boost/pfr
2
0
Fork 0
mirror of https://github.com/boostorg/pfr.git synced 2026-01-19 04:22:13 +00:00
Code Issues Projects Releases Wiki Activity

Always define is_implicitly_reflectable (#124)

Browse Source 
Always define is_implicitly_reflectable
This commit is contained in:
Antony Polukhin
2023-02-27 10:59:34 +03:00
committed by GitHub
parent d66c0a9551
commit e460ce2ddc
3 changed files with 19 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
doc/pfr.qbk
View File

@@ -1,6 +1,6 @@
[library Boost.PFR
[quickbook 1.6]
[version 2.0]
[version 2.1]
[copyright 2016-2023 Antony Polukhin]
[category Language Features Emulation]
[license

12
include/boost/pfr/detail/possible_reflectable.hpp
View File

@@ -20,6 +20,8 @@ constexpr decltype(is_reflectable<T, WhatFor>::value) possible_reflectable(long)
return is_reflectable<T, WhatFor>::value;
}
#if BOOST_PFR_ENABLE_IMPLICIT_REFLECTION
template <class T, class WhatFor>
constexpr bool possible_reflectable(int) noexcept {
# if defined(__cpp_lib_is_aggregate)
@@ -30,6 +32,16 @@ constexpr bool possible_reflectable(int) noexcept {
# endif
}
#else
template <class T, class WhatFor>
constexpr bool possible_reflectable(int) noexcept {
// negative answer here won't change behaviour in PFR-dependent libraries(like Fusion)
return false;
}
#endif
}}} // namespace boost::pfr::detail
#endif // BOOST_PFR_DETAIL_POSSIBLE_REFLECTABLE_HPP

16
include/boost/pfr/traits.hpp
View File

@@ -19,8 +19,8 @@
namespace boost { namespace pfr {
/// Has a static const member variable `value` when it known that type T can or can't be reflected using Boost.PFR; otherwise, there is no member variable.
/// Every user may(and in some difficult cases - should) specialize is_reflectable on his own.
/// Has a static const member variable `value` when it is known that type T can or can't be reflected using Boost.PFR; otherwise, there is no member variable.
/// Every user may (and in some difficult cases - should) specialize is_reflectable on his own.
///
/// \b Example:
/// \code
@@ -29,11 +29,9 @@ namespace boost { namespace pfr {
/// template<> struct is_reflectable<B, boost_fusion_tag> : std::false_type {}; // 'B' won't be interpreted as reflectable in only Boost Fusion
/// }}
/// \endcode
/// \note is_reflectable affects is_implicitly_reflectable, the decision made by is_reflectable has more priority than is_implicitly_reflectable,
/// because is_reflectable is more sharp than is_implicitly_reflectable
///
/// \note is_reflectable affects is_implicitly_reflectable, the decision made by is_reflectable is used by is_implicitly_reflectable.
template<class T, class WhatFor>
struct is_reflectable { /* do not has 'value' because value is unknown */ };
struct is_reflectable { /* does not have 'value' because value is unknown */ };
// these specs can't be inherited from 'std::integral_constant< bool, boost::pfr::is_reflectable<T, WhatFor>::value >',
// because it will break the sfinae-friendliness
@@ -46,17 +44,15 @@ struct is_reflectable<volatile T, WhatFor> : boost::pfr::is_reflectable<T, WhatF
template<class T, class WhatFor>
struct is_reflectable<const volatile T, WhatFor> : boost::pfr::is_reflectable<T, WhatFor> {};
#if BOOST_PFR_ENABLE_IMPLICIT_REFLECTION
/// Checks the input type for the potential to be reflected.
/// Specialize is_reflectable if you are disagree with is_implicitly_reflectable's default decision.
/// Specialize is_reflectable if you disagree with is_implicitly_reflectable's default decision.
template<class T, class WhatFor>
using is_implicitly_reflectable = std::integral_constant< bool, boost::pfr::detail::possible_reflectable<T, WhatFor>(1L) >;
/// Checks the input type for the potential to be reflected.
/// Specialize is_reflectable if you are disagree with is_implicitly_reflectable_v's default decision.
/// Specialize is_reflectable if you disagree with is_implicitly_reflectable_v's default decision.
template<class T, class WhatFor>
constexpr bool is_implicitly_reflectable_v = is_implicitly_reflectable<T, WhatFor>::value;
#endif
}} // namespace boost::pfr