4.1.0 (#2532)

* Adding compile time json path

* using string_view

* Adding support for compile-time json pointer as well.

* Removing unnecessary comment

* Tests now working, still will re-review.

* Adding documentation on the compile-time json path/pointer parsing feature.

* Adding benchmark showing the significant performance advantage of using compiled paths whenever you have them a priori.

* going for JSONPath (correct wording).

* minor update (mostly doc)

---------

Co-authored-by: Daniel Lemire <daniel@lemire.me>

.circleci/config.yml

@@ -1,316 +0,0 @@
-version: 2.1
-
-
-# We constantly run out of memory so please do not use parallelism (-j, -j4).
-
-# Reusable image / compiler definitions
-executors:
-  gcc8:
-    docker:
-      - image: conanio/gcc8
-        environment:
-          CXX: g++-8
-          CC: gcc-8
-          CMAKE_BUILD_FLAGS:
-          CTEST_FLAGS: --output-on-failure
-
-  gcc9:
-    docker:
-      - image: conanio/gcc9
-        environment:
-          CXX: g++-9
-          CC: gcc-9
-          CMAKE_BUILD_FLAGS:
-          CTEST_FLAGS: --output-on-failure
-
-  gcc10:
-    docker:
-      - image: conanio/gcc10
-        environment:
-          CXX: g++-10
-          CC: gcc-10
-          CMAKE_BUILD_FLAGS:
-          CTEST_FLAGS: --output-on-failure
-
-  clang10:
-    docker:
-      - image: conanio/clang10
-        environment:
-          CXX: clang++-10
-          CC: clang-10
-          CMAKE_BUILD_FLAGS:
-          CTEST_FLAGS: --output-on-failure
-
-  clang9:
-    docker:
-      - image: conanio/clang9
-        environment:
-          CXX: clang++-9
-          CC: clang-9
-          CMAKE_BUILD_FLAGS:
-          CTEST_FLAGS: --output-on-failure
-
-  clang6:
-    docker:
-      - image: conanio/clang60
-        environment:
-          CXX: clang++-6.0
-          CC: clang-6.0
-          CMAKE_BUILD_FLAGS:
-          CTEST_FLAGS: --output-on-failure
-
-# Reusable test commands (and initializer for clang 6)
-commands:
-  dependency_restore:
-    steps:
-      - restore_cache:
-          keys:
-            - cmake-cache-{{ checksum "dependencies/CMakeLists.txt" }}
-
-  dependency_cache:
-    steps:
-      - save_cache:
-          key: cmake-cache-{{ checksum "dependencies/CMakeLists.txt" }}
-          paths:
-            - dependencies/.cache
-
-  install_cmake:
-    steps:
-      - run: apt-get update -qq
-      - run: apt-get install -y cmake
-
-  cmake_prep:
-    steps:
-      - checkout
-      - run: mkdir -p build
-
-  cmake_build_cache:
-    steps:
-      - cmake_prep
-      - dependency_restore
-      - run: cmake  -DSIMDJSON_DEVELOPER_MODE=ON $CMAKE_FLAGS -DCMAKE_INSTALL_PREFIX:PATH=destination -B build .
-      - dependency_cache # dependencies are produced in the configure step
-
-  cmake_build:
-    steps:
-      - cmake_build_cache
-      - run: cmake  --build build
-
-  cmake_test:
-    steps:
-      - cmake_build
-      - run: |
-          cd build &&
-          tools/json2json -h &&
-          ctest $CTEST_FLAGS -L acceptance &&
-          ctest $CTEST_FLAGS -LE acceptance -LE explicitonly
-
-  cmake_assert_test:
