updating single

* fix: add tests related to issue 2227 (#2229)

* fix: add tests related to issue 2227

* avoiding name clash

* pedantic fix

* deprecate rvalue get on document

* selectively deprecating

* Fix ndjson spec link (#2234)

* fix ndjson spec link

The link in the readme of parse_many links to a casino spam site

* fix link

* [no-ci] Update README.md

* Make simdjson compile again

* Enable SIMDJSON_SINGLEHEADER=OFF in VS Code

With singleheader on, clangd can't find the right
include files.

* Add missing include directives to static build targets of simdjson. (#2240)

* adding a warning

* adding warning regarding SIMDJSON_BUILD_STATIC_LIB

* release candidate

* pedantic viable size

* Making tag_invoke a feeder instead of a producer

* adding missing undef silencer (#2253)

* Ignore pragma once when amalgamating source files (#2248)

With gcc it causes an error in `simdjson.cpp`:
```
simdjson.cpp:548:9: warning: #pragma once in main file
  548 | #pragma once
      |         ^~~~
```

It had previously been commented out in:
https://github.com/simdjson/simdjson/commit/6ef555e6fb79363fae057a9a46b52cd208d9e305

However, this was lost in an upgrade:
https://github.com/simdjson/simdjson/commit/2a4ff7346813b120f2b5b40e95d69352b593cc9c

* Update CI (#2254)

* adding missing undef silencer

* Updating CI

* more fixes

* fix

* big endian fix

* Moving to the new tag_invoke signature

* Fix nlohmann ambiguity on C++23-enabled clang

* Revert "Merge branch 'master' of https://github.com/simdjson/simdjson into builder_development_branch_extra"

This reverts commit 3eeecbab34, reversing
changes made to 6858b208b4.

---------

Co-authored-by: Daniel Lemire <daniel@lemire.me>
Co-authored-by: Sasha Lopoukhine <superlopuh@gmail.com>
Co-authored-by: John Keiser <john@johnkeiser.com>
Co-authored-by: Tan Li Boon <undisputed-seraphim@users.noreply.github.com>
Co-authored-by: tobil4sk <tobil4sk@outlook.com>

.github/workflows/aarch64.yml

@@ -0,0 +1,29 @@
+name: Ubuntu ppc64le (GCC 11)
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: uraimo/run-on-arch-action@v2
+        name: Test
+        id: runcmd
+        with:
+          arch: aarch64
+          distro: ubuntu_latest
+          githubToken: ${{ github.token }}
+          install: |
+            apt-get update -q -y
+            apt-get install -y cmake make g++
+          run: |
+            cmake -DSIMDJSON_SANITIZE_UNDEFINED=ON -DSIMDJSON_DEVELOPER_MODE=ON -DSIMDJSON_COMPETITION=OFF -B build
+            cmake --build build -j=2
+            ctest --output-on-failure --test-dir build

.github/workflows/cifuzz.yml

@@ -17,7 +17,7 @@ jobs:
         fuzz-seconds: 600
         dry-run: false
     - name: Upload Crash
-      uses: actions/upload-artifact@v1
+      uses: actions/upload-artifact@v4
       if: failure() && steps.build.outcome == 'success'
       with:
         name: artifacts

.github/workflows/fix-trailing-whitespace.yml

@@ -24,7 +24,7 @@ jobs:
              echo "no trailing whitespace found, good!"
           fi
       - name: Archive whitespace patch
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         if: always()
         with:
           name: whitespace-patch

.github/workflows/msys2.yml

@@ -22,7 +22,7 @@ jobs:
           - msystem: "MINGW64"
             install: mingw-w64-x86_64-cmake mingw-w64-x86_64-ninja mingw-w64-x86_64-gcc
             type: Debug
-            - msystem: "MINGW64"
+          - msystem: "MINGW64"
             install: mingw-w64-x86_64-cmake mingw-w64-x86_64-ninja mingw-w64-x86_64-gcc
             type: RelWithDebInfo
     env:

.github/workflows/ppc64.yml

@@ -24,6 +24,6 @@ jobs:
             apt-get update -q -y
             apt-get install -y cmake make g++
           run: |
-            cmake -DCMAKE_BUILD_TYPE=Release -B build
+            cmake -DCMAKE_BUILD_TYPE=Release -DSIMDJSON_DEVELOPER_MODE=ON -DSIMDJSON_COMPETITION=OFF  -B build
             cmake --build build -j=2
             ctest --output-on-failure --test-dir build

.github/workflows/riscv64.yml

@@ -24,6 +24,6 @@ jobs:
             apt-get update -q -y
             apt-get install -y cmake make g++
           run: |
-            cmake -DCMAKE_BUILD_TYPE=Release -B build
+            cmake -DCMAKE_BUILD_TYPE=Release -DSIMDJSON_DEVELOPER_MODE=ON -DSIMDJSON_COMPETITION=OFF  -B build
             cmake --build build -j=2
             ctest --output-on-failure --test-dir build

.github/workflows/s390x.yml

@@ -24,6 +24,6 @@ jobs:
             apt-get update -q -y
             apt-get install -y cmake make g++
           run: |
-            cmake -DCMAKE_BUILD_TYPE=Release -B build
+            cmake -DCMAKE_BUILD_TYPE=Release  -DSIMDJSON_DEVELOPER_MODE=ON -DSIMDJSON_COMPETITION=OFF -B build
             cmake --build build -j=2
             ctest --output-on-failure --test-dir build

.github/workflows/ubuntu24-cxx20.yml

@@ -0,0 +1,22 @@
+name: Ubuntu 24.04 CI (CXX 20)
+
+on: [push, pull_request]
+jobs:
+  ubuntu-build:
+    if: >-
+      ! contains(toJSON(github.event.commits.*.message), '[skip ci]') &&
+      ! contains(toJSON(github.event.commits.*.message), '[skip github]')
+    runs-on: ubuntu-24.04
+    strategy:
+      matrix:
+        cxx: [g++-13, clang++-16]
+    steps:
+      - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29 # v4.1.6
+      - name: Prepare
+        run: cmake -DSIMDJSON_CXX_STANDARD=20 -DSIMDJSON_DEVELOPER_MODE=ON  -B build
+        env:
+          CXX: ${{matrix.cxx}}
+      - name: Build
+        run: cmake --build build -j=2
+      - name: Test
+        run: ctest --output-on-failure --test-dir build

.github/workflows/vs17-ci.yml

@@ -26,15 +26,15 @@ jobs:
       run: |
         cmake -G "${{matrix.gen}}" -A ${{matrix.arch}} -DSIMDJSON_DEVELOPER_MODE=ON -DSIMDJSON_COMPETITION=OFF -DBUILD_SHARED_LIBS=${{matrix.shared}} -B build
     - name: Build Debug
-      run: cmake --build build --config ${{build_type}} --verbose
+      run: cmake --build build --config ${{matrix.build_type}} --verbose
     - name: Run tests
       run: |
         cd build
-        ctest -C ${{build_type}}  -LE explicitonly  --output-on-failure
+        ctest -C ${{matrix.build_type}}  -LE explicitonly  --output-on-failure
     - name: Install
       run: |
-        cmake --install build --config ${{build_type}}
+        cmake --install build --config ${{matrix.build_type}}
     - name: Test Installation
       run: |
         cmake -G "${{matrix.gen}}" -A ${{matrix.arch}}  -B build_install_test tests/installation_tests/find
-        cmake --build build_install_test --config ${{build_type}}
+        cmake --build build_install_test --config ${{matrix.build_type}}

.github/workflows/vs17-clang-ci-cxx20.yml

@@ -0,0 +1,37 @@
+name: VS17-CLANG-CI
+
+on: [push, pull_request]
+
+jobs:
+  ci:
+    if: >-
+      ! contains(toJSON(github.event.commits.*.message), '[skip ci]') &&
+      ! contains(toJSON(github.event.commits.*.message), '[skip github]')
+    name: windows-vs17
+    runs-on: windows-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - {gen: Visual Studio 17 2022, arch: x64, build_type: Debug}
+          - {gen: Visual Studio 17 2022, arch: x64, build_type: Release}
+          - {gen: Visual Studio 17 2022, arch: x64, build_type: RelWithDebInfo}
+    steps:
+    - name: checkout
+      uses: actions/checkout@v4
+    - name: Configure
+      run: |
+        cmake -G "${{matrix.gen}}" -A ${{matrix.arch}}  -T ClangCL -DSIMDJSON_DEVELOPER_MODE=ON -DSIMDJSON_COMPETITION=OFF -B build
+    - name: Build
+      run: cmake --build build --config ${{matrix.build_type}} --verbose
+    - name: Run tests
+      run: |
+        cd build
+        ctest -C ${{matrix.build_type}}  -LE explicitonly  --output-on-failure
+    - name: Install
+      run: |
+        cmake --install build --config ${{matrix.build_type}}
+    - name: Test Installation
+      run: |
+        cmake -G "${{matrix.gen}}" -A ${{matrix.arch}}  -B build_install_test tests/installation_tests/find
+        cmake --build build_install_test --config ${{matrix.build_type}}

