json_view: from_json() of the macros reads views directly

get<T>() and get_to() of a view call T's from_json() with the view itself
when that from_json() accepts views but not an unrelated probe type, and
fall back to materialize() otherwise. The from_json() functions of the
NLOHMANN_DEFINE_TYPE_*, NLOHMANN_DEFINE_DERIVED_TYPE_* and
NLOHMANN_JSON_SERIALIZE_ENUM(_STRICT) macros accept basic_json values and
views; a derived type whose base reads only json reads the base part
through materialize(). The library's own from_json() overloads are not
called with views: from_json() of a view (and of the probe) only looks up
functions by ADL.

New public trait nlohmann::is_json_view<T>, and the member type
basic_json_type of basic_json_view. With duplicate keys, the members of
such a T are those the view's lookups find (the first ones).

bench_decode.cpp measures decoding into structs (4-6x faster than
materialize().get<T>() on twitter, citm_catalog, and synthetic records).

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

.clang-tidy

@@ -1,33 +1,3 @@
-# Style or vendor rule sets that do not fit a header-only library:
-#   altera-*, fuchsia-*, llvmlibc-*, android-cloexec-fopen, boost-use-ranges, llvm-header-guard,
-#   llvm-include-order, llvm-prefer-static-over-anonymous-namespace, llvm-use-ranges,
-#   misc-use-anonymous-namespace, google-runtime-float, google-runtime-int, hicpp-signed-bitwise,
-#   bugprone-signed-bitwise, hicpp-explicit-conversions, google-explicit-constructor,
-#   cppcoreguidelines-explicit-constructor, misc-explicit-constructor (implicit conversions are the
-#   API), readability-trailing-comma,
-#   hicpp-avoid-goto / cppcoreguidelines-avoid-goto, hicpp-no-array-decay,
-#   hicpp-uppercase-literal-suffix, readability-uppercase-literal-suffix, modernize-use-trailing-return-type.
-# Constructs the library needs on purpose (the library supports C++11 and legacy compilers):
-#   cppcoreguidelines-macro-usage, cppcoreguidelines-avoid-do-while (macros),
-#   cppcoreguidelines-pro-bounds-*, cppcoreguidelines-pro-type-reinterpret-cast,
-#   cppcoreguidelines-pro-type-union-access (parsers, serializers, basic_json's value union),
-#   cppcoreguidelines-avoid-const-or-ref-data-members, cppcoreguidelines-rvalue-reference-param-not-moved,
-#   cppcoreguidelines-avoid-non-const-global-variables, misc-non-private-member-variables-in-classes,
-#   misc-no-recursion (value walks are recursive, bounded by detail::recursion_depth_limit()),
-#   modernize-type-traits, modernize-use-constraints, modernize-use-ranges, modernize-use-std-numbers,
-#   modernize-use-designated-initializers, modernize-use-nodiscard, modernize-concat-nested-namespaces,
-#   readability-redundant-typename, readability-redundant-parentheses,
-#   readability-redundant-access-specifiers, readability-simplify-boolean-expr,
-#   readability-use-concise-preprocessor-directives, modernize-use-string-view,
-#   modernize-use-integer-sign-comparison (needs std::cmp_less; the flagged
-#   static_cast<std::size_t>(end - pos) < n comparisons are deliberate)
-#   (all need a newer standard or compiler than C++11, or would change macro-generated or
-#   deliberately explicit code).
-# Too noisy to be useful (numeric parsing/formatting code, doctest, tests):
-#   bugprone-easily-swappable-parameters, cppcoreguidelines-avoid-magic-numbers, readability-magic-numbers,
-#   readability-identifier-length, readability-function-cognitive-complexity, performance-enum-size,
-#   concurrency-mt-unsafe, misc-confusable-identifiers, misc-include-cleaner (run on its own for
-#   the consumer headers in cmake/ci.cmake).
 # portability-avoid-pragma-once: kept disabled on purpose. #pragma once is accepted
 # by every supported compiler, and tools/amalgamate/amalgamate.py strips it from
 # single_include, so there is nothing left to fix here.
@@ -40,14 +10,14 @@ Checks: '*,
          -android-cloexec-fopen,
          -boost-use-ranges,
          -bugprone-easily-swappable-parameters,
-         -bugprone-signed-bitwise,
+         -cert-err58-cpp,
+         -clang-analyzer-webkit.NoUncountedMemberChecker,
          -concurrency-mt-unsafe,
          -cppcoreguidelines-avoid-const-or-ref-data-members,
          -cppcoreguidelines-avoid-do-while,
          -cppcoreguidelines-avoid-goto,
          -cppcoreguidelines-avoid-magic-numbers,
          -cppcoreguidelines-avoid-non-const-global-variables,
-         -cppcoreguidelines-explicit-constructor,
          -cppcoreguidelines-macro-usage,
          -cppcoreguidelines-pro-bounds-avoid-unchecked-container-access,
          -cppcoreguidelines-pro-bounds-array-to-pointer-decay,
@@ -56,15 +26,19 @@ Checks: '*,
          -cppcoreguidelines-pro-type-reinterpret-cast,
          -cppcoreguidelines-pro-type-union-access,
          -cppcoreguidelines-rvalue-reference-param-not-moved,
+         -cppcoreguidelines-virtual-class-destructor,
          -fuchsia-default-arguments-calls,
          -fuchsia-default-arguments-declarations,
          -fuchsia-overloaded-operator,
          -google-explicit-constructor,
+         -google-readability-function-size,
          -google-runtime-float,
          -google-runtime-int,
          -hicpp-avoid-goto,
          -hicpp-explicit-conversions,
+         -hicpp-function-size,
          -hicpp-no-array-decay,
+         -hicpp-no-assembler,
          -hicpp-signed-bitwise,
          -hicpp-uppercase-literal-suffix,
          -llvm-header-guard,
@@ -74,7 +48,6 @@ Checks: '*,
          -llvmlibc-*,
          -misc-use-anonymous-namespace,
          -misc-confusable-identifiers,
-         -misc-explicit-constructor,
          -misc-include-cleaner,
          -misc-no-recursion,
          -misc-non-private-member-variables-in-classes,
@@ -82,22 +55,20 @@ Checks: '*,
          -modernize-type-traits,
          -modernize-use-constraints,
          -modernize-use-designated-initializers,
-         -modernize-use-integer-sign-comparison,
          -modernize-use-nodiscard,
          -modernize-use-ranges,
-         -modernize-use-string-view,
          -modernize-use-std-numbers,
          -modernize-use-trailing-return-type,
          -performance-enum-size,
          -portability-avoid-pragma-once,
          -readability-function-cognitive-complexity,
+         -readability-function-size,
          -readability-identifier-length,
          -readability-magic-numbers,
          -readability-redundant-access-specifiers,
          -readability-redundant-parentheses,
          -readability-redundant-typename,
          -readability-simplify-boolean-expr,
-         -readability-trailing-comma,
          -readability-uppercase-literal-suffix,
          -readability-use-concise-preprocessor-directives'
 

.github/workflows/check_amalgamation.yml

@@ -163,9 +163,9 @@ jobs:
           python3 $GENERATOR --list-tags
           TAG_COUNT=$(python3 $GENERATOR --list-tags | wc -l)
 
-          python3 $GENERATOR --abi-tags diag,_dp,_vns --abi-tags _diag --output $RUNNER_TEMP/abi_tags.natvis
+          python3 $GENERATOR --abi-tags diag,_dp,_ns --abi-tags _diag --output $RUNNER_TEMP/abi_tags.natvis
-          grep -q '<!-- Namespace nlohmann::json_abi_diag_dp_vns -->' $RUNNER_TEMP/abi_tags.natvis
+          grep -q '<!-- Namespace nlohmann::json_abi_diag_dp_ns -->' $RUNNER_TEMP/abi_tags.natvis
-          grep -q '<!-- Namespace nlohmann::json_abi_diag_dp_vns_v[0-9_]* -->' $RUNNER_TEMP/abi_tags.natvis
+          grep -q '<!-- Namespace nlohmann::json_abi_diag_dp_ns_v[0-9_]* -->' $RUNNER_TEMP/abi_tags.natvis
           test $(grep -c '<!-- Namespace ' $RUNNER_TEMP/abi_tags.natvis) -eq $(( $(grep -c '<!-- Namespace ' nlohmann_json.natvis) + 2 ))
 
           python3 $GENERATOR --all --output $RUNNER_TEMP/all.natvis

.github/workflows/flawfinder.yml

@@ -43,8 +43,7 @@ jobs:
       - name: flawfinder_scan
         uses: david-a-wheeler/flawfinder@c4216b74cf2639ffa98503768bd6e4299b5440c9 # v2.0.20
         with:
-          # single_include/ is omitted: it is generated from include/ and would report every finding twice
+          arguments: '--sarif ./'
-          arguments: '--sarif ./cmake ./docs ./include ./src ./tests ./tools'
           output: 'flawfinder_results.sarif'
 
       - name: Upload analysis results to GitHub Security tab

BUILD.bazel

@@ -90,6 +90,7 @@ cc_library(
         "include/nlohmann/detail/view/simd.hpp",
         "include/nlohmann/detail/view/string_ref.hpp",
         "include/nlohmann/detail/view/value.hpp",
+        "include/nlohmann/detail/view/view_mode.hpp",
         "include/nlohmann/json.hpp",
         "include/nlohmann/json_fwd.hpp",
         "include/nlohmann/json_literals.hpp",

FILES.md

@@ -309,7 +309,7 @@ The "Check amalgamation" workflow fails if the file is out of date.
 
