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#ifndef RFL_INTERNAL_REMOVEFIELDS_HPP_
#define RFL_INTERNAL_REMOVEFIELDS_HPP_
#include <algorithm>
#include <tuple>
#include <type_traits>
#include "../NamedTuple.hpp"
#include "../Tuple.hpp"
#include "../define_named_tuple.hpp"
#include "StringLiteral.hpp"
namespace rfl {
namespace internal {
/// Recursively builds a new NamedTuple type from the FieldTypes, leaving out
/// the field signified by _name.
template <class _OldNamedTupleType, StringLiteral _name,
class _NewNamedTupleType, int _i>
struct remove_single_field;
/// Special case - _i == 0
template <class _OldNamedTupleType, StringLiteral _name,
class _NewNamedTupleType>
struct remove_single_field<_OldNamedTupleType, _name, _NewNamedTupleType, 0> {
using type = _NewNamedTupleType;
};
/// General case.
template <class _OldNamedTupleType, StringLiteral _name,
class _NewNamedTupleType, int _i>
struct remove_single_field {
using OldNamedTupleType = std::remove_cvref_t<_OldNamedTupleType>;
constexpr static int num_fields =
rfl::tuple_size_v<typename OldNamedTupleType::Fields>;
using FieldType = std::remove_cvref_t<
tuple_element_t<num_fields - _i, typename OldNamedTupleType::Fields>>;
using NewNamedTupleType =
std::conditional_t<_name == FieldType::name_, _NewNamedTupleType,
define_named_tuple_t<_NewNamedTupleType, FieldType>>;
using type = typename remove_single_field<OldNamedTupleType, _name,
NewNamedTupleType, _i - 1>::type;
};
/// Recursively removes all of the fields signified by _head and _tail from the
/// NamedTupleType.
template <class _NamedTupleType, StringLiteral _head, StringLiteral... _tail>
struct remove_fields;
/// Special case - only head is left.
template <class _NamedTupleType, StringLiteral _head>
struct remove_fields<_NamedTupleType, _head> {
using NamedTupleType = std::remove_cvref_t<_NamedTupleType>;
constexpr static int num_fields =
rfl::tuple_size_v<typename NamedTupleType::Fields>;
using type = typename remove_single_field<NamedTupleType, _head, NamedTuple<>,
num_fields>::type;
};
/// General case.
template <class _NamedTupleType, StringLiteral _head, StringLiteral... _tail>
struct remove_fields {
using NamedTupleType = std::remove_cvref_t<_NamedTupleType>;
constexpr static int num_fields =
rfl::tuple_size_v<typename NamedTupleType::Fields>;
using NewNamedTupleType =
typename remove_single_field<NamedTupleType, _head, NamedTuple<>,
num_fields>::type;
using type = typename remove_fields<NewNamedTupleType, _tail...>::type;
};
} // namespace internal
} // namespace rfl
#endif // RFL_REMOVEFIELDS_HPP_
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