Document how editable json_documents use the node index

The node index section on the architecture page says how edits are kept
(the edit buffer, moved elements, links, and new nodes), and the feature
page links to it.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

.github/labeler.yml

@@ -52,11 +52,12 @@ labels:
     - "single_include/nlohmann/json_view\\.hpp"
     - "tests/src/unit-json_view.*"
     - "tests/src/fuzzer-parse_json_view\\.cpp"
+    - "tests/benchmarks/json_view/.*"
     - "tools/amalgamate/config_json_view\\.json"
     - "docs/mkdocs/docs/features/json_view\\.md"
     - "docs/mkdocs/docs/api/basic_json_(document|view)/.*"
-    - "docs/mkdocs/docs/api/(ordered_)?json_(document|view)\\.md"
-    - "docs/mkdocs/docs/examples/(basic_json_(document|view)__|(ordered_)?json_(document|view)).*"
+    - "docs/mkdocs/docs/api/(ordered_)?json_(editable_)?(document|view)\\.md"
+    - "docs/mkdocs/docs/examples/(basic_json_(document|view)__|(ordered_)?json_(editable_)?(document|view)).*"
     - "tests/benchmarks/src/benchmarks_view\\.cpp"
 
 - label: "aspect: json_view"

.github/workflows/json_view_benchmarks.yml

@@ -0,0 +1,78 @@
+name: "json_view benchmarks"
+
+# On demand only: runs the comparison of json_view with yyjson, simdjson, and
+# Boost.JSON (tests/benchmarks/json_view/compare.py) on GitHub-hosted runners,
+# for numbers from x86-64 and AArch64 Linux. It runs when started by hand, or
+# when a pull request gets the label "benchmark" (on both architectures, with
+# GCC and the default settings). Shared runners are noisy: the results show
+# where json_view stands, but published numbers need a quiet machine (see
+# tests/benchmarks/json_view/README.md).
+
+on:
+  pull_request:
+    types: [labeled]
+  workflow_dispatch:
+    inputs:
+      runner:
+        description: "Runner image"
+        type: choice
+        options:
+          - ubuntu-24.04
+          - ubuntu-24.04-arm
+        default: ubuntu-24.04
+      compiler:
+        description: "Compiler"
+        type: choice
+        options:
+          - g++
+          - clang++
+        default: g++
+      native:
+        description: "Compile for the runner's CPU (-march=native)"
+        type: boolean
+        default: false
+      rounds:
+        description: "Rounds of bench_view"
+        type: number
+        default: 30
+
+permissions:
+  contents: read
+
+jobs:
+  compare:
+    if: github.event_name == 'workflow_dispatch' || github.event.label.name == 'benchmark'
+    strategy:
+      matrix:
+        runner: ${{ fromJSON(github.event_name == 'workflow_dispatch' && format('["{0}"]', inputs.runner) || '["ubuntu-24.04", "ubuntu-24.04-arm"]') }}
+    runs-on: ${{ matrix.runner }}
+    steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
+        with:
+          egress-policy: audit
+
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+
+      - name: Download test data
+        run: |
+          cmake -S . -B build -DJSON_BuildTests=On
+          cmake --build build --target download_test_data
+
+      - name: Run the comparison
+        env:
+          CXX: ${{ inputs.compiler || 'g++' }}
+          CC: ${{ inputs.compiler == 'clang++' && 'clang' || 'gcc' }}
+          ROUNDS: ${{ inputs.rounds || 30 }}
+          NATIVE: ${{ inputs.native && '--native' || '' }}
+        run: python3 tests/benchmarks/json_view/compare.py --data build/test_files --download --rounds "$ROUNDS" $NATIVE
+
+      - name: Summary
+        run: cat tests/benchmarks/json_view/results/*.md >> "$GITHUB_STEP_SUMMARY"
+
+      - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
+        with:
+          name: json_view-benchmarks-${{ matrix.runner }}-${{ inputs.compiler || 'g++' }}
+          path: tests/benchmarks/json_view/results/

BUILD.bazel

@@ -67,7 +67,10 @@ cc_library(
         "include/nlohmann/detail/string_utils.hpp",
         "include/nlohmann/detail/value_t.hpp",
         "include/nlohmann/detail/view/builder.hpp",
+        "include/nlohmann/detail/view/compare.hpp",
         "include/nlohmann/detail/view/document_data.hpp",
+        "include/nlohmann/detail/view/edit.hpp",
+        "include/nlohmann/detail/view/edit_storage.hpp",
         "include/nlohmann/detail/view/errors.hpp",
         "include/nlohmann/detail/view/input.hpp",
         "include/nlohmann/detail/view/iterator.hpp",
@@ -77,8 +80,13 @@ cc_library(
         "include/nlohmann/detail/view/materialize.hpp",
         "include/nlohmann/detail/view/node.hpp",
         "include/nlohmann/detail/view/number.hpp",
+        "include/nlohmann/detail/view/object_index.hpp",
+        "include/nlohmann/detail/view/pointer.hpp",
         "include/nlohmann/detail/view/scan.hpp",
+        "include/nlohmann/detail/view/serializer.hpp",
+        "include/nlohmann/detail/view/simd.hpp",
         "include/nlohmann/detail/view/string_ref.hpp",
+        "include/nlohmann/detail/view/value.hpp",
         "include/nlohmann/json.hpp",
         "include/nlohmann/json_fwd.hpp",
         "include/nlohmann/json_view.hpp",

README.md

@@ -1405,6 +1405,7 @@ THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR I
 - The class contains parts of [Google Abseil](https://github.com/abseil/abseil-cpp) which is licensed under the [Apache 2.0 License](https://opensource.org/licenses/Apache-2.0).
 - The class contains an adapted version of the Eisel-Lemire algorithm and its table of powers of five from [fast_float](https://github.com/fastfloat/fast_float) by Daniel Lemire and contributors, which is available under the [MIT License](https://opensource.org/licenses/MIT) (used here), the Apache 2.0 License, and the Boost Software License. Copyright © 2021 The fast_float authors
 - The view's parser (`<nlohmann/json_view.hpp>`) contains techniques and code adapted from [yyjson](https://github.com/ibireme/yyjson) by YaoYuan, which is licensed under the [MIT License](https://opensource.org/licenses/MIT) (see above): table-driven decoding of `\u` escapes and fixed-offset unrolled checks.
+- The view's parser (`<nlohmann/json_view.hpp>`) validates non-ASCII strings with the vector UTF-8 check of [simdjson](https://github.com/simdjson/simdjson) by Daniel Lemire, Geoff Langdale, John Keiser, and contributors (its "lookup4" algorithm and tables, after J. Keiser and D. Lemire, "Validating UTF-8 In Less Than One Instruction Per Byte", 2021), which is available under the [MIT License](https://opensource.org/licenses/MIT) (used here) and the Apache 2.0 License. Copyright &copy; 2018-2025 The simdjson authors
 
 <img align="right" src="https://git.fsfe.org/reuse/reuse-ci/raw/branch/master/reuse-horizontal.png" alt="REUSE Software">
 

docs/docset/docSet.sql

@@ -137,8 +137,10 @@ INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::node_cou
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::owns_source', 'Method', 'api/basic_json_document/owns_source/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::parse', 'Function', 'api/basic_json_document/parse/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::parse_copy', 'Function', 'api/basic_json_document/parse_copy/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::push_back', 'Method', 'api/basic_json_document/push_back/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::read', 'Method', 'api/basic_json_document/read/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::root', 'Method', 'api/basic_json_document/root/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::set', 'Method', 'api/basic_json_document/set/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::shrink_to_fit', 'Method', 'api/basic_json_document/shrink_to_fit/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::source', 'Method', 'api/basic_json_document/source/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view', 'Class', 'api/basic_json_view/index.html');
@@ -150,10 +152,14 @@ INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::cbegin', 'Me
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::cend', 'Method', 'api/basic_json_view/cend/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::contains', 'Method', 'api/basic_json_view/contains/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::count', 'Method', 'api/basic_json_view/count/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::dump', 'Method', 'api/basic_json_view/dump/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::empty', 'Method', 'api/basic_json_view/empty/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::end', 'Method', 'api/basic_json_view/end/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::find', 'Method', 'api/basic_json_view/find/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::front', 'Method', 'api/basic_json_view/front/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::get', 'Method', 'api/basic_json_view/get/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::get_string', 'Method', 'api/basic_json_view/get_string/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::get_to', 'Method', 'api/basic_json_view/get_to/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_array', 'Method', 'api/basic_json_view/is_array/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_binary', 'Method', 'api/basic_json_view/is_binary/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_boolean', 'Method', 'api/basic_json_view/is_boolean/index.html');
@@ -169,14 +175,22 @@ INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_string',
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_structured', 'Method', 'api/basic_json_view/is_structured/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::items', 'Method', 'api/basic_json_view/items/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::materialize', 'Method', 'api/basic_json_view/materialize/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::number_format', 'Enum', 'api/basic_json_view/number_format/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::number_token', 'Method', 'api/basic_json_view/number_token/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::operator bool', 'Method', 'api/basic_json_view/operator_bool/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::operator<<', 'Operator', 'api/basic_json_view/operator_ltlt/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::operator[]', 'Operator', 'api/basic_json_view/operator[]/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::operator==', 'Operator', 'api/basic_json_view/operator_eq/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::operator!=', 'Operator', 'api/basic_json_view/operator_ne/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::size', 'Method', 'api/basic_json_view/size/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::source_offset', 'Method', 'api/basic_json_view/source_offset/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::type', 'Method', 'api/basic_json_view/type/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::type_name', 'Method', 'api/basic_json_view/type_name/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::value', 'Method', 'api/basic_json_view/value/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json', 'Class', 'api/json/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_document', 'Class', 'api/json_document/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('json_editable_document', 'Class', 'api/json_editable_document/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('json_editable_view', 'Class', 'api/json_editable_view/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_view', 'Class', 'api/json_view/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer', 'Class', 'api/json_pointer/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::back', 'Method', 'api/json_pointer/back/index.html');
@@ -212,6 +226,8 @@ INSERT INTO searchIndex(name, type, path) VALUES ('operator<<', 'Operator', 'api
 INSERT INTO searchIndex(name, type, path) VALUES ('operator>>', 'Operator', 'api/operator_gtgt/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('ordered_json', 'Class', 'api/ordered_json/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('ordered_json_document', 'Class', 'api/ordered_json_document/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_json_editable_document', 'Class', 'api/ordered_json_editable_document/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_json_editable_view', 'Class', 'api/ordered_json_editable_view/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('ordered_json_view', 'Class', 'api/ordered_json_view/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('ordered_map', 'Class', 'api/ordered_map/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('std::hash<basic_json>', 'Class', 'api/basic_json/std_hash/index.html');
@@ -297,3 +313,5 @@ INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_JSON_SERIALIZE_ENUM'
 INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_JSON_VERSION_MAJOR', 'Macro', 'api/macros/nlohmann_json_version_major/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_JSON_VERSION_MINOR', 'Macro', 'api/macros/nlohmann_json_version_major/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_JSON_VERSION_PATCH', 'Macro', 'api/macros/nlohmann_json_version_major/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('JSON_VIEW_NO_SIMD', 'Macro', 'api/macros/json_view_no_simd/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('JSON_VIEW_USE_SSSE3', 'Macro', 'api/macros/json_view_use_ssse3/index.html');

docs/mkdocs/docs/api/basic_json/dump.md

@@ -86,6 +86,8 @@ Binary values are serialized as an object containing two keys:
 
 - [to_string](to_string.md) returns a string representation of a JSON value
 - [operator<<](../operator_ltlt.md) serialize to stream
+- [`basic_json_view::dump`](../basic_json_view/dump.md) the corresponding function of `basic_json_view`, serializing
+  directly from a flat index without building a `basic_json` value
 - [Serialization](../../features/serialization.md) - the serialization article
 
 ## Version history

docs/mkdocs/docs/api/basic_json/get.md

@@ -163,6 +163,8 @@ overload (3).
 - [get_ref](get_ref.md) get a reference to the stored value
 - [operator ValueType](operator_ValueType.md) get a value via implicit conversion
 - [Converting values](../../features/conversions.md) - the type conversions article
+- [basic_json_view::get](../basic_json_view/get.md) - the same conversion on a zero-copy view (many types are
+  converted without ever building a `basic_json` value)
 
 ## Version history
 

docs/mkdocs/docs/api/basic_json/get_ref.md

@@ -61,6 +61,8 @@ Constant.
 ## See also
 
 - [get_ptr()](get_ptr.md) get a pointer value
+- [basic_json_view::get_string](../basic_json_view/get_string.md) - the closest counterpart on a zero-copy view: a
+  string without a copy, but as a view rather than a reference to a value that must already exist
 
 ## Version history
 

docs/mkdocs/docs/api/basic_json/get_to.md

@@ -67,6 +67,7 @@ Depends on the `json_serializer<ValueType>::from_json()` implementation.
 - [get_ref](get_ref.md) get a reference to the stored value
 - [get_ptr](get_ptr.md) get a pointer to the stored value
 - [Converting values](../../features/conversions.md) - the type conversions article
+- [basic_json_view::get_to](../basic_json_view/get_to.md) - the same conversion on a zero-copy view
 
 ## Version history
 

docs/mkdocs/docs/api/basic_json/operator_eq.md

@@ -166,6 +166,8 @@ Linear.
 
 - [operator!=](operator_ne.md) compare for inequality
 - [operator<=>](operator_spaceship.md) comparison: 3-way (C++20)
+- [basic_json_view::operator==](../basic_json_view/operator_eq.md) - the same comparison on a zero-copy view, without
+  building a `basic_json` value for it
 
 ## Version history
 

docs/mkdocs/docs/api/basic_json/operator_ne.md

@@ -89,6 +89,12 @@ Linear.
     --8<-- "examples/operator__notequal__nullptr_t.output"
     ```
 
+## See also
+
+- [operator==](operator_eq.md) compare for equality
+- [basic_json_view::operator!=](../basic_json_view/operator_ne.md) - the same comparison on a zero-copy view, without
+  building a `basic_json` value for it
+
 ## Version history
 
 1. Added in version 1.0.0. Added C++20 member functions in version 3.11.0. Changed in version 3.13.0 to remove 

docs/mkdocs/docs/api/basic_json/value.md

@@ -181,6 +181,7 @@ changes to any JSON value.
 
 - see [`at`](at.md) for access by reference with range checking
 - see [`operator[]`](operator%5B%5D.md) for unchecked access by reference
+- [basic_json_view::value](../basic_json_view/value.md) - the same access on a zero-copy view
 
 ## Version history
 

docs/mkdocs/docs/api/basic_json_document/index.md

@@ -3,7 +3,7 @@
 <small>Defined in header `<nlohmann/json_view.hpp>`</small>
 
 ```cpp
-template<typename BasicJsonType>
+template<typename BasicJsonType, bool Editable = false>
 class basic_json_document;
 ```
 
@@ -19,6 +19,11 @@ it (a copy, or an rvalue `#!cpp std::string` that was moved in); see [`owns_sour
 is move-only: copying a document would either duplicate a potentially large index and text, or leave two documents
 claiming to borrow the same buffer, so it is disabled.
 
+With `#!cpp Editable == true`, the document also offers [`set`](set.md) and [`push_back`](push_back.md) to change
+values in place, see [Edits](#edits) below. The source text itself is never written; a read-only document
+(`#!cpp Editable == false`, the default) does not carry any of the bookkeeping edits need, and calling `set` or
+`push_back` on one fails to compile (`#!cpp static_assert`).
+
 ## Template parameters
 
 `BasicJsonType`
@@ -26,14 +31,22 @@ claiming to borrow the same buffer, so it is disabled.
     [`ordered_json`](../ordered_json.md). Only 64-bit `number_integer_t`/`number_unsigned_t` types are supported; this
     is checked with a `static_assert`.
 
+`Editable`
+:   whether the document supports [`set`](set.md) and [`push_back`](push_back.md) (optional, `#!cpp false` by
+    default). See [Edits](#edits) below.
+
 ## Specializations
 
-- [**json_document**](../json_document.md) - documents of the default specialization [`json`](../json.md)
-- [**ordered_json_document**](../ordered_json_document.md) - documents of [`ordered_json`](../ordered_json.md)
+- [**json_document**](../json_document.md) - read-only documents of the default specialization [`json`](../json.md)
+- [**ordered_json_document**](../ordered_json_document.md) - read-only documents of
+  [`ordered_json`](../ordered_json.md)
+- [**json_editable_document**](../json_editable_document.md) - editable documents of [`json`](../json.md)
+- [**ordered_json_editable_document**](../ordered_json_editable_document.md) - editable documents of
+  [`ordered_json`](../ordered_json.md)
 
 ## Member types
 
-- **view_type** - the type of view returned by [`root()`](root.md) (`#!cpp basic_json_view<BasicJsonType>`)
+- **view_type** - the type of view returned by [`root()`](root.md) (`#!cpp basic_json_view<BasicJsonType, Editable>`)
 - **value_t** - the JSON type enumeration, see [`basic_json::value_t`](../basic_json/value_t.md)
 
 ## Member functions
@@ -50,6 +63,37 @@ claiming to borrow the same buffer, so it is disabled.
 - [**node_count**](node_count.md) - the number of index entries (values plus object keys)
 - [**memory_usage**](memory_usage.md) - the number of bytes held by the document
 - [**shrink_to_fit**](shrink_to_fit.md) - release unused index capacity
+- [**set**](set.md) - replace a value, or set an object member, an array element, or the value a JSON pointer refers
+  to (`#!cpp Editable` documents only)
+- [**push_back**](push_back.md) - append to an array (`#!cpp Editable` documents only)
+
+## Edits
+
+An editable document (`#!cpp Editable == true`) can be changed after parsing, with [`set`](set.md) and
+[`push_back`](push_back.md); [`json_editable_document`](../json_editable_document.md) and
+[`ordered_json_editable_document`](../ordered_json_editable_document.md) are the corresponding specializations. A few
+points apply to every edit:
+
+- **The source text is never written**, and the parsed index never moves: every value keeps the node it was parsed
+  into, so [views](../basic_json_view/index.md) taken before an edit stay valid, including
+  [`root()`](root.md). New values (and the element sequences of an edited array/object) go to storage owned by the
+  document, allocated on demand.
+- **A view keeps referring to the same value.** After [`set`](set.md) replaces the value a view refers to, that view
+  sees the new value; a view of a value that a later edit replaces or drops keeps showing what it last held. An edit
+  of an array or object, however, **invalidates the iterators taken over it** (its members may now live in a
+  different sequence), and a string obtained with [`get_string()`](../basic_json_view/get_string.md) stays valid even
+  as further edits happen (earlier buffers of edited text are kept alive, not overwritten).
+- **Values are accepted three ways:** a [`basic_json_view`](../basic_json_view/index.md) of *any* document
+  (read-only or editable; it is copied, nothing is shared with the source document), a `BasicJsonType` value, or
+  anything `BasicJsonType` can be constructed from (numbers, strings, `#!cpp bool`, `#!cpp nullptr`, containers, ...).
+- [`dump()`](../basic_json_view/dump.md) writes an edited document with members in document order, new members at
+  the end, and, with [`number_format::source`](../basic_json_view/number_format.md), keeps the spelling of every
+  number that was not itself edited -- see [Editing a document](../../features/json_view.md#editing-a-document) for
+  why this matters.
+- [`read()`](read.md) discards all edits, [`shrink_to_fit()`](shrink_to_fit.md) does not move the node index once
+  there are edits, and [`memory_usage()`](memory_usage.md) includes the memory edits use.
+  [`source_offset()`](../basic_json_view/source_offset.md) of a value introduced by an edit is
+  `#!cpp static_cast<std::size_t>(-1)`, the same value it reports for a decoded string.
 
 ## Version history
 

docs/mkdocs/docs/api/basic_json_document/push_back.md

@@ -0,0 +1,100 @@
+# <small>nlohmann::basic_json_document::</small>push_back
+
+```cpp
+template<typename V>
+view_type push_back(view_type array, V&& value);
+```
+
+Appends `value` as a new last element of `array`. A [null](../basic_json_view/is_null.md) `array` first becomes an
+empty array, the same way [`set`](set.md) turns a null `object` into an empty object.
+
+`value` is accepted three ways: a [`basic_json_view`](../basic_json_view/index.md) of *any* document -- read-only or
+editable, and it does not have to be `array`'s own document -- which is copied so that nothing is shared with the
+source document afterward; a `BasicJsonType` value; or anything `BasicJsonType` can be constructed from (numbers,
+strings, `#!cpp bool`, `#!cpp nullptr`, containers, ...).
+
+Only an **editable** document (`#!cpp Editable == true`, e.g. [`json_editable_document`](../json_editable_document.md))
+has `push_back`; calling it on a read-only `basic_json_document` fails to compile (`#!cpp static_assert`).
+
+## Template parameters
+
+`V`
+:   the type of `value`, deduced; see above for what is accepted.
+
+## Parameters
+
+`array` (in)
+:   the array (or null value) to append to
+
+`value` (in)
+:   the value to append
+
+## Return value
+
+a view of the new last element of `array`, now holding `value`
+
+## Exception safety
+
+Basic exception safety: `value` is fully encoded -- including the checks below -- into storage owned by the document
+before anything already reachable from [`root()`](root.md) is touched, so a failure while encoding `value` (an
+invalid argument, or `#!cpp std::bad_alloc`) leaves the document completely unchanged, other than memory allocated
+for the encoding that is not reclaimed. A failure of a later allocation -- while `array` switches from its parsed
+layout to a growable block, or while that block grows, see [Notes](#notes) -- can still leave a partial effect, such
+as a null `array` argument already turned into an empty array even though `value` itself was not appended.
+
+## Exceptions
+
+Throws [`type_error.308`](../../home/exceptions.md#jsonexceptiontype_error308) if `array` is neither an array nor
+null -- the same message [`BasicJsonType::push_back`](../basic_json/push_back.md) throws for the same type. Throws
+[`invalid_iterator.202`](../../home/exceptions.md#jsonexceptioninvalid_iterator202) ("view does not belong to this
+document") if `array` is a [discarded](../basic_json_view/is_discarded.md) view or a view of a *different* document.
+Throws [`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302) if `value` is a
+[discarded](../basic_json_view/is_discarded.md) view or a [discarded](../basic_json/is_discarded.md) `BasicJsonType`
+value, and [`type_error.319`](../../home/exceptions.md#jsonexceptiontype_error319) if `value` is (or contains) a
+binary value -- `BasicJsonType` can hold one, but a `json_document` cannot. Throws
+[`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) if `value` is (or contains) a string that is
+not valid UTF-8, with the same message [`BasicJsonType::dump()`](../basic_json/dump.md) gives for that string.
+
+## Complexity
+
+Amortized constant, plus time linear in the size of `value` to encode it into the document's storage (constant for
+a scalar, linear in the number of nested values for an array or object): the elements of `array` move to a growable
+block of links the first time it is appended to (or [`set`](set.md) on), and that block itself grows -- doubling its
+capacity, so the cost of growing it amortizes to constant per element -- only once it runs out of room. See
+[Notes](#notes).
+
+## Notes
+
+Like [`set`](set.md) on a member or an element, `push_back` never moves an existing element itself -- only where
+`array`'s *links* to its elements live -- so a view of an existing element of `array` stays valid across a
+`push_back`, but any iterator already taken over `array` is invalidated, since it was walking the old layout. See
+[Edits](index.md#edits) for what stays valid across an edit in general.
+
+## Examples
+
+??? example
+
+    The example below appends records to an array one at a time, as they might arrive from a stream of events,
+    without ever building a `BasicJsonType` value for the array or for the records already in it, and shows that a
+    view taken from an earlier `push_back` still refers to the same element once later ones have run.
+
+    ```cpp
+    --8<-- "examples/basic_json_document__push_back.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__push_back.output"
+    ```
+
+## See also
+
+- [set](set.md) - replace a value, or set an object member, an array element, or the value a JSON pointer refers to
+- [root](root.md) - the view of the root value
+- [`BasicJsonType::push_back`](../basic_json/push_back.md) - the corresponding function of `basic_json`
+- [Edits](index.md#edits) - what an edit guarantees, for every overload
+
+## Version history
+
+- Added in version 3.13.0.

docs/mkdocs/docs/api/basic_json_document/set.md

@@ -0,0 +1,192 @@
+# <small>nlohmann::basic_json_document::</small>set
+
+```cpp
+// (1)
+template<typename V>
+view_type set(view_type target, V&& value);
+
+// (2)
+template<typename V>
+view_type set(view_type object, string_view_t key, V&& value);
+
+// (3)
+template<typename I, typename V>
+view_type set(view_type array, I idx, V&& value);
+
+// (4)
+template<typename V>
+view_type set(const json_pointer& ptr, V&& value);
+```
+
+Only an **editable** document (`#!cpp Editable == true`, e.g. [`json_editable_document`](../json_editable_document.md))
+has `set`; calling it on a read-only `basic_json_document` fails to compile (`#!cpp static_assert`).
+
+1. Replaces the value `target` refers to with `value`.
+2. Sets the member `key` of the object `object` to `value`: assigns it if `object` already has a member with this
+   key -- the first one, should the key occur more than once, and the later duplicates are then dropped (see the
+   [Notes](#notes) below) -- or appends a new member at the end otherwise. A [null](../basic_json_view/is_null.md)
+   `object` first becomes an empty object.
+3. Assigns `value` to the element at index `idx` of the array `array`, which must already exist (`#!cpp idx <
+   array.size()`).
+4. Sets the value the JSON pointer `ptr` refers to, relative to [`root()`](root.md), to `value`. The *parent* of the
+   target must already exist: an object member is set as in 2. (added if it does not exist yet), an array element is
+   assigned as in 3., and a last reference token of `#!cpp "-"`, or equal to the size of the array, appends `value`
+   instead, exactly as [`push_back`](push_back.md) would. An empty `ptr` sets [`root()`](root.md) itself, as in 1.
+
+In every overload, `value` is accepted three ways: a [`basic_json_view`](../basic_json_view/index.md) of *any*
+document -- read-only or editable, and it does not have to be `target`'s/`object`'s/`array`'s own document -- which
+is copied so that nothing is shared with the source document afterward; a `BasicJsonType` value; or anything
+`BasicJsonType` can be constructed from (numbers, strings, `#!cpp bool`, `#!cpp nullptr`, containers, ...).
+
+## Template parameters
+
+`V`
+:   the type of `value`, deduced; see above for what is accepted.
+
+`I`
+:   an integral type other than `#!cpp bool`, deduced (overloads taking a `#!cpp bool` or a non-integral type for
+    `idx` do not participate in overload resolution).
+
+## Parameters
+
+`target` (in)
+:   the value to replace
+
+`object` (in)
+:   the object (or null value) whose member to set
+
+`array` (in)
+:   the array whose element to assign
+
+`key` (in)
+:   the key of the member to set
+
+`idx` (in)
+:   the index of the element to assign; a negative value throws (see [Exceptions](#exceptions))
+
+`ptr` (in)
+:   a JSON pointer to the value to set, relative to `root()`
+
+`value` (in)
+:   the new value
+
+## Return value
+
+1. a view of `target`, now holding `value`
+2. a view of the member `key` of `object`, now holding `value`
+3. a view of the element `idx` of `array`, now holding `value`
+4. a view of the value `ptr` refers to, now holding `value`
+
+## Exception safety
+
+Basic exception safety: `value` is fully encoded -- including the checks below -- into storage owned by the document
+before anything already reachable from [`root()`](root.md) is touched, so a failure while encoding `value` (an
+invalid argument, or `#!cpp std::bad_alloc`) leaves the document completely unchanged, other than memory allocated
+for the encoding that is not reclaimed. A failure of a later allocation -- while an edited array or object switches
+from its parsed layout to a growable block, see [Notes](#notes) -- can still leave a partial effect, such as a
+[null](../basic_json_view/is_null.md) `object`/`array` argument already turned into an empty object/array even
+though `value` itself was not linked in.
+
+## Exceptions
+
+1. Throws [`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302) if `value` is a
+   [discarded](../basic_json_view/is_discarded.md) view, or a [discarded](../basic_json/is_discarded.md)
+   `BasicJsonType` value (e.g. `#!cpp BasicJsonType(value_t::discarded)`) -- an object or array `value`, of either
+   kind, is fine and is encoded as a whole subtree.
+2. Throws [`type_error.305`](../../home/exceptions.md#jsonexceptiontype_error305) if `object` is neither an object
+   nor null -- the same message [`operator[]`](../basic_json_view/operator%5B%5D.md) throws for a string argument on
+   such a value. Throws [`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) if `key` is not
+   valid UTF-8, with the same message [`BasicJsonType::dump()`](../basic_json/dump.md) gives for that string.
+   Also throws what 1. throws for `value`.
+3. Throws `type_error.305` if `array` is not an array -- the same message `operator[]` throws for a numeric argument
+   on such a value. Throws [`out_of_range.401`](../../home/exceptions.md#jsonexceptionout_of_range401) if `idx` is
+   negative, or if `#!cpp idx >= array.size()`. Also throws what 1. throws for `value`.
+4. Throws what [`at`](../basic_json_view/at.md) throws (overload 3) for resolving `ptr`'s parent, except that a
+   missing object member or an array index equal to the array's size at the very last reference token is not an
+   error there (it becomes a new member or an appended element) instead of
+   [`out_of_range.403`](../../home/exceptions.md#jsonexceptionout_of_range403)/[`out_of_range.402`](../../home/exceptions.md#jsonexceptionout_of_range402).
+   For the last reference token itself: if the parent is an object (or a primitive value, where it throws
+   `type_error.305`), throws what 2. throws; if the parent is an array, throws what 3. throws for an index that is
+   out of range, or, for a token that is not a valid array index,
+   [`parse_error.106`](../../home/exceptions.md#jsonexceptionparse_error106) (a leading `#!cpp '0'`),
+   [`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) (not a number),
+   [`out_of_range.410`](../../home/exceptions.md#jsonexceptionout_of_range410) (too large for `size_type`), or
+   [`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) (an empty token). Also throws what 1.
+   throws for `value`.
+
+Every overload also throws [`type_error.319`](../../home/exceptions.md#jsonexceptiontype_error319) if `value` is (or
+contains) a binary value -- `BasicJsonType` can hold one, but a `json_document` cannot -- and
+[`invalid_iterator.202`](../../home/exceptions.md#jsonexceptioninvalid_iterator202) ("view does not belong to this
+document") if `target`/`object`/`array` is a [discarded](../basic_json_view/is_discarded.md) view or a view of a
+*different* document (overloads 1-3 only; overload 4 always starts from this document's own [`root()`](root.md)).
+
+## Complexity
+
+1. Linear in the size of `value` (encoding it into the document's storage): constant for a scalar, linear in the
+   number of nested values for an array or object. If `target` is itself an array or object that spans more than one
+   node in its parent's original, unedited layout, and `value` is a scalar, replacing it additionally costs time
+   linear in the number of elements of that parent, the *first* time -- see [Notes](#notes).
+2. Linear in the number of members of `object`, to find an existing member with `key`, plus the complexity of 1. for
+   `value`.
+3. Constant, plus the complexity of 1. for `value`.
+4. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
+   that level or the index into the array (as [`at`](../basic_json_view/at.md)), plus the complexity of 2. or 3. for
+   the last token.
+
+## Notes
+
+!!! info "Duplicate keys"
+
+    If `object` already has more than one member with `key` (2.), the *first* one is assigned `value` and every
+    later member with the same key is removed -- so that a lookup, an iteration, and
+    [`materialize()`](../basic_json_view/materialize.md) of `object` afterward all agree on a single value for
+    `key`, the same way [`operator[]`](../basic_json_view/operator%5B%5D.md) already picks the first occurrence of a
+    duplicate key for reading. See the [Notes on duplicate keys](../basic_json_view/operator%5B%5D.md#notes) of
+    `operator[]`.
+
+Setting a member (2.) or an element (3., through 4.) of an array or object whose elements have not been edited
+before switches it from its parsed layout to a growable block holding links to its elements; a later
+[`push_back`](push_back.md) or `set` on the same container reuses that block, growing it (amortized constant time)
+only once it runs out of room. This never moves an element itself -- only where the container's *links* to its
+elements live -- so a view of an element stays valid, but any iterator already taken over the container is
+invalidated, since it was walking the old layout. See [Edits](index.md#edits) for what stays valid across an edit in
+general.
+
+The same switch happens, for the same reason, when overload 1. replaces a multi-node array/object value with a
+scalar: the *parent's* element sequence is what has to switch to links, not `target` itself, because the parent
+originally stepped over `target`'s whole subtree by its node count, which no longer applies once `target` is a
+one-node scalar.
+
+## Examples
+
+??? example "Example: (1)/(2)/(3)/(4) replace a value, set a member, assign an element, set via a JSON pointer"
+
+    The example below edits a small configuration document -- replacing a value, adding an object member, assigning
+    an array element, and reaching a field through a JSON pointer -- and shows what
+    [`dump()`](../basic_json_view/dump.md) preserves that is lost once the same edits are made on a `BasicJsonType`
+    value instead: the order object members were written in, and the exact spelling of a number that was never
+    touched.
+
+    ```cpp
+    --8<-- "examples/basic_json_document__set.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__set.output"
+    ```
+
+## See also
+
+- [push_back](push_back.md) - append to an array
+- [root](root.md) - the view of the root value, the starting point of overload 4
+- [`basic_json_view::dump`](../basic_json_view/dump.md) - serialize the document, keeping an untouched number's
+  spelling with `#!cpp number_format::source`
+- [Edits](index.md#edits) - what an edit guarantees, for every overload
+- [Editing a document](../../features/json_view.md#editing-a-document) - why editable documents keep the source
+  text's order and number spelling
+
+## Version history
+
+- Added in version 3.13.0.