 The file covers the namespace variants with up to two ABI tags. A Natvis file for other configurations can be
 generated with the `--abi-tags` or `--all` options, for example
-`make natvis NATVIS_ARGS="--abi-tags _diag,_dp,_vns --output my_nlohmann_json.natvis"`; see
+`make natvis NATVIS_ARGS="--abi-tags _diag,_dp,_ns --output my_nlohmann_json.natvis"`; see
 [`tools/generate_natvis`](tools/generate_natvis/README.md). With MSVC, CMake adds the file to the `nlohmann_json`
 target and installs it.
 

Makefile

@@ -120,7 +120,7 @@ $(AMALGAMATED_VIEW_FILE): $(SRCS)
 	tools/amalgamate/amalgamate.py -c tools/amalgamate/config_json_view.json -s . --verbose=yes
 
 NATVIS_VENV=tools/generate_natvis/venv
-# extra options for generate_natvis.py, e.g. NATVIS_ARGS="--abi-tags _diag,_dp,_vns --output my.natvis"
+# extra options for generate_natvis.py, e.g. NATVIS_ARGS="--abi-tags _diag,_dp,_ns --output my.natvis"
 NATVIS_ARGS=
 
 # regenerate nlohmann_json.natvis from the ABI tags and version in include/nlohmann/detail/abi_macros.hpp

README.md

@@ -151,7 +151,7 @@ The `json` class provides an API for manipulating a JSON value. To create a `jso
 ```cpp
 #include <fstream>
 #include <nlohmann/json.hpp>
-using nlohmann::json;
+using json = nlohmann::json;
 
 // ...
 
@@ -164,7 +164,7 @@ If using modules (enabled with `NLOHMANN_JSON_BUILD_MODULES`), this example beco
 import std;
 import nlohmann.json;
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 // ...
 
@@ -842,7 +842,7 @@ assert(p == p2);
 To make this work with one of your types, you only need to provide two functions:
 
 ```cpp
-using nlohmann::json;
+using json = nlohmann::json;
 
 namespace ns {
     void to_json(json& j, const person& p) {
@@ -1257,7 +1257,7 @@ See the page [quality assurance](https://json.nlohmann.me/community/quality_assu
 #include <nlohmann/json.hpp>
 