.vscode/settings.json

@@ -109,6 +109,23 @@
         "numbers": "cpp",
         "semaphore": "cpp",
         "stop_token": "cpp",
-        "cfenv": "cpp"
+        "cfenv": "cpp",
+        "format": "cpp",
+        "xlocmes": "cpp",
+        "xlocmon": "cpp",
+        "xlocnum": "cpp",
+        "xloctime": "cpp",
+        "xutility": "cpp",
+        "coroutine": "cpp",
+        "xfacet": "cpp",
+        "xhash": "cpp",
+        "xiosbase": "cpp",
+        "xlocale": "cpp",
+        "xlocbuf": "cpp",
+        "xlocinfo": "cpp",
+        "xmemory": "cpp",
+        "xstring": "cpp",
+        "xtr1common": "cpp",
+        "xtree": "cpp"
     }
 }

benchmark/find_tweet/nlohmann_json.h

@@ -13,7 +13,7 @@ struct nlohmann_json {
     auto root = nlohmann::json::parse(json.data(), json.data() + json.size());
     for (auto tweet : root["statuses"]) {
       if (tweet["id"] == find_id) {
-        result = tweet["text"];
+        result = to_string(tweet["text"]);
         return true;
       }
     }

benchmark/top_tweet/nlohmann_json.h

@@ -26,8 +26,8 @@ struct nlohmann_json {
       }
     }
 
-    result.text = top_tweet["text"];
+    result.text = to_string(top_tweet["text"]);
-    result.screen_name = top_tweet["user"]["screen_name"];
+    result.screen_name = to_string(top_tweet["user"]["screen_name"]);
     return result.retweet_count != -1;
   }
 };

doc/basics.md

@@ -17,6 +17,8 @@ An overview of what you need to know to use simdjson, with examples.
   - [Using the parsed JSON](#using-the-parsed-json)
     - [Using the parsed JSON: additional examples](#using-the-parsed-json-additional-examples)
   - [Adding support for custom types](#adding-support-for-custom-types)
+    - [1. Specialize `simdjson::ondemand::value::get` to get custom types](#1-specialize-simdjsonondemandvalueget-to-get-custom-types)
+    - [2. Use `tag_invoke` for custom types (C++20)](#2-use-tag_invoke-for-custom-types-c20)
   - [Minifying JSON strings without parsing](#minifying-json-strings-without-parsing)
   - [UTF-8 validation (alone)](#utf-8-validation-alone)
   - [JSON Pointer](#json-pointer)
@@ -788,6 +790,25 @@ for (ondemand::object points : parser.iterate(points_json)) {
 Adding support for custom types
 ----------------------
 
+There are 2 main ways provided by simdjson to deserialize a value into a custom type:
+
+1. Provide a [**template specialization** for member functions](https://en.cppreference.com/w/cpp/language/template_specialization#Members_of_specializations)
+   1. Specialize `simdjson::ondemand::document::get` for the whole document
+   2. Specialize `simdjson::ondemand::value::get` for each value
+2. Using `tag_invoke` *(the recommended way if your system supports C++20 or better)*
+
+The differences between the two approaches are as follows:
+
+1. Your compiler needs to support C++20 for `tag_invoke`.
+2. The first way limits you to know your type fully, but in the `tag_invoke` way, you can use C++20 concepts and template meta programming as well.
+3. Another difference between the two ways is that in `tag_invoke` way you may or may not mark your deserialization function (`tag_invoke` itself) as `noexcept`, but in the
+   *template specialization* way (the first way) you HAVE TO mark your specialization as `noexcept` which means that you may need to catch exceptions so
+   that your function does not throw any exception all the while it potentially can (for example any type like `std::string`, `std::vector`, etc. that has an allocator can potentially throw exceptions).
+4. Another difference is that the `tag_invoke` way can work on both `document` and `value` but in the first way you have to provide 2 distinct specializations.
+5. If you by mistake use both way with each other, the *specialization way* will be used silently due to backward-compatibility.
+
+### 1. Specialize `simdjson::ondemand::value::get` to get custom types
+
 Suppose you have your own types, such as a `Car` struct:
 
 ```C++
@@ -821,9 +842,14 @@ type:
 ```
 
 We may do so by providing additional template definitions to the `ondemand::value` type.
-We may start by providing a definition for `std::vector<double>` as follows:
+We may start by providing a definition for `std::vector<double>` as follows. Observe
+how we guard the code with `#ifndef __cpp_concepts`: that is because the necessary code
+is automatically provided by simdjson if C++20 (and concepts) are available.
+See [Use `tag_invoke` for custom types](#2-use-tag_invoke-for-custom-types-c20) if you have
+C++20 support.
 
 ```c++
+#ifndef __cpp_concepts // because the code is unnecessary with C++20
 template <>
 simdjson_inline simdjson_result<std::vector<double>>
 simdjson::ondemand::value::get() noexcept {
@@ -835,10 +861,11 @@ simdjson::ondemand::value::get() noexcept {
     double val;
     error = v.get_double().get(val);
     if (error) { return error; }
-    vec.push_back(val);
+    try { vec.push_back(val); } catch (...) { return simdjson::UNEXPECTED_ERROR; }
   }
   return vec;
 }
+#endif
 ```
 
 We may then provide support for our `Car` struct:
@@ -856,6 +883,7 @@ simdjson_inline simdjson_result<Car> simdjson::ondemand::value::get() noexcept {
     raw_json_string key;
     error = field.key().get(key);
     if (error) { return error; }
+
     if (key == "make") {
       error = field.value().get_string(car.make);
       if (error) { return error; }
@@ -867,7 +895,7 @@ simdjson_inline simdjson_result<Car> simdjson::ondemand::value::get() noexcept {
       if (error) { return error; }
     } else if (key == "tire_pressure") {
       error = field.value().get<std::vector<double>>().get(car.tire_pressure);
-      if (auto  error) { return error; }
+      if (error) { return error; }
     }
   }
   return car;
@@ -893,6 +921,7 @@ struct Car {
   std::vector<double> tire_pressure;
 };
 
+#ifndef __cpp_concepts // because the code is unnecessary with C++20
 template <>
 simdjson_inline simdjson_result<std::vector<double>>
 simdjson::ondemand::value::get() noexcept {
@@ -908,6 +937,7 @@ simdjson::ondemand::value::get() noexcept {
   }
   return vec;
 }
+#endif
 
 
 template <>
@@ -950,7 +980,7 @@ int main(void) {
   ondemand::parser parser;
   ondemand::document doc = parser.iterate(json);
   for (auto val : doc) {
-    Car c(val);
+    Car c(val); // an exception may be thrown
     std::cout << c.make << std::endl;
   }
   direct();
@@ -958,7 +988,7 @@ int main(void) {
 }
 ```
 
-Observe that we require an explicit cast (`Car c(val)` instead of `for (Car c : doc) {`): it is by design.
+Observe that we require an explicit cast (`Car c(val)` instead of `for (Car c : doc) {`): it is by design. We require explicit casting.
 
 If you prefer to avoid exceptions, you may modify the `main` function as follows:
 
@@ -1009,6 +1039,7 @@ struct Car {
   std::vector<double> tire_pressure;
 };
 
+#ifndef __cpp_concepts // because the code is unnecessary with C++20
 template <>
 simdjson_inline simdjson_result<std::vector<double>>
 simdjson::ondemand::value::get() noexcept {
@@ -1022,7 +1053,7 @@ simdjson::ondemand::value::get() noexcept {
   }
   return vec;
 }
-
+#endif
 
 template <>
 simdjson_inline simdjson_result<Car> simdjson::ondemand::document::get() & noexcept {
@@ -1066,6 +1097,178 @@ int main(void) {
 }
 ```
 