docs/mkdocs/docs/api/basic_json_view/at.md

@@ -9,11 +9,15 @@ basic_json_view at(const string_t& key) const;
 // (2)
 basic_json_view at(size_type idx) const;
 basic_json_view at(int idx) const;
+
+// (3)
+basic_json_view at(const json_pointer& ptr) const;
 ```
 
 1. Returns the value of the object member with key `key` -- the first one, should the key occur more than once (see
    [Notes on duplicate keys](operator[].md#notes)).
 2. Returns the array element at index `idx`.
+3. Returns the value a JSON pointer `ptr` refers to, starting at this value.
 
 ## Parameters
 
@@ -23,10 +27,14 @@ basic_json_view at(int idx) const;
 `idx` (in)
 :   index of the element to access
 
+`ptr` (in)
+:   JSON pointer to the element to access
+
 ## Return value
 
 1. the value of the first member with key `key`
 2. the element at index `idx`
+3. the value `ptr` resolves to, starting at this value
 
 ## Exception safety
 
@@ -42,6 +50,20 @@ Strong exception safety: if an exception is thrown, there are no changes to the
    [`BasicJsonType::at`](../basic_json/at.md):
     - Throws [`type_error.304`](../../home/exceptions.md#jsonexceptiontype_error304) if the value is not an array.
     - Throws [`out_of_range.401`](../../home/exceptions.md#jsonexceptionout_of_range401) if `#!cpp idx >= size()`.
+3. The function can throw the following exceptions, all with the same message as the corresponding call to
+   [`BasicJsonType::at`](../basic_json/at.md):
+    - Throws [`parse_error.106`](../../home/exceptions.md#jsonexceptionparse_error106) if an array index in `ptr`
+      begins with `#!cpp '0'`.
+    - Throws [`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) if an array index in `ptr` is
+      not a number.
+    - Throws [`out_of_range.401`](../../home/exceptions.md#jsonexceptionout_of_range401) if an array index in `ptr`
+      is out of range.
+    - Throws [`out_of_range.402`](../../home/exceptions.md#jsonexceptionout_of_range402) if a reference token is
+      `#!cpp "-"` at an array -- `at` never inserts an element, so `#!cpp "-"` is always invalid.
+    - Throws [`out_of_range.403`](../../home/exceptions.md#jsonexceptionout_of_range403) if a reference token names
+      an object member that does not exist.
+    - Throws [`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) if `ptr` cannot be resolved
+      because a reference token is used on a primitive value.
 
 None of these exceptions carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) path: the view has no
 `BasicJsonType` value to point at, so the exception is created without one, even if `BasicJsonType` was built with
@@ -52,18 +74,24 @@ None of these exceptions carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics
 1. Linear in the number of members: as for [`ordered_json`](../ordered_json.md), members are compared one after
    another, in document order, stopping at the first match. Each comparison first checks the key's length --
    already known from the index, without reading the key bytes -- before comparing its content.
+   Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time
+   on average.
 2. Linear in `idx`: elements are skipped one at a time from the first one, since they are not a fixed size in the
    index (unlike `BasicJsonType`'s array, which is random-access).
+3. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
+   that level (as 1.) or the index into the array (as 2.).
 
 ## Notes
 
 Unlike [`operator[]`](operator[].md), which returns a [discarded](is_discarded.md) view for a missing key or an
 out-of-range index, `at` always throws -- exactly as `BasicJsonType::at` does, and with the same messages, so
-existing error handling written against `BasicJsonType::at` keeps working unchanged when switched to a view.
+existing error handling written against `BasicJsonType::at` keeps working unchanged when switched to a view. This
+also holds for overload 3: unlike [`operator[]`](operator[].md) with a JSON pointer, which returns a discarded view
+for a missing key or an out-of-range index, `at` throws for those too (`out_of_range.403`/`out_of_range.401`).
 
 ## Examples
 
-??? example
+??? example "Example: (1)/(2) access specified element with bounds checking"
 
     The example below reads required fields out of a service configuration with `at`, and shows that the exceptions
     it throws -- for a wrong type and for a missing key -- carry the same messages
@@ -79,11 +107,27 @@ existing error handling written against `BasicJsonType::at` keeps working unchan
     --8<-- "examples/basic_json_view__at.output"
     ```
 
+??? example "Example: (3) access specified element via JSON pointer with bounds checking"
+
+    The example below shows that `at` with a JSON pointer throws exactly the exceptions, with exactly the messages,
+    that [`BasicJsonType::at`](../basic_json/at.md) throws for the same pointer and the same document.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__at_json_pointer.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__at_json_pointer.output"
+    ```
+
 ## See also
 
 - [operator[]](operator[].md) - access specified element (returns a discarded view instead of throwing)
 - [front](front.md), [back](back.md) - access the first or last element
 - [`BasicJsonType::at`](../basic_json/at.md) - the corresponding function of `basic_json`
+- [`json_pointer`](../json_pointer/index.md) - JSON pointer type used by overload 3
 
 ## Version history
 

docs/mkdocs/docs/api/basic_json_view/contains.md

@@ -1,21 +1,30 @@
 # <small>nlohmann::basic_json_view::</small>contains
 
 ```cpp
+// (1)
 bool contains(string_view_t key) const;
 bool contains(const char* key) const;
 bool contains(const string_t& key) const;
+
+// (2)
+bool contains(const json_pointer& ptr) const;
 ```
 
-Checks whether the value is an object with a member with key `key`.
+1. Checks whether the value is an object with a member with key `key`.
+2. Checks whether a JSON pointer `ptr` can be resolved, starting at this value.
 
 ## Parameters
 
 `key` (in)
 :   key value to check its existence
 
+`ptr` (in)
+:   JSON pointer to check its existence
+
 ## Return value
 
-`#!cpp true` if the value is an object and has a member with key `key`, `#!cpp false` otherwise.
+1. `#!cpp true` if the value is an object and has a member with key `key`, `#!cpp false` otherwise
+2. `#!cpp true` if `ptr` can be resolved to a value starting at this view, `#!cpp false` otherwise
 
 ## Exception safety
 
@@ -23,22 +32,36 @@ No-throw guarantee: this function never throws exceptions.
 
 ## Complexity
 
-Linear in the number of members: as for [`ordered_json`](../ordered_json.md), members are compared one after
-another, in document order, stopping at the first match. Each comparison first checks the key's length -- already
-known from the index, without reading the key bytes -- before comparing its content.
+1. Linear in the number of members: as for [`ordered_json`](../ordered_json.md), members are compared one after
+   another, in document order, stopping at the first match. Each comparison first checks the key's length -- already
+   known from the index, without reading the key bytes -- before comparing its content.
+   Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time
+   on average.
+2. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
+   that level or the index into the array -- as for [`operator[]`](operator[].md#complexity) and
+   [`at`](at.md#complexity) with a JSON pointer.
 
 ## Notes
 
-This method always returns `#!cpp false` when the value is not an object -- including a [discarded](is_discarded.md)
+Overload 1 always returns `#!cpp false` when the value is not an object -- including a [discarded](is_discarded.md)
 view.
 
 !!! info "Postconditions"
 
-    If `#!cpp v.contains(key)` returns `#!cpp true`, then `#!cpp v[key]` is not [discarded](is_discarded.md).
+    If `#!cpp v.contains(key)` returns `#!cpp true`, then `#!cpp v[key]` is not [discarded](is_discarded.md). If
+    `#!cpp v.contains(ptr)` returns `#!cpp true`, then `#!cpp v[ptr]` is not discarded and `#!cpp v.at(ptr)` does not
+    throw.
+
+!!! info "Overload 2 never throws"
+
+    Unlike [`BasicJsonType::contains(const json_pointer&)`](../basic_json/contains.md), which can throw for certain
+    malformed pointers (for instance an empty array-index reference token), overload 2 never throws: a missing key,
+    an out-of-range or malformed array index, a `#!cpp "-"` index, or a reference token used on a primitive all
+    simply make it return `#!cpp false`.
 
 ## Examples
 
-??? example
+??? example "Example: (1) check with key"
 
     The example below counts how many of a batch of records carry an optional `retry_of` field, using `contains()`
     to check without ever materializing a single record of the batch.
@@ -53,10 +76,26 @@ view.
     --8<-- "examples/basic_json_view__contains.output"
     ```
 
+??? example "Example: (2) check with JSON pointer"
+
+    The example below checks an optional, nested field with a JSON pointer, and shows two pointers that
+    `#!cpp contains()` resolves to `#!cpp false` without throwing.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__contains_json_pointer.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__contains_json_pointer.output"
+    ```
+
 ## See also
 
 - [find](find.md) - find a value in an object
 - [count](count.md) - returns the number of occurrences of a key
+- [at](at.md), [operator[]](operator[].md) - resolve a JSON pointer and throw, or return a discarded view
 - [`BasicJsonType::contains`](../basic_json/contains.md) - the corresponding function of `basic_json`
 
 ## Version history

docs/mkdocs/docs/api/basic_json_view/count.md

@@ -26,6 +26,8 @@ No-throw guarantee: this function never throws exceptions.
 Linear in the number of members: as for [`ordered_json`](../ordered_json.md), members are compared one after
 another, in document order, stopping at the first match. Each comparison first checks the key's length -- already
 known from the index, without reading the key bytes -- before comparing its content.
+Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time on
+average.
 
 ## Notes
 

docs/mkdocs/docs/api/basic_json_view/dump.md

@@ -0,0 +1,102 @@
+# <small>nlohmann::basic_json_view::</small>dump
+
+```cpp
+string_t dump(const int indent = -1,
+              const char indent_char = ' ',
+              const bool ensure_ascii = false,
+              const number_format numbers = number_format::shortest) const;
+```
+
+Serializes this value (and its subtree) directly from the flat index, without ever building a `BasicJsonType` value
+first. With the default `#!cpp numbers == number_format::shortest`, the result is the same string
+[`BasicJsonType::dump`](../basic_json/dump.md) would produce for the value
+[`BasicJsonType::parse()`](../basic_json/parse.md) builds from the same source text, called with the same `indent`,
+`indent_char`, and `ensure_ascii` -- except that members of an object appear in document order rather than sorted by
+key, and *every* occurrence of a repeated key is written rather than only the last one (see
+[Notes on duplicate keys](operator[].md#notes)). For a `json_view` (whose `BasicJsonType` is not ordered), this means
+`dump()` can print an object's members in a different order than [`materialize()`](materialize.md)`.dump()` of the
+same subtree.
+
+## Parameters
+
+`indent` (in)
+:   If `indent` is nonnegative, array elements and object members are pretty-printed with that indent level. An
+    indent level of `0` only inserts newlines. `-1` (the default) selects the most compact representation.
+
+`indent_char` (in)
+:   The character used for indentation if `indent` is greater than `0`. The default is ` ` (space).
+
+`ensure_ascii` (in)
+:   If `ensure_ascii` is `#!cpp true`, all non-ASCII characters in the output are escaped with `\uXXXX` sequences, and
+    the result consists of ASCII characters only.
+
+`numbers` (in)
+:   how to write numbers, see [`number_format`](number_format.md): `shortest` (the default) writes them the way
+    [`BasicJsonType::dump`](../basic_json/dump.md) would; `source` copies every number exactly as it appears in the
+    source text.
+
+## Return value
+
+string containing the serialization of this value, or `#!cpp "<discarded>"` if the view is
+[discarded](is_discarded.md).
+
+## Exception safety
+
+Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
+
+## Exceptions
+
+May throw `#!cpp std::bad_alloc` if allocating the output string fails. Unlike
+[`BasicJsonType::dump`](../basic_json/dump.md), there is no `error_handler` parameter and no
+[`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316): the view only ever holds text the parser
+already validated as UTF-8, so there is nothing to replace or ignore.
+
+## Complexity
+
+Linear in the size of the output text.
+
+## Notes
+
+The walk over the subtree is iterative, so the nesting depth it can write is limited by available memory only, not by
+the call stack -- as for [`materialize()`](materialize.md).
+
+Strings are escaped by the same rules as [`BasicJsonType::dump`](../basic_json/dump.md). With
+`#!cpp numbers == number_format::shortest`, floats are written with the library's shortest round-trip conversion,
+exactly as [`BasicJsonType::dump`](../basic_json/dump.md) would (e.g. `#!cpp 1.5`, `#!cpp 100.0`, `#!cpp 1e+100`), and
+integers are copied from the source text -- already canonical in JSON, so this matches their shortest form too --
+except that `#!cpp -0` is written as `#!cpp 0`, the way [`BasicJsonType::parse()`](../basic_json/parse.md) reads it.
+`#!cpp number_format::source` copies every number exactly as written in the source text instead, with no exception
+for `#!cpp -0` -- `#!cpp 1.50`, `#!cpp 1E2`, `#!cpp -0.0`, `#!cpp -0`, or all digits of an integer literal with more
+digits than any number type holds (such a literal is itself classified as a float, see
+[What is different](../../features/json_view.md#what-is-different)) -- something `BasicJsonType` cannot do, since
+parsing already reduces every number to its parsed value.
+
+## Examples
+
+??? example
+
+    The example below forwards a single record out of a larger batch, and re-serializes a configuration file, both
+    without ever building a `BasicJsonType` value for the surrounding array or for the parts of it that were not
+    needed. It also shows that [`materialize()`](materialize.md)`.dump()` of the configuration sorts its keys, where
+    `dump()` on the view keeps the order they appear in the source text.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__dump.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__dump.output"
+    ```
+
+## See also
+
+- [`number_format`](number_format.md) - how `dump()` writes numbers
+- [operator<<](operator_ltlt.md) - serialize this value to a stream
+- [materialize](materialize.md) - build a `BasicJsonType` value, e.g. to use `BasicJsonType::dump`'s `error_handler`
+- [`BasicJsonType::dump`](../basic_json/dump.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.

docs/mkdocs/docs/api/basic_json_view/find.md

@@ -28,6 +28,8 @@ No-throw guarantee: this function never throws exceptions.
 Linear in the number of members: as for [`ordered_json`](../ordered_json.md), members are compared one after
 another, in document order, stopping at the first match. Each comparison first checks the key's length -- already
 known from the index, without reading the key bytes -- before comparing its content.
+Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time on
+average.
 
 ## Notes
 

docs/mkdocs/docs/api/basic_json_view/get.md

@@ -0,0 +1,130 @@
+# <small>nlohmann::basic_json_view::</small>get
+
+```cpp
+template<typename T>
+T get() const;
+```
+
+Converts the value to `T`.
+
+For the types below, the conversion works directly on the flat index -- no `BasicJsonType` value is built for it:
+
+- `#!cpp bool`
+- arithmetic types other than `#!cpp bool` (from a number; from a boolean, as `#!cpp 0`/`#!cpp 1`, exactly as
+  [`BasicJsonType::get<T>()`](../basic_json/get.md) converts a boolean)
+- `#!cpp std::nullptr_t`
+- `#!cpp std::basic_string<char, Traits, Alloc>` (including `string_t`) -- a copy of the string
+- [`string_view_t`](index.md#member-types) -- **no copy**: the returned view points into the document's
+  [`source()`](../basic_json_document/source.md) text, or, for a string that contains escape sequences, into the
+  document's own buffer of decoded strings (see [`get_string()`](get_string.md))
+- `BasicJsonType` -- equivalent to [`materialize()`](materialize.md)
+- `basic_json_view` -- returns `#!cpp *this`
+- `#!cpp std::vector<U, A>` -- element by element, each converted with `#!cpp get<U>()`; `#!cpp
+  std::vector<basic_json_view>` keeps a view of every element instead of a value
+- `#!cpp std::map<K, V, C, A>` and `#!cpp std::unordered_map<K, V, H, E, A>`, if `K` is constructible from a `#!cpp
+  (const char*, std::size_t)` pair -- member by member, each value converted with `#!cpp get<V>()`; with a repeated
+  key, the *last* value is kept, as [`BasicJsonType::parse()`](../basic_json/parse.md) (and
+  [`materialize()`](materialize.md)) does; `#!cpp std::map<std::string, basic_json_view>` keeps views of the members
+  instead of values
+
+Every other `T` -- `#!cpp std::list`, `#!cpp std::pair`, `#!cpp std::array`, enumerations, user types with a
+`from_json()`, ... -- is converted by `#!cpp materialize().get<T>()`: the subtree is built into a real `BasicJsonType`
+value first (as [`BasicJsonType::parse()`](../basic_json/parse.md) would), and converted from there exactly as
+[`BasicJsonType::get<T>()`](../basic_json/get.md) would convert it.
+
+## Template parameters
+
+`T`
+:   the type to convert the value to
+
+## Return value
+
+the value, converted to `T`
+
+## Exception safety
+
+Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
+
+## Exceptions
+
+- For the directly-converted types listed above (other than `BasicJsonType` and `basic_json_view`, which never
+  throw): throws [`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302) if the value's type does not
+  match `T` -- the same exception, with the same message, that [`BasicJsonType::get<T>()`](../basic_json/get.md)
+  throws for the same JSON type and `T`.
+- For `#!cpp std::vector<U, A>`: throws `type_error.302` if the value is not an array; otherwise, whatever converting
+  an element to `U` throws.
+- For `#!cpp std::map`/`#!cpp std::unordered_map`: throws `type_error.302` if the value is not an object; otherwise,
+  whatever converting a member to the mapped type throws.
+- For every other `T`: whatever [`materialize().get<T>()`](../basic_json/get.md) throws -- typically `type_error.302`,
+  or whatever a user-provided `from_json()` throws.
+
+None of the exceptions thrown directly by this function (the first three bullets above) carry a
+[`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) path: the view has no `BasicJsonType` value to point at. An
+exception thrown while converting through `materialize()` (the last bullet) is different: it is thrown by a real
+`BasicJsonType` value, so it **does** carry a `JSON_DIAGNOSTICS` path if `BasicJsonType` was built with it enabled.
+
+## Complexity
+
+- `#!cpp bool`, arithmetic types, `#!cpp std::nullptr_t`, [`string_view_t`](index.md#member-types), `basic_json_view`:
+  constant.
+- `#!cpp std::basic_string<char, Traits, Alloc>`: constant, plus one allocation and a copy of the string's bytes.
+- `BasicJsonType`: linear in the size of the subtree, see [`materialize()`](materialize.md).
+- `#!cpp std::vector<U, A>`: linear in the number of elements, times the complexity of converting one element to `U`.
+- `#!cpp std::map`/`#!cpp std::unordered_map`: linear in the number of members for walking them, plus the container's
+  own insertion cost per member (logarithmic for `#!cpp std::map`, amortized constant for `#!cpp
+  std::unordered_map`), times the complexity of converting one member to the mapped type.
+- every other `T`: linear in the size of the subtree (building the `BasicJsonType` value), plus the complexity of
+  [`BasicJsonType::get<T>()`](../basic_json/get.md) on it.
+
+## Notes
+
+!!! info "Floating-point values"
+
+    A floating-point `T` is converted from the same digits the lexer would see during `#!cpp BasicJsonType::parse()`,
+    using the same conversion, so the result is bit-for-bit identical to `#!cpp BasicJsonType::parse(text).get<T>()`
+    for the same source text.
+
+!!! info "Duplicate keys"
+
+    `#!cpp std::map`/`#!cpp std::unordered_map` conversions keep the *last* value of a repeated key, like
+    [`materialize()`](materialize.md) and [`BasicJsonType::parse()`](../basic_json/parse.md) do. This is the opposite
+    of [`operator[]`](operator[].md)/[`at`](at.md)/[`find`](find.md)/[`contains`](contains.md), which resolve to the
+    *first* occurrence (see the [Notes on duplicate keys](operator[].md#notes)).
+
+!!! info "No pointers, references, or implicit conversion"
+
+    Unlike `BasicJsonType`, `basic_json_view` has no stored value anywhere to hand out a pointer or a reference to, so
+    it provides neither `#!cpp get_ptr()`, `#!cpp get_ref()`, nor `#!cpp operator ValueType()`.
+    [`get_string()`](get_string.md) (equivalently, `#!cpp get<string_view_t>()`) is the zero-copy alternative for
+    strings.
+
+## Examples
+
+??? example
+
+    The example below reads typed fields straight into C++ variables, collects a view of every array element with
+    `#!cpp get<std::vector<basic_json_view>>()` instead of a value, and converts a nested object into a user type
+    through its `from_json()` -- which runs on a `BasicJsonType` value `materialize()` builds for just that one
+    member.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__get.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__get.output"
+    ```
+
+## See also
+
+- [get_to](get_to.md) - convert and write into a passed value
+- [get_string](get_string.md) - the string, without a copy
+- [number_token](number_token.md) - a number's token text, without a copy
+- [materialize](materialize.md) - build the `BasicJsonType` value of this subtree
+- [`BasicJsonType::get`](../basic_json/get.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.

docs/mkdocs/docs/api/basic_json_view/get_string.md

@@ -0,0 +1,71 @@
+# <small>nlohmann::basic_json_view::</small>get_string
+
+```cpp
+string_view_t get_string() const;
+```
+
+Returns the string value as a [`string_view_t`](index.md#member-types), without copying it.
+
+## Return value
+
+The string, as a [`string_view_t`](index.md#member-types) that points either into the document's
+[`source()`](../basic_json_document/source.md) text (a string with no escape sequences), or into the document's own
+buffer of decoded strings (a string that contains escape sequences, such as `#!json "\n"` or `#!json "\u00e9"`, which
+had to be decoded once when the document was parsed).
+
+## Exception safety
+
+Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
+
+## Exceptions
+
+Throws [`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302) if the value is not a string; example:
+`"type must be string, but is array"`.
+
+This exception does not carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) path: the view has no
+`BasicJsonType` value to point at, so the exception is created without one, even if `BasicJsonType` was built with
+`JSON_DIAGNOSTICS` enabled.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+`basic_json_view` has no `BasicJsonType` value stored anywhere, so unlike `BasicJsonType`, it has no `get_ref()` to
+hand out a reference to a stored `string_t`. `get_string()` (equivalently, [`get<string_view_t>()`](get.md)) is the
+zero-copy alternative: [`BasicJsonType::get_ref<const string_t&>()`](../basic_json/get_ref.md) is its closest
+counterpart, except that it returns a view instead of a reference to a value that must already exist.
+
+The returned [`string_view_t`](index.md#member-types) is valid exactly as long as the view that produced it -- see the
+[validity rules](index.md) of `basic_json_view` -- and, for a string with no escapes, for as long as the document's
+source text.
+
+## Examples
+
+??? example
+
+    The example below pulls one field out of a JSON text that stands in for a large API response, and shows that no
+    `#!cpp std::string` was allocated for it: the returned view still points inside the original buffer. A field that
+    contains an escape sequence cannot point into the original text -- it was decoded once into the document's own
+    buffer instead -- but still avoids a per-field allocation.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__get_string.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__get_string.output"
+    ```
+
+## See also
+
+- [get](get.md) - convert the value to a given type (`#!cpp get<string_view_t>()` is equivalent to this function)
+- [number_token](number_token.md) - a number's token text, without a copy
+- [`BasicJsonType::get_ref`](../basic_json/get_ref.md) - the closest counterpart of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.

docs/mkdocs/docs/api/basic_json_view/get_to.md

@@ -0,0 +1,65 @@
+# <small>nlohmann::basic_json_view::</small>get_to
+
+```cpp
+template<typename T>
+T& get_to(T& v) const;
+```
+
+Converts the value to `T` and assigns it to `v`. Equivalent to
+
+```cpp
+v = get<T>();
+return v;
+```
+
+## Template parameters
+
+`T`
+:   the type to convert the value to
+
+## Parameters
+
+`v` (out)
+:   the variable to store the converted value in
+
+## Return value
+
+`v`, allowing calls to chain
+
+## Exception safety
+
+Strong exception safety: if an exception is thrown, `v` is not modified.
+
+## Exceptions
+
+Whatever [`get<T>()`](get.md) throws for the same value and `T`.
+
+## Complexity
+
+Whatever [`get<T>()`](get.md) has for the same `T`.
+
+## Examples
+
+??? example
+
+    The example below reads several fields of a service configuration directly into existing variables, then uses
+    the returned reference to fold the `#!cpp host`/`#!cpp port` pair into a single string in the same expression.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__get_to.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__get_to.output"
+    ```
+
+## See also
+
+- [get](get.md) - convert the value to a given type
+- [`BasicJsonType::get_to`](../basic_json/get_to.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.

docs/mkdocs/docs/api/basic_json_view/index.md

@@ -3,7 +3,7 @@
 <small>Defined in header `<nlohmann/json_view.hpp>`</small>
 
 ```cpp
-template<typename BasicJsonType>
+template<typename BasicJsonType, bool Editable = false>
 class basic_json_view;
 ```
 
@@ -20,8 +20,19 @@ Moving the document itself does not invalidate its views: the index is heap-allo
 `basic_json_document` object.
 
 `basic_json_view` provides the read-only part of the `BasicJsonType` interface: the type-inspection functions, element
-access, lookup, iteration, and [`materialize()`](materialize.md) to build the `BasicJsonType` value of a subtree on
-demand. It does not (yet) provide `get<T>()`, JSON Pointer support, `dump()`, or comparison.
+access, lookup, iteration, conversion, and comparison -- [`get<T>()`](get.md), [`get_string()`](get_string.md),
+[`number_token()`](number_token.md), and [`materialize()`](materialize.md) to build the `BasicJsonType` value of a
+subtree on demand. [`operator[]`](operator%5B%5D.md), [`at`](at.md), [`contains`](contains.md), and
+[`value`](value.md) also accept a [`json_pointer`](../json_pointer/index.md). [`operator==`](operator_eq.md) and
+[`operator!=`](operator_ne.md) compare two views, or a view and a `BasicJsonType` value, without ever building a
+`BasicJsonType` value for a view; no ordering comparison (`#!cpp operator<`) is provided.
+
+`basic_json_view` itself is always read-only -- it never has a `set` or `push_back` of its own. A view of an
+**editable** document (`#!cpp Editable == true`) sees every edit made through
+[`basic_json_document::set`](../basic_json_document/set.md) and
+[`basic_json_document::push_back`](../basic_json_document/push_back.md): once a value is changed, every view that
+still refers to it -- including ones taken before the change -- reads the new value. See
+[Edits](../basic_json_document/index.md#edits).
 
 ## Template parameters
 
@@ -29,10 +40,17 @@ demand. It does not (yet) provide `get<T>()`, JSON Pointer support, `dump()`, or
 :   a specialization of [`basic_json`](../basic_json/index.md), matching the
     [`basic_json_document`](../basic_json_document/index.md) the view was taken from.
 
+`Editable`
+:   whether the view is of an editable document, matching the [`basic_json_document`](../basic_json_document/index.md)
+    it was taken from (optional, `#!cpp false` by default). See [Edits](../basic_json_document/index.md#edits).
+
 ## Specializations
 
 - [**json_view**](../json_view.md) - views of a [`json_document`](../json_document.md)
 - [**ordered_json_view**](../ordered_json_view.md) - views of an [`ordered_json_document`](../ordered_json_document.md)
+- [**json_editable_view**](../json_editable_view.md) - views of a [`json_editable_document`](../json_editable_document.md)
+- [**ordered_json_editable_view**](../ordered_json_editable_view.md) - views of an
+  [`ordered_json_editable_document`](../ordered_json_editable_document.md)
 
 ## Member types
 
@@ -44,6 +62,7 @@ demand. It does not (yet) provide `get<T>()`, JSON Pointer support, `dump()`, or
 - **iterator**, **const_iterator** - a forward iterator over the elements of an array or the member values of an
   object, in document order; both names refer to the same type, since a view is always read-only
 - **item** - a (key, value) pair produced by [`items()`](items.md)
+- [**number_format**](number_format.md) - how [`dump()`](dump.md) writes numbers
 
 ## Member functions
 
@@ -72,6 +91,7 @@ demand. It does not (yet) provide `get<T>()`, JSON Pointer support, `dump()`, or
 
 - [**at**](at.md) - access specified element with bounds checking
 - [**operator[]**](operator[].md) - access specified element
+- [**value**](value.md) - access specified element with default value
 - [**front**](front.md) - access the first element
 - [**back**](back.md) - access the last element
 
@@ -96,8 +116,22 @@ demand. It does not (yet) provide `get<T>()`, JSON Pointer support, `dump()`, or
 
 ### Conversion
 
+- [**get**](get.md) - get a value
+- [**get_to**](get_to.md) - get a value and write it to a destination
+- [**get_string**](get_string.md) - get a string value without a copy
+- [**number_token**](number_token.md) - get a number's token text without a copy
 - [**materialize**](materialize.md) - build the `BasicJsonType` value of this subtree
 
+### Comparison
+
+- [**operator==**](operator_eq.md) - comparison: equal
+- [**operator!=**](operator_ne.md) - comparison: not equal
+
+### Serialization
+
+- [**dump**](dump.md) - serialize to a JSON-formatted string
+- [**operator<<**](operator_ltlt.md) - serialize to stream
+
 ### Source access
 
 - [**source_offset**](source_offset.md) - byte offset of this value in the document's source text

docs/mkdocs/docs/api/basic_json_view/number_format.md

@@ -0,0 +1,51 @@
+# <small>nlohmann::basic_json_view::</small>number_format
+
+```cpp
+enum class number_format {
+    shortest,
+    source
+};
+```
+
+This enumeration is used in [`dump`](dump.md) to choose how numbers are written. Two values are differentiated:
+
+shortest
+:   integers are copied from the source text -- already canonical in JSON -- except that `#!cpp -0` becomes
+    `#!cpp 0`, the way [`BasicJsonType::parse()`](../basic_json/parse.md) reads it; floats are written with the
+    library's shortest round-trip conversion, exactly as [`BasicJsonType::dump()`](../basic_json/dump.md) would (e.g.
+    `#!cpp 1.5`, `#!cpp 100.0`, `#!cpp 1e+100`)
+
+source
+:   every number is copied exactly as it appears in the source text -- `#!cpp 1.50`, `#!cpp 1E2`, `#!cpp -0`, all
+    digits of an integer literal with more digits than any number type holds -- something `BasicJsonType` cannot do,
+    since parsing already reduces every number to its parsed value
+
+## Examples
+
+??? example
+
+    The example below writes back a price list received from a supplier: with `number_format::shortest` (the
+    default), a trailing zero and scientific notation are normalized away and a long account number that overflows
+    every number type is rounded, the same way `#!cpp materialize().dump()` (or `basic_json::dump()`) would;
+    `number_format::source` keeps every number exactly as it was written in the source text instead.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__number_format.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__number_format.output"
+    ```
+
+## See also
+
+- [dump](dump.md) - serialize to a JSON-formatted string
+- [number_token](number_token.md) - get a single number's token text without dumping the whole value
+- [`BasicJsonType::error_handler_t`](../basic_json/error_handler_t.md) - the analogous enumeration for
+  `BasicJsonType::dump`'s decoding-error behavior
+
+## Version history
+
+- Added in version 3.13.0.

docs/mkdocs/docs/api/basic_json_view/number_token.md

@@ -0,0 +1,74 @@
+# <small>nlohmann::basic_json_view::</small>number_token
+
+```cpp
+string_view_t number_token() const;
+```
+
+Returns the number exactly as it appears in the source text, without parsing or rounding it.
+
+## Return value
+
+The number's token text, as a [`string_view_t`](index.md#member-types) into the document's
+[`source()`](../basic_json_document/source.md) text -- for example `#!cpp "1.50"`, `#!cpp "1E2"`, `#!cpp "-0"`, or an
+integer literal with more digits than any number type holds (such as a 30-digit integer, which [`get<T>()`](get.md)
+and [`materialize()`](materialize.md) can only represent approximately, as a `number_float_t`).
+
+## Exception safety
+
+Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
+
+## Exceptions
+
+Throws [`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302) if the value is not a number; example:
+`"type must be number, but is string"`.
+
+This exception does not carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) path: the view has no
+`BasicJsonType` value to point at, so the exception is created without one, even if `BasicJsonType` was built with
+`JSON_DIAGNOSTICS` enabled.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+`BasicJsonType` has no counterpart to this function: once a number is parsed into `number_integer_t`,
+`number_unsigned_t`, or `number_float_t`, its original textual form (leading zeros aside, which are already rejected
+by the grammar; trailing zeros in the fraction; the case and sign of the exponent; ...) is gone. `number_token()` is
+useful precisely where that form must survive -- a price or an identifier that must be reproduced exactly, or a
+number too large for any of `BasicJsonType`'s number types to hold without loss.
+
+The returned [`string_view_t`](index.md#member-types) always points into the document's
+[`source()`](../basic_json_document/source.md) text -- numbers are never decoded into the document's separate string
+buffer -- and is valid exactly as long as that text is, see the [validity rules](index.md) of `basic_json_view`.
+
+## Examples
+
+??? example
+
+    The example below keeps a price and an order ID exactly as they were written in an incoming order, where
+    converting them with [`get<T>()`](get.md) would lose information: the price picks up floating-point rounding, and
+    the order ID -- more digits than a 64-bit integer holds -- can only be approximated as a `#!cpp double` once
+    `#!cpp materialize()`d.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__number_token.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__number_token.output"
+    ```
+
+## See also
+
+- [get](get.md) - convert the value to a given type
+- [get_string](get_string.md) - the string, without a copy
+- [`BasicJsonType::number_integer_t`](../basic_json/number_integer_t.md),
+  [`number_unsigned_t`](../basic_json/number_unsigned_t.md), [`number_float_t`](../basic_json/number_float_t.md) - the
+  number types `#!cpp get<T>()` and `materialize()` convert into
+
+## Version history
+
+- Added in version 3.13.0.

docs/mkdocs/docs/api/basic_json_view/operator[].md

@@ -9,12 +9,18 @@ basic_json_view operator[](const string_t& key) const;
 // (2)
 basic_json_view operator[](size_type idx) const;
 basic_json_view operator[](int idx) const;
+
+// (3)
+basic_json_view operator[](const json_pointer& ptr) const;
 ```
 
 1. Returns the value of the object member with key `key` -- the first one, should the key occur more than once (see
    the [Notes](#notes) below) -- or a [discarded](is_discarded.md) view if there is no such member.
 2. Returns the array element at index `idx`, or a [discarded](is_discarded.md) view if `idx` is out of range. (The
    `#!cpp int` overload only exists so that an integer literal is not ambiguous between this overload and 1.)
+3. Returns the value a JSON pointer `ptr` refers to, starting at this value, or a [discarded](is_discarded.md) view
+   wherever resolving it further is not possible without inserting into or extending the document (see
+   [Return value](#return-value) and [Exceptions](#exceptions) below).
 