 // for convenience
-using nlohmann::json;
+using json = nlohmann::json;
 ```
 
 to the files you want to process JSON and set the necessary switches to enable C++11 (e.g., `-std=c++11` for GCC and Clang).

docs/mkdocs/docs/api/basic_json/binary_t.md

@@ -90,9 +90,8 @@ type `#!cpp binary_t*` must be dereferenced.
 
 - MessagePack
     - If a subtype is given and the binary array contains exactly 1, 2, 4, 8, or 16 elements, the fixext family (fixext1,
-      fixext2, fixext4, fixext8, fixext16) is used. For other sizes, the ext family (ext8, ext16, ext32) is used. The
+      fixext2, fixext4, fixext8) is used. For other sizes, the ext family (ext8, ext16, ext32) is used. The subtype is
-      subtype is then written as the signed 8-bit ext type: subtypes 128 to 255 map to the negative (reserved) ext
+      then added as a signed 8-bit integer.
-      types, and on reading the ext type is exposed as an unsigned subtype from 0 to 255.
     - If no subtype is given, the bin family (bin8, bin16, bin32) is used.
 
 - BSON

docs/mkdocs/docs/api/basic_json/bjdata_version_t.md

@@ -1,48 +0,0 @@
-# <small>nlohmann::basic_json::</small>bjdata_version_t
-
-```cpp
-enum class bjdata_version_t
-{
-    draft2,
-    draft3
-};
-```
-
-This enumeration is used in [`to_bjdata`](to_bjdata.md) to choose the version of the BJData specification to write:
-
-draft2
-:   BJData Draft 2 (the default). Binary values are written as arrays of `U` integers, and ND-arrays with
-    `"_ArrayType_": "byte"` are written as regular objects, since the `B` marker is not part of Draft 2.
-
-draft3
-:   BJData Draft 3. Binary values are written as `B` elements: as an optimized binary array (`[$B#`) if both `use_size`
-    and `use_type` are set, and as an array of `B`-prefixed elements otherwise. ND-arrays with
-    `"_ArrayType_": "byte"` are written as packed arrays (`[$B#[...]`).
-
-Only the writer is affected by the version. [`from_bjdata`](from_bjdata.md) reads the markers of both drafts.
-
-## Examples
-
-??? example
-
-    The example below shows how the different values of the `bjdata_version_t` influence the serialization of a binary
-    value with [`to_bjdata`](to_bjdata.md).
-
-    ```cpp
-    --8<-- "examples/bjdata_version_t.cpp"
-    ```
-
-    Output:
-
-    ```json
-    --8<-- "examples/bjdata_version_t.output"
-    ```
-
-## See also
-
-- [to_bjdata](to_bjdata.md) serializes a JSON value to BJData
-- [BJData](../../features/binary_formats/bjdata.md) - the article on the BJData format
-
-## Version history
-
-- Added in version 3.12.0.

docs/mkdocs/docs/api/basic_json/cbor_tag_handler_t.md

@@ -15,13 +15,11 @@ error
 :   report a parse error in case of a tag (the `from_cbor` overloads throw a `parse_error` exception by default)
 
 ignore
-:   ignore tags (also in front of a text string map key)
+:   ignore tags
 
 store
 :   store tagged byte strings (for bytes 0xd8..0xdb) as binary values with the tag as subtype; other tagged values are
-    read as if the tag were ignored. If several tags precede a byte string, only the tag directly in front of it is
+    read as if the tag were ignored. If several tags precede a byte string, only the innermost one is stored.
-    stored, and only when it has the form 0xd8..0xdb (a tag 0..23 written as 0xc0..0xd7 is skipped). Tags in front of a
-    text string map key are skipped.
 
 ## Examples
 

docs/mkdocs/docs/api/basic_json/from_bjdata.md

@@ -82,11 +82,8 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
 - Throws [parse_error.112](../../home/exceptions.md#jsonexceptionparse_error112) if a parse error occurs
 - Throws [parse_error.113](../../home/exceptions.md#jsonexceptionparse_error113) if a string could not be parsed
   successfully, or if a string value or object key is not valid UTF-8 and `error_handler` is `strict`
-- Throws [parse_error.115](../../home/exceptions.md#jsonexceptionparse_error115) if the text of a high-precision
-  number (`H`) is not a valid number
 - Throws [out_of_range.408](../../home/exceptions.md#jsonexceptionout_of_range408) if the size of an optimized container
-  cannot be represented by `std::size_t` or exceeds the container's `max_size()`, or if the product of the dimensions of
+  or n-dimensional array cannot be represented by `std::size_t`
-  an n-dimensional array overflows
 
 ## Complexity
 

docs/mkdocs/docs/api/basic_json/from_bson.md

@@ -80,8 +80,7 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
 - Throws [`parse_error.110`](../../home/exceptions.md#jsonexceptionparse_error110) if the given input ends prematurely or
   the end of the input was not reached when `strict` was set to true
 - Throws [`parse_error.112`](../../home/exceptions.md#jsonexceptionparse_error112) if a parse error occurs (e.g., an
-  invalid string or byte array length, an invalid inner length of a binary value with subtype `0x02`, or a document size
+  invalid string or byte array length)
-  that does not match the content; `strict` does not affect the document size checks)
 - Throws [`parse_error.114`](../../home/exceptions.md#jsonexceptionparse_error114) if an unsupported BSON record type is
   encountered
 - Throws [`parse_error.113`](../../home/exceptions.md#jsonexceptionparse_error113) if a string value or object key is

docs/mkdocs/docs/api/basic_json/from_cbor.md

@@ -32,10 +32,8 @@ The exact mapping and its limitations are described on a [dedicated page](../../
     
     - an `std::istream` object
     - a `FILE` pointer
-    - a C-style array of characters (its terminating NUL is read as trailing data: `parse_error.110` unless `strict` is
+    - a C-style array of characters
-      `false`)
+    - a pointer to a null-terminated string of single byte characters
-    - a pointer to a null-terminated string of single byte characters (read up to the first 0x00 byte, which is a valid
-      CBOR byte)
     - a container `obj` for which `begin(obj)` and `end(obj)` produce a valid pair of iterators
       (as found via ADL or member functions, with semantics compatible to `std::begin` and `std::end`)
 
@@ -91,14 +89,8 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
 - Throws [parse_error.112](../../home/exceptions.md#jsonexceptionparse_error112) if unsupported features from CBOR were
   used in the given input or if the input is not valid CBOR
 - Throws [parse_error.113](../../home/exceptions.md#jsonexceptionparse_error113) if a map key is not a string (keys of
-  other types are not supported, as JSON object keys are always strings), if the head of a string or byte string is
+  other types are not supported, as JSON object keys are always strings), or if a string value or object key is not
-  malformed (including a chunk of the wrong type or an indefinite-length string nested inside an indefinite-length
+  valid UTF-8 and `error_handler` is `strict`
-  string), or if a string value or object key (or one chunk of an indefinite-length string) is not valid UTF-8 and
-  `error_handler` is `strict`
-- Throws [out_of_range.408](../../home/exceptions.md#jsonexceptionout_of_range408) if an array or map announces
-  a length that `std::size_t` cannot hold, or that equals `std::size_t(-1)` (for example `9B FF FF FF FF FF FF FF FF`)
-- Throws [out_of_range.406](../../home/exceptions.md#jsonexceptionout_of_range406) if a floating-point number does not
-  fit into `number_float_t`
 
 ## Complexity
 

docs/mkdocs/docs/api/basic_json/from_ubjson.md

@@ -79,18 +79,11 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
 
 - Throws [parse_error.110](../../home/exceptions.md#jsonexceptionparse_error110) if the given input ends prematurely or
   the end of the file was not reached when `strict` was set to true
-- Throws [parse_error.112](../../home/exceptions.md#jsonexceptionparse_error112) if an invalid type marker is read
+- Throws [parse_error.112](../../home/exceptions.md#jsonexceptionparse_error112) if a parse error occurs
-  (including a type marker after `$` of an optimized container, even if its count is 0), or if `$` is not followed by `#`
 - Throws [parse_error.113](../../home/exceptions.md#jsonexceptionparse_error113) if a string could not be parsed
-  successfully (negative or non-integer length, `C` followed by a byte above 0x7F), if the count of an optimized
+  successfully, or if a string value or object key is not valid UTF-8 and `error_handler` is `strict`
-  container is negative, or if a string value or object key is not valid UTF-8 and `error_handler` is `strict`
+- Throws [out_of_range.408](../../home/exceptions.md#jsonexceptionout_of_range408) if the size of an optimized container
-- Throws [parse_error.115](../../home/exceptions.md#jsonexceptionparse_error115) if the text of a high-precision number
+  or n-dimensional array cannot be represented by `std::size_t`
-  (`H`) is not a valid JSON number
-- Throws [out_of_range.406](../../home/exceptions.md#jsonexceptionout_of_range406) if a high-precision number, or a
-  float64 when `number_float_t` is `float`, does not fit into `number_float_t`
-- Throws [out_of_range.408](../../home/exceptions.md#jsonexceptionout_of_range408) if the count of an optimized
-  container exceeds the capacity of the container (or of `std::size_t`), or if an optimized array of `Z`, `T`, or `F` has
-  more than 1,048,576 elements
 
 ## Complexity
 

docs/mkdocs/docs/api/basic_json/get_ptr.md

@@ -45,7 +45,7 @@ Constant.
     #include <iostream>
     #include <nlohmann/json.hpp>
     
-    using nlohmann::json;
+    using json = nlohmann::json;
     
     int main()
     {

docs/mkdocs/docs/api/basic_json/index.md

@@ -121,7 +121,6 @@ The class satisfies the following concept requirements:
 - [**json_pointer**](../json_pointer/index.md) - JSON Pointer implementation
 - [**json_serializer**](json_serializer.md) - type of the serializer to for conversions from/to JSON
 - [**error_handler_t**](error_handler_t.md) - type to choose behavior on decoding errors
-- [**bjdata_version_t**](bjdata_version_t.md) - type to choose the BJData version to write
 - [**cbor_tag_handler_t**](cbor_tag_handler_t.md) - type to choose how to handle CBOR tags
 - **initializer_list_t** - type for initializer lists of `basic_json` values
 - [**input_format_t**](input_format_t.md) - type to choose the format to parse

docs/mkdocs/docs/api/basic_json/to_bjdata.md

@@ -43,8 +43,7 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 `#!cpp false` by default.
 
 `version` (in)
-:   which version of BJData to use, see [`bjdata_version_t`](bjdata_version_t.md) and the note on "Binary values" on
+:   which version of BJData to use (see note on "Binary values" on [BJData](../../features/binary_formats/bjdata.md));
-[BJData](../../features/binary_formats/bjdata.md);
 optional, `#!cpp bjdata_version_t::draft2` by default.
 
 `error_handler` (in)
@@ -65,9 +64,7 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
 ## Exceptions
 
 - Throws [`other_error.502`](../../home/exceptions.md#jsonexceptionother_error502) if `use_type` is true and `use_size`
-  is false, and `j` contains a non-empty array or object, or a non-empty binary value (with
+  is false, and `j` contains a non-empty array, object, or binary value.
-  `version = bjdata_version_t::draft3`, any binary value, including an empty one).
-  Scalars, empty arrays, and empty objects do not throw.
 - Throws [type_error.316](../../home/exceptions.md#jsonexceptiontype_error316) if a string or object key in `j` is
   not valid UTF-8 and `error_handler` is `strict` (the default only if
   [`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled)

docs/mkdocs/docs/api/basic_json/to_bson.md

@@ -13,7 +13,7 @@ static void to_bson(const basic_json& j, detail::output_adapter<char> o,
 ```
 
 BSON (Binary JSON) is a binary format in which zero or more ordered key/value pairs are stored as a single entity (a
-so-called document). The members of an object are written in the order in which iteration visits them.
+so-called document).
 
 1. Returns a byte vector containing the BSON serialization.
 2. Writes the BSON serialization to an output adapter.

docs/mkdocs/docs/api/basic_json/to_cbor.md

@@ -42,8 +42,7 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 
 ## Exception safety
 
-Strong guarantee: if an exception is thrown, there are no changes in the JSON value. Bytes that were already written to
+Strong guarantee: if an exception is thrown, there are no changes in the JSON value.
-the output adapter are not taken back.
 
 ## Exceptions
 

docs/mkdocs/docs/api/basic_json/to_msgpack.md

@@ -53,7 +53,7 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
   value, array, or object exceeds 4294967295, the maximum MessagePack can store; example:
   `"MessagePack length 4294967296 exceeds maximum of 4294967295"`
 - Throws [`out_of_range.415`](../../home/exceptions.md#jsonexceptionout_of_range415) if the subtype of a binary value
-  exceeds 255, the largest value the library can store in the one-byte MessagePack ext type; example:
+  exceeds 255, the maximum of the MessagePack ext type; example:
   `"subtype 70000 is too large for the MessagePack ext type (max 255)"`
 - Throws [type_error.316](../../home/exceptions.md#jsonexceptiontype_error316) if a string or object key in `j` is
   not valid UTF-8 and `error_handler` is `strict`

docs/mkdocs/docs/api/basic_json_document/erase.md

@@ -12,7 +12,7 @@ void erase(view_type array, I idx);
 std::size_t erase(const json_pointer& ptr);
 ```
 
-Only an **editable** document (`#!cpp Editable == true`, e.g. [`json_editable_document`](../json_editable_document.md))
+Only an **editable** document (`#!cpp view_mode::editable`, e.g. [`json_editable_document`](../json_editable_document.md))
 has `erase`; calling it on a read-only `basic_json_document` fails to compile (`#!cpp static_assert`).
 
 1. Removes every member of `object` whose key is `key` (see [Notes](#notes) on duplicate keys) and returns how many

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, bool Editable = false>
+template<typename BasicJsonType, view_mode Mode = view_mode::read_only>
 class basic_json_document;
 ```
 
@@ -20,9 +20,9 @@ is move-only: a copy would duplicate the whole index, the decoded-string buffer,
 enough in every use we know of. The index, the decoded strings, and the owned text live in one heap block that the
 document holds through a `#!cpp std::unique_ptr`; this is also why views survive a move of the document.
 
-With `#!cpp Editable == true`, the document also offers [`set`](set.md), [`push_back`](push_back.md),
+With `#!cpp Mode == view_mode::editable`, the document also offers [`set`](set.md), [`push_back`](push_back.md),
 [`insert`](insert.md), and [`erase`](erase.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
+itself is never written; a read-only document (`#!cpp view_mode::read_only`, the default) does not carry any of the
 bookkeeping edits need, and calling any of them on one fails to compile (`#!cpp static_assert`).
 
