deploy: ed8ba0201f

api/basic_json/std_hash.md

@@ -7,8 +7,14 @@ namespace std {
 ```
 
 Return a hash value for a JSON object. The hash function tries to rely on `std::hash` where possible. Furthermore, the
-type of the JSON value is taken into account to have different hash values for `#!json null`, `#!cpp 0`, `#!cpp 0U`, and
-`#!cpp false`, etc.
+type of the JSON value is taken into account, so `#!json null`, `#!cpp false`, and numbers may hash differently from
+each other. Numbers that compare equal under [`operator==`](operator_eq.md) always hash equally, regardless of
+whether they are stored as signed integer, unsigned integer, or floating-point number.
+
+Numbers are hashed by their value converted to `number_float_t`. Converting an integer to `number_float_t` therefore
+keeps its hash, but converting a floating-point number to an integer type is lossy and can change it: `#!cpp 0.5`
+converts to `#!cpp 0`, which need not have the same hash. Unequal numbers can also share a hash value, for example two
+large integers that convert to the same `number_float_t`.
 
 ## Examples
 
@@ -26,7 +32,8 @@ type of the JSON value is taken into account to have different hash values for `
     --8<-- "examples/std_hash.output"
     ```
 
-    Note the output is platform-dependent.
+    The hash values shown are examples only. They depend on the platform, the compiler, and the compiler version, and
+    they can change between versions of this library. Do not persist them or rely on specific values.
 
 ## See also
 
@@ -36,3 +43,5 @@ type of the JSON value is taken into account to have different hash values for `
 
 - Added in version 1.0.0.
 - Extended for arbitrary basic_json types in version 3.10.5.
+- Numbers that compare equal hash equally since version 3.13.0; before, `#!cpp 0`, `#!cpp 0U`, and `#!cpp 0.0` had
+  different hash values.

api/basic_json/std_hash/index.md

@@ -6,7 +6,9 @@ namespace std {
 }
 ```
 
-Return a hash value for a JSON object. The hash function tries to rely on `std::hash` where possible. Furthermore, the type of the JSON value is taken into account to have different hash values for `null`, `0`, `0U`, and `false`, etc.
+Return a hash value for a JSON object. The hash function tries to rely on `std::hash` where possible. Furthermore, the type of the JSON value is taken into account, so `null`, `false`, and numbers may hash differently from each other. Numbers that compare equal under [`operator==`](https://json.nlohmann.me/api/basic_json/operator_eq/index.md) always hash equally, regardless of whether they are stored as signed integer, unsigned integer, or floating-point number.
+
+Numbers are hashed by their value converted to `number_float_t`. Converting an integer to `number_float_t` therefore keeps its hash, but converting a floating-point number to an integer type is lossy and can change it: `0.5` converts to `0`, which need not have the same hash. Unequal numbers can also share a hash value, for example two large integers that convert to the same `number_float_t`.
 
 ## Examples
 
@@ -28,6 +30,7 @@ int main()
               << "hash(false) = " << std::hash<json> {}(json(false)) << '\n'
               << "hash(0) = " << std::hash<json> {}(json(0)) << '\n'
               << "hash(0U) = " << std::hash<json> {}(json(0U)) << '\n'
+              << "hash(0.0) = " << std::hash<json> {}(json(0.0)) << '\n'
               << "hash(\"\") = " << std::hash<json> {}(json("")) << '\n'
               << "hash({}) = " << std::hash<json> {}(json::object()) << '\n'
               << "hash([]) = " << std::hash<json> {}(json::array()) << '\n'
@@ -41,15 +44,16 @@ Output:
 ```
 hash(null) = 2654435769
 hash(false) = 2654436030
-hash(0) = 2654436095
-hash(0U) = 2654436156
-hash("") = 6142509191626859748
+hash(0) = 2654436221
+hash(0U) = 2654436221
+hash(0.0) = 2654436221
+hash("") = 11160318156688833227
 hash({}) = 2654435832
 hash([]) = 2654435899
-hash({"hello": "world"}) = 4469488738203676328
+hash({"hello": "world"}) = 3701319991624763853
 ```
 
-Note the output is platform-dependent.
+The hash values shown are examples only. They depend on the platform, the compiler, and the compiler version, and they can change between versions of this library. Do not persist them or rely on specific values.
 
 ## See also
 
@@ -59,3 +63,4 @@ Note the output is platform-dependent.
 