-    steps:
-      - run: |
-          cd build &&
-          tools/json2json -h &&
-          ctest $CTEST_FLAGS -L assert
-
-  cmake_test_all:
-    steps:
-      - cmake_build
-      - run: |
-          cd build &&
-          tools/json2json -h &&
-          ctest $CTEST_FLAGS -DSIMDJSON_IMPLEMENTATION="haswell;westmere;fallback" -L acceptance -LE per_implementation &&
-          SIMDJSON_FORCE_IMPLEMENTATION=haswell ctest $CTEST_FLAGS -L per_implementation -LE explicitonly &&
-          SIMDJSON_FORCE_IMPLEMENTATION=westmere ctest $CTEST_FLAGS -L per_implementation -LE explicitonly &&
-          SIMDJSON_FORCE_IMPLEMENTATION=fallback ctest $CTEST_FLAGS -L per_implementation -LE explicitonly &&
-          ctest $CTEST_FLAGS -LE "acceptance|per_implementation" # Everything we haven't run yet, run now.
-
-
-  cmake_perftest:
-    steps:
-      - cmake_build_cache
-      - run: |
-          cmake -DSIMDJSON_ENABLE_DOM_CHECKPERF=ON --build  build --target checkperf &&
-          cd build &&
-          ctest --output-on-failure -R checkperf
-
-  # we not only want cmake to build and run tests, but we want also a successful installation from which we can build, link and run programs
-  cmake_install_test: # this version builds, install, test and then verify from the installation
-    steps:
-      - run: cd build && make install
-      - run: echo -e '#include <simdjson.h>\nint main(int argc,char**argv) {simdjson::dom::parser parser;simdjson::dom::element tweets = parser.load(argv[1]); }' > tmp.cpp && c++ -Ibuild/destination/include -Lbuild/destination/lib -std=c++17 -Wl,-rpath,build/destination/lib -o linkandrun tmp.cpp -lsimdjson && ./linkandrun jsonexamples/twitter.json
-
-  cmake_installed_test_cxx20: # assuming that it was installed, this tries to build using C++20
-    steps:
-      - run: echo -e '#include <simdjson.h>\nint main(int argc,char**argv) {simdjson::dom::parser parser;simdjson::dom::element tweets = parser.load(argv[1]); }' > tmp.cpp && c++ -Ibuild/destination/include -Lbuild/destination/lib -std=c++20 -Wl,-rpath,build/destination/lib -o linkandrun tmp.cpp -lsimdjson && ./linkandrun jsonexamples/twitter.json
-
-jobs:
-
-  # static
-  justlib-gcc10:
-    description: Build just the library, install it and do a basic test
-    executor: gcc10
-    environment: { CMAKE_FLAGS: -DSIMDJSON_JUST_LIBRARY=ON }
-    steps: [ cmake_build, cmake_install_test, cmake_installed_test_cxx20 ]
-  assert-gcc10:
-    description: Build the library with asserts on, install it and run tests
-    executor: gcc10
-    environment: { CMAKE_FLAGS: -DSIMDJSON_GOOGLE_BENCHMARKS=OFF -DCMAKE_CXX_FLAGS_RELEASE=-O3 }
-    steps: [ cmake_test, cmake_assert_test ]
-  assert-clang10:
-    description: Build just the library, install it and do a basic test
-    executor: clang10
-    environment: { CMAKE_FLAGS: -DSIMDJSON_GOOGLE_BENCHMARKS=OFF -DCMAKE_CXX_FLAGS_RELEASE=-O3 }
-    steps: [ cmake_test, cmake_assert_test ]
-  gcc10-perftest:
-    description: Build and run performance tests on GCC 10 and AVX 2 with a cmake static build, this test performance regression
-    executor: gcc10