 ## Template parameters
@@ -32,9 +32,10 @@ bookkeeping edits need, and calling any of them on one fails to compile (`#!cpp
     [`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`
+`Mode`
-:   whether the document supports [`set`](set.md), [`push_back`](push_back.md), [`insert`](insert.md), and
+:   a [`view_mode`](../view_mode.md): `#!cpp view_mode::editable` if the document supports [`set`](set.md),
-    [`erase`](erase.md) (optional, `#!cpp false` by default). See [Edits](#edits) below.
+    [`push_back`](push_back.md), [`insert`](insert.md), and [`erase`](erase.md) (optional, `#!cpp view_mode::read_only`
+    by default). See [Edits](#edits) below.
 
 ## Specializations
 
@@ -47,7 +48,7 @@ bookkeeping edits need, and calling any of them on one fails to compile (`#!cpp
 
 ## Member types
 
-- **view_type** - the type of view returned by [`root()`](root.md) (`#!cpp basic_json_view<BasicJsonType, Editable>`)
+- **view_type** - the type of view returned by [`root()`](root.md) (`#!cpp basic_json_view<BasicJsonType, Mode>`)
 - **value_t** - the JSON type enumeration, see [`basic_json::value_t`](../basic_json/value_t.md)
 - **image_check** - how [`load()`](load.md) validates an image (`full`, `bounds`, `none`), see [`image_check`](load.md#image_check)
 
@@ -80,15 +81,15 @@ bookkeeping edits need, and calling any of them on one fails to compile (`#!cpp
 ### Edits
 
 - [**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)
+  to (editable documents only)
-- [**push_back**](push_back.md) - append to an array (`#!cpp Editable` documents only)
+- [**push_back**](push_back.md) - append to an array (editable documents only)
-- [**insert**](insert.md) - insert an element into an array before a given position (`#!cpp Editable` documents only)
+- [**insert**](insert.md) - insert an element into an array before a given position (editable documents only)
 - [**erase**](erase.md) - remove an object member, an array element, or the value a JSON pointer refers to
-  (`#!cpp Editable` documents only)
+  (editable documents only)
 
 ## Edits
 
-An editable document (`#!cpp Editable == true`) can be changed after parsing, with [`set`](set.md),
+An editable document (`#!cpp view_mode::editable`) can be changed after parsing, with [`set`](set.md),
 [`push_back`](push_back.md), [`insert`](insert.md), and [`erase`](erase.md);
 [`json_editable_document`](../json_editable_document.md) and
 [`ordered_json_editable_document`](../ordered_json_editable_document.md) are the corresponding specializations. A few

docs/mkdocs/docs/api/basic_json_document/insert.md

@@ -5,7 +5,7 @@ template<typename I, typename V>
 view_type insert(view_type array, I idx, V&& value);
 ```
 
-Only an **editable** document (`#!cpp Editable == true`, e.g. [`json_editable_document`](../json_editable_document.md))
+Only an **editable** document (`#!cpp view_mode::editable`, e.g. [`json_editable_document`](../json_editable_document.md))
 has `insert`; calling it on a read-only `basic_json_document` fails to compile (`#!cpp static_assert`).
 
 Inserts `value` into `array` as a new element before position `idx`, which must not be past the end

docs/mkdocs/docs/api/basic_json_document/load.md

@@ -55,10 +55,7 @@ validate with overload 2 first, if the original vector must survive a failed loa
 
 ## Exceptions
 
-On a big-endian target, throws [`type_error.320`](../../home/exceptions.md#jsonexceptiontype_error320) -- the same
+Throws [`parse_error.116`](../../home/exceptions.md#jsonexceptionparse_error116) if `image` is not one
-exception [`save()`](save.md#exceptions) throws there, since the image format is little-endian only.
-
-Otherwise throws [`parse_error.116`](../../home/exceptions.md#jsonexceptionparse_error116) if `image` is not one
 `save()` could have written, or fails the requested `check`:
 
 | message               | when                                                                                                |
@@ -95,6 +92,9 @@ are checked once, however many nodes refer to it.
 
 ## Notes
 
+**Little-endian targets only.** On a big-endian target, `load()` does not exist, just like
+[`save()`](save.md#notes): the image format is little-endian, so a call fails to compile.
+
 ### `image_check` { #image_check }
 
 ```cpp

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

@@ -13,7 +13,7 @@ editable, and it does not have to be `array`'s own document -- which is copied s
 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))
+Only an **editable** document (`#!cpp view_mode::editable`, 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

docs/mkdocs/docs/api/basic_json_document/save.md

@@ -12,7 +12,7 @@ An edited document is written in its *current* state, with its values in documen
 parser would have produced them for that JSON text: a member [`set`](set.md) added goes at the end, an
 [`erase`](erase.md)d member leaves no trace, and a float that is not finite (NaN or positive/negative infinity)
 becomes null, the same substitution [`dump()`](../basic_json_view/dump.md) makes. The same document always saves to
-the same bytes -- also across `BasicJsonType` and `#!cpp Editable`, since the image reflects document order and
+the same bytes -- also across `BasicJsonType` and the [`view_mode`](../view_mode.md), since the image reflects document order and
 values only, not which specialization produced them.
 
 ## Return value
@@ -31,9 +31,6 @@ Throws [`type_error.320`](../../home/exceptions.md#jsonexceptiontype_error320) i
 [discarded](is_discarded.md) -- a default-constructed document, or one a failed [`parse()`](parse.md)/
 [`read()`](read.md) with `allow_exceptions == false` left discarded.
 
-On a big-endian target, throws `type_error.320` with a different message instead: the image format is little-endian
-only (see [Notes](#notes)).
-
 Throws [`out_of_range.416`](../../home/exceptions.md#jsonexceptionout_of_range416) if the node count, the text, or
 the decoded strings of the image would individually reach 4 GiB -- the same 32-bit offsets
 [`parse()`](parse.md#exceptions) and, for edits, [`set`](set.md)/[`push_back`](push_back.md) are already limited to.
@@ -44,9 +41,6 @@ the decoded strings of the image would individually reach 4 GiB -- the same 32-b
     [json.exception.type_error.320] cannot save a discarded json_document
     ```
     ```
-    [json.exception.type_error.320] json_document images need a little-endian target
-    ```
-    ```
     [json.exception.out_of_range.416] images of 4 GiB or more are not supported by json_document
     ```
 
@@ -70,9 +64,9 @@ else -- see [`load`'s Exceptions](load.md#exceptions).
     the *same* build on the *same* (little-endian) machine -- not as a long-term storage format. Keep the original
     JSON text if you need to read a saved document back with a future library version.
 
-**Little-endian only.** The image is written as raw little-endian bytes, with no byte-swapping. `save()` (and
+**Little-endian targets only.** The image is written as raw little-endian bytes, with no byte-swapping. On a
-[`load`](load.md)) throw `type_error.320` on a big-endian target rather than silently produce bytes a big-endian
+big-endian target, `save()` and [`load`](load.md) do not exist: a call fails to compile rather than produce bytes a
-reader could not interpret correctly.
+big-endian reader could not interpret correctly.
 
 ## Examples
 

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

@@ -18,7 +18,7 @@ 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))
+Only an **editable** document (`#!cpp view_mode::editable`, 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`.

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

@@ -27,8 +27,25 @@ For the types below, the conversion works directly on the flat index -- no `Basi
   [`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
+A default-constructible `T` whose `from_json()` accepts views reads the view directly as well, member by member, without
-`from_json()`, ... -- is converted by `#!cpp materialize().get<T>()`: the subtree is built into a real `BasicJsonType`
+building a `BasicJsonType` value. This covers the types of the
+[`NLOHMANN_DEFINE_TYPE_*`](../macros/nlohmann_define_type_intrusive.md) and
+[`NLOHMANN_DEFINE_DERIVED_TYPE_*`](../macros/nlohmann_define_derived_type.md) macros and the enumerations of
+[`NLOHMANN_JSON_SERIALIZE_ENUM`](../macros/nlohmann_json_serialize_enum.md), and any `from_json()` constrained to
+accept views, e.g. with [`is_json_view`](../is_json_view.md). A `from_json()` that also accepts types that are no JSON
+values at all, such as the unconstrained `#!cpp template<typename BasicJsonType> void from_json(const BasicJsonType&,
+T&)` of [arbitrary type conversions](../../features/arbitrary_types.md), is not called with a view: it may use
+`BasicJsonType` functions a view does not have. See [json_view](../../features/json_view.md).
+
+!!! warning "Duplicate keys"
+
+    Such a `from_json()` looks members up in the view, where a repeated key finds the **first** member, while
+    `#!cpp materialize().get<T>()` sees the **last** one, as [`BasicJsonType::parse()`](../basic_json/parse.md)
+    keeps it: for `#!cpp {"x":1,"x":2}`, `#!cpp get<point>()` reads `#!cpp x == 1`. See
+    [Duplicate keys](../../features/json_view.md#duplicate-keys).
+
+Every other `T` -- `#!cpp std::list`, `#!cpp std::pair`, `#!cpp std::array`, user types whose `from_json()` is
+written for `BasicJsonType` only, ... -- 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.
 
