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add support for enum classes

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Théo DELRIEU 2016-12-14 00:03:55 +01:00 • committed by Théo DELRIEU
parent 8e43d476d3
commit 3d405c6883
2 changed files with 71 additions and 12 deletions
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21
src/json.hpp
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@ -122,6 +122,17 @@ using uncvref_t = remove_cv_t<remove_reference_t<T>>;
template <bool If, typename Then, typename Else>
using conditional_t = typename std::conditional<If, Then, Else>::type;
// Taken from http://stackoverflow.com/questions/26936640/how-to-implement-is-enum-class-type-trait
template <typename T>
using is_scoped_enum =
std::integral_constant<bool, not std::is_convertible<T, int>::value and
std::is_enum<T>::value>;
template <typename T>
using is_unscoped_enum =
std::integral_constant<bool, std::is_convertible<T, int>::value and
std::is_enum<T>::value>;
// TODO update this doc
/*!
@brief unnamed namespace with internal helper functions
@ -130,6 +141,10 @@ using conditional_t = typename std::conditional<If, Then, Else>::type;
namespace detail
{
// Very useful construct against boilerplate (more boilerplate needed than in C++17: http://en.cppreference.com/w/cpp/types/void_t)
template <typename...> struct make_void { using type = void; };
template <typename... Ts> using void_t = typename make_void<Ts...>::type;
// Implementation of 3 C++17 constructs: conjunction, disjunction, negation.
// This is needed to avoid evaluating all the traits in a condition
//
@ -277,6 +292,7 @@ template <typename T, typename BasicJson>
struct is_compatible_basic_json_type
{
static auto constexpr value =
is_unscoped_enum<T>::value or
std::is_same<T, BasicJson>::value or
std::is_constructible<typename BasicJson::string_t, T>::value or
std::is_same<typename BasicJson::boolean_t, T>::value or
@ -1601,7 +1617,6 @@ class basic_json
not detail::is_compatible_basic_json_type<
uncvref_t<T>, basic_json_t>::value and
not detail::is_basic_json_nested_class<uncvref_t<T>, basic_json_t, primitive_iterator_t>::value and
not std::is_enum<uncvref_t<T>>::value and
not std::is_same<uncvref_t<T>, typename basic_json_t::array_t::iterator>::value and
not std::is_same<uncvref_t<T>, typename basic_json_t::object_t::iterator>::value and
detail::has_to_json<JSONSerializer, basic_json,
@ -1774,8 +1789,8 @@ class basic_json
@since version 1.0.0
*/
// Quickfix, accept every enum type, without looking if a to_json method is provided...
template <typename T, enable_if_t<std::is_enum<T>::value, int> = 0>
// Constructor for unscoped enums (not enum classes)
template <typename T, enable_if_t<is_unscoped_enum<T>::value, int> = 0>
basic_json(T val) noexcept
: m_type(value_t::number_integer),
m_value(static_cast<number_integer_t>(val))