1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
|
#ifndef RFL_INTERNAL_FIELD_TYPE_HPP_
#define RFL_INTERNAL_FIELD_TYPE_HPP_
#include <tuple>
#include <type_traits>
#include <variant>
#include "../NamedTuple.hpp"
#include "../TaggedUnion.hpp"
#include "../Tuple.hpp"
#include "../named_tuple_t.hpp"
#include "StringLiteral.hpp"
#include "find_index.hpp"
namespace rfl {
namespace internal {
template <class T, class... Ts>
struct are_same : std::conjunction<std::is_same<T, Ts>...> {};
/// Finds the type of the field signified by _field_name
template <StringLiteral _field_name, class T>
struct FieldType;
/// Default option - for named tuples.
template <StringLiteral _field_name, class T>
struct FieldType {
using NamedTupleType = named_tuple_t<T>;
static constexpr int field_ix_ =
internal::find_index<_field_name, typename NamedTupleType::Fields>();
using Type = typename tuple_element_t<field_ix_,
typename NamedTupleType::Fields>::Type;
};
/// For variants - in this case the FieldType returned by all options must be
/// the same.
template <StringLiteral _field_name, class FirstAlternativeType,
class... OtherAlternativeTypes>
struct FieldType<_field_name,
std::variant<FirstAlternativeType, OtherAlternativeTypes...>> {
constexpr static bool all_types_match = std::conjunction_v<std::is_same<
typename FieldType<_field_name, FirstAlternativeType>::Type,
typename FieldType<_field_name, OtherAlternativeTypes>::Type>...>;
static_assert(all_types_match, "All field types must be the same.");
using Type = typename FieldType<_field_name, FirstAlternativeType>::Type;
};
/// For tagged union - just defers to the variant.
template <StringLiteral _field_name, StringLiteral _discriminator_name,
class... VarTypes>
struct FieldType<_field_name, TaggedUnion<_discriminator_name, VarTypes...>> {
using Type =
typename FieldType<_field_name,
typename TaggedUnion<_discriminator_name,
VarTypes...>::VariantType>::Type;
};
} // namespace internal
} // namespace rfl
#endif
|