@@ -55,10 +72,13 @@ Strong guarantee: there are no changes to the view or the document it refers to.
   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 a `T` whose `from_json()` reads the view: whatever that `from_json()` throws; for the macros, the same
+  exceptions with the same messages as [`BasicJsonType::get<T>()`](../basic_json/get.md) of the same value.
 - 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
+None of the exceptions thrown directly by this function or by a `from_json()` that reads the view (the first four
+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.
@@ -76,6 +96,8 @@ document.
 - `#!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.
+- a `T` whose `from_json()` reads the view: the cost of that `from_json()`; for the macros, linear in the number of
+  members times the cost of a lookup, plus the cost of converting the members.
 - every other `T`: the cost of [`materialize()`](materialize.md) and of destroying the `BasicJsonType` value
   afterwards, plus that of [`BasicJsonType::get<T>()`](../basic_json/get.md).
 

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

@@ -5,12 +5,14 @@ template<typename T>
 T& get_to(T& v) const;
 ```
 
-Converts the value to `T` and stores it in `v`, in one of two ways:
+Converts the value to `T` and stores it in `v`, in one of three ways:
 
 - For the types that [`get<T>()`](get.md) converts directly -- arithmetic types, `#!cpp bool`,
   `#!cpp std::nullptr_t`, [`string_view_t`](index.md#member-types), `#!cpp std::basic_string`, `BasicJsonType`,
   `basic_json_view`, `#!cpp std::vector`, and `#!cpp std::map`/`#!cpp std::unordered_map` with string keys -- `v` is
   assigned: `#!cpp v = get<T>()`.
+- For a type whose `from_json()` accepts views (see [`get<T>()`](get.md)), that `from_json()` is called with the
+  view and the existing `v`, without building a `BasicJsonType` value.
 - For every other type, the subtree is built into a `BasicJsonType` value and `#!cpp materialize().get_to(v)` is
   called, i.e. `from_json()` is invoked with the existing `v`, exactly as
   [`BasicJsonType::get_to()`](../basic_json/get_to.md) does.

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, bool Editable = false>
+template<typename BasicJsonType, view_mode Mode = view_mode::read_only>
 class basic_json_view;
 ```
 
@@ -37,7 +37,7 @@ Moving the document itself does not invalidate its views: the index is heap-allo
 `#!cpp operator ValueType()`), and no `#!cpp get_ptr()` or `#!cpp get_ref()`; see [`get`](get.md).
 
 `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
+**editable** document (`#!cpp view_mode::editable`) 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
@@ -49,9 +49,10 @@ still refers to it -- including ones taken before the change -- reads the new va
 :   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`
+`Mode`
-:   whether the view is of an editable document, matching the [`basic_json_document`](../basic_json_document/index.md)
+:   a [`view_mode`](../view_mode.md): whether the view is of an editable document, matching the
-    it was taken from (optional, `#!cpp false` by default). See [Edits](../basic_json_document/index.md#edits).
+    [`basic_json_document`](../basic_json_document/index.md) it was taken from (optional, `#!cpp view_mode::read_only` by
+    default). See [Edits](../basic_json_document/index.md#edits).
 
 ## Specializations
 
@@ -63,6 +64,7 @@ still refers to it -- including ones taken before the change -- reads the new va
 
 ## Member types
 
+- **basic_json_type** - `BasicJsonType` (it also marks the class for [`is_json_view`](../is_json_view.md))
 - **value_t** - the JSON type enumeration, see [`basic_json::value_t`](../basic_json/value_t.md)
 - **string_t**, **number_integer_t**, **number_unsigned_t**, **number_float_t**, **json_pointer** - the corresponding
   member types of `BasicJsonType`

docs/mkdocs/docs/api/byte_container_with_subtype/index.md

@@ -6,7 +6,7 @@ class byte_container_with_subtype : public BinaryType;
 ```
 
 This type extends the template parameter `BinaryType` provided to [`basic_json`](../basic_json/index.md) with a subtype
-used by BSON, CBOR, and MessagePack. This type exists so that the user does not have to specify a type themselves with a
+used by BSON and MessagePack. This type exists so that the user does not have to specify a type themselves with a
 specific naming scheme in order to override the binary type.
 
 ## Template parameters

docs/mkdocs/docs/api/is_json_view.md

@@ -0,0 +1,55 @@
+# <small>nlohmann::</small>is_json_view
+
+<small>Defined in header `<nlohmann/json_view.hpp>`</small>
+
+```cpp
+template<typename T>
+struct is_json_view;
+```
+
+A type trait: `#!cpp is_json_view<T>::value` is `#!cpp true` if `T` is a [`basic_json_view`](basic_json_view/index.md)
+of any `BasicJsonType` and any [`view_mode`](view_mode.md) -- [`json_view`](json_view.md),
+[`json_editable_view`](json_editable_view.md), [`ordered_json_view`](ordered_json_view.md), ... -- and
+`#!cpp false` otherwise, for [`basic_json`](basic_json/index.md) as well.
+
+It is meant for constraining templates that accept views, in particular a `from_json()` that should read views
+directly: [`get<T>()`](basic_json_view/get.md) on a view calls a `from_json()` with the view only if that `from_json()`
+accepts views but not arbitrary types.
+
+## Template parameters
+
+`T`
+:   the type to check (without cv-qualifiers or references)
+
+## Notes
+
+A view is recognized by its member type `basic_json_type` (a [`basic_json`](basic_json/index.md) specialization) and
+its [`materialize()`](basic_json_view/materialize.md) returning that type, so the trait needs no declaration of the
+view class.
+
+## Examples
+
+??? example
+
+    The example below shows the trait, and a `from_json()` constrained to `json` values and views: `get<T>()` on a view
+    reads the view directly.
+
+    ```cpp
+    --8<-- "examples/is_json_view.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/is_json_view.output"
+    ```
+
+## See also
+
+- [basic_json_view](basic_json_view/index.md) - a handle to one value of a document
+- [get](basic_json_view/get.md) - which conversions read the view directly
+- [view_mode](view_mode.md) - read-only or editable
+
+## Version history
+
+Added in version 3.13.0.

docs/mkdocs/docs/api/json_document.md

@@ -3,7 +3,7 @@
 <small>Defined in header `<nlohmann/json_view.hpp>`</small>
 
 ```cpp
-using json_document = basic_json_document<json>;
+using json_document = basic_json_document<json, view_mode::read_only>;
 ```
 
 This type is a [`basic_json_document`](basic_json_document/index.md) of the default [`json`](json.md)

docs/mkdocs/docs/api/json_editable_document.md

@@ -3,7 +3,7 @@
 <small>Defined in header `<nlohmann/json_view.hpp>`</small>
 
 ```cpp
-using json_editable_document = basic_json_document<json, true>;
+using json_editable_document = basic_json_document<json, view_mode::editable>;
 ```
 
 This type is an **editable** [`basic_json_document`](basic_json_document/index.md) of the default

docs/mkdocs/docs/api/json_editable_view.md

@@ -3,7 +3,7 @@
 <small>Defined in header `<nlohmann/json_view.hpp>`</small>
 
 ```cpp
-using json_editable_view = basic_json_view<json, true>;
+using json_editable_view = basic_json_view<json, view_mode::editable>;
 ```
 
 This type is a [`basic_json_view`](basic_json_view/index.md) of a value of a

docs/mkdocs/docs/api/json_view.md

@@ -3,7 +3,7 @@
 <small>Defined in header `<nlohmann/json_view.hpp>`</small>
 