 ## Parameters
 
@@ -24,11 +30,18 @@ basic_json_view operator[](int idx) const;
 `idx` (in)
 :   index of the element to access
 
+`ptr` (in)
+:   JSON pointer to the element to access
+
 ## Return value
 
 1. the value of the first member with key `key`, or a discarded view if `#!cpp is_object()` is `#!cpp false` or no
    member has this key
 2. the element at index `idx`, or a discarded view if `#!cpp is_array()` is `#!cpp false` or `#!cpp idx >= size()`
+3. the value `ptr` resolves to, starting at this value, or a discarded view for exactly the reference tokens where the
+   **const** overload of [`BasicJsonType::operator[]`](../basic_json/operator%5B%5D.md) invokes undefined behavior for
+   the same pointer and the same document: an object member that does not exist, or an array index that is out of
+   range
 
 ## Exception safety
 
@@ -42,9 +55,19 @@ Strong exception safety: if an exception is thrown, there are no changes to the
 2. Throws [`type_error.305`](../../home/exceptions.md#jsonexceptiontype_error305) if the value is not an array --
    the same exception, with the same message, that the **const** overload of
    [`BasicJsonType::operator[]`](../basic_json/operator%5B%5D.md) throws for a numeric argument on a non-array value.
+3. Throws the same exceptions, with the same messages, that the **const** overload of
+   [`BasicJsonType::operator[]`](../basic_json/operator%5B%5D.md) throws for the same pointer and the same document:
+    - [`out_of_range.402`](../../home/exceptions.md#jsonexceptionout_of_range402) if a reference token is `#!cpp "-"`
+      at an array.
+    - [`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) if a reference token cannot be
+      resolved because it is used on a primitive value.
+    - [`parse_error.106`](../../home/exceptions.md#jsonexceptionparse_error106) if an array index in `ptr` begins
+      with `#!cpp '0'`.
+    - [`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) if an array index in `ptr` is not a
+      number.
 
-Neither exception carries a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) path: the view has no `BasicJsonType`
-value to point at, so the exception is created without one, even if `BasicJsonType` was built with
+None of these exceptions carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) path: the view has no
+`BasicJsonType` value to point at, so the exception is created without one, even if `BasicJsonType` was built with
 `JSON_DIAGNOSTICS` enabled.
 
 ## Complexity
@@ -53,8 +76,12 @@ value to point at, so the exception is created without one, even if `BasicJsonTy
    another, in document order, stopping at the first match. Each comparison first checks the key's length --
    already known from the index, without reading the key bytes -- before comparing its content, so a key of a
    different length than `key` is rejected without touching the source text.
+   Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time
+   on average.
 2. Linear in `idx`: elements are skipped one at a time from the first one, since they are not a fixed size in the
    index (unlike `BasicJsonType`'s array, which is random-access).
+3. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
+   that level (as 1.) or the index into the array (as 2.).
 
 ## Notes
 
@@ -74,9 +101,18 @@ document.
     early. [`begin()`](begin.md)/[`end()`](end.md) and [`items()`](items.md) iterate over *all* members, including
     duplicates, in document order. See the example below and [`size()`](size.md#notes).
 
+!!! info "JSON pointer resolution"
+
+    Overload 3 walks `ptr` one reference token at a time, starting at this value, the same way [`at`](at.md) and
+    [`contains`](contains.md) do. It only ever returns a discarded view where the **const** overload of
+    `BasicJsonType::operator[]` would be undefined behavior for the same pointer -- a missing object member or an
+    out-of-range array index -- and still throws for every other way `ptr` can fail to resolve. See
+    [`at`](at.md#exceptions) for the checked version, which throws in every case instead, and
+    [`contains`](contains.md) for a version that never throws.
+
 ## Examples
 
-??? example
+??? example "Example: (1)/(2) access specified element"
 
     The example below reads a couple of fields out of a batch of user records without ever materializing a full
     `BasicJsonType` value for the batch. `operator[]` is used both to look up an optional object member and to index
@@ -93,12 +129,29 @@ document.
     --8<-- "examples/basic_json_view__operator[].output"
     ```
 
+??? example "Example: (3) access specified element via JSON pointer"
+
+    The example below reaches straight into one deeply nested field of a large document with a single JSON pointer,
+    without ever building a tree for the rest of it, and shows the discarded-view and throwing outcomes of a pointer
+    that cannot be fully resolved.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__operator[]_json_pointer.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__operator[]_json_pointer.output"
+    ```
+
 ## See also
 
 - [at](at.md) - access specified element with bounds checking (throws instead of returning a discarded view)
 - [front](front.md), [back](back.md) - access the first or last element
 - [find](find.md), [contains](contains.md) - look up a member without throwing
 - [`BasicJsonType::operator[]`](../basic_json/operator%5B%5D.md) - the corresponding function of `basic_json`
+- [`json_pointer`](../json_pointer/index.md) - JSON pointer type used by overload 3
 
 ## Version history
 

docs/mkdocs/docs/api/basic_json_view/operator_eq.md

@@ -0,0 +1,107 @@
+# <small>nlohmann::basic_json_view::</small>operator==
+
+```cpp
+// (1)
+bool operator==(const basic_json_view& lhs, const basic_json_view& rhs);
+
+// (2)
+bool operator==(const basic_json_view& lhs, const BasicJsonType& rhs);
+bool operator==(const BasicJsonType& lhs, const basic_json_view& rhs);
+```
+
+1. Compares two views for equality: whether the values [`BasicJsonType::parse()`](../basic_json/parse.md) would
+   produce for `lhs` and `rhs` are equal, according to `BasicJsonType`'s [`operator==`](../basic_json/operator_eq.md).
+2. Compares a view and a `BasicJsonType` value for equality, in either order: whether the value `parse()` would
+   produce for the view and the other operand are equal, according to `BasicJsonType`'s
+   [`operator==`](../basic_json/operator_eq.md).
+
+Neither overload builds a `BasicJsonType` value for a view to do the comparison (see [Notes](#notes) below). Numbers
+compare by value across their types (`#!cpp 1 == 1.0`), and an object compares by its members, with duplicate keys
+resolved exactly as `parse()` resolves them -- the last value, at the position of the first occurrence of the key.
+
+## Parameters
+
+`lhs` (in)
+:   first value to consider
+
+`rhs` (in)
+:   second value to consider
+
+## Return value
+
+whether the values `lhs` and `rhs` are equal
+
+## Exception safety
+
+Strong exception safety: if an exception is thrown, there are no changes to either operand, or to the document(s) a
+view refers to.
+
+## Exceptions
+
+May throw `#!cpp std::bad_alloc`. Unlike the other comparison and most other `basic_json_view` functions,
+`operator==` is not `#!cpp noexcept`: resolving an object's members needs a temporary array to sort them by key (see
+[Complexity](#complexity) below), and that allocation can fail.
+
+## Complexity
+
+Linear in the size of the compared values: every number, string, array element, and object member is visited at most
+once, and the walk is iterative, so the nesting depth it can compare is limited by available memory only, not by the
+call stack (as for [`materialize()`](materialize.md)). Resolving an object's members takes an additional O(n log n)
+in the number of members at that level, since they are sorted by key to detect and resolve duplicates before being
+compared. Two arrays of different [`size()`](size.md) are rejected without visiting either one's elements.
+
+## Notes
+
+Only a single number, boolean, or `#!cpp null` value is ever materialized into a `BasicJsonType`, to reuse its
+`operator==` -- for numbers, so that values written differently in the source text but equal in value (e.g. an
+integer and a floating-point literal) still compare equal, following the same rules `BasicJsonType` does for special
+values such as `#!cpp NaN`. Constructing one of these scalars never allocates. Strings are compared directly, without
+allocating, either from the source text on both sides or, for overload 2, against `BasicJsonType`'s own string.
+Arrays and objects are never materialized at all; only their elements or members are visited, one pair at a time.
+
+!!! info "How objects are compared"
+
+    For a [`json_view`](../json_view.md) (`BasicJsonType::object_t` is `#!cpp std::map`), members are compared by
+    key, regardless of the order they appear in the source text. For an
+    [`ordered_json_view`](../ordered_json_view.md) (`object_t` is `ordered_map`), they are compared in the order
+    they occur, so the very same two objects with their members reordered can compare equal as `json_view`s but not
+    as `ordered_json_view`s. This is exactly how [`json`](../json.md) and [`ordered_json`](../ordered_json.md)
+    compare, see ["Comparing different `basic_json` specializations"](../basic_json/operator_eq.md#notes).
+
+!!! info "Discarded views"
+
+    A [discarded](is_discarded.md) view compares the same way a discarded `BasicJsonType` value does, which is
+    governed by
+    [`JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON`](../macros/json_use_legacy_discarded_value_comparison.md): by
+    default, a discarded view is never equal to anything, not even another discarded view.
+
+No ordering comparison (`#!cpp operator<`) is provided for `basic_json_view`; [`materialize()`](materialize.md) is
+the way to get a `BasicJsonType` value that supports it.
+
+## Examples
+
+??? example
+
+    The example below checks whether a newly received configuration differs from the previous one, and whether a
+    received document matches what a test expects -- directly on views, without ever materializing a `BasicJsonType`
+    value for either side.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__operator_eq.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__operator_eq.output"
+    ```
+
+## See also
+
+- [operator!=](operator_ne.md) - compare for inequality
+- [materialize](materialize.md) - build a `BasicJsonType` value, e.g. to keep comparing after the document is gone
+- [`BasicJsonType::operator==`](../basic_json/operator_eq.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.

docs/mkdocs/docs/api/basic_json_view/operator_ltlt.md

@@ -0,0 +1,74 @@
+# <small>nlohmann::basic_json_view::</small>operator<<
+
+```cpp
+std::ostream& operator<<(std::ostream& o, const basic_json_view& v);
+```
+
+Not available when [`JSON_NO_IO`](../macros/json_no_io.md) is defined.
+
+Serializes the given view `v` to the output stream `o`, using [`dump`](dump.md) -- exactly as
+`#!cpp operator<<(std::ostream&, const basic_json&)` does for a `basic_json` value.
+
+- The indentation of the output can be controlled with the member variable `width` of the output stream `o`. For
+  instance, using the manipulator `std::setw(4)` on `o` sets the indentation level to `4`, and the serialization
+  result is the same as calling `#!cpp v.dump(4)`. A `width` of `0` or less (the default) selects the most compact
+  representation, as `#!cpp v.dump(-1)` does.
+- The indentation character can be controlled with the member variable `fill` of the output stream `o`. For instance,
+  the manipulator `std::setfill('\t')` sets indentation to use a tab character rather than the default space
+  character.
+- As for `basic_json`, `o`'s `width` is reset to `0` after this call, whether or not it was greater than `0` before.
+
+Numbers are always written as `#!cpp v.dump()` writes them by default, i.e. as with
+[`number_format::shortest`](number_format.md); there is no way to select `#!cpp number_format::source` through the
+stream.
+
+## Parameters
+
+`o` (in, out)
+:   stream to write to
+
+`v` (in)
+:   view to serialize
+
+## Return value
+
+the stream `o`
+
+## Exceptions
+
+May throw `#!cpp std::bad_alloc`, propagated from [`dump`](dump.md#exceptions). Unlike
+`#!cpp operator<<(std::ostream&, const basic_json&)`, there is no UTF-8 decoding step that could throw
+[`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316), and no `error_handler` to choose between --
+see the [Exceptions](dump.md#exceptions) of `dump`.
+
+## Complexity
+
+Linear, as [`dump`](dump.md#complexity).
+
+## Examples
+
+??? example
+
+    The example below writes one record out of a larger batch straight to a log stream -- compact for a one-line
+    entry, and pretty-printed with `std::setw`/`std::setfill` for a readable dump -- without ever building a
+    `BasicJsonType` value for the record, or for the rest of the batch.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__operator_ltlt.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__operator_ltlt.output"
+    ```
+
+## See also
+
+- [dump](dump.md) - serialize to a JSON-formatted string
+- [`operator<<(std::ostream&)`](../operator_ltlt.md) - the corresponding operator for `basic_json`
+- [`JSON_NO_IO`](../macros/json_no_io.md) - switch off functions relying on certain C++ I/O headers
+
+## Version history
+
+- Added in version 3.13.0.

docs/mkdocs/docs/api/basic_json_view/operator_ne.md

@@ -0,0 +1,82 @@
+# <small>nlohmann::basic_json_view::</small>operator!=
+
+```cpp
+// (1)
+bool operator!=(const basic_json_view& lhs, const basic_json_view& rhs);
+
+// (2)
+bool operator!=(const basic_json_view& lhs, const BasicJsonType& rhs);
+bool operator!=(const BasicJsonType& lhs, const basic_json_view& rhs);
+```
+
+1. Compares two views for inequality. Returns `#!cpp !(lhs == rhs)`, see [operator==](operator_eq.md).
+2. Compares a view and a `BasicJsonType` value for inequality, in either order. Returns `#!cpp !(lhs == rhs)` (or,
+   for the reversed order, `#!cpp !(rhs == lhs)`), see [operator==](operator_eq.md).
+
+Since `operator!=` is defined as the negation of [`operator==`](operator_eq.md), it follows the same rules for
+special cases: for instance, since a [discarded](is_discarded.md) view is never equal to anything by default (see
+[operator=='s Notes](operator_eq.md#notes)), it is never *unequal* to anything either -- `#!cpp discarded != discarded`
+is also `#!cpp false`, exactly as for a discarded `BasicJsonType` value.
+
+## Parameters
+
+`lhs` (in)
+:   first value to consider
+
+`rhs` (in)
+:   second value to consider
+
+## Return value
+
+whether the values `lhs` and `rhs` are not equal
+
+## Exception safety
+
+Strong exception safety: if an exception is thrown, there are no changes to either operand, or to the document(s) a
+view refers to.
+
+## Exceptions
+
+May throw `#!cpp std::bad_alloc`, propagated from [`operator==`](operator_eq.md#exceptions). Unlike most other
+`basic_json_view` functions, `operator!=` is not `#!cpp noexcept`.
+
+## Complexity
+
+Linear, as [`operator==`](operator_eq.md#complexity).
+
+## Notes
+
+See the [Notes](operator_eq.md#notes) of `operator==` -- in particular for how an object's members are compared
+(order matters for [`ordered_json_view`](../ordered_json_view.md) but not for [`json_view`](../json_view.md)) and
+for how discarded views compare.
+
+No ordering comparison (`#!cpp operator<`) is provided for `basic_json_view`; [`materialize()`](materialize.md) is
+the way to get a `BasicJsonType` value that supports it.
+
+## Examples
+
+??? example
+
+    The example below asserts, as a test would, that a received document differs from an unwanted value, and shows
+    that -- as for [`json`](../json.md)/[`ordered_json`](../ordered_json.md) -- reordering an object's members is
+    detected as a difference for an `ordered_json_view` but not for a `json_view`.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__operator_ne.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__operator_ne.output"
+    ```
+
+## See also
+
+- [operator==](operator_eq.md) - compare for equality
+- [materialize](materialize.md) - build a `BasicJsonType` value, e.g. to keep comparing after the document is gone
+- [`BasicJsonType::operator!=`](../basic_json/operator_ne.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.

docs/mkdocs/docs/api/basic_json_view/value.md

@@ -0,0 +1,133 @@
+# <small>nlohmann::basic_json_view::</small>value
+
+```cpp
+// (1)
+template<typename T>
+T value(string_view_t key, const T& default_value) const;
+string_t value(string_view_t key, const char* default_value) const;
+
+// (2)
+template<typename T>
+T value(const json_pointer& ptr, const T& default_value) const;
+string_t value(const json_pointer& ptr, const char* default_value) const;
+```
+
+1. Returns the value of the object member with key `key` -- the first one, should the key occur more than once (see
+   [Notes on duplicate keys](operator[].md#notes)) -- converted to `T`, or `default_value` if there is no such member.
+2. Returns the value a JSON pointer `ptr` refers to, starting at this value, converted to `T`, or `default_value` if
+   `ptr` cannot be resolved.
+
+Both overloads have a dedicated `#!cpp const char*` overload, so `#!cpp v.value(key, "default")` (and the JSON pointer
+equivalent) deduce `string_t`, not `const char*`, for their return type and for the comparison used to pick between
+`key` and `default_value`.
+
+## Template parameters
+
+`T`
+:   the type to convert the found value to; also the type of `default_value`
+
+## Parameters
+
+`key` (in)
+:   object key of the element to access
+
+`ptr` (in)
+:   JSON pointer to the element to access
+
+`default_value` (in)
+:   the value to return if `key`/`ptr` resolves to no value
+
+## Return value
+
+1. the first member with key `key`, converted to `T`, or `default_value`
+2. the value `ptr` resolves to, converted to `T`, or `default_value`
+
+## Exception safety
+
+Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
+
+## Exceptions
+
+1. Throws [`type_error.306`](../../home/exceptions.md#jsonexceptiontype_error306) if the value is not an object --
+   the same exception, with the same message, that [`BasicJsonType::value`](../basic_json/value.md) throws for the
+   same call. If a member with key `key` is found, throws whatever converting it to `T` throws (typically
+   [`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302), with the same message
+   [`BasicJsonType::value`](../basic_json/value.md) throws for the same mismatch); a missing member never throws.
+2. Throws [`type_error.306`](../../home/exceptions.md#jsonexceptiontype_error306) if this value -- not the value `ptr`
+   resolves to -- is neither an object nor an array. Throws [`parse_error.106`](../../home/exceptions.md#jsonexceptionparse_error106)
+   or [`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) if `ptr` contains a malformed array
+   index. If `ptr` resolves to a value, throws whatever converting it to `T` throws. Every other way `ptr` can fail to
+   resolve -- a missing key, an out-of-range or "`-`" array index, an unresolvable token on a primitive -- yields
+   `default_value` instead of throwing, exactly as [`BasicJsonType::value`](../basic_json/value.md) catches
+   `out_of_range` and returns `default_value`.
+
+None of these exceptions carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) path: the view has no
+`BasicJsonType` value to point at, so the exception is created without one, even if `BasicJsonType` was built with
+`JSON_DIAGNOSTICS` enabled.
+
+## Complexity
+
+1. Linear in the number of members: as for [`operator[]`](operator[].md#complexity), members are compared one after
+   another, in document order, stopping at the first match. Plus the complexity of converting the found member to
+   `T` (see [`get`](get.md)).
+   Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time
+   on average.
+2. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
+   that level or the index into the array -- as for the [`operator[]`](operator[].md#complexity) and
+   [`at`](at.md#complexity) overloads that take a JSON pointer. Plus the complexity of converting the resolved value
+   to `T`.
+
+## Notes
+
+!!! info "Differences to `at` and `operator[]`"
+
+    Unlike [`at`](at.md), this function does not throw if `key`/`ptr` resolves to no value. Unlike
+    [`operator[]`](operator[].md), it never returns a [discarded](is_discarded.md) view -- it always returns a `T` --
+    and it is available on any view, since it never needs to insert a missing element the way the non-const
+    `BasicJsonType::operator[]` would.
+
+!!! info "Which values can be asked"
+
+    As for [`BasicJsonType::value`](../basic_json/value.md), the key overload (1) requires an object, and the JSON
+    pointer overload (2) an object or an array.
+
+## Examples
+
+??? example "Example: (1) access specified object element with default value"
+
+    The example below reads a couple of optional configuration fields with a default, so that a missing key never
+    needs a `#!cpp try`/`#!cpp catch` of its own.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__value.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__value.output"
+    ```
+
+??? example "Example: (2) access specified element via JSON pointer with default value"
+
+    The example below reads an optional, nested configuration value with a default, given as a JSON pointer.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__value_json_pointer.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__value_json_pointer.output"
+    ```
+
+## See also
+
+- [at](at.md) - access specified element with bounds checking (throws instead of returning a default value)
+- [operator[]](operator[].md) - access specified element (returns a discarded view instead of a default value)
+- [`BasicJsonType::value`](../basic_json/value.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.

docs/mkdocs/docs/api/json_editable_document.md

@@ -0,0 +1,43 @@
+# <small>nlohmann::</small>json_editable_document
+
+<small>Defined in header `<nlohmann/json_view.hpp>`</small>
+
+```cpp
+using json_editable_document = basic_json_document<json, true>;
+```
+
+This type is an **editable** [`basic_json_document`](basic_json_document/index.md) of the default
+[`json`](json.md) specialization: in addition to everything [`json_document`](json_document.md) offers,
+[`set`](basic_json_document/set.md) and [`push_back`](basic_json_document/push_back.md) change values after
+parsing, without ever rewriting the source text -- see [Edits](basic_json_document/index.md#edits) and
+[Editing a document](../features/json_view.md#editing-a-document).
+
+## Examples
+
+??? example
+
+    The example below patches two fields of a small configuration document -- changing one and adding another --
+    and dumps it back out with the member order and the spelling of the untouched number preserved, something a
+    plain [`json`](json.md) value cannot do.
+
+    ```cpp
+    --8<-- "examples/json_editable_document.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/json_editable_document.output"
+    ```
+
+## See also
+
+- [json_editable_view](json_editable_view.md) - a view of a value of a `json_editable_document`
+- [json_document](json_document.md) - the read-only document this type adds edits to
+- [ordered_json_editable_document](ordered_json_editable_document.md) - the corresponding editable document for
+  `ordered_json`
+- [Edits](basic_json_document/index.md#edits) - what an edit guarantees
+
+## Version history
+
+Since version 3.13.0.

docs/mkdocs/docs/api/json_editable_view.md

@@ -0,0 +1,41 @@
+# <small>nlohmann::</small>json_editable_view
+
+<small>Defined in header `<nlohmann/json_view.hpp>`</small>
+
+```cpp
+using json_editable_view = basic_json_view<json, true>;
+```
+
+This type is a [`basic_json_view`](basic_json_view/index.md) of a value of a
+[`json_editable_document`](json_editable_document.md). It offers the same read-only interface as
+[`json_view`](json_view.md); what is different is what it can be a view *of* -- a value that
+[`set`](basic_json_document/set.md) and [`push_back`](basic_json_document/push_back.md) can change, with every view
+still referring to it seeing the change, see [Edits](basic_json_document/index.md#edits).
+
+## Examples
+
+??? example
+
+    The example below is the same as [`json_editable_document`'s](json_editable_document.md): every view read back
+    out of the document -- `#!cpp doc.root()` and the views nested under it -- sees the edits made through `set`.
+
+    ```cpp
+    --8<-- "examples/json_editable_document.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/json_editable_document.output"
+    ```
+
+## See also
+
+- [json_editable_document](json_editable_document.md) - the document type this view refers into
+- [json_view](json_view.md) - the corresponding read-only view
+- [ordered_json_editable_view](ordered_json_editable_view.md) - the corresponding view for
+  `ordered_json_editable_document`
+
+## Version history
+
+Since version 3.13.0.

docs/mkdocs/docs/api/macros/index.md

@@ -33,6 +33,8 @@ header. See also the [macro overview page](../../features/macros.md).
 - [**JSON_SKIP_UNSUPPORTED_COMPILER_CHECK**](json_skip_unsupported_compiler_check.md) - do not warn about unsupported compilers
 - [**JSON_USE_GLOBAL_UDLS**](json_use_global_udls.md) - place user-defined string literals (UDLs) into the global namespace
 - [**JSON_USE_SIMDUTF**](json_use_simdutf.md) - use the simdutf library to accelerate UTF-8 validation
+- [**JSON_VIEW_NO_SIMD**](json_view_no_simd.md) - use only portable code in the parser of `json_view.hpp`
+- [**JSON_VIEW_USE_SSSE3**](json_view_use_ssse3.md) - validate non-ASCII strings with SSSE3 in the parser of `json_view.hpp`
 
 ## Library version
 

docs/mkdocs/docs/api/macros/json_view_no_simd.md

@@ -0,0 +1,50 @@
+# JSON_VIEW_NO_SIMD
+
+```cpp
+#define JSON_VIEW_NO_SIMD
+```
+
+When defined, the parser of [`basic_json_document`](../basic_json_document/index.md) (`<nlohmann/json_view.hpp>`)
+uses only portable C++ to scan strings. By default, it scans long runs of string bytes 16 at a time with NEON on
+AArch64 (with GCC and Clang) and SSE2 on x86-64, which are part of the baseline instruction sets of these
+architectures, and validates non-ASCII text with NEON (or SSSE3, see
+[`JSON_VIEW_USE_SSSE3`](json_view_use_ssse3.md)).
+
+The same input is accepted or rejected either way, with the same values, and errors are reported the same way; only
+the speed differs. The macro exists for platforms whose compilers lack the intrinsics headers, and to test the portable
+code.
+
+!!! warning "Define consistently"
+
+    The macro selects between two definitions of the same inline functions. It must therefore be defined identically for
+    **every** translation unit that includes `<nlohmann/json_view.hpp>`; prefer a compile definition on the target.
+
+## Default definition
+
+By default, `#!cpp JSON_VIEW_NO_SIMD` is not defined, and the vector code is used where available.
+
+```cpp
+#undef JSON_VIEW_NO_SIMD
+```
+
+## Examples
+
+??? example
+
+    The code below uses the portable string scanning of the view.
+
+    ```cpp
+    #define JSON_VIEW_NO_SIMD
+    #include <nlohmann/json_view.hpp>
+
+    ...
+    ```
+
+## See also
+
+- [JSON_VIEW_USE_SSSE3](json_view_use_ssse3.md) - validate non-ASCII strings with SSSE3 on x86-64
+- [json_view](../../features/json_view.md) - the zero-copy view
+
+## Version history
+
+- Added in version 3.13.0.

docs/mkdocs/docs/api/macros/json_view_use_ssse3.md

@@ -0,0 +1,49 @@
+# JSON_VIEW_USE_SSSE3
+
+```cpp
+#define JSON_VIEW_USE_SSSE3
+```
+
+When defined on x86-64, the parser of [`basic_json_document`](../basic_json_document/index.md)
+(`<nlohmann/json_view.hpp>`) validates non-ASCII text in strings with SSSE3, 16 bytes at a time, using the "lookup4"
+algorithm of [simdjson](https://github.com/simdjson/simdjson). Without it, non-ASCII text is validated one UTF-8
+sequence at a time on x86-64; on AArch64, the vector check uses NEON and is always on.
+
+SSSE3 is not part of the x86-64 baseline, so the code must be compiled for it: define the macro only together with a
+compiler option that enables SSSE3 (e.g. `-mssse3`, or `-march=` with a CPU that has it), and only for programs that
+run on such CPUs. The same input is accepted or rejected either way; only the speed of non-ASCII text differs.
+
+!!! warning "Define consistently"
+
+    The macro selects between two definitions of the same inline functions. It must therefore be defined identically,
+    with the same compiler options, for **every** translation unit that includes `<nlohmann/json_view.hpp>`; mixing
+    translation units that define it with ones that do not is an ODR violation. Prefer a compile definition on the
+    target.
+
+## Default definition
+
+By default, `#!cpp JSON_VIEW_USE_SSSE3` is not defined.
+
+```cpp
+#undef JSON_VIEW_USE_SSSE3
+```
+
+## Examples
+
+??? example
+
+    With CMake, for a program that only runs on CPUs with SSSE3:
+
+    ```cmake
+    target_compile_definitions(your_target PRIVATE JSON_VIEW_USE_SSSE3)
+    target_compile_options(your_target PRIVATE -mssse3)
+    ```
+
+## See also
+
+- [JSON_VIEW_NO_SIMD](json_view_no_simd.md) - use only portable code in the view's parser
+- [JSON_USE_SIMDUTF](json_use_simdutf.md) - validate UTF-8 with simdutf in `basic_json`'s parser
+
+## Version history
+
+- Added in version 3.13.0.

docs/mkdocs/docs/api/operator_ltlt.md

@@ -84,6 +84,8 @@ Linear.
 ## See also
 
 - [dump](basic_json/dump.md) - serialize to a JSON-formatted string
+- [`basic_json_view::operator<<`](basic_json_view/operator_ltlt.md) - the corresponding operator for
+  `basic_json_view`
 - [Serialization](../features/serialization.md) - the serialization article
 
 ## Version history

docs/mkdocs/docs/api/ordered_json_editable_document.md

@@ -0,0 +1,47 @@
+# <small>nlohmann::</small>ordered_json_editable_document
+
+<small>Defined in header `<nlohmann/json_view.hpp>`</small>
+
+```cpp
+using ordered_json_editable_document = basic_json_document<ordered_json, true>;
+```
+
+This type is an **editable** [`basic_json_document`](basic_json_document/index.md) of the
+[`ordered_json`](ordered_json.md) specialization: [`set`](basic_json_document/set.md) and
+[`push_back`](basic_json_document/push_back.md) change values after parsing, as for
+[`json_editable_document`](json_editable_document.md), and
+[`materialize()`](basic_json_view/materialize.md) preserves the document order of object members -- including
+members [`set`](basic_json_document/set.md) added -- instead of sorting them like
+[`json_editable_document`](json_editable_document.md) does.
+
+## Examples
+
+??? example
+
+    The example below edits a document with `set`, then shows that `materialize()` keeps the member order of the
+    source text (with the new member at the end) for `ordered_json_editable_document`, where it would sort the
+    members alphabetically for [`json_editable_document`](json_editable_document.md).
+
+    ```cpp
+    --8<-- "examples/ordered_json_editable_document.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/ordered_json_editable_document.output"
+    ```
+
+## See also
+
+- [ordered_json_editable_view](ordered_json_editable_view.md) - a view of a value of an
+  `ordered_json_editable_document`
+- [ordered_json_document](ordered_json_document.md) - the read-only document this type adds edits to
+- [json_editable_document](json_editable_document.md) - the corresponding editable document for the default `json`
+  specialization
+- [Object Order](../features/object_order.md)
+- [Edits](basic_json_document/index.md#edits) - what an edit guarantees
+
+## Version history
+
+Since version 3.13.0.