 - Added in version 1.0.0.
 - Extended for arbitrary basic_json types in version 3.10.5.
+- Numbers that compare equal hash equally since version 3.13.0 unreleased; before, `0`, `0U`, and `0.0` had different hash values.

examples/std_hash.cpp

@@ -11,6 +11,7 @@ int main()
               << "hash(false) = " << std::hash<json> {}(json(false)) << '\n'
               << "hash(0) = " << std::hash<json> {}(json(0)) << '\n'
               << "hash(0U) = " << std::hash<json> {}(json(0U)) << '\n'
+              << "hash(0.0) = " << std::hash<json> {}(json(0.0)) << '\n'
               << "hash(\"\") = " << std::hash<json> {}(json("")) << '\n'
               << "hash({}) = " << std::hash<json> {}(json::object()) << '\n'
               << "hash([]) = " << std::hash<json> {}(json::array()) << '\n'

examples/std_hash.output

@@ -1,8 +1,9 @@
 hash(null) = 2654435769
 hash(false) = 2654436030
-hash(0) = 2654436095
-hash(0U) = 2654436156
-hash("") = 6142509191626859748
+hash(0) = 2654436221
+hash(0U) = 2654436221
+hash(0.0) = 2654436221
+hash("") = 11160318156688833227
 hash({}) = 2654435832
 hash([]) = 2654435899
-hash({"hello": "world"}) = 4469488738203676328
+hash({"hello": "world"}) = 3701319991624763853

features/serialization.md

@@ -64,6 +64,7 @@ serialization fails by default. The fourth argument of `dump` selects an
 - `strict` (default) — throw a [`type_error.316`](../home/exceptions.md#jsonexceptiontype_error316) exception.
 - `replace` — replace invalid bytes with the Unicode replacement character U+FFFD (`�`).
 - `ignore` — silently drop invalid bytes.
+- `keep` — copy invalid bytes to the output unchanged; the result is not valid UTF-8.
 
 ??? example "Example: serialize invalid UTF-8 with different error handlers"
 

features/serialization/index.md

@@ -154,6 +154,7 @@ If a string contains invalid UTF-8 sequences (for example, because it holds data
 - `strict` (default) — throw a [`type_error.316`](https://json.nlohmann.me/home/exceptions/#jsonexceptiontype_error316) exception.
 - `replace` — replace invalid bytes with the Unicode replacement character U+FFFD (`�`).
 - `ignore` — silently drop invalid bytes.
+- `keep` — copy invalid bytes to the output unchanged; the result is not valid UTF-8.
 
 Example: serialize invalid UTF-8 with different error handlers
 

home/exceptions.md

@@ -771,6 +771,7 @@ as well for a string value or object key that is not valid UTF-8 if their `error
     - Pass an error handler as last parameter to the `dump()` function to avoid this exception:
         - `json::error_handler_t::replace` will replace invalid bytes sequences with `U+FFFD` 
         - `json::error_handler_t::ignore` will silently ignore invalid byte sequences
+        - `json::error_handler_t::keep` will copy invalid byte sequences to the output unchanged
 
 ### json.exception.type_error.317
 

home/exceptions/index.md

@@ -876,6 +876,7 @@ Tip
 - Pass an error handler as last parameter to the `dump()` function to avoid this exception:
   - `json::error_handler_t::replace` will replace invalid bytes sequences with `U+FFFD`
   - `json::error_handler_t::ignore` will silently ignore invalid byte sequences
+  - `json::error_handler_t::keep` will copy invalid byte sequences to the output unchanged
 
 ### json.exception.type_error.317
 

home/faq.md

@@ -85,7 +85,7 @@ The library supports **Unicode input** as follows:
 - The library will not replace [Unicode noncharacters](http://www.unicode.org/faq/private_use.html#nonchar1).
 - Invalid surrogates (e.g., incomplete pairs such as `\uDEAD`) will yield parse errors.
 - The strings stored in the library are UTF-8 encoded. When using the default string type (`std::string`), note that its length/size functions return the number of stored bytes rather than the number of characters or glyphs.
-- When you store strings with different encodings in the library, calling [`dump()`](../api/basic_json/dump.md) may throw an exception unless `json::error_handler_t::replace` or `json::error_handler_t::ignore` are used as error handlers.
+- When you store strings with different encodings in the library, calling [`dump()`](../api/basic_json/dump.md) may throw an exception unless `json::error_handler_t::replace`, `json::error_handler_t::ignore`, or `json::error_handler_t::keep` are used as error handlers.
 
 In most cases, the parser is right to complain, because the input is not UTF-8 encoded. This is especially true for Microsoft Windows, where Latin-1 or ISO 8859-1 is often the standard encoding.
 

home/faq/index.md

@@ -84,7 +84,7 @@ The library supports **Unicode input** as follows:
 - The library will not replace [Unicode noncharacters](http://www.unicode.org/faq/private_use.html#nonchar1).
 - Invalid surrogates (e.g., incomplete pairs such as `\uDEAD`) will yield parse errors.
 - The strings stored in the library are UTF-8 encoded. When using the default string type (`std::string`), note that its length/size functions return the number of stored bytes rather than the number of characters or glyphs.
-- When you store strings with different encodings in the library, calling [`dump()`](https://json.nlohmann.me/api/basic_json/dump/index.md) may throw an exception unless `json::error_handler_t::replace` or `json::error_handler_t::ignore` are used as error handlers.
+- When you store strings with different encodings in the library, calling [`dump()`](https://json.nlohmann.me/api/basic_json/dump/index.md) may throw an exception unless `json::error_handler_t::replace`, `json::error_handler_t::ignore`, or `json::error_handler_t::keep` are used as error handlers.
 