+### 2. Use `tag_invoke` for custom types (C++20)
+
+A standard approach to provide support for deserialization is to add a `tag_invoke` function
+in your own class:
+
+```C++
+/**
+ * A custom type that we want to parse.
+ */
+
+struct Car {
+  std::string make;
+  std::string model;
+  int year = 0;
+  std::vector<double> tire_pressure;
+
+  friend simdjson_result<Car>
+  tag_invoke(simdjson::deserialize_tag, std::type_identity<Car>, auto &val) {
+    simdjson::ondemand::object obj;
+    auto error = val.get_object().get(obj);
+    if (error) {
+      return error;
+    }
+    Car car{};
+    // Instead of repeatedly obj["something"], we iterate through the object
+    // which we expect to be faster.
+    for (auto field : obj) {
+      simdjson::ondemand::raw_json_string key;
+      error = field.key().get(key);
+      if (error) {
+        return error;
+      }
+      if (key == "make") {
+        error = field.value().get_string(car.make);
+        if (error) {
+          return error;
+        }
+      } else if (key == "model") {
+        error = field.value().get_string(car.model);
+        if (error) {
+          return error;
+        }
+      } else if (key == "year") {
+        error = field.value().get(car.year);
+        if (error) {
+          return error;
+        }
+      } else if (key == "tire_pressure") {
+        error = field.value().get(car.tire_pressure);
+        if (error) {
+          return error;
+        }
+      }
+    }
+    return car;
+  }
+};
+```
+
+Let us explain each argument of `tag_invoke`:
+
+- `simdjson::deserialize_tag`: it is the tag for Customization Point Object (CPO)
+- `std::type_identity<T>`: We specify the custom type we want here
+- `simdjson::ondemand::value&` or `simdjson::ondemand::document&`: the value or document that we want to deserialize from; you may want to just specify `auto&` to capture both of them.
+
+You can use it like so:
+
+```cpp
+  simdjson::padded_string json =
+      R"( { "make": "Toyota", "model": "Camry",  "year": 2018,
+       "tire_pressure": [ 40.1, 39.9 ] })"_padded;
+  simdjson::ondemand::parser parser;
+  simdjson::ondemand::document doc = parser.iterate(json);
+  Car c(doc);
+  std::cout << c.make << std::endl;
+```
+
+Observe how we first get an instance of `document` and then we cast.
+
+You can also handle errors explicitly:
+
+```cpp
+  simdjson::padded_string json =
+      R"( { "make": "Toyota", "model": "Camry",  "year": 2018,
+       "tire_pressure": [ 40.1, 39.9 ] })"_padded;
+  simdjson::ondemand::parser parser;
+  simdjson::ondemand::document doc = parser.iterate(json);
+  Car c;
+  auto error = doc.get(c);
+  if(error) { std::cerr << simdjson::error_message(error); return false; }
+  std::cout << c.make << std::endl;
+```
+
+You can also read instances of `Car` from an array or an object:
+```cpp
+  simdjson::padded_string json =
+      R"( [ { "make": "Toyota", "model": "Camry",  "year": 2018,
+       "tire_pressure": [ 40.1, 39.9 ] },
+  { "make": "Kia",    "model": "Soul",   "year": 2012,
+       "tire_pressure": [ 30.1, 31.0 ] },
+  { "make": "Toyota", "model": "Tercel", "year": 1999,
+       "tire_pressure": [ 29.8, 30.0 ] }
+])"_padded;
+
+  simdjson::ondemand::parser parser;
+  simdjson::ondemand::document doc = parser.iterate(json);
+  for (auto val : doc) {
+    Car c(val); // an exception may be thrown
+    std::cout << c.year << std::endl;
+  }
+```
+
+Observe how we first get a generic (`val`) which we cast to `Car`. It is by design: we require
+explicit casting. The cast may throw an exception.
+
+Once more, you can handle errors explicitly:
+
+```cpp
+  simdjson::ondemand::parser parser;
+  simdjson::ondemand::document doc = parser.iterate(json);
+  for (auto val : doc) {
+    Car c;
+    auto error = val.get(c);
+    if(error) { std::cerr << simdjson::error_message(error) << std::endl; return false; }
+  }
+```
+
+You can also use the custom `Car` type as part of a template such as `std::vector`:
+
+```cpp
+  simdjson::ondemand::parser parser;
+  simdjson::ondemand::document doc = parser.iterate(json);
+  std::vector<Car> cars(doc);
+  // visual studio users need an explicit call:
+  //   std::vector<Car> cars = doc.get<std::vector<Car>>();
+  // because the compiler does not know whether to convert
+  // doc to an unsigned int or to a vector.
+  for(Car& c : cars) {
+    std::cout << c.year << std::endl;
+  }
+```
+
+You can also extend support to arbitrary templates.
+Suppose your custom types are `std::unique_ptr<any type>`,
+you could add the following `tag_invoke`:
+
+```C++
+namespace simdjson {
+
+  // This tag_invoke MUST be inside simdjson namespace since we can't make it a friend of unique_ptr
+  template <typename T>
+  auto tag_invoke(deserialize_tag, std::type_identity<std::unique_ptr<T>>, auto &val) {
+    return simdjson_result{std::make_unique<T>(val.template get<T>())};
+  }
+
+} // namespace simdjson
+```
+
+You can also mark your `tag_invoke` function as `noexcept` and we will obey that, unlike the *template specialization* way.
+
+You would use it like this:
+```C++
+int main() {
+  auto const json = R"( { "make": "Toyota", "model": "Camry",  "year": 2018,
+       "tire_pressure": [ 40.1, 39.9 ] })"_padded;
+  simdjson::ondemand::parser parser;
+  simdjson::ondemand::document doc = parser.iterate(json);
+  std::unique_ptr<Car> c(doc);
+  std::cout << c->make << std::endl;
+  return EXIT_SUCCESS;
+}
+```
 
 Minifying JSON strings without parsing
 ----------------------
@@ -1343,7 +1546,7 @@ Notice how we can retrieve the exact error condition (in this instance `simdjson
 from the exception.
 
 We can write a "quick start" example where we attempt to parse the following JSON file and access some data, without triggering exceptions:
-```JavaScript
+```JSON
 {
   "statuses": [
     {

include/simdjson/compiler_check.h

@@ -50,4 +50,16 @@
 #endif
 #endif
 
+#ifdef __has_include
+#if __has_include(<version>)
+#include <version>
+#endif
+#endif
+
+#ifdef __cpp_concepts
+#include <utility>
+#define SIMDJSON_SUPPORTS_DESERIALIZATION 1
+#else // __cpp_concepts
+#define SIMDJSON_SUPPORTS_DESERIALIZATION 0
+#endif
 #endif // SIMDJSON_COMPILER_CHECK_H

include/simdjson/generic/ondemand/amalgamated.h

@@ -4,6 +4,7 @@
 
 // Stuff other things depend on
 #include "simdjson/generic/ondemand/base.h"
+#include "simdjson/generic/ondemand/deserialize.h"
 #include "simdjson/generic/ondemand/value_iterator.h"
 #include "simdjson/generic/ondemand/value.h"
 #include "simdjson/generic/ondemand/logger.h"
@@ -23,9 +24,13 @@
 #include "simdjson/generic/ondemand/object_iterator.h"
 #include "simdjson/generic/ondemand/serialization.h"
 
+// Deserialization for standard types
+#include "simdjson/generic/ondemand/std_deserialize.h"
+
 // Inline definitions
 #include "simdjson/generic/ondemand/array-inl.h"
 #include "simdjson/generic/ondemand/array_iterator-inl.h"
+#include "simdjson/generic/ondemand/value-inl.h"
 #include "simdjson/generic/ondemand/document-inl.h"
 #include "simdjson/generic/ondemand/document_stream-inl.h"
 #include "simdjson/generic/ondemand/field-inl.h"
@@ -38,5 +43,6 @@
 #include "simdjson/generic/ondemand/raw_json_string-inl.h"
 #include "simdjson/generic/ondemand/serialization-inl.h"
 #include "simdjson/generic/ondemand/token_iterator-inl.h"
-#include "simdjson/generic/ondemand/value-inl.h"
 #include "simdjson/generic/ondemand/value_iterator-inl.h"
+
+