-    environment: { CMAKE_FLAGS: -DSIMDJSON_GOOGLE_BENCHMARKS=OFF -DBUILD_SHARED_LIBS=OFF }
-    steps: [ cmake_perftest ]
-  gcc10:
-    description: Build and run tests on GCC 10 and AVX 2 with a cmake static build
-    executor: gcc10
-    environment: { CMAKE_FLAGS: -DSIMDJSON_GOOGLE_BENCHMARKS=ON -DBUILD_SHARED_LIBS=OFF }
-    steps: [ cmake_test, cmake_install_test, cmake_installed_test_cxx20 ]
-  clang6:
-    description: Build and run tests on clang 6 and AVX 2 with a cmake static build
-    executor: clang6
-    environment: { CMAKE_FLAGS: -DSIMDJSON_GOOGLE_BENCHMARKS=ON -DBUILD_SHARED_LIBS=OFF }
-    steps: [ cmake_test, cmake_install_test ]
-  clang10:
-    description: Build and run tests on clang 10 and AVX 2 with a cmake static build
-    executor: clang10
-    environment: { CMAKE_FLAGS: -DSIMDJSON_GOOGLE_BENCHMARKS=ON  -DBUILD_SHARED_LIBS=OFF }
-    steps: [ cmake_test, cmake_install_test, cmake_installed_test_cxx20 ]
-  # libcpp
-  libcpp-clang10:
-    description: Build and run tests on clang 10 and AVX 2 with a cmake static build and libc++
-    executor: clang10
-    environment: { CMAKE_FLAGS: -DSIMDJSON_USE_LIBCPP=ON  -DBUILD_SHARED_LIBS=OFF }
-    steps: [ cmake_test, cmake_install_test, cmake_installed_test_cxx20 ]
-  # sanitize
-  sanitize-gcc10:
-    description: Build and run tests on GCC 10 and AVX 2 with a cmake sanitize build
-    executor: gcc10
-    environment: { CMAKE_FLAGS: -DCMAKE_BUILD_TYPE=Debug -DBUILD_SHARED_LIBS=ON -DSIMDJSON_SANITIZE=ON, CTEST_FLAGS: --output-on-failure -LE explicitonly }
-    steps: [ cmake_test ]
-  sanitize-clang10:
-    description: Build and run tests on clang 10 and AVX 2 with a cmake sanitize build
-    executor: clang10
-    environment: { CMAKE_FLAGS: -DBUILD_SHARED_LIBS=ON -DSIMDJSON_NO_FORCE_INLINING=ON -DSIMDJSON_SANITIZE=ON, CTEST_FLAGS: --output-on-failure -LE explicitonly }
-    steps: [ cmake_test ]
-  threadsanitize-gcc10:
-    description: Build and run tests on GCC 10 and AVX 2 with a cmake sanitize build
-    executor: gcc10
-    environment: { CMAKE_FLAGS: -DBUILD_SHARED_LIBS=ON -DSIMDJSON_SANITIZE_THREADS=ON, CTEST_FLAGS: --output-on-failure -LE explicitonly }
-    steps: [ cmake_test ]
-  threadsanitize-clang10:
-    description: Build and run tests on clang 10 and AVX 2 with a cmake sanitize build
-    executor: clang10
-    environment: { CMAKE_FLAGS: -DBUILD_SHARED_LIBS=ON  -DSIMDJSON_NO_FORCE_INLINING=ON -DSIMDJSON_SANITIZE_THREADS=ON, CTEST_FLAGS: --output-on-failure -LE explicitonly }
-    steps: [ cmake_test ]
-  # dynamic
-  dynamic-gcc10:
-    description: Build and run tests on GCC 10 and AVX 2 with a cmake dynamic build
-    executor: gcc10
-    environment: { CMAKE_FLAGS: -DBUILD_SHARED_LIBS=ON }
-    steps: [ cmake_test, cmake_install_test ]
-  dynamic-clang10:
-    description: Build and run tests on clang 10 and AVX 2 with a cmake dynamic build
-    executor: clang10
-    environment: { CMAKE_FLAGS: -DBUILD_SHARED_LIBS=ON }
-    steps: [ cmake_test, cmake_install_test ]
-
-  # unthreaded
-  unthreaded-gcc10:
-    description: Build and run tests on GCC 10 and AVX 2 *without* threads
