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};
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template<> struct AddRvalueReference<const void> {
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typedef const void type;
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};
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template<> struct AddRvalueReference<volatile void> {
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typedef volatile void type;
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};
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template<> struct AddRvalueReference<const volatile void> {
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typedef const volatile void type;
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};
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template<typename T> using AddRvalueReference = internal::AddRvalueReference<T>;
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/* is array */
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template<typename > struct IsArray : false_t {};
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template<typename T > struct IsArray<T[] >: true_t {};
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template<typename T, size_t N> struct IsArray<T[N]>: true_t {};
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/* result of call at compile time */
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namespace internal {
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template<typename F, typename ...A>
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inline auto result_of_invoke(F &&f, A &&...args) ->
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decltype(forward<F>(f)(forward<A>(args)...)) {
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return forward<F>(f)(forward<A>(args)...);
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}
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template<typename B, typename T, typename D>
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inline auto result_of_invoke(T B::*pmd, D &&ref) ->
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decltype(forward<D>(ref).*pmd) {
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return forward<D>(ref).*pmd;
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}
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template<typename PMD, typename P>
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inline auto result_of_invoke(PMD &&pmd, P &&ptr) ->
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decltype((*forward<P>(ptr)).*forward<PMD>(pmd)) {
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return (*forward<P>(ptr)).*forward<PMD>(pmd);
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}
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template<typename B, typename T, typename D, typename ...A>
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inline auto result_of_invoke(T B::*pmf, D &&ref, A &&...args) ->
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decltype((forward<D>(ref).*pmf)(forward<A>(args)...)) {
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return (forward<D>(ref).*pmf)(forward<A>(args)...);
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}
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template<typename PMF, typename P, typename ...A>
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inline auto result_of_invoke(PMF &&pmf, P &&ptr, A &&...args) ->
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decltype(((*forward<P>(ptr)).*forward<PMF>(pmf))(forward<A>(args)...)) {
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return ((*forward<P>(ptr)).*forward<PMF>(pmf))(forward<A>(args)...);
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}
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template<typename, typename = void>
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struct ResultOf {};
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template<typename F, typename ...A>
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struct ResultOf<F(A...), decltype(void(internal::result_of_invoke(
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declval<F>(), declval<A>()...)))> {
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using type = decltype(internal::result_of_invoke(declval<F>(),
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declval<A>()...));
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};
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}
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/* cppreference.com used for reference */
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template<typename T> struct ResultOf: internal::ResultOf<T> {};
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}
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#endif
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@ -8,8 +8,6 @@
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#include <stddef.h>
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#include "octa/traits.h"
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/* must be in std namespace otherwise the compiler won't know about it */
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namespace std {
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template<typename T>
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@ -51,23 +49,48 @@ namespace octa {
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}
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}
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/* aliased in traits.h later */
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namespace internal {
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template<typename T> struct RemoveReference { typedef T type; };
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template<typename T> struct RemoveReference<T&> { typedef T type; };
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template<typename T> struct RemoveReference<T&&> { typedef T type; };
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template<typename T> struct AddRvalueReference { typedef T &&type; };
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template<typename T> struct AddRvalueReference<T &> { typedef T &&type; };
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template<typename T> struct AddRvalueReference<T &&> { typedef T &&type; };
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template<> struct AddRvalueReference<void> {
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typedef void type;
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};
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template<> struct AddRvalueReference<const void> {
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typedef const void type;
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};
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template<> struct AddRvalueReference<volatile void> {
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typedef volatile void type;
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};
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template<> struct AddRvalueReference<const volatile void> {
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typedef const volatile void type;
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};
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}
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template<typename T>
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static inline constexpr typename RemoveReference<T>::type &&
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static inline constexpr typename internal::RemoveReference<T>::type &&
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move(T &&v) noexcept {
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return static_cast<typename RemoveReference<T>::type &&>(v);
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return static_cast<typename internal::RemoveReference<T>::type &&>(v);
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}
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template<typename T>
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static inline constexpr T &&
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forward(typename RemoveReference<T>::type &v) noexcept {
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forward(typename internal::RemoveReference<T>::type &v) noexcept {
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return static_cast<T &&>(v);
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}
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template<typename T>
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static inline constexpr T &&
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forward(typename RemoveReference<T>::type &&v) noexcept {
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forward(typename internal::RemoveReference<T>::type &&v) noexcept {
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return static_cast<T &&>(v);
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}
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template<typename T> typename internal::AddRvalueReference<T>::type declval();
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}
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#endif
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