include/simdjson/generic/ondemand/deserialize.h

@@ -0,0 +1,114 @@
+#if SIMDJSON_SUPPORTS_DESERIALIZATION
+
+#ifndef SIMDJSON_ONDEMAND_DESERIALIZE_H
+#ifndef SIMDJSON_CONDITIONAL_INCLUDE
+#define SIMDJSON_ONDEMAND_DESERIALIZE_H
+#include "simdjson/generic/ondemand/base.h"
+#include "simdjson/generic/ondemand/array.h"
+#endif // SIMDJSON_CONDITIONAL_INCLUDE
+
+#include <concepts>
+namespace simdjson {
+
+namespace tag_invoke_fn_ns {
+void tag_invoke();
+
+struct tag_invoke_fn {
+  template <typename Tag, typename... Args>
+    requires requires(Tag tag, Args &&...args) {
+      tag_invoke(std::forward<Tag>(tag), std::forward<Args>(args)...);
+    }
+  constexpr auto operator()(Tag tag, Args &&...args) const
+      noexcept(noexcept(tag_invoke(std::forward<Tag>(tag),
+                                   std::forward<Args>(args)...)))
+          -> decltype(tag_invoke(std::forward<Tag>(tag),
+                                 std::forward<Args>(args)...)) {
+    return tag_invoke(std::forward<Tag>(tag), std::forward<Args>(args)...);
+  }
+};
+} // namespace tag_invoke_fn_ns
+
+inline namespace tag_invoke_ns {
+inline constexpr tag_invoke_fn_ns::tag_invoke_fn tag_invoke = {};
+} // namespace tag_invoke_ns
+
+template <typename Tag, typename... Args>
+concept tag_invocable = requires(Tag tag, Args... args) {
+  tag_invoke(std::forward<Tag>(tag), std::forward<Args>(args)...);
+};
+
+template <typename Tag, typename... Args>
+concept nothrow_tag_invocable =
+    tag_invocable<Tag, Args...> && requires(Tag tag, Args... args) {
+      {
+        tag_invoke(std::forward<Tag>(tag), std::forward<Args>(args)...)
+      } noexcept;
+    };
+
+template <typename Tag, typename... Args>
+using tag_invoke_result =
+    std::invoke_result<decltype(tag_invoke), Tag, Args...>;
+
+template <typename Tag, typename... Args>
+using tag_invoke_result_t =
+    std::invoke_result_t<decltype(tag_invoke), Tag, Args...>;
+
+template <auto &Tag> using tag_t = std::decay_t<decltype(Tag)>;
+
+
+struct deserialize_tag;
+
+/// These types are deserializable in a built-in way
+template <typename> struct is_builtin_deserializable : std::false_type {};
+template <> struct is_builtin_deserializable<int64_t> : std::true_type {};
+template <> struct is_builtin_deserializable<uint64_t> : std::true_type {};
+template <> struct is_builtin_deserializable<double> : std::true_type {};
+template <> struct is_builtin_deserializable<bool> : std::true_type {};
+template <> struct is_builtin_deserializable<SIMDJSON_IMPLEMENTATION::ondemand::array> : std::true_type {};
+template <> struct is_builtin_deserializable<SIMDJSON_IMPLEMENTATION::ondemand::object> : std::true_type {};
+template <> struct is_builtin_deserializable<SIMDJSON_IMPLEMENTATION::ondemand::value> : std::true_type {};
+template <> struct is_builtin_deserializable<SIMDJSON_IMPLEMENTATION::ondemand::raw_json_string> : std::true_type {};
+template <> struct is_builtin_deserializable<std::string_view> : std::true_type {};
+
+template <typename T>
+concept is_builtin_deserializable_v = is_builtin_deserializable<T>::value;
+
+template <typename T, typename ValT = SIMDJSON_IMPLEMENTATION::ondemand::value>
+concept custom_deserializable = tag_invocable<deserialize_tag, ValT&, T&>;
+
+template <typename T, typename ValT = SIMDJSON_IMPLEMENTATION::ondemand::value>
+concept deserializable = custom_deserializable<T, ValT> || is_builtin_deserializable_v<T>;
+
+template <typename T, typename ValT = SIMDJSON_IMPLEMENTATION::ondemand::value>
+concept nothrow_custom_deserializable = nothrow_tag_invocable<deserialize_tag, ValT&, T&>;
+
+// built-in types are noexcept and if an error happens, the value simply gets ignored and the error is returned.
+template <typename T, typename ValT = SIMDJSON_IMPLEMENTATION::ondemand::value>
+concept nothrow_deserializable = nothrow_custom_deserializable<T, ValT> || is_builtin_deserializable_v<T>;
+
+/// Deserialize Tag
+inline constexpr struct deserialize_tag {
+  using value_type = SIMDJSON_IMPLEMENTATION::ondemand::value;
+  using document_type = SIMDJSON_IMPLEMENTATION::ondemand::document;
+
+  // Customization Point for value
+  template <typename T>
+    requires custom_deserializable<T, value_type>
+  [[nodiscard]] constexpr /* error_code */ auto operator()(value_type &object, T& output) const noexcept(nothrow_custom_deserializable<T, value_type>) {
+    return tag_invoke(*this, object, output);
+  }
+
+  // Customization Point for document
+  template <typename T>
+    requires custom_deserializable<T, document_type>
+  [[nodiscard]] constexpr /* error_code */ auto operator()(document_type &object, T& output) const noexcept(nothrow_custom_deserializable<T, document_type>) {
+    return tag_invoke(*this, object, output);
+  }
+
+} deserialize{};
+
+} // namespace simdjson
+
+#endif // SIMDJSON_ONDEMAND_DESERIALIZE_H
+#endif // SIMDJSON_SUPPORTS_DESERIALIZATION
+

include/simdjson/generic/ondemand/document-inl.h

@@ -13,7 +13,9 @@
 #include "simdjson/generic/ondemand/object-inl.h"
 #include "simdjson/generic/ondemand/raw_json_string.h"
 #include "simdjson/generic/ondemand/value.h"
+#include "simdjson/generic/ondemand/value-inl.h"
 #include "simdjson/generic/ondemand/value_iterator-inl.h"
+#include "simdjson/generic/ondemand/deserialize.h"
 #endif // SIMDJSON_CONDITIONAL_INCLUDE
 
 namespace simdjson {
@@ -167,20 +169,16 @@ template<> simdjson_inline simdjson_result<int64_t> document::get() & noexcept {
 template<> simdjson_inline simdjson_result<bool> document::get() & noexcept { return get_bool(); }
 template<> simdjson_inline simdjson_result<value> document::get() & noexcept { return get_value(); }
 
-template<> simdjson_inline simdjson_result<raw_json_string> document::get() && noexcept { return get_raw_json_string(); }
+template<> simdjson_inline error_code document::get(array& out) & noexcept { return get_array().get(out); }
-template<> simdjson_inline simdjson_result<std::string_view> document::get() && noexcept { return get_string(false); }
+template<> simdjson_inline error_code document::get(object& out) & noexcept { return get_object().get(out); }
-template<> simdjson_inline simdjson_result<double> document::get() && noexcept { return std::forward<document>(*this).get_double(); }
+template<> simdjson_inline error_code document::get(raw_json_string& out) & noexcept { return get_raw_json_string().get(out); }
-template<> simdjson_inline simdjson_result<uint64_t> document::get() && noexcept { return std::forward<document>(*this).get_uint64(); }
+template<> simdjson_inline error_code document::get(std::string_view& out) & noexcept { return get_string(false).get(out); }
-template<> simdjson_inline simdjson_result<int64_t> document::get() && noexcept { return std::forward<document>(*this).get_int64(); }
+template<> simdjson_inline error_code document::get(double& out) & noexcept { return get_double().get(out); }
-template<> simdjson_inline simdjson_result<bool> document::get() && noexcept { return std::forward<document>(*this).get_bool(); }
+template<> simdjson_inline error_code document::get(uint64_t& out) & noexcept { return get_uint64().get(out); }
-template<> simdjson_inline simdjson_result<value> document::get() && noexcept { return get_value(); }
+template<> simdjson_inline error_code document::get(int64_t& out) & noexcept { return get_int64().get(out); }
+template<> simdjson_inline error_code document::get(bool& out) & noexcept { return get_bool().get(out); }
+template<> simdjson_inline error_code document::get(value& out) & noexcept { return get_value().get(out); }
 
-template<typename T> simdjson_inline error_code document::get(T &out) & noexcept {
-  return get<T>().get(out);
-}
-template<typename T> simdjson_inline error_code document::get(T &out) && noexcept {
-  return std::forward<document>(*this).get<T>().get(out);
-}
 
 #if SIMDJSON_EXCEPTIONS
 template <class T>

include/simdjson/generic/ondemand/document.h

@@ -4,8 +4,11 @@
 #define SIMDJSON_GENERIC_ONDEMAND_DOCUMENT_H
 #include "simdjson/generic/ondemand/base.h"
 #include "simdjson/generic/ondemand/json_iterator.h"
+#include "simdjson/generic/ondemand/deserialize.h"
+#include "simdjson/generic/ondemand/value.h"
 #endif // SIMDJSON_CONDITIONAL_INCLUDE
 
+
 namespace simdjson {
 namespace SIMDJSON_IMPLEMENTATION {
 namespace ondemand {
@@ -178,24 +181,39 @@ public:
    * @returns A value of the given type, parsed from the JSON.
    * @returns INCORRECT_TYPE If the JSON value is not the given type.
    */
-  template<typename T> simdjson_inline simdjson_result<T> get() & noexcept {
+  template <typename T>
-    // Unless the simdjson library or the user provides an inline implementation, calling this method should
+  simdjson_inline simdjson_result<T> get() &
-    // immediately fail.
+#if SIMDJSON_SUPPORTS_DESERIALIZATION
-    static_assert(!sizeof(T), "The get method with given type is not implemented by the simdjson library. "
+    noexcept(custom_deserializable<T, document> ? nothrow_custom_deserializable<T, document> : true)
-      "The supported types are ondemand::object, ondemand::array, raw_json_string, std::string_view, uint64_t, "
+#else
-      "int64_t, double, and bool. We recommend you use get_double(), get_bool(), get_uint64(), get_int64(), "
+    noexcept
-      " get_object(), get_array(), get_raw_json_string(), or get_string() instead of the get template."
+#endif
-      " You may also add support for custom types, see our documentation.");
+  {
+    static_assert(std::is_default_constructible<T>::value, "Cannot initialize the specified type.");
+    T out{};
+    SIMDJSON_TRY(get<T>(out));
+    return out;
   }
-  /** @overload template<typename T> simdjson_result<T> get() & noexcept */
+  /**
-  template<typename T> simdjson_inline simdjson_result<T> get() && noexcept {
+   * @overload template<typename T> simdjson_result<T> get() & noexcept
-    // Unless the simdjson library or the user provides an inline implementation, calling this method should
+   *
-    // immediately fail.
+   * We disallow the use tag_invoke CPO on a moved document; it may create UB
-    static_assert(!sizeof(T), "The get method with given type is not implemented by the simdjson library. "
+   * if user uses `ondemand::array` or `ondemand::object` in their custom type.
-      "The supported types are ondemand::object, ondemand::array, raw_json_string, std::string_view, uint64_t, "
+   *
-      "int64_t, double, and bool. We recommend you use get_double(), get_bool(), get_uint64(), get_int64(), "
+   * The member function is still remains specialize-able for compatibility
-      " get_object(), get_array(), get_raw_json_string(), or get_string() instead of the get template."
+   * reasons, but we completely disallow its use when a tag_invoke customization
-      " You may also add support for custom types, see our documentation.");
+   * is provided.
+   */
+  template<typename T>
+  simdjson_inline simdjson_result<T> get() &&
+#if SIMDJSON_SUPPORTS_DESERIALIZATION
+    noexcept(custom_deserializable<T, document> ? nothrow_custom_deserializable<T, document> : true)
+#else
+    noexcept
+#endif
+  {
+      static_assert(!std::is_same<T, array>::value && !std::is_same<T, object>::value, "You should never hold either an ondemand::array or ondemand::object without a corresponding ondemand::document being alive; that would be Undefined Behaviour.");
+      return static_cast<document&>(*this).get<T>();
   }
 