-    executor: gcc10
-    environment: { CMAKE_FLAGS: -DSIMDJSON_ENABLE_THREADS=OFF }
-    steps: [ cmake_test, cmake_install_test ]
-  unthreaded-clang10:
-    description: Build and run tests on Clang 10 and AVX 2 *without* threads
-    executor: clang10
-    environment: { CMAKE_FLAGS: -DSIMDJSON_ENABLE_THREADS=OFF }
-    steps: [ cmake_test, cmake_install_test ]
-
-  # noexcept
-  noexcept-gcc10:
-    description: Build and run tests on GCC 10 and AVX 2 with exceptions off
-    executor: gcc10
-    environment: { CMAKE_FLAGS: -DSIMDJSON_EXCEPTIONS=OFF }
-    steps: [ cmake_test, cmake_install_test ]
-  noexcept-clang10:
-    description: Build and run tests on Clang 10 and AVX 2 with exceptions off
-    executor: clang10
-    environment: { CMAKE_FLAGS: -DSIMDJSON_EXCEPTIONS=OFF }
-    steps: [ cmake_test, cmake_install_test ]
-
-  #
-  # Misc.
-  #
-
-  # make (test and checkperf)
-  arch-haswell-gcc10:
-    description: Build, run tests and check performance on GCC 10 with -march=haswell
-    executor: gcc10
-    environment: { CXXFLAGS: -march=haswell }
-    steps: [ cmake_test ]
-  arch-nehalem-gcc10:
-    description: Build, run tests and check performance on GCC 10 with -march=nehalem
-    executor: gcc10
-    environment: { CXXFLAGS: -march=nehalem }
-    steps: [ cmake_test ]
-  sanitize-haswell-gcc10:
-    description: Build and run tests on GCC 10 and AVX 2 with a cmake sanitize build
-    executor: gcc10
-    environment: {  CXXFLAGS: -march=haswell, CMAKE_FLAGS: -DCMAKE_BUILD_TYPE=Debug -DBUILD_SHARED_LIBS=ON -DSIMDJSON_SANITIZE=ON, CTEST_FLAGS: --output-on-failure -LE explicitonly }
-    steps: [ cmake_test ]
-  sanitize-haswell-clang10:
-    description: Build and run tests on clang 10 and AVX 2 with a cmake sanitize build
-    executor: clang10
-    environment: { CXXFLAGS: -march=haswell, CMAKE_FLAGS: -DBUILD_SHARED_LIBS=ON  -DSIMDJSON_NO_FORCE_INLINING=ON -DSIMDJSON_SANITIZE=ON, CTEST_FLAGS: --output-on-failure -LE explicitonly }
-    steps: [ cmake_test ]
-
-workflows:
-  version: 2.1
-  build_and_test:
-    jobs:
-      # full multi-implementation tests
-      #- gcc7 tested on GitHub actions
-      - gcc10 # do not delete this as it tests our performance
-      - clang6
-      #- clang10 # this gets tested a lot below
-
-      # libc++
-      - libcpp-clang10
-
-      # full single-implementation tests
-      - sanitize-gcc10
-      - sanitize-clang10
-      - threadsanitize-gcc10
-      - threadsanitize-clang10
-      - dynamic-gcc10
-      - dynamic-clang10
-      - unthreaded-gcc10
-      - unthreaded-clang10
-
-      # no exceptions
-      - noexcept-gcc10
-      - noexcept-clang10
-
-      # quicker make single-implementation tests
-      - arch-haswell-gcc10
-      - arch-nehalem-gcc10
-
-
-      # sanitized single-implementation tests
-      - sanitize-haswell-gcc10
-      - sanitize-haswell-clang10
-
-      # testing "just the library"
-      - justlib-gcc10
-
-      # testing asserts
-      - assert-gcc10
-      - assert-clang10
-
-      # TODO add windows: https://circleci.com/docs/2.0/configuration-reference/#windows

