cheatah
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stdlib/parsers/json/object.hpp

1// Copyright (c) 2026 BigBrain LLC. MIT-licensed (see LICENSE).
2// Original work; see ACKNOWLEDGMENTS.md for the open-source ideas we build upon.
3#pragma once
5// cheatah::parsers::json — the JSON object token, mirroring Array<S>: a class template over its
6// backing storage type S (ObjectStorage), MOVE-ONLY. Members read uniformly as a
7// std::span<const Member> via value(), whether owned or viewed:
8// - Object<std::vector<Member>> (OwnedObject) — owns its members (self-contained).
9// - Object<std::span<const Member>> (ObjectView) — views members in a Parser's pool, no copy.
10//
11// Being a template, its members instantiate lazily (so the constructor can be in-class even
12// though Node is recursive — no out-of-line workaround needed). No runtime polymorphism.
14#include <span>
15#include <utility>
16#include <vector>
18#include "fwd.hpp" // forward declarations + the ObjectStorage concept (standalone-clean)
20namespace cheatah::parsers::json {
22/**
23 * @brief A JSON object token, templated on its backing storage @p S: Object<std::vector<Member>>
24 * (OwnedObject) owns its members, Object<std::span<const Member>> (ObjectView) views members
25 * in a Parser's pool with no copy. Move-only; both backings read uniformly via value().
26 * @tparam S the member storage: std::vector<Member> (owning) or std::span<const Member> (viewing).
27 */
28template <ObjectStorage S>
29class Object {
30private:
31 S value_;
33public:
34 /**
35 * Construct from the backing storage (moved in).
36 * @param value the member storage (an owning vector or a non-owning span).
37 * @complexity O(1) — a vector move or a span copy; the members are never copied.
38 * @alloc none.
39 * @test CheatahParsersJson.ContainerTokenLifecycle
40 */
41 Object(S value) : value_(std::move(value)) {}
42 ~Object() = default;
44 // Move-only: no object is copied; all are moved by default.
45 Object(const Object&) = delete;
46 Object& operator=(const Object&) = delete;
47 /**
48 * Move-construct, taking over the other object's storage.
49 * @param other the object to move from.
50 */
51 Object(Object&& other) noexcept = default;
52 /**
53 * Move-assign, taking over the other object's storage.
54 * @param other the object to move from.
55 * @return reference to this object.
56 */
57 Object& operator=(Object&& other) noexcept = default;
59 /**
60 * Read the members uniformly as a view, whether owned or viewed (no setter).
61 * @return a std::span<const Member> over the object's key/value members.
62 * @complexity O(1).
63 * @alloc none.
64 * @test CheatahParsersJson.ContainerTokenLifecycle
65 */
66 [[nodiscard]] std::span<const Member> value() const noexcept { return value_; }
67};
69} // namespace cheatah::parsers::json