   /**
@@ -209,7 +227,32 @@ public:
    * @returns INCORRECT_TYPE If the JSON value is not an object.
    * @returns SUCCESS If the parse succeeded and the out parameter was set to the value.
    */
-  template<typename T> simdjson_inline error_code get(T &out) & noexcept;
+  template<typename T>
+  simdjson_inline error_code get(T &out) &
+#if SIMDJSON_SUPPORTS_DESERIALIZATION
+    noexcept(custom_deserializable<T, document> ? nothrow_custom_deserializable<T, document> : true)
+#else
+    noexcept
+#endif
+  {
+#if SIMDJSON_SUPPORTS_DESERIALIZATION
+    if constexpr (custom_deserializable<T, document>) {
+        return deserialize(*this, out);
+    } else {
+#endif // SIMDJSON_SUPPORTS_DESERIALIZATION
+      // Unless the simdjson library or the user provides an inline implementation, calling this method should
+      // immediately fail.
+      static_assert(!sizeof(T), "The get method with given type is not implemented by the simdjson library. "
+        "The supported types are ondemand::object, ondemand::array, raw_json_string, std::string_view, uint64_t, "
+        "int64_t, double, and bool. We recommend you use get_double(), get_bool(), get_uint64(), get_int64(), "
+        " get_object(), get_array(), get_raw_json_string(), or get_string() instead of the get template."
+        " You may also add support for custom types, see our documentation.");
+      static_cast<void>(out); // to get rid of unused errors
+      return UNINITIALIZED;
+#if SIMDJSON_SUPPORTS_DESERIALIZATION
+    }
+#endif
+  }
   /** @overload template<typename T> error_code get(T &out) & noexcept */
   template<typename T> simdjson_inline error_code get(T &out) && noexcept;
 

include/simdjson/generic/ondemand/std_deserialize.h

@@ -0,0 +1,196 @@
+#if SIMDJSON_SUPPORTS_DESERIALIZATION
+
+#ifndef SIMDJSON_ONDEMAND_DESERIALIZE_H
+#ifndef SIMDJSON_CONDITIONAL_INCLUDE
+#define SIMDJSON_ONDEMAND_DESERIALIZE_H
+#include "simdjson/generic/ondemand/base.h"
+#include "simdjson/generic/ondemand/array.h"
+#endif // SIMDJSON_CONDITIONAL_INCLUDE
+
+#include <concepts>
+#include <limits>
+#include <list>
+#include <memory>
+#include <string>
+#include <vector>
+
+namespace simdjson {
+
+//////////////////////////////
+// Number deserialization
+//////////////////////////////
+
+template <std::unsigned_integral T>
+error_code tag_invoke(deserialize_tag, auto &val, T &out) noexcept {
+  using limits = std::numeric_limits<T>;
+
+  uint64_t x;
+  SIMDJSON_TRY(val.get_uint64().get(x));
+  if (x > (limits::max)()) {
+    return NUMBER_OUT_OF_RANGE;
+  }
+  out = static_cast<T>(x);
+  return SUCCESS;
+}
+
+template <std::floating_point T>
+error_code tag_invoke(deserialize_tag, auto &val, T &out) noexcept {
+  double x;
+  SIMDJSON_TRY(val.get_double().get(x));
+  out = static_cast<T>(x);
+  return SUCCESS;
+}
+
+template <std::signed_integral T>
+error_code tag_invoke(deserialize_tag, auto &val, T &out) noexcept {
+  using limits = std::numeric_limits<T>;
+
+  int64_t x;
+  SIMDJSON_TRY(val.get_int64().get(x));
+  if (x > (limits::max)() || x < (limits::min)()) {
+    return NUMBER_OUT_OF_RANGE;
+  }
+  out = static_cast<T>(x);
+  return SUCCESS;
+}
+
+//////////////////////////////
+// STL list deserialization
+//////////////////////////////
+
+template <typename T, typename AllocT, typename ValT>
+error_code tag_invoke(deserialize_tag, ValT &val,
+                      std::list<T, AllocT> &out) noexcept(false) {
+
+  // For better error messages, don't use these as constraints on
+  // the tag_invoke CPO.
+  static_assert(
+      deserializable<T, ValT>,
+      "The specified type inside the list must itself be deserializable");
+  static_assert(
+      std::is_default_constructible_v<T>,
+      "The specified type inside the list must default constructible.");
+
+  SIMDJSON_IMPLEMENTATION::ondemand::array arr;
+  SIMDJSON_TRY(val.get_array().get(arr));
+  for (auto v : arr) {
+    if (auto const err = v.get<T>().get(out.emplace_back()); err) {
+      // If an error occurs, the empty element that we just inserted gets
+      // removed. We're not using a temp variable because if T is a heavy type,
+      // we want the valid path to be the fast path and the slow path be the
+      // path that has errors in it.
+      static_cast<void>(out.pop_back());
+      return err;
+    }
+  }
+  return SUCCESS;
+}
+
+//////////////////////////////
+// std::string deserialization
+//////////////////////////////
+
+template <typename CharT,
+          typename TraitsT,
+          typename AllocT,
+          typename ValT>
+error_code tag_invoke(deserialize_tag, ValT &val, std::basic_string<CharT, TraitsT, AllocT> &out) noexcept(false) {
+  using string_type = std::basic_string<CharT, TraitsT, AllocT>;
+
+  if constexpr (std::same_as<string_type, string_type>) {
+    SIMDJSON_TRY(val.get_string(out));
+  } else {
+    // todo: optimize performance
+    std::string tmp;
+    SIMDJSON_TRY(val.get_string(tmp));
+    for (auto const ch : tmp) {
+      out.push_back(ch);
+    }
+  }
+  return SUCCESS;
+}
+
+//////////////////////////////
+// STL Vector deserialization
+//////////////////////////////
+
+/**
+ * STL containers have several constructors including one that takes a single
+ * size argument. Thus, some compilers (Visual Studio) will not be able to
+ * disambiguate between the size and container constructor. Users should
+ * explicitly specify the type of the container as needed: e.g.,
+ * doc.get<std::vector<int>>().
+ */
+template <typename T, typename AllocT, typename ValT>
+error_code tag_invoke(deserialize_tag, ValT &val,
+                      std::vector<T, AllocT> &out) noexcept(false) {
+
+  // For better error messages, don't use these as constraints on
+  // the tag_invoke CPO.
+  static_assert(
+      deserializable<T, ValT>,
+      "The specified type inside the vector must itself be deserializable");
+  static_assert(
+      std::is_default_constructible_v<T>,
+      "The specified type inside the vector must default constructible.");
+
+  SIMDJSON_IMPLEMENTATION::ondemand::array arr;
+  SIMDJSON_TRY(val.get_array().get(arr));
+  for (auto v : arr) {
+    if (auto const err = v.get<T>().get(out.emplace_back()); err) {
+      // If an error occurs, the empty element that we just inserted gets
+      // removed. We're not using a temp variable because if T is a heavy type,
+      // we want the valid path to be the fast path and the slow path be the
+      // path that has errors in it.
+      static_cast<void>(out.pop_back());
+      return err;
+    }
+  }
+  return SUCCESS;
+}
+
+//////////////////////////////
+// std::unique_ptr deserialization
+//////////////////////////////
+
+/**
+ * This CPO (Customization Point Object) will help deserialize into
+ * `unique_ptr`s.
+ *
+ * If constructing T is nothrow, this conversion should be nothrow as well since
+ * we return MEMALLOC if we're not able to allocate memory instead of throwing
+ * the the error message.
+ *
+ * @tparam T The type inside the unique_ptr
+ * @tparam Deleter The Deleter of the unique_ptr
+ * @tparam ValT document/value type
+ * @param val document/value
+ * @param out output unique_ptr
+ * @return status of the conversion
+ */
+template <typename T, typename Deleter, typename ValT>
+error_code tag_invoke(deserialize_tag, ValT &val,
+                      std::unique_ptr<T, Deleter>
+                          &out) noexcept(nothrow_deserializable<T, ValT>) {
+
+  // For better error messages, don't use these as constraints on
+  // the tag_invoke CPO.
+  static_assert(
+      deserializable<T, ValT>,
+      "The specified type inside the unique_ptr must itself be deserializable");
+  static_assert(
+      std::is_default_constructible_v<T>,
+      "The specified type inside the unique_ptr must default constructible.");
+
+  auto ptr = new (std::nothrow) T();
+  if (ptr == nullptr) {
+    return MEMALLOC;
+  }
+  SIMDJSON_TRY(val.template get<T>(*ptr));
+  out.reset(ptr);
+  return SUCCESS;
+}
+} // namespace simdjson
+
+#endif // SIMDJSON_ONDEMAND_DESERIALIZE_H
+#endif // SIMDJSON_SUPPORTS_DESERIALIZATION

include/simdjson/generic/ondemand/value-inl.h

@@ -80,6 +80,7 @@ simdjson_inline simdjson_result<bool> value::get_bool() noexcept {
 simdjson_inline simdjson_result<bool> value::is_null() noexcept {
   return iter.is_null();
 }
+
 template<> simdjson_inline simdjson_result<array> value::get() noexcept { return get_array(); }
 template<> simdjson_inline simdjson_result<object> value::get() noexcept { return get_object(); }
 template<> simdjson_inline simdjson_result<raw_json_string> value::get() noexcept { return get_raw_json_string(); }
@@ -90,9 +91,16 @@ template<> simdjson_inline simdjson_result<uint64_t> value::get() noexcept { ret
 template<> simdjson_inline simdjson_result<int64_t> value::get() noexcept { return get_int64(); }
 template<> simdjson_inline simdjson_result<bool> value::get() noexcept { return get_bool(); }
 