.github/pull_request_template.md

@@ -1,8 +1,53 @@
+Short title (summary):
+
+Description
+- What did you change and why? (1-3 sentences)
+- Issue reproduced / related issue: link the issue if relevant (e.g. #123)
+
+Type of change
+- [ ] Bug fix
+- [ ] New feature
+- [ ] Refactor / cleanup
+- [ ] Documentation / tests
+- [ ] Other (please describe):
+
+How to verify / test
+- Add additional tests to verify bugs or new features.
+- If you claim performance gains, you should provide benchmark numbers using high quality benchmarking code.
 
 
-Our tests check whether you have introduced trailing white space. If such a test fails, please check the "artifacts button" above, which if you click it gives a link to a downloadable file to help you identify the issue. You can also run scripts/remove_trailing_whitespace.sh locally if you have a bash shell and the sed command available on your system.
+Please read before contributing:
+- CONTRIBUTING: https://github.com/simdjson/simdjson/blob/master/CONTRIBUTING.md
+- HACKING: https://github.com/simdjson/simdjson/blob/master/HACKING.md
 
-If you plan to contribute to simdjson, please read our
 
-CONTRIBUTING guide: https://github.com/simdjson/simdjson/blob/master/CONTRIBUTING.md and our
-HACKING guide: https://github.com/simdjson/simdjson/blob/master/HACKING.md
+
+If you can, we recommend running our tests with the sanitizers turned on.
+For non-Visual Studio users, it is as easy as doing:
+
+
+
+```bash
+cmake -B build -D SIMDJSON_SANITIZE=ON -D SIMDJSON_DEVELOPER_MODE=ON
+cmake --build build
+ctest --test-dir build
+```
+
+
+Our CI checks, among other things, for trailing whitespace. If a test fails for that reason,
+use the "artifacts" button to download the artifact and inspect the problematic lines,
+or run `scripts/remove_trailing_whitespace.sh` locally if you have a bash shell and `sed`.
+
+
+Checklist before submitting
+- [ ] I added/updated tests covering my change (if applicable)
+- [ ] Code builds locally and passes my check
+- [ ] Documentation / README updated if needed
+- [ ] Commits are atomic and messages are clear
+- [ ] I linked the related issue (if applicable)
+
+Final notes
+- For large PRs, prefer smaller incremental PRs or request staged review.
+
+Thanks for the contribution!
+

.github/workflows/aarch64.yml

@@ -1,4 +1,4 @@
-name: Ubuntu ppc64le (GCC 11)
+name: Ubuntu aarch64 (GCC 13)
 
 on:
   push:

.github/workflows/documentation.yml

@@ -2,7 +2,13 @@ name: Doxygen GitHub Pages
 
 on:
   release:
-    types: [created]
+    # Trigger when a release object is created and when it's published.
+    # Some GitHub flows create a release object then publish it later; include both.
+    types: [created, published]
+  # Also trigger on tag creation pushes so releasing via Git tags still runs the workflow
+  push:
+    tags:
+      - "v*"  # common release tag pattern like v1.2.3
   # Allows you to run this workflow manually from the Actions tab
   workflow_dispatch:
 
@@ -27,7 +33,7 @@ jobs:
       - name: Generate Doxygen Documentation
         run: doxygen
       - name: Deploy to GitHub Pages
-        uses: peaceiris/actions-gh-pages@v3
+        uses: peaceiris/actions-gh-pages@v4
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: doc/api/html