 ```cpp
-using json_view = basic_json_view<json>;
+using json_view = basic_json_view<json, view_mode::read_only>;
 ```
 
 This type is a [`basic_json_view`](basic_json_view/index.md) of a value of a [`json_document`](json_document.md).

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

@@ -43,8 +43,6 @@ 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_assert.md

@@ -38,7 +38,7 @@ Therefore, assertions can be switched off by defining `NDEBUG`.
     ```cpp
     #include <nlohmann/json.hpp>
     
-    using nlohmann::json;
+    using json = nlohmann::json;
     
     int main()
     {
@@ -64,7 +64,7 @@ Therefore, assertions can be switched off by defining `NDEBUG`.
     
     #include <nlohmann/json.hpp>
     
-    using nlohmann::json;
+    using json = nlohmann::json;
     
     int main()
     {

docs/mkdocs/docs/api/macros/json_brace_init_copy_semantics.md

@@ -79,7 +79,7 @@ The default value is `0` (disabled — existing behavior is preserved).
     ```cpp
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     int main()
     {
@@ -98,7 +98,7 @@ The default value is `0` (disabled — existing behavior is preserved).
     #define JSON_BRACE_INIT_COPY_SEMANTICS 1
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     int main()
     {

docs/mkdocs/docs/api/macros/json_delete_deprecated_functions.md

@@ -54,7 +54,7 @@ The default value is `0` (disabled, the deprecated functions can still be called
     ```cpp
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     int main()
     {
@@ -72,7 +72,7 @@ The default value is `0` (disabled, the deprecated functions can still be called
     #define JSON_DELETE_DEPRECATED_FUNCTIONS 1
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     int main()
     {

docs/mkdocs/docs/api/macros/json_disable_enum_serialization.md

@@ -39,7 +39,7 @@ The default value is `0`.
     #define JSON_DISABLE_ENUM_SERIALIZATION 1
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     enum class Choice
     {
@@ -66,7 +66,7 @@ The default value is `0`.
     #define JSON_DISABLE_ENUM_SERIALIZATION 1
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     enum class Choice
     {
@@ -99,7 +99,7 @@ The default value is `0`.
     #define JSON_DISABLE_ENUM_SERIALIZATION 1
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     enum class Choice
     {

docs/mkdocs/docs/api/macros/json_disable_stream_bulk_scan.md

@@ -92,7 +92,7 @@ The default value is `0`: streams are scanned in bulk.
     #include <sstream>
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     int main()
     {
@@ -115,7 +115,7 @@ The default value is `0`: streams are scanned in bulk.
     #include <sstream>
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     int main()
     {

docs/mkdocs/docs/api/macros/json_disable_tuple_reference_conversion.md

@@ -72,7 +72,7 @@ The default value is `0` (disabled — existing behavior is preserved).
     ```cpp
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     int main()
     {
@@ -89,7 +89,7 @@ The default value is `0` (disabled — existing behavior is preserved).
     #define JSON_DISABLE_TUPLE_REFERENCE_CONVERSION 1
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     int main()
     {

docs/mkdocs/docs/api/macros/json_disable_unlocked_file_io.md

@@ -73,7 +73,7 @@ The default value is `0`: the file is locked once and read with the unlocked std
     #include <cstdio>
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     int main()
     {
@@ -92,7 +92,7 @@ The default value is `0`: the file is locked once and read with the unlocked std
     #include <cstdio>
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     int main()
     {

docs/mkdocs/docs/api/macros/json_no_simd.md

@@ -5,7 +5,8 @@
 ```
 
 When defined, the library uses only portable C++ code where it would otherwise use vector instructions: when scanning
-strings during parsing, and when writing floating-point numbers during serialization.
+strings during parsing, and when writing floating-point numbers during serialization. This includes the parser of
+[`basic_json_document`](../basic_json_document/index.md) (`<nlohmann/json_view.hpp>`).
 
 The macro is an escape hatch, for example for toolchains that cannot compile the vector code, for sanitizers or
 analyzers that do not understand it, or to compare the speed of both variants. It does not change any result: values,
@@ -61,7 +62,7 @@ By default, `#!cpp JSON_NO_SIMD` is not defined, and vector instructions are use
     #include <iostream>
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     int main()
     {
@@ -77,6 +78,7 @@ By default, `#!cpp JSON_NO_SIMD` is not defined, and vector instructions are use
 - [**JSON_USE_SIMDUTF**](json_use_simdutf.md) - use the simdutf library to accelerate UTF-8 validation
 - [**JSON_DISABLE_STREAM_BULK_SCAN**](json_disable_stream_bulk_scan.md) - read a `std::istream` one character at a time
 - [Parsing: input sources and performance](../../features/parsing/index.md#input-sources-and-performance)
+- [json_view](../../features/json_view.md) - the zero-copy view, whose parser the macro also affects
 
 ## Version history
 

docs/mkdocs/docs/api/macros/json_precise_stream_position.md

@@ -94,7 +94,7 @@ The default value is `0` (disabled — existing behavior is preserved).
     #include <sstream>
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     int main()
     {
@@ -115,7 +115,7 @@ The default value is `0` (disabled — existing behavior is preserved).
     #include <sstream>
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     int main()
     {

docs/mkdocs/docs/api/macros/json_strict_binary_utf8.md

@@ -64,7 +64,7 @@ The default value is `0` (disabled, the behavior of version 3.12.0 and earlier i
     ```cpp
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     int main()
     {
@@ -81,7 +81,7 @@ The default value is `0` (disabled, the behavior of version 3.12.0 and earlier i
     #define JSON_STRICT_BINARY_UTF8 1
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     int main()
     {

docs/mkdocs/docs/api/macros/json_strict_nul_handling.md

@@ -92,7 +92,7 @@ The default value is `0` (disabled — existing behavior is preserved).
     ```cpp
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     int main()
     {
@@ -109,7 +109,7 @@ The default value is `0` (disabled — existing behavior is preserved).
     #define JSON_STRICT_NUL_HANDLING 1
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     int main()
     {

docs/mkdocs/docs/api/macros/json_use_objects_for_enum_keyed_maps.md

@@ -77,7 +77,7 @@ The default value is `0` (disabled — existing behavior is preserved).
     #include <map>
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     enum TaskState { TS_STOPPED, TS_RUNNING, TS_COMPLETED };
 
@@ -105,7 +105,7 @@ The default value is `0` (disabled — existing behavior is preserved).
     #include <map>
     #include <nlohmann/json.hpp>
 
-    using nlohmann::json;
+    using json = nlohmann::json;
 
     enum TaskState { TS_STOPPED, TS_RUNNING, TS_COMPLETED };
 

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

@@ -1,52 +0,0 @@
-# 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.
-
-!!! note "ABI compatibility"
-
-    The macro selects between two definitions of the same inline functions. Whether it is defined is encoded in the
-    [namespace](../../features/namespace.md) (tag `_vns`), resulting in distinct symbol names. Translation units
-    compiled with and without it can therefore be linked into the same program without One Definition Rule (ODR)
-    violations, but they cannot exchange instances of library types.
-
-## 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

@@ -1,53 +0,0 @@
-# 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 without asking the CPU first.
-
-By default, the parser checks once at run time whether the CPU has SSSE3 (all x86-64 CPUs since about 2011 have it)
-and then validates non-ASCII text 16 bytes at a time, using the "lookup4" algorithm of
-[simdjson](https://github.com/simdjson/simdjson); on CPUs without SSSE3, it validates one UTF-8 sequence at a time.
-The vector check is compiled for SSSE3 with a function attribute (GCC 4.9 and later, Clang), so this needs no compiler
-option. With MSVC, the check uses `__cpuid`. On AArch64, the vector check uses NEON and is always on.
-
-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. It saves the check of the CPU, which costs little. The same
-input is accepted or rejected either way; only the speed of non-ASCII text differs.
-
-!!! note "ABI compatibility"
-
-    The macro selects between two definitions of the same inline functions. Whether it is defined is encoded in the
-    [namespace](../../features/namespace.md) (tag `_vssse3`, on every architecture), resulting in distinct symbol
-    names. Translation units compiled with and without it can therefore be linked into the same program without One
-    Definition Rule (ODR) violations, but they cannot exchange instances of library types.
-
-## 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/macros/nlohmann_define_derived_type.md

@@ -147,6 +147,13 @@ void to_json(BasicJsonType& j, const B& b) {
     See Implementation limits for [NLOHMANN_DEFINE_TYPE_INTRUSIVE](nlohmann_define_type_intrusive.md) and
     [NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE](nlohmann_define_type_non_intrusive.md), respectively.
 
+!!! info "Views"
+
+    The generated `from_json()` also reads the views of [`json_document`](../json_document.md)s
+    (`<nlohmann/json_view.hpp>`): [`get<T>()`](../basic_json_view/get.md) on a view looks the members up in the
+    view, without building a `json` value first. The base part is read from the view as well if the base's
+    `from_json()` accepts views, and from [`materialize()`](../basic_json_view/materialize.md) otherwise.
+
 ## Examples
 
 ??? example "Example: (1) NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE"
@@ -192,3 +199,5 @@ void to_json(BasicJsonType& j, const B& b) {
 6. Added in version 3.12.0.
 
 All six macros were changed to allow an empty member list in version 3.13.0.
+
+The generated `from_json()` reads the views of `json_document`s since version 3.13.0.

docs/mkdocs/docs/api/macros/nlohmann_define_type_intrusive.md

@@ -81,6 +81,12 @@ See the examples below for the concrete generated code.
       that serializes a struct's members positionally into a JSON array; for that, write `to_json`/`from_json` by
       hand, building/reading a `json::array()` of the members in order.
 