docs/mkdocs/docs/api/ordered_json_editable_view.md

@@ -0,0 +1,40 @@
+# <small>nlohmann::</small>ordered_json_editable_view
+
+<small>Defined in header `<nlohmann/json_view.hpp>`</small>
+
+```cpp
+using ordered_json_editable_view = basic_json_view<ordered_json, true>;
+```
+
+This type is a [`basic_json_view`](basic_json_view/index.md) of a value of an
+[`ordered_json_editable_document`](ordered_json_editable_document.md), the corresponding view for
+[`ordered_json_view`](ordered_json_view.md) the way [`json_editable_view`](json_editable_view.md) is for
+[`json_view`](json_view.md).
+
+## Examples
+
+??? example
+
+    The example below is the same as [`ordered_json_editable_document`'s](ordered_json_editable_document.md): the
+    views `set` returns see the document's member order preserved on `materialize()`, unlike for a
+    [`json_editable_document`](json_editable_document.md).
+
+    ```cpp
+    --8<-- "examples/ordered_json_editable_document.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/ordered_json_editable_document.output"
+    ```
+
+## See also
+
+- [ordered_json_editable_document](ordered_json_editable_document.md) - the document type this view refers into
+- [ordered_json_view](ordered_json_view.md) - the corresponding read-only view
+- [json_editable_view](json_editable_view.md) - the corresponding view for `json_editable_document`
+
+## Version history
+
+Since version 3.13.0.

docs/mkdocs/docs/examples/basic_json_document__push_back.cpp

@@ -0,0 +1,24 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+
+using json = nlohmann::json;
+using json_editable_document = nlohmann::json_editable_document;
+
+int main()
+{
+    // "events" starts out null -- the first push_back() turns it into an
+    // array, exactly like set() turns a null object member into an object
+    json_editable_document doc = json_editable_document::parse(R"({"source": "sensor-1", "events": null})");
+
+    const auto first = doc.push_back(doc.root()["events"], json{{"type", "start"}, {"t", 0}});
+    for (int t = 1; t <= 3; ++t)
+    {
+        doc.push_back(doc.root()["events"], json{{"type", "tick"}, {"t", t}});
+    }
+
+    // push_back() never moves an existing element: a view taken from an
+    // earlier call still refers to the same element after later ones
+    std::cout << first.dump() << '\n';
+    std::cout << doc.root()["events"].size() << '\n';
+    std::cout << doc.root().dump(2) << '\n';
+}

docs/mkdocs/docs/examples/basic_json_document__push_back.output

@@ -0,0 +1,23 @@
+{"t":0,"type":"start"}
+4
+{
+  "source": "sensor-1",
+  "events": [
+    {
+      "t": 0,
+      "type": "start"
+    },
+    {
+      "t": 1,
+      "type": "tick"
+    },
+    {
+      "t": 2,
+      "type": "tick"
+    },
+    {
+      "t": 3,
+      "type": "tick"
+    }
+  ]
+}

docs/mkdocs/docs/examples/basic_json_document__set.cpp

@@ -0,0 +1,41 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+
+using json = nlohmann::json;
+using json_editable_document = nlohmann::json_editable_document;
+using json_editable_view = nlohmann::json_editable_view;
+
+int main()
+{
+    // a configuration file, as it might be read from disk -- "price" is
+    // written with a trailing zero that has no effect on its value
+    const std::string text = R"({
+  "name": "cache",
+  "host": "db1",
+  "port": 6379,
+  "price": 19.90,
+  "replicas": ["db2", "db3"],
+  "timeout": 30
+})";
+
+    json_editable_document doc = json_editable_document::parse(text);
+
+    doc.set(doc.root()["port"], 6380);                    // (1) replace a value
+    doc.set(doc.root(), "region", "us-east");              // (2) add a member
+    doc.set(doc.root()["replicas"], 0, "db4");             // (3) assign an element
+    doc.set(json::json_pointer("/timeout"), 45);           // (4) via a JSON pointer
+
+    // members stay in document order (the new one at the end), and a number
+    // that was not itself edited keeps its exact spelling
+    std::cout << doc.root().dump(2, ' ', false, json_editable_view::number_format::source) << "\n\n";
+
+    // the same edits on a plain json value: object_t is a std::map, so
+    // parsing already sorted the keys, and dump() rewrites every number to
+    // its shortest form, even "price", which was never touched
+    json plain = json::parse(text);
+    plain["port"] = 6380;
+    plain["region"] = "us-east";
+    plain["replicas"][0] = "db4";
+    plain[json::json_pointer("/timeout")] = 45;
+    std::cout << plain.dump(2) << '\n';
+}

docs/mkdocs/docs/examples/basic_json_document__set.output

@@ -0,0 +1,25 @@
+{
+  "name": "cache",
+  "host": "db1",
+  "port": 6380,
+  "price": 19.90,
+  "replicas": [
+    "db4",
+    "db3"
+  ],
+  "timeout": 45,
+  "region": "us-east"
+}
+
+{
+  "host": "db1",
+  "name": "cache",
+  "port": 6380,
+  "price": 19.9,
+  "region": "us-east",
+  "replicas": [
+    "db4",
+    "db3"
+  ],
+  "timeout": 45
+}

docs/mkdocs/docs/examples/basic_json_view__at_json_pointer.cpp

@@ -0,0 +1,34 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+
+using json_document = nlohmann::json_document;
+using json_pointer = nlohmann::json::json_pointer;
+
+int main()
+{
+    json_document doc = json_document::parse(R"({"region": "eu", "servers": ["eu-1", "eu-2"]})");
+    const auto root = doc.root();
+
+    std::cout << root.at(json_pointer("/servers/1")).materialize().dump() << '\n';
+
+    // at() throws for every resolution failure -- with the very same
+    // message json::at(ptr) would throw for the same pointer and the same
+    // document
+    try
+    {
+        static_cast<void>(root.at(json_pointer("/servers/5")));
+    }
+    catch (const nlohmann::json::out_of_range& e)
+    {
+        std::cout << e.what() << '\n';
+    }
+
+    try
+    {
+        static_cast<void>(root.at(json_pointer("/missing")));
+    }
+    catch (const nlohmann::json::out_of_range& e)
+    {
+        std::cout << e.what() << '\n';
+    }
+}

docs/mkdocs/docs/examples/basic_json_view__at_json_pointer.output

@@ -0,0 +1,3 @@
+"eu-2"
+[json.exception.out_of_range.401] array index 5 is out of range
+[json.exception.out_of_range.403] key 'missing' not found

docs/mkdocs/docs/examples/basic_json_view__contains_json_pointer.cpp

@@ -0,0 +1,39 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+
+using json_document = nlohmann::json_document;
+using json_pointer = nlohmann::json::json_pointer;
+
+int main()
+{
+    // "retry_of" is only present on some records, nested a level down
+    // inside "meta"
+    json_document batch = json_document::parse(R"(
+      [
+        {"id": 1, "meta": {}},
+        {"id": 2, "meta": {"retry_of": 1}}
+      ]
+    )");
+
+    const auto records = batch.root();
+    const json_pointer retry_of("/meta/retry_of");
+    for (std::size_t i = 0; i < records.size(); ++i)
+    {
+        const auto record = records[i];
+        if (record.contains(retry_of))
+        {
+            std::cout << "record " << i << " is a retry of " << record[retry_of].get<int>() << '\n';
+        }
+        else
+        {
+            std::cout << "record " << i << " is original\n";
+        }
+    }
+
+    // contains() with a JSON pointer never throws -- not even for a
+    // pointer that indexes into a primitive ("/0/id/x") or uses a
+    // malformed array index ("/01"), either of which would need a
+    // try/catch with json::contains(ptr)
+    std::cout << std::boolalpha << records.contains(json_pointer("/0/id/x")) << '\n';
+    std::cout << std::boolalpha << records.contains(json_pointer("/01")) << '\n';
+}

docs/mkdocs/docs/examples/basic_json_view__contains_json_pointer.output

@@ -0,0 +1,4 @@
+record 0 is original
+record 1 is a retry of 1
+false
+false

docs/mkdocs/docs/examples/basic_json_view__dump.cpp

@@ -0,0 +1,25 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+
+using json_document = nlohmann::json_document;
+using json_view = nlohmann::json_view;
+
+int main()
+{
+    // a large batch of sensor readings -- forward just the one that changed,
+    // without ever building a basic_json value for the batch or for the
+    // readings that are not needed
+    const json_document batch = json_document::parse(R"(
+      [{"id": 1, "temp": 21.5}, {"id": 2, "temp": 87.3}, {"id": 3, "temp": 21.7}]
+    )");
+    const json_view readings = batch.root();
+    std::cout << readings[1].dump() << '\n';
+
+    // a configuration file -- dump() on the view keeps the member order of
+    // the source text; a json value's object_t is std::map, so
+    // materialize().dump() of the very same view sorts the keys instead
+    const json_document config = json_document::parse(
+        R"({"name": "cache", "host": "db1", "port": 6379, "timeout": 30})");
+    std::cout << config.root().dump(2) << "\n\n";
+    std::cout << config.root().materialize().dump(2) << '\n';
+}

docs/mkdocs/docs/examples/basic_json_view__dump.output

@@ -0,0 +1,14 @@
+{"id":2,"temp":87.3}
+{
+  "name": "cache",
+  "host": "db1",
+  "port": 6379,
+  "timeout": 30
+}
+
+{
+  "host": "db1",
+  "name": "cache",
+  "port": 6379,
+  "timeout": 30
+}

docs/mkdocs/docs/examples/basic_json_view__get.cpp

@@ -0,0 +1,55 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+#include <string>
+#include <vector>
+
+using json_document = nlohmann::json_document;
+using json_view = nlohmann::json_view;
+
+// address has no direct conversion in get<T>(), so get<address>() falls back
+// to materialize().get<address>() -- a real nlohmann::json value is built
+// for just this one member, and its own from_json() runs on that
+struct address
+{
+    std::string city;
+    int zip = 0;
+};
+
+void from_json(const nlohmann::json& j, address& a)
+{
+    j.at("city").get_to(a.city);
+    j.at("zip").get_to(a.zip);
+}
+
+int main()
+{
+    json_document doc = json_document::parse(R"(
+      {
+        "name": "Alice",
+        "active": true,
+        "orders": [1, 2, 3],
+        "address": {"city": "Berlin", "zip": 10115}
+      }
+    )");
+    const json_view customer = doc.root();
+
+    // read typed fields straight into C++ variables -- none of these build
+    // a nlohmann::json value
+    const std::string name = customer["name"].get<std::string>();
+    const bool active = customer["active"].get<bool>();
+    std::cout << name << (active ? " (active)" : " (inactive)") << '\n';
+
+    // std::vector<json_view> keeps views of the array elements instead of
+    // copies of their values
+    bool first = true;
+    for (const json_view order : customer["orders"].get<std::vector<json_view>>())
+    {
+        std::cout << (first ? "" : " ") << order.get<int>();
+        first = false;
+    }
+    std::cout << '\n';
+
+    // everything else goes through materialize()
+    const address a = customer["address"].get<address>();
+    std::cout << a.city << ' ' << a.zip << '\n';
+}

docs/mkdocs/docs/examples/basic_json_view__get.output

@@ -0,0 +1,3 @@
+Alice (active)
+1 2 3
+Berlin 10115

docs/mkdocs/docs/examples/basic_json_view__get_string.cpp

@@ -0,0 +1,31 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+#include <string>
+
+using json_document = nlohmann::json_document;
+using json_view = nlohmann::json_view;
+
+int main()
+{
+    // a "large response" stand-in: only the "id" field is ever read out of it
+    const std::string text =
+        R"({"id": "8f14e45f-ceea-467e-bb92-963f5e3c7a08", "note": "created via API\n", "payload": "..."})";
+    const json_document doc = json_document::parse(text);
+    const json_view response = doc.root();
+
+    const json_view::string_view_t id = response["id"].get_string();
+    std::cout << id << '\n';
+
+    // no std::string was allocated for "id": its bytes still live inside
+    // the original buffer, so id's data lies inside [text.data(),
+    // text.data() + text.size())
+    const bool id_in_source = id.data() >= text.data() && id.data() + id.size() <= text.data() + text.size();
+    std::cout << std::boolalpha << id_in_source << '\n';
+
+    // "note" contains an escape sequence ('\n'), so it was decoded once
+    // into the document's own buffer -- get_string() still avoids a copy
+    // into a new std::string, but the bytes no longer live inside "text"
+    const json_view::string_view_t note = response["note"].get_string();
+    const bool note_in_source = note.data() >= text.data() && note.data() + note.size() <= text.data() + text.size();
+    std::cout << std::boolalpha << note_in_source << '\n';
+}

docs/mkdocs/docs/examples/basic_json_view__get_string.output

@@ -0,0 +1,3 @@
+8f14e45f-ceea-467e-bb92-963f5e3c7a08
+true
+false

docs/mkdocs/docs/examples/basic_json_view__get_to.cpp

@@ -0,0 +1,28 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+#include <string>
+
+using json_document = nlohmann::json_document;
+using json_view = nlohmann::json_view;
+
+int main()
+{
+    json_document doc = json_document::parse(R"({"host": "db.example.com", "port": 5432, "ssl": true})");
+    const json_view config = doc.root();
+
+    // get_to() writes directly into existing variables -- handy for filling
+    // in the members of a struct one field at a time, without an
+    // intermediate value from get<T>() for each one
+    std::string host;
+    int port = 0;
+    bool ssl = false;
+    config["host"].get_to(host);
+    config["port"].get_to(port);
+    config["ssl"].get_to(ssl);
+    std::cout << host << ':' << port << (ssl ? " (tls)" : "") << '\n';
+
+    // the return value is a reference to the argument, so a call can be
+    // used directly in a larger expression
+    std::string other_host;
+    std::cout << config["host"].get_to(other_host).size() << '\n';
+}

docs/mkdocs/docs/examples/basic_json_view__get_to.output

@@ -0,0 +1,2 @@
+db.example.com:5432 (tls)
+14

docs/mkdocs/docs/examples/basic_json_view__number_format.cpp

@@ -0,0 +1,28 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+
+using json_document = nlohmann::json_document;
+using json_view = nlohmann::json_view;
+
+int main()
+{
+    // a price list received from a supplier feed -- prices and account
+    // numbers must be forwarded exactly, e.g. into an invoice
+    const json_document doc = json_document::parse(R"(
+      [{"sku": "A1", "price": 19.90, "account_id": 12345678901234567890123456},
+       {"sku": "A2", "price": 1E2, "account_id": 98765432109876543210987654}]
+    )");
+    const json_view list = doc.root();
+
+    // number_format::shortest (the default) writes numbers the way
+    // basic_json::dump() would: "19.90" becomes "19.9", "1E2" becomes
+    // "100.0", and each account number -- far beyond any 64-bit integer --
+    // is rounded to the nearest double, exactly as materialize().dump()
+    // (or a plain nlohmann::json) would round it
+    std::cout << list.dump() << '\n';
+
+    // number_format::source copies every number exactly as it was written
+    // in the source text instead -- something basic_json cannot do at all,
+    // since parsing already reduces every number to its parsed value
+    std::cout << list.dump(-1, ' ', false, json_view::number_format::source) << '\n';
+}

docs/mkdocs/docs/examples/basic_json_view__number_format.output

@@ -0,0 +1,2 @@
+[{"sku":"A1","price":19.9,"account_id":1.2345678901234568e+25},{"sku":"A2","price":100.0,"account_id":9.876543210987655e+25}]
+[{"sku":"A1","price":19.90,"account_id":12345678901234567890123456},{"sku":"A2","price":1E2,"account_id":98765432109876543210987654}]

docs/mkdocs/docs/examples/basic_json_view__number_token.cpp

@@ -0,0 +1,29 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+
+using json_document = nlohmann::json_document;
+using json_view = nlohmann::json_view;
+
+int main()
+{
+    // a price and an order id from an incoming order -- both need to be
+    // reproduced exactly, e.g. for an invoice or an audit log
+    json_document doc = json_document::parse(R"(
+      {"price": 19.90, "order_id": 1234567890123456789012345, "quantity": 3}
+    )");
+    const json_view order = doc.root();
+
+    // number_token() returns the number exactly as written in the source
+    std::cout << order["price"].number_token() << '\n';
+    std::cout << order["order_id"].number_token() << '\n';
+
+    // get<double>() converts it instead -- the exact source text is gone:
+    // "19.90" becomes the double closest to 19.9, printed without the
+    // trailing zero, and the 25-digit order id -- far beyond any 64-bit
+    // integer -- can only be approximated as a double
+    std::cout << order["price"].get<double>() << '\n';
+    std::cout << order.materialize()["order_id"].dump() << '\n';
+
+    // an ordinary quantity has nothing to lose either way
+    std::cout << order["quantity"].number_token() << " == " << order["quantity"].get<int>() << '\n';
+}

docs/mkdocs/docs/examples/basic_json_view__number_token.output

@@ -0,0 +1,5 @@
+19.90
+1234567890123456789012345
+19.9
+1.2345678901234568e+24
+3 == 3

docs/mkdocs/docs/examples/basic_json_view__operator[]_json_pointer.cpp

@@ -0,0 +1,47 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+
+using json_document = nlohmann::json_document;
+using json_pointer = nlohmann::json::json_pointer;
+
+int main()
+{
+    // a larger document; operator[] with a JSON pointer reaches straight to
+    // one deeply nested field, without ever building a tree for the rest
+    json_document doc = json_document::parse(R"(
+      {
+        "region": {
+          "servers": [
+            {"name": "eu-1", "metrics": {"cpu": 0.42}},
+            {"name": "eu-2", "metrics": {"cpu": 0.71}}
+          ]
+        }
+      }
+    )");
+
+    const auto root = doc.root();
+    std::cout << root[json_pointer("/region/servers/1/metrics/cpu")].materialize().dump() << '\n';
+
+    // a missing key or an out-of-range index along the path gives a
+    // discarded view, exactly where const json::operator[] would be
+    // undefined behavior for the same pointer
+    if (const auto missing = root[json_pointer("/region/servers/5/metrics/cpu")])
+    {
+        std::cout << missing.materialize().dump() << '\n';
+    }
+    else
+    {
+        std::cout << "no such server\n";
+    }
+
+    // indexing into a primitive still throws, as basic_json::operator[]
+    // does for the same pointer
+    try
+    {
+        static_cast<void>(root[json_pointer("/region/servers/0/name/x")]);
+    }
+    catch (const nlohmann::json::out_of_range& e)
+    {
+        std::cout << e.what() << '\n';
+    }
+}

docs/mkdocs/docs/examples/basic_json_view__operator[]_json_pointer.output

@@ -0,0 +1,3 @@
+0.71
+no such server
+[json.exception.out_of_range.404] unresolved reference token 'x'

docs/mkdocs/docs/examples/basic_json_view__operator_eq.cpp

@@ -0,0 +1,30 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+
+using json_document = nlohmann::json_document;
+using json = nlohmann::json;
+
+int main()
+{
+    // two snapshots of a polled configuration endpoint -- compare them
+    // directly as views, without ever building a nlohmann::json value for
+    // either one
+    const json_document previous = json_document::parse(
+                                        R"({"name": "cache", "port": 6379, "timeout": 30})");
+    const json_document current = json_document::parse(
+                                       R"({"port": 6379.0, "timeout": 30, "name": "cache"})");
+
+    // same members, reordered, and 6379 written as a float -- operator==
+    // treats them the same way BasicJsonType::operator== would
+    std::cout << std::boolalpha << (previous.root() == current.root()) << '\n';
+
+    // an actually changed value is detected the same way
+    const json_document changed = json_document::parse(
+                                       R"({"name": "cache", "port": 6380, "timeout": 30})");
+    std::cout << (previous.root() == changed.root()) << '\n';
+
+    // comparing a view directly against an expected json value -- handy in a
+    // test, without materializing the received document at all
+    const json expected = {{"name", "cache"}, {"port", 6379}, {"timeout", 30}};
+    std::cout << (previous.root() == expected) << '\n';
+}

docs/mkdocs/docs/examples/basic_json_view__operator_eq.output

@@ -0,0 +1,3 @@
+true
+false
+true

docs/mkdocs/docs/examples/basic_json_view__operator_ltlt.cpp

@@ -0,0 +1,26 @@
+#include <iostream>
+#include <iomanip>
+#include <nlohmann/json_view.hpp>
+
+using json_document = nlohmann::json_document;
+using json_view = nlohmann::json_view;
+
+int main()
+{
+    // one order out of a large incoming batch -- write it straight to a log
+    // stream without ever building a basic_json value for it, or for the
+    // rest of the batch
+    const json_document doc = json_document::parse(R"(
+      [{"id": 1, "item": "cable"}, {"id": 2, "item": "adapter"}]
+    )");
+    const json_view orders = doc.root();
+
+    // compact, for a one-line log entry
+    std::cout << orders[1] << '\n';
+
+    // std::setw sets the indentation level, exactly as for basic_json
+    std::cout << std::setw(2) << orders[1] << "\n\n";
+
+    // std::setfill changes the indentation character
+    std::cout << std::setw(1) << std::setfill('\t') << orders[1] << '\n';
+}

docs/mkdocs/docs/examples/basic_json_view__operator_ltlt.output

@@ -0,0 +1,10 @@
+{"id":2,"item":"adapter"}
+{
+  "id": 2,
+  "item": "adapter"
+}
+
+{
+	"id": 2,
+	"item": "adapter"
+}

docs/mkdocs/docs/examples/basic_json_view__operator_ne.cpp

@@ -0,0 +1,28 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+
+using json_document = nlohmann::json_document;
+using ordered_json_document = nlohmann::ordered_json_document;
+using json = nlohmann::json;
+
+int main()
+{
+    // assert, as a test would, that a received document differs from an
+    // unwanted shape -- without ever materializing it into a json value just
+    // to compare
+    const json_document received = json_document::parse(
+                                        R"({"status": "ok", "code": 200})");
+    const json unwanted = {{"status", "error"}, {"code", 500}};
+    std::cout << std::boolalpha << (received.root() != unwanted) << '\n';
+
+    // json (std::map) compares object members regardless of order ...
+    const json_document a = json_document::parse(R"({"a": 1, "b": 2})");
+    const json_document b = json_document::parse(R"({"b": 2, "a": 1})");
+    std::cout << (a.root() != b.root()) << '\n';
+
+    // ... but ordered_json (ordered_map) compares them in the order they
+    // appear, so the very same reordering is detected as a difference
+    const ordered_json_document oa = ordered_json_document::parse(R"({"a": 1, "b": 2})");
+    const ordered_json_document ob = ordered_json_document::parse(R"({"b": 2, "a": 1})");
+    std::cout << (oa.root() != ob.root()) << '\n';
+}

docs/mkdocs/docs/examples/basic_json_view__operator_ne.output

@@ -0,0 +1,3 @@
+true
+false
+true

docs/mkdocs/docs/examples/basic_json_view__value.cpp

@@ -0,0 +1,29 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+#include <string>
+
+using json_document = nlohmann::json_document;
+using json_view = nlohmann::json_view;
+
+int main()
+{
+    json_document doc = json_document::parse(R"({"server": {"host": "localhost"}})");
+    const json_view server = doc.root()["server"];
+
+    // "port" is missing -- value() returns the default instead of
+    // throwing, so optional configuration fields never need their own
+    // try/catch
+    std::cout << server.value("host", std::string("0.0.0.0")) << '\n';
+    std::cout << server.value("port", 8080) << '\n';
+
+    // a present but wrong-typed default still throws -- value() only
+    // replaces "not found", not "wrong type", exactly as basic_json::value
+    try
+    {
+        static_cast<void>(server.value("host", 0));
+    }
+    catch (const nlohmann::json::type_error& e)
+    {
+        std::cout << e.what() << '\n';
+    }
+}

docs/mkdocs/docs/examples/basic_json_view__value.output

@@ -0,0 +1,3 @@
+localhost
+8080
+[json.exception.type_error.302] type must be number, but is string

docs/mkdocs/docs/examples/basic_json_view__value_json_pointer.cpp

@@ -0,0 +1,21 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+
+using json_document = nlohmann::json_document;
+using json_view = nlohmann::json_view;
+using json_pointer = nlohmann::json::json_pointer;
+
+int main()
+{
+    json_document doc = json_document::parse(R"({"server": {"host": "localhost", "limits": {"connections": 100}}})");
+    const json_view config = doc.root();
+
+    // a nested, optional setting read with a default -- no exception, even
+    // though "timeout" is missing several levels down
+    std::cout << config.value(json_pointer("/server/limits/connections"), 10) << '\n';
+    std::cout << config.value(json_pointer("/server/limits/timeout"), 30) << '\n';
+
+    // an out-of-range array index also falls back to the default
+    json_document list_doc = json_document::parse(R"({"servers": ["a", "b"]})");
+    std::cout << list_doc.root().value(json_pointer("/servers/5"), std::string("none")) << '\n';
+}

docs/mkdocs/docs/examples/basic_json_view__value_json_pointer.output

@@ -0,0 +1,3 @@
+100
+30
+none

docs/mkdocs/docs/examples/json_editable_document.cpp

@@ -0,0 +1,30 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+
+using json = nlohmann::json;
+using json_editable_document = nlohmann::json_editable_document;
+using json_editable_view = nlohmann::json_editable_view;
+
+int main()
+{
+    // a configuration file, as it might be read from disk
+    const std::string text = R"({"name": "cache", "host": "db1", "port": 6379, "price": 19.90})";
+    std::cout << text << "\n\n";
+
+    // patch two fields -- "price" is never touched
+    json_editable_document doc = json_editable_document::parse(text);
+    doc.set(doc.root(), "host", "db2");
+    doc.set(doc.root(), "retries", 3);
+
+    // member order (the new member at the end) and the untouched number's
+    // exact spelling survive
+    std::cout << doc.root().dump(-1, ' ', false, json_editable_view::number_format::source) << '\n';
+
+    // the same patch on a plain json value: keys are sorted (object_t is a
+    // std::map), and "price" is rewritten even though the patch never
+    // touched it
+    json plain = json::parse(text);
+    plain["host"] = "db2";
+    plain["retries"] = 3;
+    std::cout << plain.dump() << '\n';
+}

docs/mkdocs/docs/examples/json_editable_document.output

@@ -0,0 +1,4 @@
+{"name": "cache", "host": "db1", "port": 6379, "price": 19.90}
+
+{"name":"cache","host":"db2","port":6379,"price":19.90,"retries":3}
+{"host":"db2","name":"cache","port":6379,"price":19.9,"retries":3}

docs/mkdocs/docs/examples/ordered_json_editable_document.cpp

@@ -0,0 +1,15 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+
+using ordered_json_editable_document = nlohmann::ordered_json_editable_document;
+
+int main()
+{
+    // ordered_json_editable_document is basic_json_document<nlohmann::ordered_json, true>
+    ordered_json_editable_document doc = ordered_json_editable_document::parse(R"({"z": 1, "a": 2, "m": 3})");
+    doc.set(doc.root(), "b", 4); // set() always appends a new member at the end
+
+    // materialize() preserves the document order (with "b" at the end),
+    // instead of sorting the keys the way json_editable_document does
+    std::cout << doc.root().materialize().dump() << '\n';
+}

docs/mkdocs/docs/examples/ordered_json_editable_document.output

@@ -0,0 +1 @@
+{"z":1,"a":2,"m":3,"b":4}

docs/mkdocs/docs/features/index.md

@@ -13,6 +13,7 @@ C++ types, and finally serialize it again.
   [SAX interface](parsing/sax_interface.md), and [error handling](parsing/parse_exceptions.md).
 - [Zero-copy JSON views](json_view.md) — read a JSON text through a flat index instead of building a `json` tree;
   strings and numbers stay in the input and are only decoded when needed.
+  [Editable documents](json_view.md#editing-a-document) can also be modified.
 - [Comments](comments.md) and [trailing commas](trailing_commas.md) — opt-in relaxations of the JSON grammar.
 
 ## Accessing and modifying values

docs/mkdocs/docs/features/json_view.md

@@ -139,17 +139,121 @@ whenever any of the other conditions above was not met.
   element access and lookup functions never carry the JSON Pointer path `JSON_DIAGNOSTICS` would otherwise add: the
   view has no `basic_json` value to point at, so the exception is created without one, regardless of how
   `BasicJsonType` was built.
-- **`get<T>()`, JSON Pointer, `dump()`, and comparison are not (yet) provided** by `basic_json_view`. For now,
-  [`materialize()`](../api/basic_json_view/materialize.md) is the way to get a value you can do those things with.
+- **Ordering comparisons are not provided** by `basic_json_view` -- there is no `#!cpp operator<`.
+  [`operator==`](../api/basic_json_view/operator_eq.md) and [`operator!=`](../api/basic_json_view/operator_ne.md) are
+  provided, though: two views, or a view and a `BasicJsonType` value, compare equal exactly when
+  [`materialize()`](../api/basic_json_view/materialize.md) or [`parse()`](../api/basic_json/parse.md) would produce
+  equal values for them, without ever building a tree to do it. For ordering, too,
+  [`materialize()`](../api/basic_json_view/materialize.md) is the way to get a value you can compare.
+
+## Getting values out without copying
+
+[`get<T>()`](../api/basic_json_view/get.md) converts many `T` directly from the flat index, without ever building a
+`basic_json` value for the conversion: `#!cpp bool`, arithmetic types, `#!cpp std::nullptr_t`,
+`#!cpp std::string`/other `#!cpp std::basic_string`s (copied once), `basic_json`/`ordered_json` (via
+[`materialize()`](../api/basic_json_view/materialize.md)), `basic_json_view` itself, `#!cpp std::vector<U>`, and
+`#!cpp std::map`/`#!cpp std::unordered_map` with string-like keys. Every other type -- `#!cpp std::list`,
+`#!cpp std::pair`, `#!cpp std::array`, enumerations, user types with a `from_json()` -- goes through
+[`materialize()`](../api/basic_json_view/materialize.md)`.get<T>()` instead: the subtree is built into a real
+`basic_json` value first, exactly as [`parse()`](../api/basic_json/parse.md) would, and converted from there.
+
+Two conversions never copy at all:
+
+- [`get_string()`](../api/basic_json_view/get_string.md) (equivalently, `#!cpp get<string_view_t>()`) returns a
+  string as a `string_view_t` pointing into the document's [`source()`](../api/basic_json_document/source.md) text --
+  or, for a string that contains escape sequences, into the document's own buffer of decoded strings -- instead of
+  allocating a new `#!cpp std::string`.
+- [`number_token()`](../api/basic_json_view/number_token.md) returns a number exactly as it was written in the
+  source, e.g. `#!cpp "1.50"`, `#!cpp "1E2"`, or an integer with more digits than any number type holds, instead of
+  rounding it into a `#!cpp double`/`#!cpp int64_t` the way `#!cpp get<T>()` (and
+  [`basic_json::parse()`](../api/basic_json/parse.md)) would.
+
+Both results are only valid as long as the view -- and, for a string with no escapes, the borrowed source text -- is.
+
+## Writing a view back
+
+[`dump()`](../api/basic_json_view/dump.md) serializes a view directly from the flat index, without ever building a
+`basic_json` value. An object's members are written in document order, not sorted by key, and *every* occurrence of a
+repeated key is written, not only the last one -- the same two ways [iteration](#what-is-different) already differs
+from a [`materialize()`](../api/basic_json_view/materialize.md)d value, see above. `#!cpp materialize().dump()` gives
+a different result in both respects for a `json_view`.
+
+By default, numbers are written the way [`basic_json::dump()`](../api/basic_json/dump.md) would.
+[`number_format::source`](../api/basic_json_view/number_format.md) instead copies every number exactly as it was
+written in the source text -- a price like `#!cpp 19.90`, a long order or account ID with more digits than any number
+type holds, or a high-precision coordinate -- something `basic_json` cannot do at all, since parsing already reduces
+a number to its parsed `#!cpp double`/`#!cpp int64_t` value.
+
+[`operator<<`](../api/basic_json_view/operator_ltlt.md) writes a view to a stream the way `basic_json`'s does, using
+the stream's `width`/`fill` for indentation.
+
+## Editing a document
+
+Everything above is read-only: a `json_document`/`json_view` lets you look at a parsed text without copying it, but
+not change it. [`basic_json_document<BasicJsonType, true>`](../api/basic_json_document/index.md) -- more conveniently
+spelled [`json_editable_document`](../api/json_editable_document.md) or
+[`ordered_json_editable_document`](../api/ordered_json_editable_document.md) -- also lets you
+[`set`](../api/basic_json_document/set.md) a value and [`push_back`](../api/basic_json_document/push_back.md) onto
+an array, still without ever building a `basic_json` tree for parts you do not touch.
+
+`#!cpp Editable` defaults to `#!cpp false`, so `json_document`/`ordered_json_document` are unaffected -- they carry
+none of the bookkeeping edits need, and calling `set`/`push_back` on one is a compile error, not a runtime one.
+
+### Why: editing without reformatting
+
+The `#!cpp 19.90` price from [above](#writing-a-view-back) is exactly the kind of value that makes editing a `json`
+or `ordered_json` value in place lossy. Say you parse a configuration file, patch one field, and write it back:
+
+- **`json`** re-sorts every key on the way in (`object_t` is a `#!cpp std::map`) and rewrites every number to its
+  shortest round-trip form on the way out -- a one-field patch turns into a diff that reorders the whole file and
+  rewrites `#!cpp 19.90` to `#!cpp 19.9`.
+- **`ordered_json`** keeps the key order, but still rewrites every number the same way: parsing has already reduced
+  it to a `#!cpp double`/`#!cpp int64_t`, and there is no way back to how it was spelled in the source text.
+
+An editable document keeps both. [`dump()`](../api/basic_json_view/dump.md) of an edited document writes members in
+document order -- a member [`set`](../api/basic_json_document/set.md) added goes at the end, exactly where it was
+inserted -- and [`number_format::source`](../api/basic_json_view/number_format.md) keeps the exact spelling of
+every number an edit did not itself touch; a number an edit *did* touch is written the way
+[`BasicJsonType::dump()`](../api/basic_json/dump.md) would write it, since there is no source spelling for a brand
+new value.
+
+??? example "Example: patch a configuration, keeping member order and number spellings"
+
+    ```cpp
+    --8<-- "examples/json_editable_document.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/json_editable_document.output"
+    ```
+
+### What stays valid, and what an edit costs
+
+The source text itself is **never written**, and the parsed index never moves -- a value keeps the node it was
+parsed into for as long as it is not itself replaced. So every [view](../api/basic_json_view/index.md) taken before
+an edit, including a previously obtained [`root()`](../api/basic_json_document/root.md), stays valid and, if it
+still refers to the edited value, sees the edit; a view of a value a later edit drops or replaces just keeps showing
+what it last held. New values go to storage the document allocates and owns on demand. The one thing an edit does
+invalidate is the **iterators** taken over an edited array or object: the first time one of its elements is set or
+appended to, its elements move from the parsed, fixed layout to a growable block of links so that
+[`push_back`](../api/basic_json_document/push_back.md) can later grow it in amortized constant time -- existing
+elements are not touched, but an iterator that was walking the old layout no longer matches. A string obtained with
+[`get_string()`](../api/basic_json_view/get_string.md) is unaffected either way and stays valid across further
+edits. See [`basic_json_document`'s Edits](../api/basic_json_document/index.md#edits) for the details, and
+[`set`'s Exception safety](../api/basic_json_document/set.md#exception-safety) for what an edit guarantees if it
+throws (the *basic* guarantee, not the strong one `dump()` and the read-only functions provide). How edits are kept in
+the index is described in the [architecture overview](../home/architecture.md#node-index-of-json-views).
 