-template<typename T> simdjson_inline error_code value::get(T &out) noexcept {
+
-  return get<T>().get(out);
+template<> simdjson_inline error_code value::get(array& out) noexcept { return get_array().get(out); }
-}
+template<> simdjson_inline error_code value::get(object& out) noexcept { return get_object().get(out); }
+template<> simdjson_inline error_code value::get(raw_json_string& out) noexcept { return get_raw_json_string().get(out); }
+template<> simdjson_inline error_code value::get(std::string_view& out) noexcept { return get_string(false).get(out); }
+template<> simdjson_inline error_code value::get(number& out) noexcept { return get_number().get(out); }
+template<> simdjson_inline error_code value::get(double& out) noexcept { return get_double().get(out); }
+template<> simdjson_inline error_code value::get(uint64_t& out) noexcept { return get_uint64().get(out); }
+template<> simdjson_inline error_code value::get(int64_t& out) noexcept { return get_int64().get(out); }
+template<> simdjson_inline error_code value::get(bool& out) noexcept { return get_bool().get(out); }
 
 #if SIMDJSON_EXCEPTIONS
 template <class T>
@@ -416,6 +424,12 @@ simdjson_inline simdjson_result<bool> simdjson_result<SIMDJSON_IMPLEMENTATION::o
   return first.is_null();
 }
 
+template<> simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value>::get<SIMDJSON_IMPLEMENTATION::ondemand::value>(SIMDJSON_IMPLEMENTATION::ondemand::value &out) noexcept {
+  if (error()) { return error(); }
+  out = first;
+  return SUCCESS;
+}
+
 template<typename T> simdjson_inline simdjson_result<T> simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value>::get() noexcept {
   if (error()) { return error(); }
   return first.get<T>();
@@ -429,11 +443,6 @@ template<> simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::va
   if (error()) { return error(); }
   return std::move(first);
 }
-template<> simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value>::get<SIMDJSON_IMPLEMENTATION::ondemand::value>(SIMDJSON_IMPLEMENTATION::ondemand::value &out) noexcept {
-  if (error()) { return error(); }
-  out = first;
-  return SUCCESS;
-}
 
 simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::json_type> simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value>::type() noexcept {
   if (error()) { return error(); }
@@ -467,7 +476,7 @@ simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::number> simdj
 template <class T>
 simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value>::operator T() noexcept(false) {
   if (error()) { throw simdjson_error(error()); }
-  return static_cast<T>(first);
+  return first.get<T>();
 }
 simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value>::operator SIMDJSON_IMPLEMENTATION::ondemand::array() noexcept(false) {
   if (error()) { throw simdjson_error(error()); }

include/simdjson/generic/ondemand/value.h

@@ -5,12 +5,15 @@
 #include "simdjson/generic/ondemand/base.h"
 #include "simdjson/generic/implementation_simdjson_result_base.h"
 #include "simdjson/generic/ondemand/value_iterator.h"
+#include "simdjson/generic/ondemand/deserialize.h"
 #endif // SIMDJSON_CONDITIONAL_INCLUDE
 
+#include <type_traits>
+
 namespace simdjson {
+
 namespace SIMDJSON_IMPLEMENTATION {
 namespace ondemand {
-
 /**
  * An ephemeral JSON value returned during iteration. It is only valid for as long as you do
  * not access more data in the JSON document.
@@ -35,16 +38,21 @@ public:
    * @returns A value of the given type, parsed from the JSON.
    * @returns INCORRECT_TYPE If the JSON value is not the given type.
    */
-  template<typename T> simdjson_inline simdjson_result<T> get() noexcept {
+  template <typename T>
-    // Unless the simdjson library or the user provides an inline implementation, calling this method should
+  simdjson_inline simdjson_result<T> get()
-    // immediately fail.
+#if SIMDJSON_SUPPORTS_DESERIALIZATION
-    static_assert(!sizeof(T), "The get method with given type is not implemented by the simdjson library. "
+    noexcept(custom_deserializable<T, value> ? nothrow_custom_deserializable<T, value> : true)
-      "The supported types are ondemand::object, ondemand::array, raw_json_string, std::string_view, uint64_t, "
+#else
-      "int64_t, double, and bool. We recommend you use get_double(), get_bool(), get_uint64(), get_int64(), "
+    noexcept
-      " get_object(), get_array(), get_raw_json_string(), or get_string() instead of the get template."
+#endif
-      " You may also add support for custom types, see our documentation.");
+  {
+    static_assert(std::is_default_constructible<T>::value, "The specified type is not default constructible.");
+    T out{};
+    SIMDJSON_TRY(get<T>(out));
+    return out;
   }
 
+
   /**
    * Get this value as the given type.
    *
@@ -54,7 +62,32 @@ public:
    * @returns INCORRECT_TYPE If the JSON value is not an object.
    * @returns SUCCESS If the parse succeeded and the out parameter was set to the value.
    */
-  template<typename T> simdjson_inline error_code get(T &out) noexcept;
+  template <typename T>
+  simdjson_inline error_code get(T &out)
+#if SIMDJSON_SUPPORTS_DESERIALIZATION
+    noexcept(custom_deserializable<T, value> ? nothrow_custom_deserializable<T, value> : true)
+#else
+    noexcept
+#endif
+ {
+#if SIMDJSON_SUPPORTS_DESERIALIZATION
+    if constexpr (custom_deserializable<T, value>) {
+      return deserialize(*this, out);
+    } else {
+#endif // SIMDJSON_SUPPORTS_DESERIALIZATION
+      // Unless the simdjson library or the user provides an inline implementation, calling this method should
+      // immediately fail.
+      static_assert(!sizeof(T), "The get method with given type is not implemented by the simdjson library. "
+        "The supported types are ondemand::object, ondemand::array, raw_json_string, std::string_view, uint64_t, "
+        "int64_t, double, and bool. We recommend you use get_double(), get_bool(), get_uint64(), get_int64(), "
+        " get_object(), get_array(), get_raw_json_string(), or get_string() instead of the get template."
+        " You may also add support for custom types, see our documentation.");
+      static_cast<void>(out); // to get rid of unused errors
+      return UNINITIALIZED;
+#if SIMDJSON_SUPPORTS_DESERIALIZATION
+    }
+#endif
+  }
 
   /**
    * Cast this JSON value to an array.

singleheader/simdjson.cpp

@@ -1,4 +1,4 @@
-/* auto-generated on 2024-08-01 09:31:50 -0400. Do not edit! */
+/* auto-generated on 2024-07-15 08:51:57 -0400. Do not edit! */
 /* including simdjson.cpp:  */
 /* begin file simdjson.cpp */
 #define SIMDJSON_SRC_SIMDJSON_CPP
@@ -77,6 +77,18 @@
 #endif
 #endif
 