+!!! info "Views"
+
+    The generated `from_json()` also reads the views of [`json_document`](../json_document.md)s
+    (`<nlohmann/json_view.hpp>`): [`get<T>()`](../basic_json_view/get.md) on a view looks the members up in the
+    view, without building a `json` value first.
+
 ## Examples
 
 ??? example "Example: (1) NLOHMANN_DEFINE_TYPE_INTRUSIVE"
@@ -189,3 +195,5 @@ See the examples below for the concrete generated code.
 
 All three macros were changed to work with any `basic_json` specialization (not only `nlohmann::json`) in version 3.12.0,
 and to allow an empty member list in version 3.13.0.
+
+The generated `from_json()` reads the views of `json_document`s since version 3.13.0.

docs/mkdocs/docs/api/macros/nlohmann_define_type_non_intrusive.md

@@ -80,6 +80,12 @@ See the examples below for the concrete generated code.
       that serializes a struct's members positionally into a JSON array; for that, write `to_json`/`from_json` by
       hand, building/reading a `json::array()` of the members in order.
 
+!!! info "Views"
+
+    The generated `from_json()` also reads the views of [`json_document`](../json_document.md)s
+    (`<nlohmann/json_view.hpp>`): [`get<T>()`](../basic_json_view/get.md) on a view looks the members up in the
+    view, without building a `json` value first.
+
 ## Examples
 
 ??? example "Example: (1) NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE"
@@ -188,3 +194,5 @@ See the examples below for the concrete generated code.
 
 All three macros were changed to work with any `basic_json` specialization (not only `nlohmann::json`) in version 3.12.0,
 and to allow an empty member list in version 3.13.0.
+
+The generated `from_json()` reads the views of `json_document`s since version 3.13.0.

docs/mkdocs/docs/api/macros/nlohmann_json_namespace.md

@@ -39,6 +39,6 @@ the library.
 ## Version history
 
 - Added in version 3.11.0. Changed inline namespace name in version 3.11.2. Added the ABI tag `_dp` in
-  version 3.12.0, and the ABI tags `_bics`, `_psp`, `_snul`, `_sbu8`, `_ekmo`, `_dsbs`, `_dufio`, `_ns`, `_vns`,
+  version 3.12.0, and the ABI tags `_bics`, `_psp`, `_snul`, `_sbu8`, `_ekmo`, `_dsbs`, `_dufio`, and `_ns` in
-  and `_vssse3` in version 3.13.0; see
+  version 3.13.0; see
   [`nlohmann` Namespace](../../features/namespace.md#structure).

docs/mkdocs/docs/api/macros/nlohmann_json_serialize_enum.md

@@ -45,6 +45,12 @@ inline void from_json(const BasicJsonType& j, type& e);
       Define [`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](json_use_objects_for_enum_keyed_maps.md) to store them as objects
       with the converted keys. Such maps can be read from both forms.
 
+!!! info "Views"
+
+    The generated `from_json()` also reads the views of [`json_document`](../json_document.md)s
+    (`<nlohmann/json_view.hpp>`), comparing the view with the entries of the mapping, without building a `json` value
+    first.
+
 ## Examples
 
 ??? example "Example: Basic usage"
@@ -88,3 +94,5 @@ inline void from_json(const BasicJsonType& j, type& e);
 ## Version history
 
 Added in version 3.4.0.
+
+The generated `from_json()` reads the views of `json_document`s since version 3.13.0.

docs/mkdocs/docs/api/macros/nlohmann_json_serialize_enum_strict.md

@@ -48,6 +48,12 @@ inline void from_json(const BasicJsonType& j, type& e);
       Define [`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](json_use_objects_for_enum_keyed_maps.md) to store them as objects
       with the converted keys. Such maps can be read from both forms.
 
+!!! info "Views"
+
+    The generated `from_json()` also reads the views of [`json_document`](../json_document.md)s
+    (`<nlohmann/json_view.hpp>`), comparing the view with the entries of the mapping, without building a `json` value
+    first.
+
 ## Examples
 
 ??? example "Example: Basic usage"

docs/mkdocs/docs/api/ordered_json_document.md

@@ -3,7 +3,7 @@
 <small>Defined in header `<nlohmann/json_view.hpp>`</small>
 
 ```cpp
-using ordered_json_document = basic_json_document<ordered_json>;
+using ordered_json_document = basic_json_document<ordered_json, view_mode::read_only>;
 ```
 
 This type is a [`basic_json_document`](basic_json_document/index.md) of the [`ordered_json`](ordered_json.md)

docs/mkdocs/docs/api/ordered_json_editable_document.md

@@ -3,7 +3,7 @@
 <small>Defined in header `<nlohmann/json_view.hpp>`</small>
 
 ```cpp
-using ordered_json_editable_document = basic_json_document<ordered_json, true>;
+using ordered_json_editable_document = basic_json_document<ordered_json, view_mode::editable>;
 ```
 
 This type is an **editable** [`basic_json_document`](basic_json_document/index.md) of the

docs/mkdocs/docs/api/ordered_json_editable_view.md

@@ -3,7 +3,7 @@
 <small>Defined in header `<nlohmann/json_view.hpp>`</small>
 
 ```cpp
-using ordered_json_editable_view = basic_json_view<ordered_json, true>;
+using ordered_json_editable_view = basic_json_view<ordered_json, view_mode::editable>;
 ```
 
 This type is a [`basic_json_view`](basic_json_view/index.md) of a value of an

docs/mkdocs/docs/api/ordered_json_view.md

@@ -3,7 +3,7 @@
 <small>Defined in header `<nlohmann/json_view.hpp>`</small>
 
 ```cpp
-using ordered_json_view = basic_json_view<ordered_json>;
+using ordered_json_view = basic_json_view<ordered_json, view_mode::read_only>;
 ```
 
 This type is a [`basic_json_view`](basic_json_view/index.md) of a value of an

docs/mkdocs/docs/api/view_mode.md

@@ -0,0 +1,80 @@
+# <small>nlohmann::</small>view_mode
+
+<small>Defined in header `<nlohmann/json_view.hpp>`</small>
+
+```cpp
+enum class view_mode : std::uint8_t
+{
+    read_only,
+    editable
+};
+```
+
+The second template parameter of [`basic_json_document`](basic_json_document/index.md) and
+[`basic_json_view`](basic_json_view/index.md): whether a document can be changed after parsing, and whether a view is
+of such a document.
+
+`read_only`
+:   the default: the document is parsed once and then only read. It carries none of the bookkeeping edits need, and
+    calling [`set`](basic_json_document/set.md), [`push_back`](basic_json_document/push_back.md),
+    [`insert`](basic_json_document/insert.md), or [`erase`](basic_json_document/erase.md) on it fails to compile.
+
+`editable`
+:   the document also offers [`set`](basic_json_document/set.md), [`push_back`](basic_json_document/push_back.md),
+    [`insert`](basic_json_document/insert.md), and [`erase`](basic_json_document/erase.md); its views see every edit,
+    see [Edits](basic_json_document/index.md#edits).
+
+The shortcuts name both modes: [`json_document`](json_document.md) and [`json_view`](json_view.md) are read-only,
+[`json_editable_document`](json_editable_document.md) and [`json_editable_view`](json_editable_view.md) are editable
+(and likewise for `ordered_json`).
+
+## Notes
+
+The mode is a compile-time property of the document's and the view's type, not a setting of a call, and there is no conversion between the two modes: a read-only view reads a
+container in place, while a view of an editable document follows the links that edits leave behind. A function that
+accepts views therefore names the modes it accepts in its signature:
+
+```cpp
+// views of editable documents only
+template<typename BasicJsonType>
+void f(basic_json_view<BasicJsonType, view_mode::editable> v);
+
+// views of read-only documents only
+template<typename BasicJsonType>
+void f(basic_json_view<BasicJsonType, view_mode::read_only> v);
+
+// either
+template<typename BasicJsonType, view_mode Mode>
+void f(basic_json_view<BasicJsonType, Mode> v);
+```
+
+A function that takes a [`json_view`](json_view.md) accepts neither an [`ordered_json_view`](ordered_json_view.md)
+nor a [`json_editable_view`](json_editable_view.md). Views of the two modes still compare with
+[`operator==`](basic_json_view/operator_eq.md).
+
+## Examples
+
+??? example
+
+    The example below shows a function template that accepts the views of both modes, and one that accepts only
+    views of editable documents.
+
+    ```cpp
+    --8<-- "examples/view_mode.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/view_mode.output"
+    ```
+
+## See also
+
+- [basic_json_document](basic_json_document/index.md) - a parsed JSON text
+- [basic_json_view](basic_json_view/index.md) - a handle to one value of a document
+- [json_editable_document](json_editable_document.md) - an editable document of `json`
+
+## Version history
+
+Added in version 3.13.0.

docs/mkdocs/docs/community/quality_assurance.md

@@ -188,13 +188,10 @@ Note: Some modern features (like C++20 ranges or filesystem support) may be disa
         ```
 
 - [x] The code is checked with the latest [Cppcheck](https://cppcheck.sourceforge.io) with all warnings enabled.
-- [x] The code is checked with the latest [Clang Static Analyzer](https://clang-analyzer.llvm.org) with 52 enabled
+- [x] The code is checked with the latest [Clang Static Analyzer](https://clang-analyzer.llvm.org) with 89 enabled
-  checkers.
+  rules.
 - [x] The code is checked with [Infer](https://fbinfer.com).
 - [x] The code is checked with [Codacy](https://app.codacy.com/gh/nlohmann/json/dashboard).
-- [x] The code is scanned with [CodeQL](https://codeql.github.com), [Semgrep](https://semgrep.dev), and
-  [Flawfinder](https://dwheeler.com/flawfinder/) on every push and pull request and on a schedule; the findings are
-  reported to GitHub's code scanning.
 