 In most cases, the parser is right to complain, because the input is not UTF-8 encoded. This is especially true for Microsoft Windows, where Latin-1 or ISO 8859-1 is often the standard encoding.
 

integration/package_managers.md

@@ -125,10 +125,24 @@ meson wrap install nlohmann_json
 Please see the Meson project for any issues regarding the packaging.
 
 The provided `meson.build` can also be used as an alternative to CMake for installing `nlohmann_json` system-wide in
-which case a [pkg-config](pkg-config.md) file is installed. To use it, have your build system require the
-`nlohmann_json` pkg-config dependency. In Meson, it is preferred to use the
-[`dependency()`](https://mesonbuild.com/Reference-manual.html#dependency) object with a subproject fallback, rather than
-using the subproject directly.
+which case a [pkg-config](pkg-config.md) file and the CMake package config files are installed. To use it, have your build system require
+the `nlohmann_json` pkg-config dependency, or use [`find_package(nlohmann_json)`](cmake.md#external) in CMake. In Meson,
+it is preferred to use the [`dependency()`](https://mesonbuild.com/Reference-manual.html#dependency) object with a
+subproject fallback, rather than using the subproject directly.
+
+The options that change the library's configuration are available in Meson as well, named like the
+[CMake options](cmake.md#cmake-options) without the `JSON_` prefix: `MultipleHeaders`, `GlobalUDLs`,
+`ImplicitConversions`, `DisableEnumSerialization`, `DisableTupleReferenceConversion`, `Diagnostics`,
+`Diagnostic_Positions`, `LegacyDiscardedValueComparison`, `StrictNulHandling`, `StrictBinaryUTF8`, and
+`DeleteDeprecatedFunctions`. They have the same defaults as in CMake, except that
+`MultipleHeaders` is `false`. Set them with `-D` when setting up the build, or with the subproject name as prefix when
+the library is used as a subproject:
+
+```shell
+meson setup build -Dnlohmann_json:Diagnostics=true
+```
+
+The resulting compile definitions are part of the Meson dependency, the pkg-config file, and the CMake target.
 
 ??? example "Example: Wrap"
 

integration/package_managers/index.md

@@ -161,7 +161,15 @@ meson wrap install nlohmann_json
 
 Please see the Meson project for any issues regarding the packaging.
 
-The provided `meson.build` can also be used as an alternative to CMake for installing `nlohmann_json` system-wide in which case a [pkg-config](https://json.nlohmann.me/integration/pkg-config/index.md) file is installed. To use it, have your build system require the `nlohmann_json` pkg-config dependency. In Meson, it is preferred to use the [`dependency()`](https://mesonbuild.com/Reference-manual.html#dependency) object with a subproject fallback, rather than using the subproject directly.
+The provided `meson.build` can also be used as an alternative to CMake for installing `nlohmann_json` system-wide in which case a [pkg-config](https://json.nlohmann.me/integration/pkg-config/index.md) file and the CMake package config files are installed. To use it, have your build system require the `nlohmann_json` pkg-config dependency, or use [`find_package(nlohmann_json)`](https://json.nlohmann.me/integration/cmake/#external) in CMake. In Meson, it is preferred to use the [`dependency()`](https://mesonbuild.com/Reference-manual.html#dependency) object with a subproject fallback, rather than using the subproject directly.
+
+The options that change the library's configuration are available in Meson as well, named like the [CMake options](https://json.nlohmann.me/integration/cmake/#cmake-options) without the `JSON_` prefix: `MultipleHeaders`, `GlobalUDLs`, `ImplicitConversions`, `DisableEnumSerialization`, `DisableTupleReferenceConversion`, `Diagnostics`, `Diagnostic_Positions`, `LegacyDiscardedValueComparison`, `StrictNulHandling`, `StrictBinaryUTF8`, and `DeleteDeprecatedFunctions`. They have the same defaults as in CMake, except that `MultipleHeaders` is `false`. Set them with `-D` when setting up the build, or with the subproject name as prefix when the library is used as a subproject:
+
+```
+meson setup build -Dnlohmann_json:Diagnostics=true
+```
+
+The resulting compile definitions are part of the Meson dependency, the pkg-config file, and the CMake target.
 
 Example: Wrap