+#ifdef __has_include
+#if __has_include(<version>)
+#include <version>
+#endif
+#endif
+
+#ifdef __cpp_concepts
+#include <utility>
+#define SIMDJSON_SUPPORTS_DESERIALIZATION 1
+#else // __cpp_concepts
+#define SIMDJSON_SUPPORTS_DESERIALIZATION 0
+#endif
 #endif // SIMDJSON_COMPILER_CHECK_H
 /* end file simdjson/compiler_check.h */
 /* including simdjson/portability.h: #include "simdjson/portability.h" */

tests/ondemand/CMakeLists.txt

@@ -2,32 +2,35 @@
 link_libraries(simdjson)
 include_directories(..)
 add_subdirectory(compilation_failure_tests)
-add_cpp_test(ondemand_log_tests              LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_log_tests                      LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_log_error_tests        LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_log_error_tests                LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_tostring_tests         LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_tostring_tests                 LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_active_tests           LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_active_tests                   LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_array_tests            LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_array_tests                    LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_array_error_tests      LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_array_error_tests              LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_compilation_tests      LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_compilation_tests              LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_document_stream_tests  LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_document_stream_tests          LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_error_tests            LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_error_tests                    LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_error_location_tests   LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_error_location_tests           LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_json_pointer_tests     LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_json_pointer_tests             LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_json_path_tests        LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_json_path_tests                LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_key_string_tests       LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_key_string_tests               LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_misc_tests             LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_misc_tests                     LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_number_tests           LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_number_tests                   LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_number_in_string_tests LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_number_in_string_tests         LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_object_tests           LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_object_tests                   LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_object_error_tests     LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_object_error_tests             LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_ordering_tests         LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_ordering_tests                 LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_parse_api_tests        LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_parse_api_tests                LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_readme_examples        LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_readme_examples                LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_scalar_tests           LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_scalar_tests                   LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_to_string              LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_to_string                      LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_twitter_tests          LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_twitter_tests                  LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_wrong_type_error_tests LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_wrong_type_error_tests         LABELS ondemand acceptance per_implementation)
-add_cpp_test(ondemand_iterate_many_csv       LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_iterate_many_csv               LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_custom_types_tests             LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_custom_types_document_tests    LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_stl_types_tests                LABELS ondemand acceptance per_implementation)
 if(NOT SIMDJSON_SANITIZE)
   add_cpp_test(ondemand_cacheline              LABELS ondemand acceptance per_implementation)
 endif()

tests/ondemand/ondemand_custom_types_document_tests.cpp

@@ -0,0 +1,192 @@
+#include "simdjson.h"
+#include "test_ondemand.h"
+
+#include <string>
+#include <vector>
+
+#if SIMDJSON_SUPPORTS_DESERIALIZATION
+
+namespace simdjson {
+
+// unique_ptr<T>
+template <typename T>
+error_code tag_invoke(deserialize_tag, auto &val, std::unique_ptr<T>& out) {
+  out = std::make_unique<T>(val.template get<T>());
+  return SUCCESS;
+}
+
+} // namespace simdjson
+
+#endif // SIMDJSON_SUPPORTS_DESERIALIZATION
+
+namespace doc_custom_types_tests {
+#if SIMDJSON_EXCEPTIONS && defined(__cpp_concepts)
+struct Car {
+  std::string make{};
+  std::string model{};
+  int64_t year{};
+  std::vector<double> tire_pressure{};
+
+  friend error_code tag_invoke(simdjson::deserialize_tag,
+                                         auto &val, Car& car) {
+    simdjson::ondemand::object obj;
+    if (auto const error = val.get_object().get(obj)) {
+      return error;
+    }
+    // Instead of repeatedly obj["something"], we iterate through the object
+    // which we expect to be faster.
+    for (auto field : obj) {
+      simdjson::ondemand::raw_json_string key;
+      if (auto const error = field.key().get(key)) {
+        return error;
+      }
+      if (key == "make") {
+        if (auto const error = field.value().get_string(car.make)) {
+          return error;
+        }
+      } else if (key == "model") {
+        if (auto const error = field.value().get_string(car.model)) {
+          return error;
+        }
+      } else if (key == "year") {
+        if (auto const error = field.value().get_int64().get(car.year)) {
+          return error;
+        }
+      } else if (key == "tire_pressure") {
+        if (auto const error = field.value().get<std::vector<double>>().get(
+                car.tire_pressure)) {
+          return error;
+        }
+      }
+    }
+    return error_code::SUCCESS;
+  }
+};
+
+static_assert(simdjson::custom_deserializable<std::unique_ptr<Car>, simdjson::ondemand::value>, "It should be invocable");
+static_assert(simdjson::custom_deserializable<std::unique_ptr<Car>, simdjson::ondemand::document>, "Tag_invoke should work with document as well.");
+static_assert(simdjson::custom_deserializable<std::vector<Car>, simdjson::ondemand::value>, "It should be invocable");
+static_assert(simdjson::custom_deserializable<std::vector<Car>, simdjson::ondemand::document>, "Tag_invoke should work with document as well.");
+
+bool custom_test() {
+  TEST_START();
+  auto const json = R"( {
+      "make": "Toyota",
+      "model": "Camry",
+      "year": 2018,
+      "tire_pressure": [ 40.1, 39.9 ]
+ } )"_padded;
+
+  simdjson::ondemand::parser parser;
+  simdjson::ondemand::document doc = parser.iterate(json);
+
+  // creating car directly from "doc":
+  const std::unique_ptr<Car> car(doc);
+  if (car->make != "Toyota") {
+    return false;
+  }
+  if (car->model != "Camry") {
+    return false;
+  }
+  if (car->year != 2018) {
+    return false;
+  }
+  if (car->tire_pressure.size() != 2) {
+    return false;
+  }
+  TEST_SUCCEED();
+}
+
+bool readme_test() {
+  TEST_START();
+  auto const json = R"( { "make": "Toyota", "model": "Camry",  "year": 2018,
+       "tire_pressure": [ 40.1, 39.9 ] })"_padded;
+  simdjson::ondemand::parser parser;
+  simdjson::ondemand::document doc = parser.iterate(json);
+  std::unique_ptr<Car> c(doc);
+  std::cout << c->make << std::endl;
+  TEST_SUCCEED();
+}
+
+
+bool simple_document_test() {
+  TEST_START();
+  simdjson::padded_string json =
+      R"( { "make": "Toyota", "model": "Camry",  "year": 2018,
+       "tire_pressure": [ 40.1, 39.9 ] })"_padded;
+  simdjson::ondemand::parser parser;
+  simdjson::ondemand::document doc = parser.iterate(json);
+  Car c(doc);
+  std::cout << c.make << std::endl;
+  ASSERT_EQUAL(c.make, "Toyota");
+  TEST_SUCCEED();
+}
+
+bool custom_test_crazier() {
+  TEST_START();
+  simdjson::padded_string json =
+      R"( [ { "make": "Toyota", "model": "Camry",  "year": 2018,
+       "tire_pressure": [ 40.1, 39.9 ] },
+  { "make": "Kia",    "model": "Soul",   "year": 2012,
+       "tire_pressure": [ 30.1, 31.0 ] },
+  { "make": "Toyota", "model": "Tercel", "year": 1999,
+       "tire_pressure": [ 29.8, 30.0 ] }
+])"_padded;
+
+  simdjson::ondemand::parser parser;
+  simdjson::ondemand::document doc = parser.iterate(json);
+#if SIMDJSON_REGULAR_VISUAL_STUDIO
+  std::vector<Car> cars = doc.get<std::vector<Car>>();
+#else
+  std::vector<Car> cars(doc);
+#endif
+  for(Car& c : cars) {
+    std::cout << c.year << std::endl;
+    if (c.make != "Toyota" && c.make != "Kia") {
+      return false;
+    }
+    if (c.model != "Camry" && c.model != "Soul" && c.model != "Tercel") {
+      return false;
+    }
+    if (c.year != 2018 && c.year != 2012 && c.year != 1999) {
+      return false;
+    }
+    if (c.tire_pressure.size() != 2) {
+      return false;
+    }
+  }
+  TEST_SUCCEED();
+}
+
+bool simple_document_test_no_except() {
+  TEST_START();
+  simdjson::padded_string json =
+      R"( { "make": "Toyota", "model": "Camry",  "year": 2018,
+       "tire_pressure": [ 40.1, 39.9 ] })"_padded;
+  simdjson::ondemand::parser parser;
+  simdjson::ondemand::document doc = parser.iterate(json);
+  Car c;
+  auto error = doc.get(c);
+  if(error) { std::cerr << simdjson::error_message(error); return false; }
+  std::cout << c.make << std::endl;
+  ASSERT_EQUAL(c.make, "Toyota");
+  TEST_SUCCEED();
+}
+#endif // SIMDJSON_EXCEPTIONS
+bool run() {
+  return
+#if SIMDJSON_EXCEPTIONS && defined(__cpp_concepts)
+      readme_test() &&
+      custom_test() &&
+      simple_document_test() &&
+      simple_document_test_no_except() &&
+      custom_test_crazier() &&
+#endif // SIMDJSON_EXCEPTIONS
+      true;
+}
+
+} // namespace doc_custom_types_tests
+
+int main(const int argc, char *argv[]) {
+  return test_main(argc, argv, doc_custom_types_tests::run);
+}