.github/workflows/rvv-1024-clang-18.yml

@@ -0,0 +1,29 @@
+name: Ubuntu rvv VLEN=1024 (clang 18)
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  build:
+    runs-on: ubuntu-24.04
+    steps:
+    - uses: actions/checkout@v4
+    - name: Install packages
+      run: |
+        sudo apt-get update -q -y
+        sudo apt-get install -y cmake make g++-riscv64-linux-gnu qemu-user-static clang-18
+    - name: Build
+      run: |
+        CXX=clang++-18 CXXFLAGS="--target=riscv64-linux-gnu -march=rv64gcv_zvbb" \
+        cmake --toolchain=cmake/toolchains-ci/riscv64-linux-gnu.cmake -DCMAKE_BUILD_TYPE=Release -B build
+        cmake --build build/ -j$(nproc)
+    - name: Test VLEN=1024
+      run: |
+        export QEMU_LD_PREFIX="/usr/riscv64-linux-gnu"
+        export QEMU_CPU="rv64,v=on,zvbb=on,vlen=1024,rvv_ta_all_1s=on,rvv_ma_all_1s=on"
+        ctest --timeout 1800 --output-on-failure --test-dir build -j $(nproc)

.github/workflows/rvv-128-clang-17.yml

@@ -0,0 +1,29 @@
+name: Ubuntu rvv VLEN=128 (clang 17)
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  build:
+    runs-on: ubuntu-24.04
+    steps:
+    - uses: actions/checkout@v4
+    - name: Install packages
+      run: |
+        sudo apt-get update -q -y
+        sudo apt-get install -y cmake make g++-riscv64-linux-gnu qemu-user-static clang-17
+    - name: Build
+      run: |
+        CXX=clang++-17 CXXFLAGS="--target=riscv64-linux-gnu -march=rv64gcv" \
+        cmake --toolchain=cmake/toolchains-ci/riscv64-linux-gnu.cmake -DCMAKE_BUILD_TYPE=Release -B build
+        cmake --build build/ -j$(nproc)
+    - name: Test VLEN=128
+      run: |
+        export QEMU_LD_PREFIX="/usr/riscv64-linux-gnu"
+        export QEMU_CPU="rv64,v=on,vlen=128,rvv_ta_all_1s=on,rvv_ma_all_1s=on"
+        ctest --timeout 1800 --output-on-failure --test-dir build -j $(nproc)

.github/workflows/rvv-256-gcc-14.yml

@@ -0,0 +1,29 @@
+name: Ubuntu rvv VLEN=256 (gcc 14)
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  build:
+    runs-on: ubuntu-24.04
+    steps:
+    - uses: actions/checkout@v4
+    - name: Install packages
+      run: |
+        sudo apt-get update -q -y
+        sudo apt-get install -y cmake make g++-14-riscv64-linux-gnu qemu-user-static
+    - name: Build
+      run: |
+        CXX=riscv64-linux-gnu-g++-14 CXXFLAGS=-march=rv64gcv \
+        cmake --toolchain=cmake/toolchains-ci/riscv64-linux-gnu.cmake -DCMAKE_BUILD_TYPE=Release -B build
+        cmake --build build/ -j$(nproc)
+    - name: Test VLEN=256
+      run: |
+        export QEMU_LD_PREFIX="/usr/riscv64-linux-gnu"
+        export QEMU_CPU="rv64,v=on,zvbb=on,vlen=256,rvv_ta_all_1s=on,rvv_ma_all_1s=on"
+        ctest --timeout 1800 --output-on-failure --test-dir build -j $(nproc)

.github/workflows/ubuntu24-cxx20-noexcept.yml

@@ -0,0 +1,22 @@
+name: Ubuntu 24.04 CI (CXX 20, noexcept)
+
+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_EXCEPTIONS=OFF -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/ubuntu24-noexcept.yml