 ## Dynamic analysis
 
@@ -207,8 +204,6 @@ Note: Some modern features (like C++20 ranges or filesystem support) may be disa
 - [x] The test suite is executed with [Valgrind](https://valgrind.org) (Memcheck) to detect memory leaks.
 - [x] The test suite is executed with [Sanitizers](https://github.com/google/sanitizers) (address sanitizer, undefined
   behavior sanitizer, integer overflow detection, nullability violations).
-- [x] The fuzz targets are run with [CIFuzz](https://google.github.io/oss-fuzz/getting-started/continuous-integration/)
-  on every pull request to catch regressions before they are merged.
 
 ## Dependencies
 
@@ -228,8 +223,6 @@ Note: Some modern features (like C++20 ranges or filesystem support) may be disa
   No release is made while such an alert is open.
 - [x] Third-party code included in the repository for testing, such as [doctest](https://github.com/doctest/doctest),
   is updated manually.
-- [x] The repository is evaluated with the [OpenSSF Scorecard](https://securityscorecards.dev) on a schedule and on
-  every push to the default branch, and the results are reported to GitHub's code scanning.
 
 ## Style check
 
@@ -265,21 +258,4 @@ Note: Some modern features (like C++20 ranges or filesystem support) may be disa
 - [x] The library is tested against relevant CMake versions:
   - CMake 3.5 (the earliest supported)
   - CMake 3.31.6 (the latest 3.x release)
-  - CMake 4.0.0 (the first 4.x release)
+  - CMake 4.0.0 (a very recent release)
-!!! success "Requirement: Other build systems"
-
-    The library can be used with build systems and package managers other than CMake.
-
-- [x] The library can be consumed with [Meson](https://json.nlohmann.me/integration/package_managers/) and the Swift
-  Package Manager; the installation with Meson and the resolution of `Package.swift` are tested in the CI.
-
-!!! success "Requirement: Reproducible and verifiable builds"
-
-    The library can be built and tested without network access or a Git checkout, and its licensing is machine-readable.
-
-- [x] The test suite is executed from an exported source tree without the `.git` directory and with the test data
-  being available offline.
-- [x] The test suite is executed without the tests that change installed files to check that builds are reproducible.
-- [x] The repository is checked for compliance with the [REUSE specification](https://reuse.software) so that the
-  license and copyright of every file is machine-readable.
-- [x] The documentation is built with warnings treated as errors, and its links are checked regularly.

docs/mkdocs/docs/examples/README.cpp

@@ -2,7 +2,7 @@
 #include <iomanip>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/accept__iterator_pair.cpp

@@ -2,7 +2,7 @@
 #include <vector>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/accept__string.cpp

@@ -2,19 +2,19 @@
 #include <iomanip>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {
     // a valid JSON text
-    const auto* valid_text = R"(
+    auto valid_text = R"(
     {
         "numbers": [1, 2, 3]
     }
     )";
 
     // an invalid JSON text
-    const auto* invalid_text = R"(
+    auto invalid_text = R"(
     {
         "strings": ["extra", "comma", ]
     }

docs/mkdocs/docs/examples/accept__wide_string.cpp

@@ -2,7 +2,7 @@
 #include <string>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/array.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/array_t.cpp

@@ -2,9 +2,9 @@
 #include <iomanip>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {
-    std::cout << std::boolalpha << std::is_same<std::vector<json>, json::array_t>::value << '\n';
+    std::cout << std::boolalpha << std::is_same<std::vector<json>, json::array_t>::value << std::endl;
 }

docs/mkdocs/docs/examples/at__json_pointer.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 using namespace nlohmann::literals;
 
 int main()

docs/mkdocs/docs/examples/at__json_pointer_const.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 using namespace nlohmann::literals;
 
 int main()

docs/mkdocs/docs/examples/at__keytype.c++17.cpp

@@ -3,7 +3,7 @@
 #include <nlohmann/json.hpp>
 
 using namespace std::string_view_literals;
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/at__keytype_const.c++17.cpp

@@ -3,7 +3,7 @@
 #include <nlohmann/json.hpp>
 
 using namespace std::string_view_literals;
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/at__object_t_key_type.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/at__object_t_key_type_const.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/at__size_type.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/at__size_type_const.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/back.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json__BasicJsonType.cpp

@@ -1,8 +1,8 @@
 #include <iostream>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
-using nlohmann::ordered_json;
+using ordered_json = nlohmann::ordered_json;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json__CompatibleType.cpp

@@ -8,7 +8,7 @@
 #include <valarray>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json__InputIt_InputIt.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json__basic_json.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json__copyassignment.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json__list_init_t.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json__moveconstructor.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json__nullptr_t.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json__size_type_basic_json.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json__value_t.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json_document__accept.cpp

@@ -2,7 +2,7 @@
 #include <nlohmann/json.hpp>
 #include <nlohmann/json_view.hpp>
 
-using nlohmann::json_document;
+using json_document = nlohmann::json_document;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json_document__basic_json_document.cpp

@@ -2,7 +2,7 @@
 #include <utility>
 #include <nlohmann/json_view.hpp>
 
-using nlohmann::json_document;
+using json_document = nlohmann::json_document;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json_document__erase.cpp

@@ -1,9 +1,9 @@
 #include <iostream>
 #include <nlohmann/json_view.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
-using nlohmann::json_editable_document;
+using json_editable_document = nlohmann::json_editable_document;
-using nlohmann::json_editable_view;
+using json_editable_view = nlohmann::json_editable_view;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json_document__insert.cpp

@@ -1,9 +1,9 @@
 #include <iostream>
 #include <nlohmann/json_view.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
-using nlohmann::json_editable_document;
+using json_editable_document = nlohmann::json_editable_document;
-using nlohmann::json_editable_view;
+using json_editable_view = nlohmann::json_editable_view;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json_document__is_discarded.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json_view.hpp>
 
-using nlohmann::json_document;
+using json_document = nlohmann::json_document;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json_document__load.cpp

@@ -4,8 +4,8 @@
 #include <vector>
 #include <nlohmann/json_view.hpp>
 
-using nlohmann::json;
+using json = nlohmann::json;
-using nlohmann::json_document;
+using json_document = nlohmann::json_document;
 using image_check = json_document::image_check;
 
 int main()

docs/mkdocs/docs/examples/basic_json_document__memory_usage.cpp

@@ -2,7 +2,7 @@
 #include <string>
 #include <nlohmann/json_view.hpp>
 
-using nlohmann::json_document;
+using json_document = nlohmann::json_document;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json_document__node_count.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json_view.hpp>
 
-using nlohmann::json_document;
+using json_document = nlohmann::json_document;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json_document__owns_source.cpp

@@ -2,7 +2,7 @@
 #include <string>
 #include <nlohmann/json_view.hpp>
 
-using nlohmann::json_document;
+using json_document = nlohmann::json_document;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json_document__parse.cpp

@@ -3,7 +3,7 @@
 #include <nlohmann/json.hpp>
 #include <nlohmann/json_view.hpp>
 
-using nlohmann::json_document;
+using json_document = nlohmann::json_document;
 
 int main()
 {

docs/mkdocs/docs/examples/basic_json_document__parse_copy.cpp

@@ -1,7 +1,7 @@
 #include <iostream>
 #include <nlohmann/json_view.hpp>
 
-using nlohmann::json_document;
+using json_document = nlohmann::json_document;
 
 json_document parse_from_temporary_buffer()
 {

docs/mkdocs/docs/examples/basic_json_document__parse_iterator_pair.cpp

@@ -2,7 +2,7 @@
 #include <vector>
 #include <nlohmann/json_view.hpp>
 
-using nlohmann::json_document;
+using json_document = nlohmann::json_document;
 
 int main()
 {