 ## Choosing between `json`, `ordered_json`, the SAX interface, and `json_view`
 
-| | [`json`](../api/json.md) / [`ordered_json`](../api/ordered_json.md) | [SAX interface](parsing/sax_interface.md) | [`json_document`](../api/json_document.md) / [`json_view`](../api/json_view.md) |
-|---|---|---|---|
-| **Ownership** | owns every value | owns nothing; you decide what to keep, in your handler | borrows or owns the *text*; the index is always owned by the document |
-| **Mutability** | freely mutable | not applicable (a one-shot event stream) | read-only |
-| **What you get** | a full tree you can read, write, and keep as long as you like | a sequence of callbacks; whatever your handler builds from them | a flat index plus, on demand, [`materialize()`](../api/basic_json_view/materialize.md)d `json`/`ordered_json` values for the parts you actually use |
-| **Typical use** | general-purpose JSON handling: config, request/response bodies you build or modify, anything you hold onto | validating or projecting a text into your own data structure without ever holding the whole thing as JSON | large or high-volume input where you only need part of it, or need it repeatedly, and can keep the source text (or a copy) alive for as long as the document lives |
+| | [`json`](../api/json.md) / [`ordered_json`](../api/ordered_json.md) | [SAX interface](parsing/sax_interface.md) | [`json_document`](../api/json_document.md) / [`json_view`](../api/json_view.md) | [`json_editable_document`](../api/json_editable_document.md) / [`json_editable_view`](../api/json_editable_view.md) |
+|---|---|---|---|---|
+| **Ownership** | owns every value | owns nothing; you decide what to keep, in your handler | borrows or owns the *text*; the index is always owned by the document | same as `json_document`; edits go to storage the document owns |
+| **Mutability** | freely mutable | not applicable (a one-shot event stream) | read-only | [`set`](../api/basic_json_document/set.md)/[`push_back`](../api/basic_json_document/push_back.md) edit in place; the source text is never rewritten |
+| **What you get** | a full tree you can read, write, and keep as long as you like | a sequence of callbacks; whatever your handler builds from them | a flat index plus, on demand, [`materialize()`](../api/basic_json_view/materialize.md)d `json`/`ordered_json` values for the parts you actually use | the same, plus [`dump()`](../api/basic_json_view/dump.md) of an edited document that keeps the member order and, with [`number_format::source`](../api/basic_json_view/number_format.md), the spelling of every untouched number |
+| **Typical use** | general-purpose JSON handling: config, request/response bodies you build or modify, anything you hold onto | validating or projecting a text into your own data structure without ever holding the whole thing as JSON | large or high-volume input where you only need part of it, or need it repeatedly, and can keep the source text (or a copy) alive for as long as the document lives | a document you read, patch a few fields of, and write back -- a configuration file, for instance -- where the rest of it should come back exactly as it was |
 
 ## Version history
 

docs/mkdocs/docs/home/architecture.md

@@ -194,9 +194,9 @@ packet-beta
 
 | Bytes | Field   | Type       | Contents                                                                                                                      |
 |-------|---------|------------|-------------------------------------------------------------------------------------------------------------------------------|
-| 0     | `kind`  | `uint8_t`  | the type, numbered as [`value_t`](../api/basic_json/value_t.md): 0 null, 1 object, 2 array, 3 string, 4 boolean, 5 signed integer, 6 unsigned integer, 7 float |
-| 1     | `flags` | `uint8_t`  | bits 0-1: where a string's bytes are (0: the source text, 1: the buffer of decoded strings, for strings with escapes); bit 2: the value of a boolean |
-| 2-3   | `extra` | `uint16_t` | numbers: the number of integer digits (low byte) and fraction digits (high byte), 255 for more; otherwise 0                      |
+| 0     | `kind`  | `uint8_t`  | the type, numbered as [`value_t`](../api/basic_json/value_t.md): 0 null, 1 object, 2 array, 3 string, 4 boolean, 5 signed integer, 6 unsigned integer, 7 float; 10 for a link (see below) |
+| 1     | `flags` | `uint8_t`  | bits 0-1: where a string's bytes (or a number's token) are (0: the source text, 1: the buffer of decoded strings, for strings with escapes, 2: the edit buffer); bit 2: the value of a boolean; bits 3 and 4: moved and new (see below) |
+| 2-3   | `extra` | `uint16_t` | numbers: the number of integer digits (low byte) and fraction digits (high byte), 255 for more; objects: the number of their hash index (1-based), or 0; otherwise 0 |
 | 4-7   | `off`   | `uint32_t` | where the value starts: the first byte after a string's opening quote (or its position in the buffer of decoded strings), the first byte of a number or literal, the bracket of an array or object |
 | 8-11  | `len`   | `uint32_t` | strings: the length after decoding; floats and literals: the length of the token; arrays and objects: the number of elements |
 | 12-15 | `next`  | `uint32_t` | arrays and objects: the number of nodes of the subtree, including the node itself                                              |
@@ -211,6 +211,11 @@ packet-beta
   subtree is `next` nodes further for an array or object, and the next node otherwise (`document_data::after`). Views
   step from element to element this way and skip whole subtrees in constant time.
 - **Offsets** are 32 bits wide, so a document is limited to 4 GiB (`out_of_range.416`).
+- **Large objects** (128 members or more) get a hash index after parsing
+  ([`detail/view/object_index.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/view/object_index.hpp)):
+  an open-addressing table whose slots hold the distance from the object's node to a key's node, so that a lookup does
+  not compare every key. The object's `extra` holds the number of its table. Only 65,535 tables fit into `extra`;
+  objects beyond them are searched linearly.
 
 For example, `#!json {"a": [1, 2.5]}` becomes five nodes. Each node's elements follow it, and `next` leads from an
 array or object past its subtree:
@@ -239,6 +244,21 @@ flowchart LR
 All `flags` are 0. The integer's bytes 8-15 hold its value, 1; its `extra` says it has one digit. The float's `extra`
 says it has one integer and one fraction digit, and its `len` is that of the token `2.5`.
 
+Editable documents ([`json_editable_document`](../api/json_editable_document.md),
+[`detail/view/edit.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/view/edit.hpp) and
+[`detail/view/edit_storage.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/view/edit_storage.hpp))
+never write the source text and never move or resize the parsed index, so views stay valid while the document is
+edited:
+
+- A new scalar is written over its node. Its text (a string, or the token of a number as `dump()` writes it) goes to
+  the edit buffer, which `flags` bits 0-1 then name.
+- An array or object whose elements change gets the flag *moved* (bit 3): its elements then live in a separate
+  sequence (a header node, then the entries), whose number is in `off`. The entries are links (`kind` 10), whose bytes
+  8-15 hold the address of the value's node, so values never move.
+- A node written by an edit gets the flag *new* (bit 4): it has no position in the source text.
+- Views of read-only documents compile without any of this: how views walk the index is a template parameter
+  (`navigation<Editable>`).
+
 ## Input adapters
 
 Input is read via **input adapters** that abstract a source. Every input adapter provides this interface:

docs/mkdocs/docs/home/exceptions.md

@@ -782,6 +782,24 @@ The dynamic type of the object cannot be represented in the requested serializat
 
     Encapsulate the JSON value in an object. That is, instead of serializing `#!json true`, serialize `#!json {"value": true}`
 
+### json.exception.type_error.319
+
+[`basic_json_document::set`](../api/basic_json_document/set.md) and
+[`basic_json_document::push_back`](../api/basic_json_document/push_back.md) can store any `basic_json` value except
+a binary one: a `json_document` has no representation for [binary values](../features/binary_values.md), which only
+ever arise from parsing a binary format or from an explicit [`json::binary`](../api/basic_json/binary.md) value, not
+from JSON text.
+
+!!! failure "Example message"
+
+    ```
+    [json.exception.type_error.319] cannot store a binary value in a json_document
+    ```
+
+!!! note
+
+    This exception was added in version 3.13.0, together with editable [`json_document`s](../features/json_view.md).
+
 ## Out of range
 
 This exception is thrown in case a library function is called on an input parameter that exceeds the expected range, for instance, in the case of array indices or nonexisting object keys.
@@ -1006,13 +1024,19 @@ MessagePack's ext type and BSON's binary subtype are each stored in a single byt
 
 [`basic_json_document::parse()`](../api/basic_json_document/parse.md) and the other parsing functions of
 [`basic_json_document`](../api/basic_json_document/index.md) index a value's position in the source text in 32 bits,
-so they do not support an input of 4 GiB or more.
+so they do not support an input of 4 GiB or more. The same 32-bit limit applies to an **editable** document's own
+storage: [`set`](../api/basic_json_document/set.md) and [`push_back`](../api/basic_json_document/push_back.md) throw
+this exception once the strings and number tokens written by edits reach 4 GiB in total, or once more than
+4294967295 arrays/objects have had an element set or appended to them.
 
-!!! failure "Example message"
+!!! failure "Example messages"
 
     ```
     [json.exception.out_of_range.416] input of 4 GiB or more is not supported by json_document
     ```
+    ```
+    [json.exception.out_of_range.416] edits of 4 GiB or more are not supported by json_document
+    ```
 
 !!! note
 

docs/mkdocs/docs/home/license.md

@@ -23,3 +23,5 @@ The class contains a copy of [Hedley](https://nemequ.github.io/hedley/) from Eva
 The class contains an adapted version of the Eisel-Lemire algorithm and its table of powers of five from [fast_float](https://github.com/fastfloat/fast_float) by Daniel Lemire and contributors, which is available under the [MIT License](https://opensource.org/licenses/MIT) (used here), the Apache 2.0 License, and the Boost Software License. Copyright © 2021 The fast_float authors
 
 The view's parser (`<nlohmann/json_view.hpp>`) contains techniques and code adapted from [yyjson](https://github.com/ibireme/yyjson) by YaoYuan, which is licensed under the [MIT License](https://opensource.org/licenses/MIT) (see above): table-driven decoding of `\u` escapes and fixed-offset unrolled checks.
+
+The view's parser (`<nlohmann/json_view.hpp>`) validates non-ASCII strings with the vector UTF-8 check of [simdjson](https://github.com/simdjson/simdjson) by Daniel Lemire, Geoff Langdale, John Keiser, and contributors (its "lookup4" algorithm and tables, after J. Keiser and D. Lemire, "Validating UTF-8 In Less Than One Instruction Per Byte", 2021), which is available under the [MIT License](https://opensource.org/licenses/MIT) (used here) and the Apache 2.0 License. Copyright &copy; 2018-2025 The simdjson authors

docs/mkdocs/mkdocs.yml

@@ -239,8 +239,10 @@ nav:
           - 'owns_source': api/basic_json_document/owns_source.md
           - 'parse': api/basic_json_document/parse.md
           - 'parse_copy': api/basic_json_document/parse_copy.md
+          - 'push_back': api/basic_json_document/push_back.md
           - 'read': api/basic_json_document/read.md
           - 'root': api/basic_json_document/root.md
+          - 'set': api/basic_json_document/set.md
           - 'shrink_to_fit': api/basic_json_document/shrink_to_fit.md
           - 'source': api/basic_json_document/source.md
       - basic_json_view:
@@ -253,10 +255,14 @@ nav:
           - 'cend': api/basic_json_view/cend.md
           - 'contains': api/basic_json_view/contains.md
           - 'count': api/basic_json_view/count.md
+          - 'dump': api/basic_json_view/dump.md
           - 'empty': api/basic_json_view/empty.md
           - 'end': api/basic_json_view/end.md
           - 'find': api/basic_json_view/find.md
           - 'front': api/basic_json_view/front.md
+          - 'get': api/basic_json_view/get.md
+          - 'get_string': api/basic_json_view/get_string.md
+          - 'get_to': api/basic_json_view/get_to.md
           - 'is_array': api/basic_json_view/is_array.md
           - 'is_binary': api/basic_json_view/is_binary.md
           - 'is_boolean': api/basic_json_view/is_boolean.md
@@ -272,12 +278,18 @@ nav:
           - 'is_structured': api/basic_json_view/is_structured.md
           - 'items': api/basic_json_view/items.md
           - 'materialize': api/basic_json_view/materialize.md
+          - 'number_format': api/basic_json_view/number_format.md
+          - 'number_token': api/basic_json_view/number_token.md
           - 'operator bool': api/basic_json_view/operator_bool.md
+          - 'operator<<': api/basic_json_view/operator_ltlt.md
           - 'operator[]': api/basic_json_view/operator[].md
+          - 'operator==': api/basic_json_view/operator_eq.md
+          - 'operator!=': api/basic_json_view/operator_ne.md
           - 'size': api/basic_json_view/size.md
           - 'source_offset': api/basic_json_view/source_offset.md
           - 'type': api/basic_json_view/type.md
           - 'type_name': api/basic_json_view/type_name.md
+          - 'value': api/basic_json_view/value.md
       - byte_container_with_subtype:
           - 'Overview': api/byte_container_with_subtype/index.md
           - '(constructor)': api/byte_container_with_subtype/byte_container_with_subtype.md
@@ -291,6 +303,8 @@ nav:
           - 'to_json': api/adl_serializer/to_json.md
       - 'json': api/json.md
       - 'json_document': api/json_document.md
+      - 'json_editable_document': api/json_editable_document.md
+      - 'json_editable_view': api/json_editable_view.md
       - json_pointer:
           - 'Overview': api/json_pointer/index.md
           - '(Constructor)': api/json_pointer/json_pointer.md
@@ -331,6 +345,8 @@ nav:
       - 'operator""_json_pointer': api/operator_literal_json_pointer.md
       - 'ordered_json': api/ordered_json.md
       - 'ordered_json_document': api/ordered_json_document.md
+      - 'ordered_json_editable_document': api/ordered_json_editable_document.md
+      - 'ordered_json_editable_view': api/ordered_json_editable_view.md
       - 'ordered_json_view': api/ordered_json_view.md
       - 'ordered_map': api/ordered_map.md
       - macros:
@@ -358,6 +374,8 @@ nav:
           - 'JSON_USE_IMPLICIT_CONVERSIONS': api/macros/json_use_implicit_conversions.md
           - 'JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON': api/macros/json_use_legacy_discarded_value_comparison.md
           - 'JSON_USE_SIMDUTF': api/macros/json_use_simdutf.md
+          - 'JSON_VIEW_NO_SIMD': api/macros/json_view_no_simd.md
+          - 'JSON_VIEW_USE_SSSE3': api/macros/json_view_use_ssse3.md
           - 'NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_ONLY_SERIALIZE, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE': api/macros/nlohmann_define_derived_type.md
           - 'NLOHMANN_DEFINE_TYPE_INTRUSIVE, NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE': api/macros/nlohmann_define_type_intrusive.md
           - 'NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE': api/macros/nlohmann_define_type_non_intrusive.md

include/nlohmann/detail/json_pointer.hpp

@@ -30,6 +30,11 @@
 
 NLOHMANN_JSON_NAMESPACE_BEGIN
 
+namespace detail
+{
+struct json_pointer_access;
+}  // namespace detail
+
 /// @brief JSON Pointer defines a string syntax for identifying a specific value within a JSON document
 /// @sa https://json.nlohmann.me/api/json_pointer/
 template<typename RefStringType>
@@ -42,6 +47,8 @@ class json_pointer
     template<typename>
     friend class json_pointer;
 
+    friend struct detail::json_pointer_access;
+
     template<typename T>
     struct string_t_helper
     {
@@ -1164,4 +1171,18 @@ inline bool operator<(const json_pointer<RefStringTypeLhs>& lhs,
 }
 #endif
 
+namespace detail
+{
+/// the reference tokens of a json_pointer, for code that resolves pointers
+/// without a basic_json value (such as the zero-copy view)
+struct json_pointer_access
+{
+    template<typename RefStringType>
+    static const std::vector<typename json_pointer<RefStringType>::string_t>& reference_tokens(const json_pointer<RefStringType>& ptr) noexcept
+    {
+        return ptr.reference_tokens;
+    }
+};
+}  // namespace detail
+
 NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/detail/view/builder.hpp

@@ -115,6 +115,13 @@ class builder
     frame shallow[64]; // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays): not initialized on purpose; filled as containers open
     std::vector<frame> deep{};
 
+    /// remember an object to index after parsing (out of line, so that the
+    /// parse loop only has a call for it)
+    NLOHMANN_VIEW_NOINLINE void note_large_object(std::uint32_t idx)
+    {
+        doc.large_objects.push_back(idx);
+    }
+
     NLOHMANN_VIEW_NOINLINE bool fail(error_code c, const unsigned char* at) noexcept
     {
         m_failure.code = c;
@@ -492,7 +499,7 @@ class builder
     switch (cur())                                                                              \
     {                                                                                           \
         case '"':                                                                               \
-            if (NLOHMANN_VIEW_UNLIKELY(!string())) { return false; }                      \
+            if (NLOHMANN_VIEW_UNLIKELY(!string<true>())) { return false; }                \
             goto NEXT;                                                                          \
         case '{':                                                                               \
             open(value_t::object);                                                              \
@@ -576,7 +583,7 @@ obj_key:
             {
                 return fail(error_code::expected_key);
             }
-            if (NLOHMANN_VIEW_UNLIKELY(!string()))
+            if (NLOHMANN_VIEW_UNLIKELY(!string<false>()))
             {
                 return false;
             }
@@ -617,19 +624,27 @@ obj_next:
                 if (TrailingCommas && cur() == '}')
                 {
                     ++p;
-                    goto close_container;
+                    goto close_object;
                 }
                 goto obj_key;
             }
             if (cur() == '}')
             {
                 ++p;
-                goto close_container;
+                goto close_object;
             }
             return fail(error_code::expected_object_end);
 
 #undef NLOHMANN_VIEW_VALUE
 
+close_object:
+            // a large object gets a hash index (objects only, so that closing
+            // an array pays nothing for this)
+            if (NLOHMANN_VIEW_UNLIKELY(cur_count >= document_data::index_min_members))
+            {
+                cold.note_large_object(cur_idx);
+            }
+
 close_container:
             close();
             if (NLOHMANN_VIEW_UNLIKELY(depth == 0))
@@ -679,7 +694,7 @@ root_done:
             switch (cur())
             {
                 case '"':
-                    return string();
+                    return string<true>();
                 case 't':
                     return literal("true", 4, value_t::boolean, node_flags::is_true);
                 case 'f':
@@ -965,12 +980,13 @@ indent_done:
             return true;
         }
 
-        /// a string (value or key) at p
+        /// a string at p: a value (Value) or a key
+        template<bool Value>
         NLOHMANN_VIEW_ALWAYS_INLINE bool string()
         {
             ++p; // opening quote
             const unsigned char* const s = p;
-            p = scan_string_run(p, e);
+            p = scan_string_run<Value>(p, e);
             if (NLOHMANN_VIEW_LIKELY(p != e && *p == '"'))
             {
                 emit(value_t::string, 0, 0, static_cast<std::size_t>(s - b), static_cast<std::uint64_t>(p - s));

include/nlohmann/detail/view/compare.hpp

@@ -0,0 +1,317 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <algorithm> // sort, stable_sort
+#include <cstddef> // size_t
+#include <string> // string
+#include <utility> // move, pair
+#include <vector> // vector
+
+#include <nlohmann/json.hpp>
+#include <nlohmann/detail/view/macro_scope.hpp>
+
+NLOHMANN_JSON_NAMESPACE_BEGIN
+namespace detail
+{
+namespace view
+{
+
+// Equality of views, and of views with basic_json values, with the semantics
+// of basic_json's operator== applied to the values parse() would produce:
+// numbers compare by value across their types, an object is compared by its
+// members with duplicate keys resolved as parse() resolves them (the last
+// value, at the position of the first occurrence), and in document order if
+// the object type keeps an order (ordered_json), by key otherwise.
+
+/// one side of a comparison: a view
+template<typename BasicJsonType, typename View>
+class view_side
+{
+  public:
+    using string_view_t = typename View::string_view_t;
+
+    explicit view_side(const View& v) noexcept
+        : m_view(v)
+    {}
+
+    value_t type() const noexcept
+    {
+        return m_view.type();
+    }
+
+    std::size_t size() const noexcept
+    {
+        return m_view.size();
+    }
+
+    string_view_t string() const
+    {
+        return m_view.get_string();
+    }
+
+    /// a number, boolean, or null as a basic_json value (no allocation)
+    BasicJsonType scalar() const
+    {
+        switch (m_view.type())
+        {
+            case value_t::number_integer:
+                return BasicJsonType(m_view.template get<typename BasicJsonType::number_integer_t>());
+            case value_t::number_unsigned:
+                return BasicJsonType(m_view.template get<typename BasicJsonType::number_unsigned_t>());
+            case value_t::number_float:
+                return BasicJsonType(m_view.template get<typename BasicJsonType::number_float_t>());
+            case value_t::boolean:
+                return BasicJsonType(m_view.template get<bool>());
+            case value_t::null:
+            case value_t::object:
+            case value_t::array:
+            case value_t::string:
+            case value_t::binary:
+            case value_t::discarded:
+            default:
+                return BasicJsonType(nullptr);
+        }
+    }
+
+    void elements(std::vector<view_side>& out) const
+    {
+        out.reserve(m_view.size());
+        for (const View e : m_view)
+        {
+            out.emplace_back(e);
+        }
+    }
+
+    /// the members as parse() keeps them: one per key, the last value at the
+    /// position of the first occurrence; in that order, or sorted by key
+    void members(std::vector<std::pair<string_view_t, view_side>>& out, bool ordered) const
+    {
+        struct member
+        {
+            string_view_t key;
+            View value;
+            std::size_t position;
+        };
+        std::vector<member> all;
+        all.reserve(m_view.size());
+        std::size_t position = 0;
+        for (auto it = m_view.begin(); it != m_view.end(); ++it)
+        {
+            all.push_back(member{it.key(), it.value(), position++});
+        }
+        std::stable_sort(all.begin(), all.end(), [](const member & a, const member & b)
+        {
+            return a.key < b.key;
+        });
+        std::vector<member> unique;
+        unique.reserve(all.size());
+        for (std::size_t i = 0; i < all.size();)
+        {
+            std::size_t last = i;
+            while (last + 1 < all.size() && all[last + 1].key == all[i].key)
+            {
+                ++last;
+            }
+            unique.push_back(member{all[i].key, all[last].value, all[i].position});
+            i = last + 1;
+        }
+        if (ordered)
+        {
+            std::sort(unique.begin(), unique.end(), [](const member & a, const member & b)
+            {
+                return a.position < b.position;
+            });
+        }
+        out.reserve(unique.size());
+        for (const member& m : unique)
+        {
+            out.emplace_back(m.key, view_side(m.value));
+        }
+    }
+
+  private:
+    View m_view;
+};
+
+/// the other side of a comparison: a basic_json value
+template<typename BasicJsonType, typename StringView>
+class json_side
+{
+  public:
+    using string_view_t = StringView;
+
+    explicit json_side(const BasicJsonType& j) noexcept
+        : m_json(&j)
+    {}
+
+    value_t type() const noexcept
+    {
+        return m_json->type();
+    }
+
+    std::size_t size() const noexcept
+    {
+        return m_json->size();
+    }
+
+    string_view_t string() const
+    {
+        const auto& s = m_json->template get_ref<const typename BasicJsonType::string_t&>();
+        return string_view_t(s.data(), s.size());
+    }
+
+    BasicJsonType scalar() const
+    {
+        return *m_json;
+    }
+
+    void elements(std::vector<json_side>& out) const
+    {
+        out.reserve(m_json->size());
+        for (const auto& e : *m_json)
+        {
+            out.emplace_back(e);
+        }
+    }
+
+    void members(std::vector<std::pair<string_view_t, json_side>>& out, bool ordered) const
+    {
+        out.reserve(m_json->size());
+        for (auto it = m_json->cbegin(); it != m_json->cend(); ++it)
+        {
+            out.emplace_back(string_view_t(it.key().data(), it.key().size()), json_side(it.value()));
+        }
+        if (!ordered)
+        {
+            std::sort(out.begin(), out.end(), [](const std::pair<string_view_t, json_side>& a, const std::pair<string_view_t, json_side>& b)
+            {
+                return a.first < b.first;
+            });
+        }
+    }
+
+  private:
+    const BasicJsonType* m_json;
+};
+
+/// whether two sides are equal; iterative, so that the nesting depth is
+/// limited by memory only
+template<typename BasicJsonType, typename A, typename B>
+bool equal(const A& a0, const B& b0)
+{
+    using string_view_t = typename A::string_view_t;
+    const bool ordered = is_ordered_map<typename BasicJsonType::object_t>::value;
+
+    struct frame
+    {
+        std::vector<A> elements_a{};
+        std::vector<B> elements_b{};
+        std::vector<std::pair<string_view_t, A>> members_a{};
+        std::vector<std::pair<string_view_t, B>> members_b{};
+        bool object = false;
+        std::size_t next = 0;
+    };
+    std::vector<frame> stack;
+    A a = a0;
+    B b = b0;
+    for (;;)
+    {
+        const value_t ta = a.type();
+        const value_t tb = b.type();
+        const bool numbers = (ta == value_t::number_integer || ta == value_t::number_unsigned || ta == value_t::number_float)
+                             && (tb == value_t::number_integer || tb == value_t::number_unsigned || tb == value_t::number_float);
+        if (ta == value_t::discarded || tb == value_t::discarded)
+        {
+            // basic_json decides (JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON)
+            if (ta != tb || !(BasicJsonType(value_t::discarded) == BasicJsonType(value_t::discarded)))
+            {
+                return false;
+            }
+        }
+        else
+        {
+            if (!numbers && ta != tb)
+            {
+                return false;
+            }
+            if (ta == value_t::string)
+            {
+                if (!(a.string() == b.string()))
+                {
+                    return false;
+                }
+            }
+            else if (ta == value_t::array || ta == value_t::object)
+            {
+                if (a.size() != b.size() && ta == value_t::array)
+                {
+                    return false;
+                }
+                frame f;
+                f.object = ta == value_t::object;
+                if (f.object)
+                {
+                    a.members(f.members_a, ordered);
+                    b.members(f.members_b, ordered);
+                    if (f.members_a.size() != f.members_b.size())
+                    {
+                        return false;
+                    }
+                }
+                else
+                {
+                    a.elements(f.elements_a);
+                    b.elements(f.elements_b);
+                }
+                stack.push_back(std::move(f));
+            }
+            else if (!(a.scalar() == b.scalar())) // numbers (also of different types), null, boolean
+            {
+                return false;
+            }
+        }
+
+        // the next pair of values
+        for (;;)
+        {
+            if (stack.empty())
+            {
+                return true;
+            }
+            frame& f = stack.back();
+            const std::size_t count = f.object ? f.members_a.size() : f.elements_a.size();
+            if (f.next == count)
+            {
+                stack.pop_back();
+                continue;
+            }
+            if (f.object)
+            {
+                if (!(f.members_a[f.next].first == f.members_b[f.next].first))
+                {
+                    return false;
+                }
+                a = f.members_a[f.next].second;
+                b = f.members_b[f.next].second;
+            }
+            else
+            {
+                a = f.elements_a[f.next];
+                b = f.elements_b[f.next];
+            }
+            ++f.next;
+            break;
+        }
+    }
+}
+
+}  // namespace view
+}  // namespace detail
+NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/detail/view/document_data.hpp

@@ -10,9 +10,14 @@
 
 #include <array> // array
 #include <cstddef> // size_t
+#include <cstdint> // uint32_t
 #include <cstring> // memcpy
+#include <functional> // less
+#include <map> // map
+#include <memory> // unique_ptr
 #include <new> // operator new, placement new
 #include <string> // string
+#include <vector> // vector
 
 #include <nlohmann/json.hpp>
 #include <nlohmann/detail/view/macro_scope.hpp>
@@ -37,9 +42,41 @@ struct document_data
     std::size_t inline_cap = 0;
     std::string arena{}; ///< decoded strings that contained escapes // NOLINT(readability-redundant-member-init)
     std::string owned{}; ///< owned copy of the input, if any // NOLINT(readability-redundant-member-init)
-    std::array<const char*, 4> base = {{nullptr, nullptr, nullptr, nullptr}}; ///< string bases: source, arena (indexed by flags & node_flags::storage)
+
+    // hash indexes of large objects (see object_index.hpp)
+    static constexpr std::uint32_t index_min_members = 128;
+    struct object_index
+    {
+        std::size_t start;  ///< first slot in index_slots
+        std::uint32_t mask; ///< slot count - 1 (a power of two minus one)
+    };
+    std::vector<object_index> indexes{}; // NOLINT(readability-redundant-member-init)
+    std::vector<std::uint32_t> index_slots{}; // NOLINT(readability-redundant-member-init)
+    std::vector<std::uint32_t> large_objects{}; ///< positions of the objects to index (noted while parsing) // NOLINT(readability-redundant-member-init)
+    std::array<const char*, 4> base = {{nullptr, nullptr, nullptr, nullptr}}; ///< string bases: source, arena, edit arena (indexed by flags & node_flags::storage)
     bool discarded = true;
 