@@ -31,4 +31,4 @@ jobs:
           echo -e '#include <simdjson.h>\nint main(int argc,char**argv) {simdjson::dom::parser parser;simdjson::dom::element tweets = parser.load(argv[1]); }' > tmp.cpp && c++ -Idestination/include -Ldestination/lib -std=c++17 -Wl,-rpath,destination/lib -o linkandrun tmp.cpp -lsimdjson && ./linkandrun jsonexamples/twitter.json &&
           mkdir testfindpackage &&
           cd testfindpackage &&
-          echo -e 'cmake_minimum_required(VERSION 3.1)\nproject(simdjsontester)\nset(CMAKE_CXX_STANDARD 17)\nfind_package(simdjson REQUIRED)'> CMakeLists.txt && mkdir build && cd build && cmake -DCMAKE_INSTALL_PREFIX:PATH=../destination .. &&  cmake --build .
+          echo -e 'cmake_minimum_required(VERSION 3.14)\nproject(simdjsontester)\nset(CMAKE_CXX_STANDARD 17)\nfind_package(simdjson REQUIRED)'> CMakeLists.txt && mkdir build && cd build && cmake -DCMAKE_INSTALL_PREFIX:PATH=../destination .. &&  cmake --build .

.github/workflows/ubuntu24-nothread.yml

@@ -31,4 +31,4 @@ jobs:
           echo -e '#include <simdjson.h>\nint main(int argc,char**argv) {simdjson::dom::parser parser;simdjson::dom::element tweets = parser.load(argv[1]); }' > tmp.cpp && c++ -Idestination/include -Ldestination/lib -std=c++17 -Wl,-rpath,destination/lib -o linkandrun tmp.cpp -lsimdjson && ./linkandrun jsonexamples/twitter.json &&
           mkdir testfindpackage &&
           cd testfindpackage &&
-          echo -e 'cmake_minimum_required(VERSION 3.1)\nproject(simdjsontester)\nset(CMAKE_CXX_STANDARD 17)\nfind_package(simdjson REQUIRED)'> CMakeLists.txt && mkdir build && cd build && cmake -DCMAKE_INSTALL_PREFIX:PATH=../destination .. &&  cmake --build .
+          echo -e 'cmake_minimum_required(VERSION 3.14)\nproject(simdjsontester)\nset(CMAKE_CXX_STANDARD 17)\nfind_package(simdjson REQUIRED)'> CMakeLists.txt && mkdir build && cd build && cmake -DCMAKE_INSTALL_PREFIX:PATH=../destination .. &&  cmake --build .

.github/workflows/vs17-ci-sani.yml

@@ -0,0 +1,30 @@
+name: VS17-CI-SANITIZE
+
+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, shared: OFF, build_type: Debug}
+          - {gen: Visual Studio 17 2022, arch: x64, shared: OFF, build_type: Release}
+          - {gen: Visual Studio 17 2022, arch: x64, shared: OFF, build_type: RelWithDebInfo}
+    steps:
+    - name: checkout
+      uses: actions/checkout@v4
+    - name: Configure
+      run: |
+        cmake -G "${{matrix.gen}}" -A ${{matrix.arch}} -DSANITIZE=ON -DSIMDJSON_DEVELOPER_MODE=ON -DSIMDJSON_COMPETITION=OFF -DBUILD_SHARED_LIBS=${{matrix.shared}} -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

.vscode/settings.json

@@ -3,6 +3,9 @@
         {"column": 95 },
         {"column": 120 }
     ],
+    "cmake.configureArgs": [
+        "-DSIMDJSON_DEVELOPER_MODE=ON"
+    ],
     "files.trimTrailingWhitespace": true,
     "files.associations": {
         ".clangd": "yaml",

CMakeLists.txt

@@ -3,7 +3,7 @@ cmake_minimum_required(VERSION 3.14)
 project(
     simdjson
     # The version number is modified by tools/release.py
-    VERSION 4.0.0
+    VERSION 4.1.0
     DESCRIPTION "Parsing gigabytes of JSON per second"
     HOMEPAGE_URL "https://simdjson.org/"
     LANGUAGES CXX C

Doxyfile

@@ -38,7 +38,7 @@ PROJECT_NAME           = simdjson
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = "4.0.0"
+PROJECT_NUMBER         = "4.1.0"
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a

HACKING.md

@@ -20,13 +20,54 @@ If you plan to contribute to simdjson, please read our [CONTRIBUTING](https://gi
 Build Quickstart
 ------------------------------
 