tests/ondemand/ondemand_custom_types_tests.cpp

@@ -0,0 +1,229 @@
+#include "simdjson.h"
+#include "test_ondemand.h"
+
+#include <string>
+#include <vector>
+
+#if SIMDJSON_SUPPORTS_DESERIALIZATION
+
+template <typename T>
+struct is_unique_ptr : std::false_type {
+};
+
+
+template <typename T>
+struct is_unique_ptr<std::unique_ptr<T>> : std::true_type {
+};
+
+template <typename T>
+concept is_unique_ptr_v = is_unique_ptr<T>::value;
+
+
+namespace simdjson {
+
+// this is to demonstrate that we can use concept; otherwise a simple
+// type_identity<unique_ptr<T>> as the second argument would have done the job.
+//
+// This tag_invoke MUST be inside simdjson namespace
+template <typename T>
+  requires is_unique_ptr_v<T>
+auto tag_invoke(deserialize_tag, auto &val, T& out) {
+  using type = typename T::element_type;
+  out = std::make_unique<type>(val.template get<type>());
+  return SUCCESS;
+}
+
+} // namespace simdjson
+
+
+#endif // SIMDJSON_SUPPORTS_DESERIALIZATION
+
+
+namespace custom_types_tests {
+#if SIMDJSON_EXCEPTIONS && SIMDJSON_SUPPORTS_DESERIALIZATION
+struct Car {
+  std::string make{};
+  std::string model{};
+  int year{};
+  std::vector<double> tire_pressure{};
+
+  friend simdjson::error_code tag_invoke(simdjson::deserialize_tag, auto &val, Car& car) {
+    simdjson::ondemand::object obj;
+    auto error = val.get_object().get(obj);
+    if (error) {
+      return error;
+    }
+    // Instead of repeatedly obj["something"], we iterate through the object
+    // which we expect to be faster.
+    for (auto field : obj) {
+      simdjson::ondemand::raw_json_string key;
+      error = field.key().get(key);
+      if (error) {
+        return error;
+      }
+      if (key == "make") {
+        error = field.value().get_string(car.make);
+        if (error) {
+          return error;
+        }
+      } else if (key == "model") {
+        error = field.value().get_string(car.model);
+        if (error) {
+          return error;
+        }
+      } else if (key == "year") {
+        error = field.value().get(car.year);
+        if (error) {
+          return error;
+        }
+      } else if (key == "tire_pressure") {
+        error = field.value().get(car.tire_pressure);
+        if (error) {
+          return error;
+        }
+      }
+    }
+    return simdjson::SUCCESS;
+  }
+};
+
+static_assert(simdjson::custom_deserializable<std::unique_ptr<Car>>, "It should be deserializable");
+
+bool custom_uniqueptr_test() {
+  TEST_START();
+  simdjson::padded_string json =
+      R"( [ { "make": "Toyota", "model": "Camry",  "year": 2018,
+       "tire_pressure": [ 40.1, 39.9 ] },
+  { "make": "Kia",    "model": "Soul",   "year": 2012,
+       "tire_pressure": [ 30.1, 31.0 ] },
+  { "make": "Toyota", "model": "Tercel", "year": 1999,
+       "tire_pressure": [ 29.8, 30.0 ] }
+])"_padded;
+
+  simdjson::ondemand::parser parser;
+  simdjson::ondemand::document doc = parser.iterate(json);
+  for (auto val : doc) {
+    std::unique_ptr<Car> c(val);
+    if (c->make != "Toyota" && c->make != "Kia") {
+      return false;
+    }
+    if (c->model != "Camry" && c->model != "Soul" && c->model != "Tercel") {
+      return false;
+    }
+    if (c->year != 2018 && c->year != 2012 && c->year != 1999) {
+      return false;
+    }
+    if (c->tire_pressure.size() != 2) {
+      return false;
+    }
+  }
+
+  TEST_SUCCEED();
+}
+
+
+
+bool custom_test() {
+  TEST_START();
+  simdjson::padded_string json =
+      R"( [ { "make": "Toyota", "model": "Camry",  "year": 2018,
+       "tire_pressure": [ 40.1, 39.9 ] },
+  { "make": "Kia",    "model": "Soul",   "year": 2012,
+       "tire_pressure": [ 30.1, 31.0 ] },
+  { "make": "Toyota", "model": "Tercel", "year": 1999,
+       "tire_pressure": [ 29.8, 30.0 ] }
+])"_padded;
+
+  simdjson::ondemand::parser parser;
+  simdjson::ondemand::document doc = parser.iterate(json);
+  for (auto val : doc) {
+    Car c(val);
+    if (c.make != "Toyota" && c.make != "Kia") {
+      return false;
+    }
+    if (c.model != "Camry" && c.model != "Soul" && c.model != "Tercel") {
+      return false;
+    }
+    if (c.year != 2018 && c.year != 2012 && c.year != 1999) {
+      return false;
+    }
+    if (c.tire_pressure.size() != 2) {
+      return false;
+    }
+  }
+
+  TEST_SUCCEED();
+}
+
+
+
+bool custom_test_crazy() {
+  TEST_START();
+  simdjson::padded_string json =
+      R"( [ { "make": "Toyota", "model": "Camry",  "year": 2018,
+       "tire_pressure": [ 40.1, 39.9 ] },
+  { "make": "Kia",    "model": "Soul",   "year": 2012,
+       "tire_pressure": [ 30.1, 31.0 ] },
+  { "make": "Toyota", "model": "Tercel", "year": 1999,
+       "tire_pressure": [ 29.8, 30.0 ] }
+])"_padded;
+
+  simdjson::ondemand::parser parser;
+  simdjson::ondemand::document doc = parser.iterate(json);
+  for (auto val : doc) {
+    Car c(val);
+    std::cout << c.year << std::endl;
+    if (c.make != "Toyota" && c.make != "Kia") {
+      return false;
+    }
+    if (c.model != "Camry" && c.model != "Soul" && c.model != "Tercel") {
+      return false;
+    }
+    if (c.year != 2018 && c.year != 2012 && c.year != 1999) {
+      return false;
+    }
+    if (c.tire_pressure.size() != 2) {
+      return false;
+    }
+  }
+
+  TEST_SUCCEED();
+}
+
+bool custom_no_except() {
+  TEST_START();
+  simdjson::padded_string json =
+      R"( [ { "make": "Toyota", "model": "Camry",  "year": 2018,
+       "tire_pressure": [ 40.1, 39.9 ] },
+  { "make": "Kia",    "model": "Soul",   "year": 2012,
+       "tire_pressure": [ 30.1, 31.0 ] },
+  { "make": "Toyota", "model": "Tercel", "year": 1999,
+       "tire_pressure": [ 29.8, 30.0 ] }
+])"_padded;
+
+  simdjson::ondemand::parser parser;
+  simdjson::ondemand::document doc = parser.iterate(json);
+  for (auto val : doc) {
+    Car c;
+    auto error = val.get(c);
+    if(error) { std::cerr << simdjson::error_message(error) << std::endl; return false; }
+  }
+
+  TEST_SUCCEED();
+}
+#endif // SIMDJSON_EXCEPTIONS
+bool run() {
+  return
+#if SIMDJSON_EXCEPTIONS && SIMDJSON_SUPPORTS_DESERIALIZATION
+      custom_test() &&
+      custom_uniqueptr_test() &&
+      custom_no_except() &&
+#endif // SIMDJSON_EXCEPTIONS
+      true;
+}
+
+} // namespace custom_types_tests
+
+int main(int argc, char *argv[]) {
+  return test_main(argc, argv, custom_types_tests::run);
+}

tests/ondemand/ondemand_readme_examples.cpp

@@ -49,6 +49,7 @@ struct Car {
   std::vector<double> tire_pressure;
 };
 
+#ifndef __cpp_concepts
 template <>
 simdjson_inline simdjson_result<std::vector<double>>
 simdjson::ondemand::value::get() noexcept {
@@ -66,7 +67,7 @@ simdjson::ondemand::value::get() noexcept {
   }
   return vec;
 }
-
+#endif
 
 
 template <>
@@ -193,8 +194,8 @@ int custom_type_with_exceptions() {
 ])"_padded;
   ondemand::parser parser;
   ondemand::document doc = parser.iterate(json);
-  for (auto val : doc) {
+  for (auto value : doc) {
-    Car c(val);
+    Car c(value);
     std::cout << c.make << std::endl;
   }
   return 0;

tests/ondemand/ondemand_stl_types_tests.cpp

@@ -0,0 +1,48 @@
+#include "simdjson.h"
+#include "test_ondemand.h"
+
+#include <string>
+#include <vector>
+
+namespace stl_types {
+#if SIMDJSON_EXCEPTIONS && SIMDJSON_SUPPORTS_DESERIALIZATION
+
+bool basic_general_madness() {
+  TEST_START();
+  simdjson::padded_string json =
+      R"( [ { "codes": [1.2, 3.4, 5.6, 7.8, 9.0] },
+            { "codes": [2.2, 4.4, 6.6, 8.8, 10.0] } ])"_padded;
+
+  simdjson::ondemand::parser parser;
+  simdjson::ondemand::document doc = parser.iterate(json);
+  std::vector<std::unique_ptr<float>> codes;
+  for (auto val : doc) {
+    simdjson::ondemand::object obj;
+    SIMDJSON_TRY(val.get_object().get(obj));
+    obj["codes"].get(codes); // append to it
+  }
+
+  if (codes.size() != 10) {
+    return false;
+  }
+  if (*codes[5] != 2.2f || *codes[7] != 6.6f || *codes[9] != 10.0f) {
+    return false;
+  }
+
+  TEST_SUCCEED();
+}
+
+#endif // SIMDJSON_EXCEPTIONS
+bool run() {
+  return
+#if SIMDJSON_EXCEPTIONS && SIMDJSON_SUPPORTS_DESERIALIZATION
+      basic_general_madness() &&
+#endif // SIMDJSON_EXCEPTIONS
+      true;
+}
+
+} // namespace stl_types
+
+int main(int argc, char *argv[]) {
+  return test_main(argc, argv, stl_types::run);
+}