+    /// The storage of edits (editable documents only; see edit_storage.hpp).
+    /// Edits never move or resize the parsed index, so views stay valid: an
+    /// array/object whose elements change gets node_flags::moved, and its
+    /// elements then live in a separate sequence (a header node, then the
+    /// entries), whose entries link to the values.
+    struct edit_state
+    {
+        std::vector<node*> moved{};                    ///< element sequences of moved arrays/objects (header node first) // NOLINT(readability-redundant-member-init)
+        std::vector<std::size_t> moved_cap{};          ///< capacity in nodes of a growable block; 0: a fixed sequence (a new value) // NOLINT(readability-redundant-member-init)
+        std::vector<std::unique_ptr<node[]>> chunks{}; ///< storage of new values and blocks; never moved // NOLINT(readability-redundant-member-init,cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
+        std::map<const node*, node*, std::less<const node*>> regions{}; ///< new arrays/objects: root -> container that uses it as its element sequence (nullptr: linked from a block) // NOLINT(readability-redundant-member-init)
+        node* chunk_cur = nullptr;
+        node* chunk_end = nullptr;
+        std::size_t chunk_next = 64;
+        std::vector<std::unique_ptr<char[]>> texts{}; ///< edit arena, the current buffer last; earlier ones stay alive for string views // NOLINT(readability-redundant-member-init,cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
+        std::size_t text_used = 0;
+        std::size_t text_cap = 0;
+        std::size_t bytes = 0; ///< memory held by edits
+    };
+    std::unique_ptr<edit_state> edits{}; ///< created by the first edit // NOLINT(readability-redundant-member-init)
+
     /// one allocation for the header and room for `nodes` nodes; large
     /// documents get a separate node array instead (so it can be trimmed)
     static document_data* create(std::size_t nodes)
@@ -123,6 +160,78 @@ struct document_data
     {
         return n + n->next;
     }
+
+    /// (editable documents) first element or key, also of a moved container
+    NLOHMANN_VIEW_ALWAYS_INLINE const node* first_child_edited(const node* n) const noexcept
+    {
+        return NLOHMANN_VIEW_LIKELY((n->flags & node_flags::moved) == 0) ? n + 1 : edits->moved[n->off] + 1;
+    }
+
+    /// (editable documents) end of the elements, also of a moved container
+    NLOHMANN_VIEW_ALWAYS_INLINE const node* child_end_edited(const node* n) const noexcept
+    {
+        if (NLOHMANN_VIEW_LIKELY((n->flags & node_flags::moved) == 0))
+        {
+            return n + n->next;
+        }
+        const node* const h = edits->moved[n->off];
+        return h + h->next;
+    }
+
+    /// (editable documents) the value at an element position: entries of
+    /// moved sequences are links. The link case is out of line, so that this
+    /// compiles to a predicted branch rather than a select that delays the
+    /// following loads.
+    static NLOHMANN_VIEW_ALWAYS_INLINE const node* deref(const node* n) noexcept
+    {
+        return NLOHMANN_VIEW_LIKELY(n->kind != kind_link) ? n : follow_link(n);
+    }
+
+    static NLOHMANN_VIEW_NOINLINE const node* follow_link(const node* n) noexcept
+    {
+        return link_target(*n);
+    }
+};
+
+/// How the index is walked: views of read-only documents follow the node
+/// array alone and compile without any of the edit handling; views of
+/// editable documents also follow moved element sequences and links.
+template<bool Editable>
+struct navigation
+{
+    static NLOHMANN_VIEW_ALWAYS_INLINE const node* first(const document_data& /*d*/, const node* n) noexcept
+    {
+        return n + 1;
+    }
+
+    static NLOHMANN_VIEW_ALWAYS_INLINE const node* end(const document_data& /*d*/, const node* n) noexcept
+    {
+        return n + n->next;
+    }
+
+    static NLOHMANN_VIEW_ALWAYS_INLINE const node* value(const node* n) noexcept
+    {
+        return n;
+    }
+};
+
+template<>
+struct navigation<true>
+{
+    static NLOHMANN_VIEW_ALWAYS_INLINE const node* first(const document_data& d, const node* n) noexcept
+    {
+        return d.first_child_edited(n);
+    }
+
+    static NLOHMANN_VIEW_ALWAYS_INLINE const node* end(const document_data& d, const node* n) noexcept
+    {
+        return d.child_end_edited(n);
+    }
+
+    static NLOHMANN_VIEW_ALWAYS_INLINE const node* value(const node* n) noexcept
+    {
+        return document_data::deref(n);
+    }
 };
 
 }  // namespace view

include/nlohmann/detail/view/edit.hpp

@@ -0,0 +1,711 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <array> // array
+#include <cmath> // isinf, isnan
+#include <cstddef> // size_t
+#include <cstdint> // int64_t, uint8_t, uint32_t, uint64_t
+#include <cstring> // memcmp, memmove
+#include <limits> // numeric_limits
+#include <string> // string, to_string
+#include <type_traits> // decay, enable_if, integral_constant, is_arithmetic, is_convertible, is_floating_point, is_same, is_signed
+#include <utility> // forward
+
+#include <nlohmann/json.hpp>
+#include <nlohmann/detail/view/document_data.hpp>
+#include <nlohmann/detail/view/edit_storage.hpp>
+#include <nlohmann/detail/view/errors.hpp>
+#include <nlohmann/detail/view/lookup.hpp>
+#include <nlohmann/detail/view/macro_scope.hpp>
+#include <nlohmann/detail/view/node.hpp>
+
+NLOHMANN_JSON_NAMESPACE_BEGIN
+
+template<typename BasicJsonType, bool Editable>
+class basic_json_view;
+
+namespace detail
+{
+namespace view
+{
+
+/// the index of the first true condition (the number of conditions if none is)
+template<bool... Conditions>
+struct first_true : std::integral_constant<int, 0> {};
+
+template<bool... Conditions>
+struct first_true<false, Conditions...> : std::integral_constant < int, 1 + first_true<Conditions...>::value > {};
+
+/// Checks a string the way basic_json's serializer does when it writes it
+/// (type_error.316 with the same message), so that an editable document
+/// only holds valid UTF-8: the error is at the first byte that no
+/// well-formed sequence can continue with (Unicode, Table 3-7).
+inline void check_utf8(const char* s, std::size_t n)
+{
+    const auto* const p = reinterpret_cast<const unsigned char*>(s); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
+    const auto hex = [](unsigned char c)
+    {
+        constexpr const char* digits = "0123456789ABCDEF";
+        return std::string{digits[c >> 4u], digits[c & 0xFu]};
+    };
+    for (std::size_t i = 0; i < n;)
+    {
+        const unsigned char c = p[i];
+        if (c < 0x80)
+        {
+            ++i;
+            continue;
+        }
+        std::size_t len = 0;
+        unsigned char lo = 0x80;
+        unsigned char hi = 0xBF;
+        if (c >= 0xC2 && c <= 0xDF)
+        {
+            len = 2;
+        }
+        else if (c >= 0xE0 && c <= 0xEF)
+        {
+            len = 3;
+            lo = c == 0xE0 ? 0xA0 : 0x80;
+            hi = c == 0xED ? 0x9F : 0xBF;
+        }
+        else if (c >= 0xF0 && c <= 0xF4)
+        {
+            len = 4;
+            lo = c == 0xF0 ? 0x90 : 0x80;
+            hi = c == 0xF4 ? 0x8F : 0xBF;
+        }
+        else
+        {
+            throw_type_error(316, concat("invalid UTF-8 byte at index ", std::to_string(i), ": 0x", hex(c)));
+        }
+        for (std::size_t k = 1; k < len; ++k)
+        {
+            if (i + k == n)
+            {
+                throw_type_error(316, concat("incomplete UTF-8 string; last byte: 0x", hex(p[n - 1])));
+            }
+            const unsigned char b = p[i + k];
+            if (b < (k == 1 ? lo : 0x80) || b > (k == 1 ? hi : 0xBF))
+            {
+                throw_type_error(316, concat("invalid UTF-8 byte at index ", std::to_string(i + k), ": 0x", hex(b)));
+            }
+        }
+        i += len;
+    }
+}
+
+/*!
+@brief the edits of an editable basic_json_document
+
+Values are accepted as views (of any document), BasicJsonType values, and
+everything BasicJsonType can be constructed from. The source text is never
+written: new values go to storage owned by the document (see
+edit_storage.hpp).
+*/
+template<typename BasicJsonType, typename View>
+class editor
+{
+    using number_integer_t = typename BasicJsonType::number_integer_t;
+    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
+    using number_float_t = typename BasicJsonType::number_float_t;
+    using string_t = typename BasicJsonType::string_t;
+    using string_view_t = typename View::string_view_t;
+    using nav = navigation<true>;
+
+  public:
+    explicit editor(document_data& d) noexcept
+        : m_doc(d)
+    {}
+
+    /// replace a value; returns its view
+    template<typename V>
+    View set(const View& target, V&& value)
+    {
+        node* const slot = own(target);
+        const encoded e = encode(std::forward<V>(value));
+        assign(slot, e, nullptr, false);
+        return View(&m_doc, slot);
+    }
+
+    /// set a member (appended if missing; a null value becomes an object);
+    /// returns a view of the member value
+    template<typename V>
+    View set(const View& object, string_view_t key, V&& value)
+    {
+        node* const o = own(object);
+        if (o->kind != static_cast<std::uint8_t>(value_t::object) && o->kind != static_cast<std::uint8_t>(value_t::null))
+        {
+            throw_type_error(305, "cannot use operator[] with a string argument with ", object.type_name());
+        }
+        check_utf8(key.data(), key.size());
+        const encoded e = encode(std::forward<V>(value));
+        if (o->kind == static_cast<std::uint8_t>(value_t::null))
+        {
+            become_empty(o, value_t::object);
+        }
+        // an existing member: assign it (and drop later duplicates, so that
+        // lookups, iteration, and materialize() agree)
+        node* slot = nullptr;
+        bool duplicates = false;
+        for (const node* k = nav::first(m_doc, o), *end = nav::end(m_doc, o); k != end; k = document_data::after(k + 1))
+        {
+            if (key_equals(*k, key))
+            {
+                if (slot != nullptr)
+                {
+                    duplicates = true;
+                    break;
+                }
+                slot = const_cast<node*>(nav::value(k + 1)); // NOLINT(cppcoreguidelines-pro-type-const-cast): the nodes belong to this document
+            }
+        }
+        if (slot != nullptr)
+        {
+            if (duplicates)
+            {
+                erase_members(o, key, true);
+            }
+            assign(slot, e, o, true);
+            return View(&m_doc, slot);
+        }
+        const node k = string_node(key.data(), key.size());
+        slot = new_slot(e);
+        node* const h = block_of(m_doc, o, 2);
+        h[h->next] = k;
+        make_link(h[h->next + 1], slot);
+        h->next += 2;
+        ++h->len;
+        ++o->len;
+        return View(&m_doc, slot);
+    }
+
+    /// assign an existing array element; returns a view of it
+    template<typename V>
+    View set(const View& array, std::size_t idx, V&& value)
+    {
+        node* const a = own(array);
+        if (a->kind != static_cast<std::uint8_t>(value_t::array))
+        {
+            throw_type_error(305, "cannot use operator[] with a numeric argument with ", array.type_name());
+        }
+        check_index(idx, a->len);
+        const encoded e = encode(std::forward<V>(value));
+        node* const slot = const_cast<node*>(nav::value(element_at<true>(m_doc, a, idx))); // NOLINT(cppcoreguidelines-pro-type-const-cast)
+        assign(slot, e, a, true);
+        return View(&m_doc, slot);
+    }
+
+    /// append to an array (a null value becomes an array); returns a view of
+    /// the new element
+    template<typename V>
+    View push_back(const View& array, V&& value)
+    {
+        node* const a = own(array);
+        if (a->kind != static_cast<std::uint8_t>(value_t::array) && a->kind != static_cast<std::uint8_t>(value_t::null))
+        {
+            throw_type_error(308, "cannot use push_back() with ", array.type_name());
+        }
+        const encoded e = encode(std::forward<V>(value));
+        if (a->kind == static_cast<std::uint8_t>(value_t::null))
+        {
+            become_empty(a, value_t::array);
+        }
+        node* const slot = new_slot(e);
+        node* const h = block_of(m_doc, a, 1);
+        make_link(h[h->next], slot);
+        ++h->next;
+        ++h->len;
+        ++a->len;
+        return View(&m_doc, slot);
+    }
+
+  private:
+    /// an encoded value: a scalar node, or the root of a new array/object
+    struct encoded
+    {
+        node scalar{};
+        node* region = nullptr;
+    };
+
+    /// the node of a view of this document
+    node* own(const View& v)
+    {
+        if (NLOHMANN_VIEW_UNLIKELY(v.m_doc != &m_doc || v.m_node == nullptr))
+        {
+            throw_invalid_iterator(202, "view does not belong to this document");
+        }
+        edit_state_of(m_doc);
+        return const_cast<node*>(v.m_node); // NOLINT(cppcoreguidelines-pro-type-const-cast): the nodes belong to this document
+    }
+
+    static void check_index(std::size_t idx, std::size_t limit)
+    {
+        if (idx >= limit)
+        {
+            throw_out_of_range(401, concat("array index ", std::to_string(idx), " is out of range"));
+        }
+    }
+
+    bool key_equals(const node& k, string_view_t key) const noexcept
+    {
+        return k.len == key.size() && (key.size() == 0 || std::memcmp(m_doc.str(k), key.data(), key.size()) == 0);
+    }
+
+    /// remove the members with this key (all, or all but the first) from an object
+    std::size_t erase_members(node* o, string_view_t key, bool keep_first)
+    {
+        node* const h = block_of(m_doc, o, 0);
+        node* w = h + 1;
+        std::size_t erased = 0;
+        bool kept = false;
+        for (node* r = h + 1, *end = h + h->next; r != end; r += 2)
+        {
+            const bool match = key_equals(*r, key);
+            if (match && (kept || !keep_first))
+            {
+                ++erased;
+                continue;
+            }
+            kept = kept || match;
+            if (w != r)
+            {
+                w[0] = r[0];
+                w[1] = r[1];
+            }
+            w += 2;
+        }
+        h->next = static_cast<std::uint32_t>(w - h);
+        h->len -= static_cast<std::uint32_t>(erased);
+        o->len -= static_cast<std::uint32_t>(erased);
+        return erased;
+    }
+
+    /// turn a null into an empty array/object in place
+    static void become_empty(node* n, value_t k) noexcept
+    {
+        *n = node{};
+        n->kind = static_cast<std::uint8_t>(k);
+        n->flags = node_flags::is_new;
+        n->next = 1;
+    }
+
+    /// Replace the value at slot; `parent` is the container whose elements
+    /// include slot (if known).
+    void assign(node* slot, const encoded& e, node* parent, bool parent_known)
+    {
+        if (e.region == nullptr)
+        {
+            if (is_container(*slot) && slot->next > 1 && slot != m_doc.tape)
+            {
+                // The slot spans its old elements in the enclosing sequence, but
+                // a scalar is one node: the enclosing container first switches to
+                // links (then the extent of the slot no longer matters).
+                node* const p = parent_known ? parent : find_parent(m_doc, slot);
+                if (p != nullptr && ((p->flags & node_flags::moved) == 0 || moved_capacity(m_doc, p) == 0))
+                {
+                    block_of(m_doc, p, 0);
+                }
+            }
+            *slot = e.scalar;
+            return;
+        }
+        // an array/object: the slot keeps its extent (so that the enclosing
+        // sequence still steps over it), and the elements come from the new
+        // sequence
+        const node* const r = e.region;
+        const std::uint32_t extent = is_container(*slot) ? slot->next : 1;
+        const bool was_moved = (slot->flags & node_flags::moved) != 0;
+        slot->kind = r->kind;
+        slot->extra = 0;
+        slot->len = r->len;
+        slot->next = extent;
+        slot->flags = was_moved ? static_cast<std::uint8_t>(node_flags::moved | node_flags::is_new) : std::uint8_t{0};
+        set_moved(m_doc, slot, e.region, 0);
+        edit_state_of(m_doc).regions[e.region] = slot;
+    }
+
+    /// a node for a new element (links point to it; it never moves)
+    node* new_slot(const encoded& e)
+    {
+        if (e.region != nullptr)
+        {
+            return e.region;
+        }
+        node* const s = alloc_nodes(m_doc, 1);
+        *s = e.scalar;
+        return s;
+    }
+
+    //////////////
+    // encoding //
+    //////////////
+
+    template<int N>
+    using encode_tag = std::integral_constant<int, N>;
+
+    template<typename T>
+    struct is_view : std::false_type {};
+
+    template<typename J, bool E>
+    struct is_view<basic_json_view<J, E>> : std::true_type {};
+
+    template<typename V>
+    encoded encode(V&& v)
+    {
+        using D = typename std::decay<V>::type;
+        return encode_impl(std::forward<V>(v), encode_tag<first_true<is_view<D>::value,
+                           std::is_same<D, BasicJsonType>::value,
+                           std::is_same<D, std::nullptr_t>::value,
+                           std::is_same<D, bool>::value,
+                           std::is_arithmetic<D>::value,
+                           std::is_convertible<const D&, string_view_t>::value>::value> {});
+    }
+
+    /// a view of any document (copied; nothing is shared with it)
+    template<typename J, bool E>
+    encoded encode_impl(const basic_json_view<J, E>& v, encode_tag<0> /*view*/)
+    {
+        if (NLOHMANN_VIEW_UNLIKELY(v.m_node == nullptr))
+        {
+            throw_type_error(302, "type must be a value, but is ", "discarded");
+        }
+        encoded r;
+        if (!is_container(*v.m_node))
+        {
+            r.scalar = copy_scalar(*v.m_doc, *v.m_node);
+            return r;
+        }
+        r.region = alloc_nodes(m_doc, count_nodes<E>(*v.m_doc, v.m_node));
+        fill_nodes<E>(*v.m_doc, v.m_node, r.region);
+        edit_state_of(m_doc).regions.emplace(r.region, nullptr);
+        return r;
+    }
+
+    encoded encode_impl(const BasicJsonType& j, encode_tag<1> /*json*/)
+    {
+        encoded r;
+        if (!j.is_structured())
+        {
+            r.scalar = json_scalar(j);
+            return r;
+        }
+        r.region = alloc_nodes(m_doc, count_nodes(j));
+        fill_nodes(j, r.region);
+        edit_state_of(m_doc).regions.emplace(r.region, nullptr);
+        return r;
+    }
+
+    encoded encode_impl(std::nullptr_t /*unused*/, encode_tag<2> /*null*/)
+    {
+        encoded r;
+        r.scalar = plain_node(value_t::null);
+        return r;
+    }
+
+    encoded encode_impl(bool b, encode_tag<3> /*boolean*/)
+    {
+        encoded r;
+        r.scalar = plain_node(value_t::boolean);
+        r.scalar.flags = static_cast<std::uint8_t>(r.scalar.flags | (b ? node_flags::is_true : 0));
+        return r;
+    }
+
+    template<typename T>
+    encoded encode_impl(T x, encode_tag<4> /*number*/)
+    {
+        encoded r;
+        r.scalar = number_node(x, std::integral_constant<int, first_true<std::is_floating_point<T>::value, std::is_signed<T>::value>::value> {});
+        return r;
+    }
+
+    template<typename T>
+    encoded encode_impl(const T& s, encode_tag<5> /*string*/)
+    {
+        const string_view_t sv(s);
+        check_utf8(sv.data(), sv.size());
+        encoded r;
+        r.scalar = string_node(sv.data(), sv.size());
+        return r;
+    }
+
+    template<typename T>
+    encoded encode_impl(T&& x, encode_tag<6> /*other*/)
+    {
+        return encode_impl(BasicJsonType(std::forward<T>(x)), encode_tag<1> {});
+    }
+
+    static node plain_node(value_t k) noexcept
+    {
+        node n{};
+        n.kind = static_cast<std::uint8_t>(k);
+        n.flags = node_flags::is_new;
+        return n;
+    }
+
+    template<typename T>
+    node number_node(T x, std::integral_constant<int, 0> /*floating-point*/)
+    {
+        return float_node(static_cast<number_float_t>(x));
+    }
+
+    template<typename T>
+    node number_node(T x, std::integral_constant<int, 1> /*signed*/)
+    {
+        return integer_node(static_cast<std::uint64_t>(static_cast<std::int64_t>(x)), value_t::number_integer);
+    }
+
+    template<typename T>
+    node number_node(T x, std::integral_constant<int, 2> /*unsigned*/)
+    {
+        return integer_node(static_cast<std::uint64_t>(x), value_t::number_unsigned);
+    }
+
+    /// an integer with its canonical token in the edit arena
+    node integer_node(std::uint64_t bits, value_t k)
+    {
+        const bool negative = k == value_t::number_integer && static_cast<std::int64_t>(bits) < 0;
+        std::uint64_t magnitude = negative ? 0 - bits : bits;
+        std::array<char, 24> buf{};
+        char* p = buf.data() + buf.size();
+        do
+        {
+            *--p = static_cast<char>('0' + (magnitude % 10));
+            magnitude /= 10;
+        }
+        while (magnitude != 0);
+        if (negative)
+        {
+            *--p = '-';
+        }
+        const auto len = static_cast<std::size_t>(buf.data() + buf.size() - p);
+        node n = plain_node(k);
+        n.flags = static_cast<std::uint8_t>(n.flags | node_flags::edited);
+        n.off = append_text(m_doc, p, len);
+        // number_length() adds one for the sign of number_integer nodes
+        n.extra = static_cast<std::uint16_t>(k == value_t::number_integer ? len - 1 : len);
+        set_integer_bits(n, bits);
+        return n;
+    }
+
+    /// a float with its shortest round-trip token (as basic_json::dump()
+    /// writes it), or nan, inf, -inf, in the edit arena
+    node float_node(number_float_t x)
+    {
+        string_t text;
+        if (std::isnan(x))
+        {
+            text = "nan";
+        }
+        else if (std::isinf(x))
+        {
+            text = x > 0 ? "inf" : "-inf";
+        }
+        else
+        {
+            text = BasicJsonType(x).dump();
+        }
+        node n = plain_node(value_t::number_float);
+        n.flags = static_cast<std::uint8_t>(n.flags | node_flags::edited);
+        n.extra = 0xFFFFu; // (the digit layout is not recorded)
+        n.off = append_text(m_doc, text.data(), text.size());
+        n.len = static_cast<std::uint32_t>(text.size());
+        return n;
+    }
+
+    /// a string (or key) in the edit arena
+    node string_node(const char* s, std::size_t len)
+    {
+        if (NLOHMANN_VIEW_UNLIKELY(len >= 0xFFFFFFFFu))
+        {
+            throw_out_of_range(416, "strings of 4 GiB or more are not supported by json_document"); // LCOV_EXCL_LINE
+        }
+        node n = plain_node(value_t::string);
+        n.flags = static_cast<std::uint8_t>(n.flags | node_flags::edited);
+        n.off = append_text(m_doc, s, len);
+        n.len = static_cast<std::uint32_t>(len);
+        return n;
+    }
+
+    /// a scalar of a view (of any document) as a node of this document
+    node copy_scalar(const document_data& from, const node& n)
+    {
+        if (&from == &m_doc)
+        {
+            return n; // the same storage
+        }
+        switch (static_cast<value_t>(n.kind))
+        {
+            case value_t::string:
+                return string_node(from.str(n), n.len);
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+                return integer_node(integer_bits(n), static_cast<value_t>(n.kind));
+            case value_t::number_float:
+            {
+                node r = plain_node(value_t::number_float);
+                r.flags = static_cast<std::uint8_t>(r.flags | node_flags::edited);
+                r.off = append_text(m_doc, from.str(n), n.len);
+                r.len = n.len;
+                r.extra = n.extra;
+                return r;
+            }
+            case value_t::boolean:
+            {
+                node r = plain_node(value_t::boolean);
+                r.flags = static_cast<std::uint8_t>(r.flags | (n.flags & node_flags::is_true));
+                return r;
+            }
+            case value_t::null:
+            case value_t::object:
+            case value_t::array:
+            case value_t::binary:
+            case value_t::discarded:
+            default:
+                return plain_node(value_t::null);
+        }
+    }
+
+    node json_scalar(const BasicJsonType& j)
+    {
+        switch (j.type())
+        {
+            case value_t::null:
+                return plain_node(value_t::null);
+            case value_t::boolean:
+            {
+                node r = plain_node(value_t::boolean);
+                r.flags = static_cast<std::uint8_t>(r.flags | (j.template get<bool>() ? node_flags::is_true : 0));
+                return r;
+            }
+            case value_t::number_integer:
+                return integer_node(static_cast<std::uint64_t>(static_cast<std::int64_t>(j.template get<number_integer_t>())), value_t::number_integer);
+            case value_t::number_unsigned:
+                return integer_node(static_cast<std::uint64_t>(j.template get<number_unsigned_t>()), value_t::number_unsigned);
+            case value_t::number_float:
+                return float_node(j.template get<number_float_t>());
+            case value_t::string:
+            {
+                const auto& s = j.template get_ref<const string_t&>();
+                check_utf8(s.data(), s.size());
+                return string_node(s.data(), s.size());
+            }
+            case value_t::binary:
+                throw_type_error(319, "cannot store a binary value in a json_document", "");
+            case value_t::discarded:
+            case value_t::object:
+            case value_t::array:
+            default:
+                throw_type_error(302, "type must be a value, but is ", "discarded");
+        }
+    }
+
+    /// number of nodes of a subtree (containers, keys, scalars)
+    template<bool E>
+    static std::size_t count_nodes(const document_data& d, const node* n)
+    {
+        if (!is_container(*n))
+        {
+            return 1;
+        }
+        const bool object = n->kind == static_cast<std::uint8_t>(value_t::object);
+        std::size_t r = 1;
+        for (const node* c = navigation<E>::first(d, n), *end = navigation<E>::end(d, n); c != end;)
+        {
+            const node* const v = object ? c + 1 : c;
+            r += (object ? 1 : 0) + count_nodes<E>(d, navigation<E>::value(v));
+            c = document_data::after(v);
+        }
+        return r;
+    }
+
+    /// copy a subtree (of any document) as a contiguous sequence; returns its end
+    template<bool E>
+    node* fill_nodes(const document_data& d, const node* n, node* out)
+    {
+        if (!is_container(*n))
+        {
+            *out = copy_scalar(d, *n);
+            return out + 1;
+        }
+        node* const self = out++;
+        *self = plain_node(static_cast<value_t>(n->kind));
+        self->len = n->len;
+        const bool object = n->kind == static_cast<std::uint8_t>(value_t::object);
+        for (const node* c = navigation<E>::first(d, n), *end = navigation<E>::end(d, n); c != end;)
+        {
+            if (object)
+            {
+                *out++ = copy_scalar(d, *c);
+                ++c;
+            }
+            out = fill_nodes<E>(d, navigation<E>::value(c), out);
+            c = document_data::after(c);
+        }
+        self->next = static_cast<std::uint32_t>(out - self);
+        return out;
+    }
+
+    static std::size_t count_nodes(const BasicJsonType& j)
+    {
+        std::size_t r = 1;
+        if (j.is_object())
+        {
+            for (const auto& member : j.items())
+            {
+                r += 1 + count_nodes(member.value());
+            }
+        }
+        else if (j.is_array())
+        {
+            for (const auto& e : j)
+            {
+                r += count_nodes(e);
+            }
+        }
+        return r;
+    }
+
+    node* fill_nodes(const BasicJsonType& j, node* out)
+    {
+        if (!j.is_structured())
+        {
+            *out = json_scalar(j);
+            return out + 1;
+        }
+        node* const self = out++;
+        *self = plain_node(j.type());
+        self->len = static_cast<std::uint32_t>(j.size());
+        if (j.is_object())
+        {
+            for (const auto& member : j.items())
+            {
+                check_utf8(member.key().data(), member.key().size());
+                *out++ = string_node(member.key().data(), member.key().size());
+                out = fill_nodes(member.value(), out);
+            }
+        }
+        else
+        {
+            for (const auto& e : j)
+            {
+                out = fill_nodes(e, out);
+            }
+        }
+        self->next = static_cast<std::uint32_t>(out - self);
+        return out;
+    }
+
+    document_data& m_doc;
+};
+
+}  // namespace view
+}  // namespace detail
+NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/detail/view/edit_storage.hpp

@@ -0,0 +1,242 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <algorithm> // max, min
+#include <cstddef> // size_t
+#include <cstdint> // uint8_t, uint32_t
+#include <cstring> // memcpy
+#include <functional> // less
+#include <memory> // unique_ptr
+#include <utility> // move
+
+#include <nlohmann/json.hpp>
+#include <nlohmann/detail/view/document_data.hpp>
+#include <nlohmann/detail/view/errors.hpp>
+#include <nlohmann/detail/view/macro_scope.hpp>
+#include <nlohmann/detail/view/node.hpp>
+
+// The storage of edits. Edits never move or resize the parsed index: every
+// value keeps its node, so views stay valid. New values and element sequences
+// live in chunks that never move; strings and number tokens written by edits
+// live in the edit arena. An array/object whose elements change gets
+// node_flags::moved: its elements then live in a separate sequence (a header
+// node, then the entries), whose entries link to the values (kind_link).
+
+NLOHMANN_JSON_NAMESPACE_BEGIN
+namespace detail
+{
+namespace view
+{
+
+inline document_data::edit_state& edit_state_of(document_data& d)
+{
+    if (!d.edits)
+    {
+        d.edits.reset(new document_data::edit_state()); // NOLINT(cppcoreguidelines-owning-memory): owned by the unique_ptr
+    }
+    return *d.edits;
+}
+
+/// k consecutive nodes that never move (new values and blocks)
+inline node* alloc_nodes(document_data& d, std::size_t k)
+{
+    document_data::edit_state& e = edit_state_of(d);
+    if (NLOHMANN_VIEW_UNLIKELY(static_cast<std::size_t>(e.chunk_end - e.chunk_cur) < k))
+    {
+        const std::size_t count = (std::max)(k, e.chunk_next);
+        std::unique_ptr<node[]> fresh(new node[count]()); // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
+        e.chunks.push_back(std::move(fresh));
+        e.chunk_cur = e.chunks.back().get();
+        e.chunk_end = e.chunk_cur + count;
+        e.chunk_next = (std::min)(e.chunk_next * 2, std::size_t{65536});
+        e.bytes += count * sizeof(node);
+    }
+    node* const r = e.chunk_cur;
+    e.chunk_cur += k;
+    return r;
+}
+
+/// copy n bytes into the edit arena and return their offset; a new buffer
+/// leaves the old one alive, so that string views into it remain valid
+inline std::uint32_t append_text(document_data& d, const char* s, std::size_t n)
+{
+    document_data::edit_state& e = edit_state_of(d);
+    if (NLOHMANN_VIEW_UNLIKELY(e.text_cap - e.text_used < n))
+    {
+        const std::size_t cap = (std::max)(e.text_cap * 2, e.text_used + n + 256);
+        if (cap > 0xFFFFFFFFu)
+        {
+            throw_out_of_range(416, "edits of 4 GiB or more are not supported by json_document"); // LCOV_EXCL_LINE (4 GiB)
+        }
+        std::unique_ptr<char[]> fresh(new char[cap]); // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
+        if (e.text_used != 0)
+        {
+            std::memcpy(fresh.get(), e.texts.back().get(), e.text_used);
+        }
+        e.texts.push_back(std::move(fresh));
+        e.text_cap = cap;
+        e.bytes += cap;
+        d.base[2] = e.texts.back().get();
+    }
+    const auto off = static_cast<std::uint32_t>(e.text_used);
+    if (n != 0)
+    {
+        std::memcpy(e.texts.back().get() + e.text_used, s, n);
+    }
+    e.text_used += n;
+    return off;
+}
+
+/// the capacity in nodes of the block of a moved container (0: a fixed
+/// sequence, the elements of a new value)
+inline std::size_t moved_capacity(const document_data& d, const node* n) noexcept
+{
+    return d.edits->moved_cap[n->off];
+}
+
+/// let container n take its elements from `seq` (header node first)
+inline void set_moved(document_data& d, node* n, node* seq, std::size_t cap)
+{
+    document_data::edit_state& e = edit_state_of(d);
+    if ((n->flags & node_flags::moved) != 0)
+    {
+        e.moved[n->off] = seq;
+        e.moved_cap[n->off] = cap;
+        return;
+    }
+    if (e.moved.size() >= 0xFFFFFFFFu)
+    {
+        throw_out_of_range(416, "more than 4294967295 edited arrays and objects are not supported by json_document"); // LCOV_EXCL_LINE
+    }
+    if (e.moved.size() == e.moved.capacity() || e.moved_cap.size() == e.moved_cap.capacity())
+    {
+        // both grow before either changes, so that the push_backs cannot throw
+        e.moved.reserve((2 * e.moved.size()) + 16);
+        e.moved_cap.reserve((2 * e.moved.size()) + 16);
+    }
+    e.moved.push_back(seq);
+    e.moved_cap.push_back(cap);
+    n->off = static_cast<std::uint32_t>(e.moved.size() - 1);
+    n->flags = static_cast<std::uint8_t>(n->flags | node_flags::moved | node_flags::is_new);
+}
+
+/// Make the elements of container n a growable block with room for `extra`
+/// more nodes, and return its header. The entries link to the existing
+/// values, which stay where they are. A block that grows is copied (its old
+/// space is not reused).
+inline node* block_of(document_data& d, node* n, std::size_t extra)
+{
+    if ((n->flags & node_flags::moved) != 0 && moved_capacity(d, n) != 0)
+    {
+        node* const h = d.edits->moved[n->off];
+        if (h->next + extra <= moved_capacity(d, n))
+        {
+            return h;
+        }
+        const std::size_t cap = (std::max)(2 * moved_capacity(d, n), h->next + extra);
+        node* const nh = alloc_nodes(d, cap);
+        std::memcpy(nh, h, h->next * sizeof(node));
+        set_moved(d, n, nh, cap);
+        return nh;
+    }
+    const bool object = n->kind == static_cast<std::uint8_t>(value_t::object);
+    const std::size_t used = 1 + (static_cast<std::size_t>(n->len) * (object ? 2 : 1));
+    const std::size_t cap = used + extra;
+    node* const h = alloc_nodes(d, cap);
+    *h = node{};
+    h->kind = n->kind;
+    h->len = n->len;
+    h->next = static_cast<std::uint32_t>(used);
+    node* o = h + 1;
+    for (const node* c = d.first_child_edited(n), *e = d.child_end_edited(n); c != e;)
+    {
+        if (object)
+        {
+            *o++ = *c++; // the key
+        }
+        make_link(*o, document_data::deref(c));
+        ++o;
+        c = document_data::after(c);
+    }
+    set_moved(d, n, h, cap);
+    return h;
+}
+
+/// The container whose elements include `target`; nullptr for the root, for
+/// a value that is no longer part of the document, and for a value that is
+/// only reached through a link. Values never move between allocations, so
+/// the path to `target` stays inside the allocation that holds it (the parsed
+/// index, or one new value), where the extent of each container (`next`)
+/// still covers its original subtree.
+inline node* find_parent(const document_data& d, const node* target)
+{
+    const std::less<const node*> lt;
+    const node* lo = d.tape;
+    const node* hi = d.tape + d.tape_size;
+    const node* c = d.tape;
+    if (lt(target, lo) || !lt(target, hi))
+    {
+        if (!d.edits)
+        {
+            return nullptr; // LCOV_EXCL_LINE (nodes outside the index exist only after edits)
+        }
+        auto it = d.edits->regions.upper_bound(target);
+        if (it == d.edits->regions.begin())
+        {
+            return nullptr; // LCOV_EXCL_LINE (an array/object with elements is in the index or a new value)
+        }
+        --it;
+        lo = it->first;
+        hi = lo + lo->next;
+        if (!lt(target, hi))
+        {
+            return nullptr; // LCOV_EXCL_LINE (a single-node value, reached through a link)
+        }
+        // the root of a new value is the element sequence of its owner, or a linked value
+        c = it->second != nullptr ? it->second : lo;
+    }
+    if (target == lo)
+    {
+        return nullptr;
+    }
+    for (;;)
+    {
+        if (!is_container(*c))
+        {
+            return nullptr; // LCOV_EXCL_LINE (the value is inside c)
+        }
+        const bool object = c->kind == static_cast<std::uint8_t>(value_t::object);
+        const node* down = nullptr;
+        for (const node* p = d.first_child_edited(c), *e = d.child_end_edited(c); p != e;)
+        {
+            const node* const at = object ? p + 1 : p;
+            const node* const v = document_data::deref(at);
+            if (v == target)
+            {
+                return const_cast<node*>(c); // NOLINT(cppcoreguidelines-pro-type-const-cast): the nodes belong to the document
+            }
+            if (is_container(*v) && !lt(v, lo) && lt(v, target) && lt(target, v + v->next))
+            {
+                down = v;
+                break;
+            }
+            p = document_data::after(at);
+        }
+        if (down == nullptr)
+        {
+            return nullptr;
+        }
+        c = down;
+    }
+}
+
+}  // namespace view
+}  // namespace detail
+NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/detail/view/errors.hpp

@@ -30,6 +30,11 @@ namespace view
     NLOHMANN_VIEW_THROW(type_error::create(id, concat(prefix, type), nullptr));
 }
 
+[[noreturn]] NLOHMANN_VIEW_NOINLINE inline void throw_type_error(int id, const std::string& msg)
+{
+    NLOHMANN_VIEW_THROW(type_error::create(id, msg, nullptr));
+}
+
 [[noreturn]] NLOHMANN_VIEW_NOINLINE inline void throw_out_of_range(int id, const std::string& msg)
 {
     NLOHMANN_VIEW_THROW(out_of_range::create(id, msg, nullptr));
@@ -40,6 +45,12 @@ namespace view
     NLOHMANN_VIEW_THROW(invalid_iterator::create(id, msg, nullptr));
 }
 
+/// a parse error without a position (as those of json_pointer)
+[[noreturn]] NLOHMANN_VIEW_NOINLINE inline void throw_parse_error(int id, const std::string& msg)
+{
+    NLOHMANN_VIEW_THROW(parse_error::create(id, 0, msg, nullptr));
+}
+
 /*!
 @brief throw the exception BasicJsonType::parse would throw for this input
 

include/nlohmann/detail/view/iterator.hpp

@@ -73,7 +73,7 @@ class view_iterator
 
     NLOHMANN_VIEW_ALWAYS_INLINE View operator*() const noexcept
     {
-        return View(m_doc, m_pos + m_value_offset);
+        return View(m_doc, View::navigation::value(m_pos + m_value_offset));
     }
 
     pointer operator->() const noexcept

include/nlohmann/detail/view/lookup.hpp

@@ -16,6 +16,7 @@
 #include <nlohmann/detail/view/document_data.hpp>
 #include <nlohmann/detail/view/macro_scope.hpp>
 #include <nlohmann/detail/view/node.hpp>
+#include <nlohmann/detail/view/object_index.hpp>
 
 NLOHMANN_JSON_NAMESPACE_BEGIN
 namespace detail
@@ -83,14 +84,20 @@ class short_key
 
 /// the key node of the first member of an object with the given key, or
 /// nullptr; most keys are rejected by their length, from the index alone
-inline const node* find_member(const document_data& d, const node* object, const char* key, std::size_t n) noexcept
+template<bool Editable>
+const node* find_member(const document_data& d, const node* object, const char* key, std::size_t n) noexcept
 {
-    const node* const end = document_data::child_end(object);
+    using nav = navigation<Editable>;
+    if (NLOHMANN_VIEW_UNLIKELY(object->extra != 0) && (!Editable || (object->flags & node_flags::moved) == 0))
+    {
+        return find_indexed(d, object, key, n); // a large object (whose members have not been edited)
+    }
+    const node* const end = nav::end(d, object);
     const auto* const k = reinterpret_cast<const unsigned char*>(key); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
     if (NLOHMANN_VIEW_LIKELY(n <= 16))
     {
         const short_key probe(k, n);
-        for (const node* m = document_data::first_child(object); m != end; m = document_data::after(m + 1))
+        for (const node* m = nav::first(d, object); m != end; m = document_data::after(m + 1))
         {
             if (m->len == n && probe.matches(reinterpret_cast<const unsigned char*>(d.str(*m)))) // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
             {
@@ -99,7 +106,7 @@ inline const node* find_member(const document_data& d, const node* object, const
         }
         return nullptr;
     }
-    for (const node* m = document_data::first_child(object); m != end; m = document_data::after(m + 1))
+    for (const node* m = nav::first(d, object); m != end; m = document_data::after(m + 1))
     {
         if (m->len == n && std::memcmp(d.str(*m), key, n) == 0)
         {
@@ -109,10 +116,16 @@ inline const node* find_member(const document_data& d, const node* object, const
     return nullptr;
 }
 
-/// the element of an array at an index below its size
-inline const node* element_at(const node* array, std::size_t idx) noexcept
+/// the entry of the element of an array at an index below its size (a link
+/// in the moved sequences of editable documents)
+template<bool Editable>
+const node* element_at(const document_data& d, const node* array, std::size_t idx) noexcept
 {
-    const node* e = document_data::first_child(array);
+    const node* e = navigation<Editable>::first(d, array);
+    if (Editable && (array->flags & node_flags::moved) != 0 && d.edits->moved_cap[array->off] != 0)
+    {
+        return e + idx; // a growable block: one link per element
+    }
     for (std::size_t i = 0; i < idx; ++i)
     {
         e = document_data::after(e);
@@ -120,13 +133,14 @@ inline const node* element_at(const node* array, std::size_t idx) noexcept
     return e;
 }
 
-/// the last element of a non-empty array, or the key of the last member of a
-/// non-empty object
-inline const node* last_child(const node* container) noexcept
+/// the entry of the last element of a non-empty array, or the key of the
+/// last member of a non-empty object
+template<bool Editable>
+const node* last_child(const document_data& d, const node* container) noexcept
 {
     const std::size_t value_offset = container->kind == static_cast<std::uint8_t>(value_t::object) ? 1 : 0;
-    const node* const end = document_data::child_end(container);
-    const node* last = document_data::first_child(container);
+    const node* const end = navigation<Editable>::end(d, container);
+    const node* last = navigation<Editable>::first(d, container);
     for (const node* c = document_data::after(last + value_offset); c != end; c = document_data::after(c + value_offset))
     {
         last = c;

include/nlohmann/detail/view/macro_unscope.hpp

@@ -19,3 +19,8 @@
 #undef NLOHMANN_VIEW_THROW
 #undef NLOHMANN_VIEW_LITTLE_ENDIAN
 #undef NLOHMANN_VIEW_REPEAT16
+#undef NLOHMANN_VIEW_NEON
+#undef NLOHMANN_VIEW_SSE2
+#undef NLOHMANN_VIEW_SSSE3
+#undef NLOHMANN_VIEW_VECTOR
+#undef NLOHMANN_VIEW_VECTOR_UTF8

include/nlohmann/detail/view/materialize.hpp

@@ -34,17 +34,24 @@ iterative, so the nesting depth is limited by memory only, as for parse().
 Without a lexer the handler records no source positions
 (JSON_DIAGNOSTIC_POSITIONS).
 */
-template<typename BasicJsonType>
+template<typename BasicJsonType, bool Editable>
 BasicJsonType materialize(const document_data& d, const node* n)
 {
     using string_t = typename BasicJsonType::string_t;
     using sax_t = json_sax_dom_parser<BasicJsonType, iterator_input_adapter<const char*>>;
+    using nav = navigation<Editable>;
+
+    struct frame
+    {
+        const node* pos; ///< next element, or key of the next member
+        const node* end;
+        bool object;
+    };
 
     BasicJsonType result;
     sax_t sax(result, true);
     const string_t no_token{};
-    // the ends of the open containers, and whether they are objects
-    std::vector<std::pair<const node*, bool>> open;
+    std::vector<frame> open;
     for (;;)
     {
         switch (static_cast<value_t>(n->kind))
@@ -61,67 +68,66 @@ BasicJsonType materialize(const document_data& d, const node* n)
                 {
                     sax.start_array(n->len);
                 }
-                open.emplace_back(document_data::child_end(n), object);
-                n = document_data::first_child(n);
+                open.push_back(frame{nav::first(d, n), nav::end(d, n), object});
                 break;
             }
             case value_t::string:
             {
                 string_t s(d.str(*n), n->len);
                 sax.string(s);
-                ++n;
                 break;
             }
             case value_t::number_integer:
                 sax.number_integer(static_cast<typename BasicJsonType::number_integer_t>(static_cast<std::int64_t>(integer_bits(*n))));
-                ++n;
                 break;
             case value_t::number_unsigned:
                 sax.number_unsigned(static_cast<typename BasicJsonType::number_unsigned_t>(integer_bits(*n)));
-                ++n;
                 break;
             case value_t::number_float:
-                sax.number_float(float_value<typename BasicJsonType::number_float_t>(d.str(*n), *n), no_token);
-                ++n;
+                sax.number_float(float_value<typename BasicJsonType::number_float_t>(d, *n), no_token);
                 break;
             case value_t::boolean:
                 sax.boolean((n->flags & node_flags::is_true) != 0);
-                ++n;
                 break;
             case value_t::null:
             case value_t::binary:
             case value_t::discarded:
             default:
                 sax.null();
-                ++n;
                 break;
         }
+
+        // the next value: close finished containers, then read the key
         for (;;)
         {
             if (open.empty())
             {
                 return result;
             }
-            if (n != open.back().first)
+            frame& f = open.back();
+            if (f.pos == f.end)
             {
-                break;
+                if (f.object)
+                {
+                    sax.end_object();
+                }
+                else
+                {
+                    sax.end_array();
+                }
+                open.pop_back();
+                continue;
             }
-            if (open.back().second)
+            const node* entry = f.pos;
+            if (f.object)
             {
-                sax.end_object();
+                string_t key(d.str(*entry), entry->len);
+                sax.key(key);
+                ++entry;
             }
-            else
-            {
-                sax.end_array();
-            }
-            open.pop_back();
-        }
-        if (open.back().second)
-        {
-            // the key of the next member
-            string_t key(d.str(*n), n->len);
-            sax.key(key);
-            ++n;
+            n = nav::value(entry);
+            f.pos = document_data::after(entry);
+            break;
         }
     }
 }

include/nlohmann/detail/view/node.hpp

@@ -33,20 +33,27 @@ static_assert(static_cast<std::uint8_t>(value_t::null) == 0 && static_cast<std::
 struct node_flags
 {
     static constexpr std::uint8_t escaped = 1; ///< string payload lives in the decode arena, not the source
+    static constexpr std::uint8_t edited = 2;  ///< string or number token lives in the edit arena (editable documents)
     static constexpr std::uint8_t storage = 3; ///< mask: where a string or number token lives (index into document_data::base)
     static constexpr std::uint8_t is_true = 4; ///< boolean value
+    static constexpr std::uint8_t moved = 8;   ///< array/object: the elements live in a separate sequence (editable documents)
+    static constexpr std::uint8_t is_new = 16; ///< written by an edit: no source position
 };
 
+/// kind of an entry of an edited sequence that stands for a value stored
+/// elsewhere (the address of the value's node is kept in the len/next bytes)
+constexpr std::uint8_t kind_link = 10;
+
 /// One entry of the flat index, in document order. An object's members are
 /// stored as key node followed by the value's subtree. Integers keep their
 /// converted 64-bit value in the len/next bytes (the node after a scalar is
 /// always the next one, and the token length follows from `extra`).
 struct node
 {
-    std::uint8_t kind;   ///< value_t
+    std::uint8_t kind;   ///< value_t, or kind_link
     std::uint8_t flags;  ///< node_flags
-    std::uint16_t extra; ///< numbers: integer digits (low byte) and fraction digits (high byte), 255 = "many"; otherwise 0
-    std::uint32_t off;   ///< source offset (string content, number token, literal, bracket); arena offset if node_flags::escaped
+    std::uint16_t extra; ///< numbers: integer digits (low byte) and fraction digits (high byte), 255 = "many"; objects: number of the hash index; otherwise 0
+    std::uint32_t off;   ///< source offset (string content, number token, literal, bracket); arena offset if escaped/edited; number of the element sequence if moved
     std::uint32_t len;   ///< string: decoded bytes; float: token bytes; array/object: element count
     std::uint32_t next;  ///< array/object: number of nodes of the subtree (its extent in the enclosing sequence)
 };
@@ -57,6 +64,21 @@ NLOHMANN_VIEW_ALWAYS_INLINE bool is_container(const node& n) noexcept
     return static_cast<unsigned>(n.kind) - 1u <= 1u;
 }
 
+/// the value a link node stands for
+NLOHMANN_VIEW_ALWAYS_INLINE const node* link_target(const node& n) noexcept
+{
+    const node* t = nullptr;
+    std::memcpy(static_cast<void*>(&t), reinterpret_cast<const unsigned char*>(&n) + 8, sizeof(const node*)); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
+    return t;
+}
+
+inline void make_link(node& n, const node* target) noexcept
+{
+    n = node{};
+    n.kind = kind_link;
+    std::memcpy(reinterpret_cast<unsigned char*>(&n) + 8, static_cast<const void*>(&target), sizeof(const node*)); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
+}
+
 /// the converted value of an integer node (stored in len/next)
 NLOHMANN_VIEW_ALWAYS_INLINE std::uint64_t integer_bits(const node& n) noexcept
 {

include/nlohmann/detail/view/number.hpp

@@ -8,12 +8,20 @@
 
 #pragma once
 
+#include <array> // array
+#include <cfloat> // FLT_EVAL_METHOD
 #include <cstddef> // size_t
+#include <cstdint> // int64_t, uint64_t
+#include <cstring> // memcpy
+#include <limits> // numeric_limits
 #include <string> // string
+#include <type_traits> // integral_constant, is_same
 
 #include <nlohmann/json.hpp>
+#include <nlohmann/detail/view/document_data.hpp>
 #include <nlohmann/detail/view/macro_scope.hpp>
 #include <nlohmann/detail/view/node.hpp>
+#include <nlohmann/detail/view/scan.hpp>
 
 NLOHMANN_JSON_NAMESPACE_BEGIN
 namespace detail
@@ -68,6 +76,116 @@ NLOHMANN_VIEW_NOINLINE FloatType float_value(const char* first, const node& n)
     return v;
 }
 
+/*!
+@brief the double of a float token with at most 19 digits, from its layout
+
+The digit layout recorded while parsing says where the integer digits, the
+fraction digits, and the exponent are, so the digits are read eight at a
+time without scanning. The result is correctly rounded (Clinger's fast path
+where both operands are exact, else the Eisel-Lemire algorithm, which needs
+no fallback for up to 19 digits), so it is the value parse() produces.
+
+@param[in] p  first character of the token
+@param[in] e  end of the token
+@param[in] limit  end of the readable memory (the source text)
+*/
+NLOHMANN_VIEW_ALWAYS_INLINE double layout_double(const unsigned char* p, const unsigned char* e, unsigned int_digits, unsigned frac_digits, const unsigned char* limit) noexcept
+{
+    const bool negative = *p == '-';
+    p += negative ? 1 : 0;
+    std::uint64_t w = parse_upto19(p, int_digits, limit);
+    p += int_digits;
+    std::int64_t q = 0;
+    if (frac_digits != 0)
+    {
+        w = (w * int_pow10(frac_digits)) + parse_upto19(p + 1, frac_digits, limit);
+        p += 1 + frac_digits;
+        q = -static_cast<std::int64_t>(frac_digits);
+    }
+    if (p != e)
+    {
+        // [eE][+-]digits; huge exponents saturate (the parser rejected overflow)
+        ++p;
+        const bool exp_negative = *p == '-';
+        p += (*p == '-' || *p == '+') ? 1 : 0;
+        std::int64_t exp_value = 0;
+        for (; p != e; ++p)
+        {
+            if (exp_value < 0x10000000)
+            {
+                exp_value = (exp_value * 10) + (*p - '0');
+            }
+        }
+        q += exp_negative ? -exp_value : exp_value;
+    }
+
+    double result = 0;
+    if (w != 0)
+    {
+#if !defined(FLT_EVAL_METHOD) || FLT_EVAL_METHOD == 0
+        static const std::array<double, 23> pow10 = {{1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9, 1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19, 1e20, 1e21, 1e22}};
+        if (q >= -22 && q <= 22 && w <= (std::uint64_t{1} << 53))
+        {
+            // Clinger's fast path: both operands exact, one rounding
+            result = static_cast<double>(w);
+            result = q < 0 ? result / pow10[static_cast<std::size_t>(-q)] : result * pow10[static_cast<std::size_t>(q)];
+            return negative ? -result : result;
+        }
+#endif
+        const std::uint64_t bits = eisel_lemire(q, w);
+        std::memcpy(&result, &bits, sizeof(result));
+    }
+    return negative ? -result : result;
+}
+
+/// the value of a float set by an edit: its token (the shortest round-trip
+/// text, or "nan", "inf", "-inf") in the edit arena
+template<typename FloatType>
+NLOHMANN_VIEW_NOINLINE FloatType edited_float(const char* token, const node& n)
+{
+    if (token[0] == 'n')
+    {
+        return std::numeric_limits<FloatType>::quiet_NaN();
+    }
+    if (token[0] == 'i' || (token[0] == '-' && token[1] == 'i'))
+    {
+        return token[0] == 'i' ? std::numeric_limits<FloatType>::infinity() : -std::numeric_limits<FloatType>::infinity();
+    }
+    return float_value<FloatType>(token, n);
+}
+
+/// the value of the float token of a node, as parse() converts it; doubles
+/// with at most 19 digits are converted from the digit layout
+template<typename FloatType>
+FloatType float_value(const document_data& d, const node& n)
+{
+    if (NLOHMANN_VIEW_UNLIKELY((n.flags & node_flags::storage) == node_flags::edited))
+    {
+        return edited_float<FloatType>(d.str(n), n);
+    }
+    return float_value<FloatType>(d, n, std::is_same<FloatType, double> {});
+}
+
+template<typename FloatType>
+FloatType float_value(const document_data& d, const node& n, std::true_type /*double*/)
+{
+    const unsigned int_digits = n.extra & 0xFFu;
+    const unsigned frac_digits = n.extra >> 8u;
+    if (NLOHMANN_VIEW_LIKELY(int_digits + frac_digits <= 19)) // (255 marks "many")
+    {
+        // (a float token not written by an edit is in the text)
+        const auto* const first = reinterpret_cast<const unsigned char*>(d.src + n.off); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
+        return layout_double(first, first + n.len, int_digits, frac_digits, reinterpret_cast<const unsigned char*>(d.src + d.size)); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
+    }
+    return float_value<FloatType>(d.str(n), n);
+}
+
+template<typename FloatType>
+FloatType float_value(const document_data& d, const node& n, std::false_type /*other*/)
+{
+    return float_value<FloatType>(d.str(n), n);
+}
+
 }  // namespace view
 }  // namespace detail
 NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/detail/view/object_index.hpp

@@ -0,0 +1,129 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <cstddef> // size_t
+#include <cstdint> // uint32_t, uint64_t
+#include <cstring> // memcmp
+
+#include <nlohmann/json.hpp>
+#include <nlohmann/detail/view/document_data.hpp>
+#include <nlohmann/detail/view/macro_scope.hpp>
+#include <nlohmann/detail/view/node.hpp>
+
+// Hash indexes of large objects, so that a lookup does not compare thousands
+// of keys (as Boost.JSON switches from a linear search to a hash table for
+// large objects). An object with document_data::index_min_members members or
+// more gets an open-addressing table after parsing; its node stores the
+// number of the table (1-based) in `extra`. A slot holds the offset of a key
+// node from its object node (0: empty). Of duplicate keys, the first is kept,
+// as for the linear search.
+
+NLOHMANN_JSON_NAMESPACE_BEGIN
+namespace detail
+{
+namespace view
+{
+
+/// hash of a key: its bytes, eight at a time, in a fixed byte order
+inline std::uint64_t key_hash(const char* s, std::size_t n) noexcept
+{
+    std::uint64_t h = 0x9E3779B97F4A7C15u * (n + 1);
+    const auto* p = reinterpret_cast<const unsigned char*>(s); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
+    while (n >= 8)
+    {
+        h = (h ^ read_eight_bytes(p)) * 0xBF58476D1CE4E5B9u;
+        h ^= h >> 29u;
+        p += 8;
+        n -= 8;
+    }
+    std::uint64_t w = 0;
+    for (std::size_t i = 0; i < n; ++i)
+    {
+        w |= static_cast<std::uint64_t>(p[i]) << (8u * i);
+    }
+    h = (h ^ w) * 0x94D049BB133111EBu;
+    return h ^ (h >> 31u);
+}
+
+/// build the table of a large object
+inline void build_object_index(document_data& d, node* obj)
+{
+    if (d.indexes.size() >= 0xFFFFu)
+    {
+        return; // LCOV_EXCL_LINE (the number must fit `extra`; more large objects are searched linearly)
+    }
+    std::size_t cap = 16;
+    while (cap < 2 * static_cast<std::size_t>(obj->len))
+    {
+        cap *= 2;
+    }
+    const std::size_t start = d.index_slots.size();
+    d.index_slots.resize(start + cap, 0);
+    std::uint32_t* const slots = d.index_slots.data() + start;
+    const std::size_t mask = cap - 1;
+    for (const node* k = document_data::first_child(obj), *end = document_data::child_end(obj); k != end; k = document_data::after(k + 1))
+    {
+        const char* const key = d.str(*k);
+        std::size_t i = static_cast<std::size_t>(key_hash(key, k->len)) & mask;
+        bool duplicate = false;
+        while (slots[i] != 0)
+        {
+            const node* const other = obj + slots[i];
+            if (other->len == k->len && (k->len == 0 || std::memcmp(d.str(*other), key, k->len) == 0))
+            {
+                duplicate = true; // keep the first
+                break;
+            }
+            i = (i + 1) & mask;
+        }
+        if (!duplicate)
+        {
+            slots[i] = static_cast<std::uint32_t>(k - obj);
+        }
+    }
+    d.indexes.push_back(document_data::object_index{start, static_cast<std::uint32_t>(mask)});
+    obj->extra = static_cast<std::uint16_t>(d.indexes.size());
+}
+
+/// build the tables of the large objects the parser noted
+inline void build_object_indexes(document_data& d)
+{
+    for (const std::uint32_t i : d.large_objects)
+    {
+        build_object_index(d, d.tape + i);
+    }
+}
+
+/// the key node of the first member with this key of an indexed object, or
+/// nullptr
+inline const node* find_indexed(const document_data& d, const node* obj, const char* key, std::size_t n) noexcept
+{
+    const document_data::object_index& ix = d.indexes[obj->extra - 1u];
+    const std::uint32_t* const slots = d.index_slots.data() + ix.start;
+    std::size_t i = static_cast<std::size_t>(key_hash(key, n)) & ix.mask;
+    for (;;)
+    {
+        const std::uint32_t s = slots[i];
+        if (s == 0)
+        {
+            return nullptr;
+        }
+        const node* const k = obj + s;
+        if (k->len == n && (n == 0 || std::memcmp(d.str(*k), key, n) == 0))
+        {
+            return k;
+        }
+        i = (i + 1) & ix.mask;
+    }
+}
+
+}  // namespace view
+}  // namespace detail
+NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/detail/view/pointer.hpp

@@ -0,0 +1,171 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <cstddef> // size_t
+#include <cstdint> // uint64_t
+#include <limits> // numeric_limits
+#include <string> // string, to_string
+
+#include <nlohmann/json.hpp>
+#include <nlohmann/detail/view/errors.hpp>
+#include <nlohmann/detail/view/macro_scope.hpp>
+
+NLOHMANN_JSON_NAMESPACE_BEGIN
+namespace detail
+{
+namespace view
+{
+
+/// what resolving a JSON pointer does where it cannot continue
+enum class pointer_mode
+{
+    unchecked, ///< as const basic_json::operator[]: a discarded view where basic_json's behavior is undefined
+    checked,   ///< as basic_json::at(): out_of_range.401/403
+    value,     ///< as basic_json::value(): no out_of_range exceptions (the default value is used)
+    contains,  ///< as basic_json::contains(): no exceptions at all
+};
+
+/// the outcome of reading an array index from a reference token
+enum class index_status
+{
+    ok,
+    leading_zero, ///< parse_error.106
+    not_number,   ///< parse_error.109
+    unresolved,   ///< out_of_range.404
+    too_large,    ///< out_of_range.410
+};
+
+/// reads an array index like json_pointer::array_index (RFC 6901, Sect. 4),
+/// but reports errors instead of throwing them
+template<typename StringType>
+index_status array_index(const StringType& s, std::size_t& idx) noexcept
+{
+    if (s.size() > 1 && s[0] == '0')
+    {
+        return index_status::leading_zero;
+    }
+    if (s.size() > 1 && !(s[0] >= '1' && s[0] <= '9'))
+    {
+        return index_status::not_number;
+    }
+    if (s.empty())
+    {
+        return index_status::unresolved;
+    }
+    std::uint64_t v = 0;
+    for (std::size_t i = 0; i < s.size(); ++i)
+    {
+        const auto d = static_cast<unsigned>(static_cast<unsigned char>(s[i])) - '0';
+        if (d > 9 || v > ((std::numeric_limits<std::uint64_t>::max)() - d) / 10)
+        {
+            return index_status::unresolved; // not a number, or beyond unsigned long long
+        }
+        v = (v * 10) + d;
+    }
+    if (v >= static_cast<std::uint64_t>((std::numeric_limits<std::size_t>::max)()))
+    {
+        return index_status::too_large;
+    }
+    idx = static_cast<std::size_t>(v);
+    return index_status::ok;
+}
+
+/// throws the exception json_pointer::array_index throws for this status
+template<typename StringType>
+[[noreturn]] NLOHMANN_VIEW_NOINLINE void throw_array_index_error(index_status status, const StringType& s)
+{
+    switch (status)
+    {
+        case index_status::leading_zero:
+            throw_parse_error(106, concat("array index '", s, "' must not begin with '0'"));
+        case index_status::not_number:
+            throw_parse_error(109, concat("array index '", s, "' is not a number"));
+        case index_status::too_large:
+            throw_out_of_range(410, concat("array index ", s, " exceeds size_type")); // LCOV_EXCL_LINE
+        case index_status::unresolved:
+        case index_status::ok:
+        default:
+            throw_out_of_range(404, concat("unresolved reference token '", s, "'"));
+    }
+}
+
+/*!
+@brief resolve the reference tokens of a JSON pointer, starting at a view
+
+The exceptions are those basic_json throws for the same pointer; where
+basic_json's behavior is undefined (a missing key or an index out of range
+with const operator[]), the result is a discarded view.
+*/
+template<typename View, typename Tokens>
+View resolve_pointer(View cur, const Tokens& tokens, pointer_mode mode)
+{
+    using string_view_t = typename View::string_view_t;
+    const bool throwing = mode == pointer_mode::unchecked || mode == pointer_mode::checked;
+    for (const auto& token : tokens)
+    {
+        if (cur.is_object())
+        {
+            const auto it = cur.find(string_view_t(token.data(), token.size()));
+            if (it == cur.end())
+            {
+                if (mode == pointer_mode::checked)
+                {
+                    throw_out_of_range(403, concat("key '", token, "' not found"));
+                }
+                return View();
+            }
+            cur = *it;
+        }
+        else if (cur.is_array())
+        {
+            if (token.size() == 1 && token[0] == '-')
+            {
+                if (throwing)
+                {
+                    throw_out_of_range(402, concat("array index '-' (", std::to_string(cur.size()), ") is out of range"));
+                }
+                return View();
+            }
+            std::size_t idx = 0;
+            const index_status status = array_index(token, idx);
+            if (status != index_status::ok)
+            {
+                const bool parse_error = status == index_status::leading_zero || status == index_status::not_number;
+                if (throwing || (mode == pointer_mode::value && parse_error))
+                {
+                    throw_array_index_error(status, token);
+                }
+                return View();
+            }
+            if (idx >= cur.size())
+            {
+                if (mode == pointer_mode::checked)
+                {
+                    throw_out_of_range(401, concat("array index ", std::to_string(idx), " is out of range"));
+                }
+                return View();
+            }
+            cur = cur[idx];
+        }
+        else
+        {
+            if (throwing)
+            {
+                throw_out_of_range(404, concat("unresolved reference token '", token, "'"));
+            }
+            return View();
+        }
+    }
+    return cur;
+}
+
+}  // namespace view
+}  // namespace detail
+NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/detail/view/scan.hpp

@@ -16,6 +16,7 @@
 
 #include <nlohmann/json.hpp>
 #include <nlohmann/detail/view/macro_scope.hpp>
+#include <nlohmann/detail/view/simd.hpp>
 
 // Scanning primitives of the view's parser. The unrolled checks at fixed
 // offsets follow yyjson (https://github.com/ibireme/yyjson, MIT license): the
@@ -62,9 +63,12 @@ NLOHMANN_VIEW_ALWAYS_INLINE std::uint16_t load16(const unsigned char* p) noexcep
 
 /// Advance over plain string bytes and well-formed UTF-8. Stops at a quote,
 /// a backslash, a control character, ill-formed UTF-8, or the end. The first
-/// 16 bytes are checked one by one, so that the position advances by
-/// constants in predicted branches (most strings are short); longer runs
-/// continue eight bytes at a time.
+/// bytes are checked one by one, so that the position advances by constants
+/// in predicted branches: 16 for keys, whose lengths repeat from record to
+/// record, and 8 for string values (Value) where a vector loop follows, as
+/// their lengths vary more. Longer runs continue 16 bytes at a time with NEON
+/// or SSE2, else eight bytes at a time.
+template<bool Value = false>
 NLOHMANN_VIEW_ALWAYS_INLINE const unsigned char* scan_string_run(const unsigned char* p, const unsigned char* e) noexcept
 {
     const std::uint8_t* plain = string_plain();
@@ -73,9 +77,23 @@ NLOHMANN_VIEW_ALWAYS_INLINE const unsigned char* scan_string_run(const unsigned
         if (e - p >= 16)
         {
 #define NLOHMANN_VIEW_STEP(i) if (NLOHMANN_VIEW_LIKELY(plain[p[i]] != 0)) {} else { p += (i); goto stop; }
-            NLOHMANN_VIEW_REPEAT16(NLOHMANN_VIEW_STEP)
+            NLOHMANN_VIEW_STEP(0) NLOHMANN_VIEW_STEP(1) NLOHMANN_VIEW_STEP(2) NLOHMANN_VIEW_STEP(3)
+            NLOHMANN_VIEW_STEP(4) NLOHMANN_VIEW_STEP(5) NLOHMANN_VIEW_STEP(6) NLOHMANN_VIEW_STEP(7)
+            if (!Value || !NLOHMANN_VIEW_VECTOR)
+            {
+                NLOHMANN_VIEW_STEP(8) NLOHMANN_VIEW_STEP(9) NLOHMANN_VIEW_STEP(10) NLOHMANN_VIEW_STEP(11)
+                NLOHMANN_VIEW_STEP(12) NLOHMANN_VIEW_STEP(13) NLOHMANN_VIEW_STEP(14) NLOHMANN_VIEW_STEP(15)
+                p += 8;
+            }
 #undef NLOHMANN_VIEW_STEP
-            p += 16;
+            p += 8;
+#if NLOHMANN_VIEW_VECTOR
+            p = vector_plain_run(p, e);
+            if (p != e && plain[*p] == 0)
+            {
+                goto stop;
+            }
+#else
             while (e - p >= 8)
             {
                 const std::uint64_t special = swar_string_special(read_eight_bytes(p));
@@ -86,6 +104,7 @@ NLOHMANN_VIEW_ALWAYS_INLINE const unsigned char* scan_string_run(const unsigned
                 }
                 p += 8;
             }
+#endif
             continue;
         }
         while (p != e && plain[*p] != 0)
@@ -101,6 +120,10 @@ stop:
         {
             return p; // quote, backslash, or control character
         }
+#if NLOHMANN_VIEW_VECTOR_UTF8
+        // non-ASCII: the vector check, out of line
+        return scan_string_vector(p, e, plain);
+#else
         // non-ASCII: a run of well-formed sequences (the library's check, so
         // that exactly what json::parse accepts is accepted)
         do
@@ -113,6 +136,7 @@ stop:
             p += n;
         }
         while (p != e && *p >= 0x80);
+#endif
     }
 }
 

include/nlohmann/detail/view/serializer.hpp

@@ -0,0 +1,421 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <algorithm> // max
+#include <array> // array
+#include <cmath> // isfinite
+#include <cstddef> // size_t
+#include <cstdint> // uint8_t, uint32_t
+#include <cstring> // memcpy, memset
+#include <limits> // numeric_limits
+#include <type_traits> // integral_constant
+#include <vector> // vector
+
+#include <nlohmann/json.hpp>
+#include <nlohmann/detail/view/document_data.hpp>
+#include <nlohmann/detail/view/macro_scope.hpp>
+#include <nlohmann/detail/view/node.hpp>
+#include <nlohmann/detail/view/number.hpp>
+
+NLOHMANN_JSON_NAMESPACE_BEGIN
+namespace detail
+{
+namespace view
+{
+
+/// append-only output buffer: writes through a raw pointer into a string that
+/// is resized ahead, and trimmed by finish()
+template<typename StringType>
+class output_buffer
+{
+  public:
+    output_buffer(StringType& out, std::size_t estimate)
+        : m_out(sized(out, estimate))
+        , m_pos(&m_out[0])
+        , m_end(m_pos + m_out.size())
+    {}
+
+    void finish()
+    {
+        m_out.resize(static_cast<std::size_t>(m_pos - m_out.data()));
+    }
+
+    NLOHMANN_VIEW_ALWAYS_INLINE void reserve(std::size_t n)
+    {
+        if (NLOHMANN_VIEW_UNLIKELY(static_cast<std::size_t>(m_end - m_pos) < n))
+        {
+            grow(n);
+        }
+    }
+
+    NLOHMANN_VIEW_ALWAYS_INLINE void put(char c)
+    {
+        reserve(1);
+        *m_pos++ = c;
+    }
+
+    NLOHMANN_VIEW_ALWAYS_INLINE void put(const char* s, std::size_t n)
+    {
+        reserve(n);
+        std::memcpy(m_pos, s, n);
+        m_pos += n;
+    }
+
+    void put_repeated(char c, std::size_t n)
+    {
+        reserve(n);
+        std::memset(m_pos, c, n);
+        m_pos += n;
+    }
+
+  private:
+    static StringType& sized(StringType& out, std::size_t estimate)
+    {
+        out.resize((std::max)(estimate, static_cast<std::size_t>(64)));
+        return out;
+    }
+
+    NLOHMANN_VIEW_NOINLINE void grow(std::size_t n)
+    {
+        const auto used = static_cast<std::size_t>(m_pos - m_out.data());
+        m_out.resize((std::max)(m_out.size() * 2, used + n + 256));
+        m_pos = &m_out[0] + used;
+        m_end = &m_out[0] + m_out.size();
+    }
+
+    StringType& m_out;
+    char* m_pos;
+    char* m_end;
+};
+
+/// how the view's dump() writes a value
+struct dump_style
+{
+    bool pretty = false;           ///< indent >= 0
+    std::size_t indent = 0;        ///< characters per level
+    char indent_char = ' ';
+    bool ensure_ascii = false;
+    bool source_numbers = false;   ///< copy number tokens from the source
+};
+
+/*!
+@brief write a view's subtree as basic_json::dump() writes the value
+
+The output of a subtree equals ordered_json::parse(text).dump() of it for
+the same arguments (members in document order): strings are escaped by the
+same rules, with the library's scanning kernels; floats are written with
+the library's conversion; integers are copied from the source, where they
+are canonical (except "-0", which parse() reads as 0). The walk is
+iterative, so the nesting depth is limited by memory only.
+*/
+template<typename BasicJsonType, bool Editable>
+class view_serializer
+{
+    using nav = navigation<Editable>;
+    using string_t = typename BasicJsonType::string_t;
+    using number_float_t = typename BasicJsonType::number_float_t;
+
+  public:
+    view_serializer(const document_data& d, string_t& out, std::size_t estimate, const dump_style& style)
+        : m_doc(d), m_out(out, estimate), m_style(style)
+    {}
+
+    void dump(const node* root)
+    {
+        struct frame
+        {
+            const node* pos; ///< next element, or key of the next member
+            const node* end;
+            bool object;
+            bool first;  ///< nothing written yet
+        };
+        std::vector<frame> stack;
+        const node* n = root;
+        for (;;)
+        {
+            // write the value at n
+            if (is_container(*n))
+            {
+                const bool object = n->kind == static_cast<std::uint8_t>(value_t::object);
+                if (n->len == 0)
+                {
+                    m_out.put(object ? "{}" : "[]", 2);
+                }
+                else
+                {
+                    m_out.put(object ? '{' : '[');
+                    stack.push_back(frame{nav::first(m_doc, n), nav::end(m_doc, n), object, true});
+                }
+            }
+            else
+            {
+                write_scalar(*n);
+            }
+
+            // go to the next value: close finished containers, then separate
+            for (;;)
+            {
+                if (stack.empty())
+                {
+                    m_out.finish();
+                    return;
+                }
+                frame& f = stack.back();
+                if (f.pos == f.end)
+                {
+                    const bool object = f.object;
+                    stack.pop_back();
+                    newline(stack.size());
+                    m_out.put(object ? '}' : ']');
+                    continue;
+                }
+                if (!f.first)
+                {
+                    m_out.put(',');
+                }
+                f.first = false;
+                newline(stack.size());
+                if (f.object)
+                {
+                    write_string(*f.pos);
+                    if (m_style.pretty)
+                    {
+                        m_out.put(": ", 2);
+                    }
+                    else
+                    {
+                        m_out.put(':');
+                    }
+                    n = nav::value(f.pos + 1);
+                    f.pos = document_data::after(f.pos + 1);
+                }
+                else
+                {
+                    n = nav::value(f.pos);
+                    f.pos = document_data::after(f.pos);
+                }
+                break;
+            }
+        }
+    }
+
+  private:
+    void newline(std::size_t level)
+    {
+        if (m_style.pretty)
+        {
+            m_out.put('\n');
+            m_out.put_repeated(m_style.indent_char, level * m_style.indent);
+        }
+    }
+
+    void write_scalar(const node& n)
+    {
+        switch (static_cast<value_t>(n.kind))
+        {
+            case value_t::null:
+                m_out.put("null", 4);
+                break;
+            case value_t::boolean:
+                if ((n.flags & node_flags::is_true) != 0)
+                {
+                    m_out.put("true", 4);
+                }
+                else
+                {
+                    m_out.put("false", 5);
+                }
+                break;
+            case value_t::string:
+                write_string(n);
+                break;
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            {
+                const char* const token = m_doc.str(n);
+                const std::uint32_t len = number_length(n);
+                if (!m_style.source_numbers && len == 2 && token[0] == '-' && token[1] == '0')
+                {
+                    m_out.put('0'); // parse() reads -0 as the integer 0
+                }
+                else
+                {
+                    m_out.put(token, len);
+                }
+                break;
+            }
+            case value_t::number_float:
+                if (m_style.source_numbers && (n.flags & node_flags::storage) != node_flags::edited)
+                {
+                    m_out.put(m_doc.str(n), n.len); // (a float set by an edit is written as with shortest)
+                }
+                else
+                {
+                    write_float(float_value<number_float_t>(m_doc, n));
+                }
+                break;
+            case value_t::object:    // LCOV_EXCL_LINE (containers are written by dump())
+            case value_t::array:     // LCOV_EXCL_LINE
+            case value_t::binary:    // LCOV_EXCL_LINE (not in a document)
+            case value_t::discarded: // LCOV_EXCL_LINE
+            default:                 // LCOV_EXCL_LINE
+                break;               // LCOV_EXCL_LINE
+        }
+    }
+
+    /// as serializer::dump_float()
+    void write_float(number_float_t x)
+    {
+        if (!std::isfinite(x))
+        {
+            m_out.put("null", 4);
+            return;
+        }
+        write_float(x, std::integral_constant < bool,
+                    (std::numeric_limits<number_float_t>::is_iec559 && std::numeric_limits<number_float_t>::digits == 24 && std::numeric_limits<number_float_t>::max_exponent == 128)
+                    || (std::numeric_limits<number_float_t>::is_iec559 && std::numeric_limits<number_float_t>::digits == 53 && std::numeric_limits<number_float_t>::max_exponent == 1024) > {});
+    }
+
+    void write_float(number_float_t x, std::true_type /*is_ieee_single_or_double*/)
+    {
+        std::array<char, 64> buf{};
+        const char* const end = ::nlohmann::detail::to_chars(buf.data(), buf.data() + buf.size(), x);
+        m_out.put(buf.data(), static_cast<std::size_t>(end - buf.data()));
+    }
+
+    void write_float(number_float_t x, std::false_type /*is_ieee_single_or_double*/)
+    {
+        // other types (e.g. long double) are rare: the library writes them
+        const string_t s = BasicJsonType(x).dump();
+        m_out.put(s.data(), s.size());
+    }
+
+    void write_string(const node& n)
+    {
+        const char* const s = m_doc.str(n);
+        m_out.put('"');
+        if ((n.flags & node_flags::storage) == 0 && !m_style.ensure_ascii)
+        {
+            // a string of the source without escape sequences has nothing to escape
+            m_out.put(s, n.len);
+        }
+        else if (m_style.ensure_ascii)
+        {
+            write_escaped<true>(reinterpret_cast<const unsigned char*>(s), n.len); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
+        }
+        else
+        {
+            write_escaped<false>(reinterpret_cast<const unsigned char*>(s), n.len); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
+        }
+        m_out.put('"');
+    }
+
+    /// as serializer::dump_escaped() for valid UTF-8 (the view has no other)
+    template<bool EnsureAscii>
+    void write_escaped(const unsigned char* s, std::size_t n)
+    {
+        std::size_t i = 0;
+        while (i < n)
+        {
+            std::size_t run = 0;
+            if (!EnsureAscii)
+            {
+                run = string_bulk_run(s + i, n - i);
+            }
+            else if (is_ascii_copyable(s[i]))
+            {
+                run = find_ascii_copyable_run(s + i, n - i);
+            }
+            if (run != 0)
+            {
+                m_out.put(reinterpret_cast<const char*>(s + i), run); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
+                i += run;
+                continue;
+            }
+            std::uint32_t codepoint = s[i];
+            std::size_t len = 1;
+            if (codepoint >= 0xC0)
+            {
+                len = 2;
+                if (codepoint >= 0xE0)
+                {
+                    len = codepoint >= 0xF0 ? 4 : 3;
+                }
+                codepoint &= 0xFFu >> (len + 1);
+                for (std::size_t k = 1; k < len; ++k)
+                {
+                    codepoint = (codepoint << 6u) | (s[i + k] & 0x3Fu);
+                }
+            }
+            write_codepoint<EnsureAscii>(codepoint, s + i, len);
+            i += len;
+        }
+    }
+
+    template<bool EnsureAscii>
+    void write_codepoint(std::uint32_t codepoint, const unsigned char* bytes, std::size_t len)
+    {
+        switch (codepoint)
+        {
+            case 0x08:
+                m_out.put("\\b", 2);
+                return;
+            case 0x09:
+                m_out.put("\\t", 2);
+                return;
+            case 0x0A:
+                m_out.put("\\n", 2);
+                return;
+            case 0x0C:
+                m_out.put("\\f", 2);
+                return;
+            case 0x0D:
+                m_out.put("\\r", 2);
+                return;
+            case 0x22:
+                m_out.put("\\\"", 2);
+                return;
+            case 0x5C:
+                m_out.put("\\\\", 2);
+                return;
+            default:
+                break;
+        }
+        if (codepoint <= 0x1F || (EnsureAscii && codepoint >= 0x7F))
+        {
+            if (codepoint <= 0xFFFF)
+            {
+                write_u_escape(codepoint);
+            }
+            else
+            {
+                write_u_escape(0xD7C0u + (codepoint >> 10u));
+                write_u_escape(0xDC00u + (codepoint & 0x3FFu));
+            }
+            return;
+        }
+        m_out.put(reinterpret_cast<const char*>(bytes), len); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast) LCOV_EXCL_LINE (printable characters are copied in runs)
+    }
+
+    void write_u_escape(std::uint32_t u)
+    {
+        static constexpr const char* hex = "0123456789abcdef";
+        const std::array<char, 6> e = {{'\\', 'u', hex[(u >> 12u) & 0xFu], hex[(u >> 8u) & 0xFu], hex[(u >> 4u) & 0xFu], hex[u & 0xFu]}};
+        m_out.put(e.data(), e.size());
+    }
+
+    const document_data& m_doc;
+    output_buffer<string_t> m_out;
+    const dump_style m_style;
+};
+
+}  // namespace view
+}  // namespace detail
+NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/detail/view/simd.hpp

@@ -0,0 +1,281 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
+// SPDX-FileCopyrightText: 2018-2025 The simdjson authors <https://github.com/simdjson/simdjson>
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <array> // array
+#include <cstddef> // size_t
+#include <cstdint> // uint8_t, uint64_t
+
+#include <nlohmann/json.hpp>
+#include <nlohmann/detail/view/macro_scope.hpp>
+
+// Vector code for long runs of string bytes. NEON (AArch64) and SSE2 (x86-64)
+// belong to the baseline instruction sets and are used by default. The vector
+// UTF-8 check needs NEON, or SSSE3 if JSON_VIEW_USE_SSSE3 is defined: SSSE3 is
+// not part of x86-64, so it must not depend on the flags of a translation unit
+// (two translation units with different flags would have different
+// definitions of the same inline functions). JSON_VIEW_NO_SIMD selects the
+// portable code.
+#if !defined(JSON_VIEW_NO_SIMD) && defined(__aarch64__) && (defined(__GNUC__) || defined(__clang__)) && NLOHMANN_VIEW_LITTLE_ENDIAN
+    #include <arm_neon.h>
+    #define NLOHMANN_VIEW_NEON 1
+#else
+    #define NLOHMANN_VIEW_NEON 0
+#endif
+#if !defined(JSON_VIEW_NO_SIMD) && !NLOHMANN_VIEW_NEON && (defined(__SSE2__) || defined(_M_X64) || (defined(_M_IX86_FP) && _M_IX86_FP >= 2))
+    #include <emmintrin.h>
+    #define NLOHMANN_VIEW_SSE2 1
+#else
+    #define NLOHMANN_VIEW_SSE2 0
+#endif
+#if NLOHMANN_VIEW_SSE2 && defined(JSON_VIEW_USE_SSSE3)
+    #include <tmmintrin.h>
+    #define NLOHMANN_VIEW_SSSE3 1 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)
+#else
+    #define NLOHMANN_VIEW_SSSE3 0 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)
+#endif
+#define NLOHMANN_VIEW_VECTOR (NLOHMANN_VIEW_NEON || NLOHMANN_VIEW_SSE2)
+#define NLOHMANN_VIEW_VECTOR_UTF8 (NLOHMANN_VIEW_NEON || NLOHMANN_VIEW_SSSE3)
+
+NLOHMANN_JSON_NAMESPACE_BEGIN
+namespace detail
+{
+namespace view
+{
+
+#if NLOHMANN_VIEW_VECTOR
+/*!
+@brief the first byte of a string run that is a quote, a backslash, a control
+character, or not ASCII, 16 bytes per step
+
+Stops at such a byte, or where fewer than 16 bytes are left (the caller tells
+the two apart). A signed compare with 0x20 finds control characters and
+non-ASCII bytes at once.
+*/
+NLOHMANN_VIEW_ALWAYS_INLINE const unsigned char* vector_plain_run(const unsigned char* p, const unsigned char* e) noexcept
+{
+    while (e - p >= 16)
+    {
+#if NLOHMANN_VIEW_NEON
+        const uint8x16_t in = vld1q_u8(p);
+        const uint8x16_t special = vorrq_u8(vorrq_u8(vceqq_u8(in, vdupq_n_u8('"')), vceqq_u8(in, vdupq_n_u8('\\'))),
+                                            vcltq_s8(vreinterpretq_s8_u8(in), vdupq_n_s8(0x20)));
+        // one nibble per byte (the usual NEON replacement of x86's movemask, see
+        // D. Kutenin, "Porting x86 vector bitmask optimizations to Arm NEON", 2022)
+        const std::uint64_t bits = vget_lane_u64(vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(special), 4)), 0);
+        if (bits != 0)
+        {
+            return p + (count_trailing_zeros(bits) >> 2u);
+        }
+#else
+        const __m128i in = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(p)));
+        const __m128i special = _mm_or_si128(_mm_or_si128(_mm_cmpeq_epi8(in, _mm_set1_epi8('"')), _mm_cmpeq_epi8(in, _mm_set1_epi8('\\'))),
+                                             _mm_cmplt_epi8(in, _mm_set1_epi8(0x20)));
+        const auto bits = static_cast<std::uint64_t>(static_cast<unsigned>(_mm_movemask_epi8(special)));
+        if (bits != 0)
+        {
+            return p + count_trailing_zeros(bits);
+        }
+#endif
+        p += 16;
+    }
+    return p;
+}
+#endif
+
+#if NLOHMANN_VIEW_VECTOR_UTF8
+/// Tables of the UTF-8 check of J. Keiser and D. Lemire, "Validating UTF-8 In
+/// Less Than One Instruction Per Byte" (2021), as in simdjson ("lookup4"): each
+/// maps a nibble (high and low nibble of the previous byte, high nibble of the
+/// current byte) to the errors it allows; a byte pair is ill-formed if all
+/// three have an error bit in common.
+template<typename Dummy = void>
+struct utf8_lookup4
+{
+    static constexpr std::uint8_t too_short = 1u << 0u, too_long = 1u << 1u, overlong_3 = 1u << 2u, too_large = 1u << 3u;
+    static constexpr std::uint8_t surrogate = 1u << 4u, overlong_2 = 1u << 5u, too_large_1000 = 1u << 6u, overlong_4 = 1u << 6u;
+    static constexpr std::uint8_t two_conts = 1u << 7u, carry = too_short | too_long | two_conts;
+    static const std::array<std::uint8_t, 16> byte_1_high;
+    static const std::array<std::uint8_t, 16> byte_1_low;
+    static const std::array<std::uint8_t, 16> byte_2_high;
+};
+
+template<typename Dummy>
+const std::array<std::uint8_t, 16> utf8_lookup4<Dummy>::byte_1_high =
+{
+    {
+        too_long, too_long, too_long, too_long, too_long, too_long, too_long, too_long,
+        two_conts, two_conts, two_conts, two_conts,
+        too_short | overlong_2, too_short, too_short | overlong_3 | surrogate, too_short | too_large | too_large_1000 | overlong_4
+    }
+};
+
+template<typename Dummy>
+const std::array<std::uint8_t, 16> utf8_lookup4<Dummy>::byte_1_low =
+{
+    {
+        carry | overlong_3 | overlong_2 | overlong_4, carry | overlong_2, carry, carry,
+        carry | too_large, carry | too_large | too_large_1000, carry | too_large | too_large_1000, carry | too_large | too_large_1000,
+        carry | too_large | too_large_1000, carry | too_large | too_large_1000, carry | too_large | too_large_1000, carry | too_large | too_large_1000,
+        carry | too_large | too_large_1000, carry | too_large | too_large_1000 | surrogate, carry | too_large | too_large_1000, carry | too_large | too_large_1000
+    }
+};
+
+template<typename Dummy>
+const std::array<std::uint8_t, 16> utf8_lookup4<Dummy>::byte_2_high =
+{
+    {
+        too_short, too_short, too_short, too_short, too_short, too_short, too_short, too_short,
+        static_cast<std::uint8_t>(too_long | overlong_2 | two_conts | overlong_3 | too_large_1000 | overlong_4),
+        static_cast<std::uint8_t>(too_long | overlong_2 | two_conts | overlong_3 | too_large),
+        static_cast<std::uint8_t>(too_long | overlong_2 | two_conts | surrogate | too_large),
+        static_cast<std::uint8_t>(too_long | overlong_2 | two_conts | surrogate | too_large),
+        too_short, too_short, too_short, too_short
+    }
+};
+
+/// the end of scan_string_vector from block, where the vector loop stopped
+/// (ill-formed UTF-8, or fewer than 16 bytes left): one byte or sequence at a
+/// time, from the start of a sequence that crosses into the block
+inline const unsigned char* scan_string_finish(const unsigned char* p, const unsigned char* block, const unsigned char* e, const std::uint8_t* plain) noexcept
+{
+    for (int i = 1; i <= 3 && block - i >= p; ++i)
+    {
+        const unsigned char c = block[-i];
+        if (c < 0x80)
+        {
+            break;
+        }
+        if (c >= 0xC0)
+        {
+            const int len = 2 + static_cast<int>(c >= 0xE0) + static_cast<int>(c >= 0xF0);
+            if (len > i)
+            {
+                block -= i;
+            }
+            break;
+        }
+    }
+    for (p = block; p != e;)
+    {
+        if (*p < 0x80)
+        {
+            if (plain[*p] == 0)
+            {
+                return p;
+            }
+            ++p;
+            continue;
+        }
+        const std::size_t n = validate_one_utf8(p, static_cast<std::size_t>(e - p));
+        if (n == 0)
+        {
+            return p;
+        }
+        p += n;
+    }
+    return p;
+}
+
+/*!
+@brief the rest of a string from p (a character boundary), 16 bytes per step
+
+The first quote, backslash, or control character is found with vector
+compares, and the UTF-8 check covers the bytes up to it. Returns where the
+string scan stops, like scan_string_run: before ill-formed UTF-8 and for the
+last bytes of the input, the bytes are checked one sequence at a time. Out of
+line, so that no constants of the check occupy registers in the parse loop.
+*/
+NLOHMANN_VIEW_NOINLINE inline const unsigned char* scan_string_vector(const unsigned char* p, const unsigned char* e, const std::uint8_t* plain) noexcept
+{
+    using lookup = utf8_lookup4<>;
+    const unsigned char* block = p;
+#if NLOHMANN_VIEW_NEON
+    const uint8x16_t t1h = vld1q_u8(lookup::byte_1_high.data());
+    const uint8x16_t t1l = vld1q_u8(lookup::byte_1_low.data());
+    const uint8x16_t t2h = vld1q_u8(lookup::byte_2_high.data());
+    uint8x16_t prev = vdupq_n_u8(0);
+    while (e - block >= 16)
+    {
+        const uint8x16_t in = vld1q_u8(block);
+        const uint8x16_t special = vorrq_u8(vorrq_u8(vceqq_u8(in, vdupq_n_u8('"')), vceqq_u8(in, vdupq_n_u8('\\'))), vcltq_u8(in, vdupq_n_u8(0x20)));
+        const uint8x16_t prev1 = vextq_u8(prev, in, 15);
+        const uint8x16_t sc = vandq_u8(vandq_u8(vqtbl1q_u8(t1h, vshrq_n_u8(prev1, 4)), vqtbl1q_u8(t1l, vandq_u8(prev1, vdupq_n_u8(0x0F)))), vqtbl1q_u8(t2h, vshrq_n_u8(in, 4)));
+        const uint8x16_t must23 = vorrq_u8(vqsubq_u8(vextq_u8(prev, in, 14), vdupq_n_u8(0xE0 - 0x80)), vqsubq_u8(vextq_u8(prev, in, 13), vdupq_n_u8(0xF0 - 0x80)));
+        const uint8x16_t err = veorq_u8(vandq_u8(must23, vdupq_n_u8(0x80)), sc);
+        const std::uint64_t special_bits = vget_lane_u64(vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(special), 4)), 0);
+        const std::uint64_t err_bits = vget_lane_u64(vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(vtstq_u8(err, err)), 4)), 0);
+        if (special_bits != 0)
+        {
+            // errors up to the special byte count (an incomplete sequence
+            // before a quote shows at the quote); the bytes after it do not
+            const unsigned k = static_cast<unsigned>(count_trailing_zeros(special_bits)) >> 2u;
+            const std::uint64_t upto = k == 15 ? ~std::uint64_t{0} :
+                                       (std::uint64_t{1} << (4u * (k + 1u))) - 1u;
+            if ((err_bits & upto) == 0)
+            {
+                return block + k;
+            }
+            break;
+        }
+        if (err_bits != 0)
+        {
+            break;
+        }
+        prev = in;
+        block += 16;
+    }
+#else
+    // the same with SSSE3 (pshufb for the table lookups; nibbles from 16-bit
+    // shifts, as there are no byte shifts)
+    const __m128i t1h = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(lookup::byte_1_high.data())));
+    const __m128i t1l = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(lookup::byte_1_low.data())));
+    const __m128i t2h = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(lookup::byte_2_high.data())));
+    const __m128i nibble = _mm_set1_epi8(0x0F);
+    const __m128i zero = _mm_setzero_si128();
+    __m128i prev = zero;
+    while (e - block >= 16)
+    {
+        const __m128i in = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(block)));
+        const __m128i special = _mm_or_si128(_mm_or_si128(_mm_cmpeq_epi8(in, _mm_set1_epi8('"')), _mm_cmpeq_epi8(in, _mm_set1_epi8('\\'))),
+                                             _mm_cmpeq_epi8(_mm_subs_epu8(in, _mm_set1_epi8(0x1F)), zero)); // in < 0x20
+        const __m128i prev1 = _mm_alignr_epi8(in, prev, 15);
+        const __m128i sc = _mm_and_si128(_mm_and_si128(_mm_shuffle_epi8(t1h, _mm_and_si128(_mm_srli_epi16(prev1, 4), nibble)),
+                                         _mm_shuffle_epi8(t1l, _mm_and_si128(prev1, nibble))),
+                                         _mm_shuffle_epi8(t2h, _mm_and_si128(_mm_srli_epi16(in, 4), nibble)));
+        const __m128i must23 = _mm_or_si128(_mm_subs_epu8(_mm_alignr_epi8(in, prev, 14), _mm_set1_epi8(0xE0 - 0x80)),
+                                            _mm_subs_epu8(_mm_alignr_epi8(in, prev, 13), _mm_set1_epi8(0xF0 - 0x80)));
+        const __m128i err = _mm_xor_si128(_mm_and_si128(must23, _mm_set1_epi8(static_cast<char>(-128))), sc);
+        const auto special_bits = static_cast<unsigned>(_mm_movemask_epi8(special));
+        const auto err_bits = ~static_cast<unsigned>(_mm_movemask_epi8(_mm_cmpeq_epi8(err, zero))) & 0xFFFFu;
+        if (special_bits != 0)
+        {
+            const unsigned k = static_cast<unsigned>(count_trailing_zeros(static_cast<std::uint64_t>(special_bits)));
+            if ((err_bits & ((2u << k) - 1u)) == 0)
+            {
+                return block + k;
+            }
+            break;
+        }
+        if (err_bits != 0)
+        {
+            break;
+        }
+        prev = in;
+        block += 16;
+    }
+#endif
+    return scan_string_finish(p, block, e, plain);
+}
+#endif
+
+}  // namespace view
+}  // namespace detail
+NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/detail/view/value.hpp

@@ -0,0 +1,108 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <cstdint> // int64_t
+#include <map> // map
+#include <string> // basic_string
+#include <type_traits> // enable_if, is_constructible
+#include <unordered_map> // unordered_map
+#include <vector> // vector
+
+#include <nlohmann/json.hpp>
+#include <nlohmann/detail/view/document_data.hpp>
+#include <nlohmann/detail/view/errors.hpp>
+#include <nlohmann/detail/view/macro_scope.hpp>
+#include <nlohmann/detail/view/node.hpp>
+#include <nlohmann/detail/view/number.hpp>
+
+NLOHMANN_JSON_NAMESPACE_BEGIN
+namespace detail
+{
+namespace view
+{
+
+/// selects a conversion by its target type
+template<typename T>
+struct value_tag {};
+
+/*!
+@brief the number or boolean of a node converted to an arithmetic type
+
+As basic_json's get<T>() for arithmetic types: integers and floats are
+converted with static_cast, booleans give 0 or 1, and other types throw
+type_error.302.
+*/
+template<typename T, typename BasicJsonType>
+NLOHMANN_VIEW_ALWAYS_INLINE T arithmetic_value(const document_data& d, const node& n)
+{
+    switch (static_cast<value_t>(n.kind))
+    {
+        case value_t::number_unsigned:
+            return static_cast<T>(static_cast<typename BasicJsonType::number_unsigned_t>(integer_bits(n)));
+        case value_t::number_integer:
+            return static_cast<T>(static_cast<typename BasicJsonType::number_integer_t>(static_cast<std::int64_t>(integer_bits(n))));
+        case value_t::number_float:
+            return static_cast<T>(float_value<typename BasicJsonType::number_float_t>(d, n));
+        case value_t::boolean:
+            return static_cast<T>((n.flags & node_flags::is_true) != 0);
+        case value_t::null:
+        case value_t::object:
+        case value_t::array:
+        case value_t::string:
+        case value_t::binary:
+        case value_t::discarded:
+        default:
+            throw_type_error(302, "type must be number, but is ", value_type_name(static_cast<value_t>(n.kind)));
+    }
+}
+
+/// std::vector from an array, element by element (type_error.302 otherwise)
+template<typename View, typename U, typename A>
+std::vector<U, A> vector_value(const View& v)
+{
+    if (NLOHMANN_VIEW_UNLIKELY(!v.is_array()))
+    {
+        throw_type_error(302, "type must be array, but is ", v.type_name());
+    }
+    std::vector<U, A> r;
+    r.reserve(v.size());
+    for (const View e : v)
+    {
+        r.push_back(e.template get<U>());
+    }
+    return r;
+}
+
+/// a map with string keys from an object; with duplicate keys, the last
+/// value is kept, as parse() does (type_error.302 for other types)
+template<typename Map, typename View>
+Map map_value(const View& v)
+{
+    if (NLOHMANN_VIEW_UNLIKELY(!v.is_object()))
+    {
+        throw_type_error(302, "type must be object, but is ", v.type_name());
+    }
+    Map r;
+    for (auto it = v.begin(); it != v.end(); ++it)
+    {
+        const auto key = it.key();
+        r[typename Map::key_type(key.data(), key.size())] = it.value().template get<typename Map::mapped_type>();
+    }
+    return r;
+}
+
+/// whether a map type is read member by member (its keys are made from
+/// characters and a length); other maps go through basic_json
+template<typename Key>
+struct is_string_key : std::is_constructible<Key, const char*, std::size_t> {};
+
+}  // namespace view
+}  // namespace detail
+NLOHMANN_JSON_NAMESPACE_END