+For non-Windows system,
+
 ```bash
-mkdir build
-cd build
-cmake -D SIMDJSON_DEVELOPER_MODE=ON ..
-cmake --build .
+cmake -B -D SIMDJSON_DEVELOPER_MODE=ON ..
+cmake --build build
+ctest --test-dir build
 ```
 
+It is similar for Visual Studio users, please see the CMake or Visual Studio documentation.
+
+By default the library is built in Release mode.
+
+
+Assertions and development checks
+------------------------------
+
+We do not use conventional `assert` in simdjson. Instead we use the macro
+`SIMDJSON_ASSUME`:
+
+```cpp
+SIMDJSON_ASSUME(something_that_is_true());
+```
+
+Sometimes, you need to do a bit more work that a simple check.
+The `SIMDJSON_DEVELOPMENT_CHECKS` macro is true only in Debug mode unless manually set.
+It is acceptable to add checks that you would not do in Release mode as long as
+they are guarded:
+
+```cpp
+#if SIMDJSON_DEVELOPMENT_CHECKS
+// do sanity checks here
+```
+
+
+Working with sanitizers
+------------------------------
+
+The simdjson library must be memory-safe. We cannot allow buffer overruns.
+During development, if you system supports it, we recommend configuring
+the project with `-D SIMDJSON_SANITIZE=ON`.
+
+```bash
+cmake -B -D SIMDJSON_SANITIZE=ON -D SIMDJSON_DEVELOPER_MODE=ON ..
+cmake --build build
+ctest --test-dir build
+```
+
+
 Design notes
 ------------------------------
 
@@ -103,12 +144,9 @@ simdjson's source structure, from the top level, looks like this:
     * generic/stage2/*.h: `simdjson::<implementation>::stage2` namespace. Generic implementation of the tape creator, which consumes the index from stage 1 and actually parses numbers and string and such. Used for the DOM interface.
 
 Other important files and directories:
-* **.drone.yml:** Definitions for Drone CI.
-* **.appveyor.yml:** Definitions for Appveyor CI (Windows).
-* **.circleci:** Definitions for Circle CI.
 * **.github/workflows:** Definitions for GitHub Actions (CI).
 * **singleheader:** Contains generated `simdjson.h` and `simdjson.cpp` that we release. The files `singleheader/simdjson.h` and `singleheader/simdjson.cpp` should never be edited by hand.
-* **singleheader/amalgamate.py:** Generates `singleheader/simdjson.h` and `singleheader/simdjson.cpp` for release (python script).
+* **singleheader/amalgamate.py:** Generates `singleheader/simdjson.h` and `singleheader/simdjson.cpp` for release (python script). If you add a new implementation (e.g., rvv), you need to edit this file (IMPLEMENTATIONS).
 * **benchmark:** This is where we do benchmarking. Benchmarking is core to every change we make; the
   cardinal rule is don't regress performance without knowing exactly why, and what you're trading
   for it. Many of our benchmarks are microbenchmarks. We are effectively doing controlled scientific experiments for the purpose of understanding what affects our performance. So we simplify as much as possible. We try to avoid irrelevant factors such as page faults, interrupts, unnecessary system calls. We recommend checking the performance as follows:

README.md

@@ -1,5 +1,3 @@
-
-[![Fuzzing Status](https://oss-fuzz-build-logs.storage.googleapis.com/badges/simdjson.svg)](https://bugs.chromium.org/p/oss-fuzz/issues/list?sort=-opened&can=1&q=proj:simdjson)
 [![][license img]][license] [![][licensemit img]][licensemit]
 
 
@@ -64,10 +62,14 @@ Real-world usage
 - [WasmEdge](https://wasmedge.org)
 - [RonDB](https://github.com/logicalclocks/rondb)
 - [GreptimeDB](https://github.com/GreptimeTeam/greptimedb)
+- [mamba](https://github.com/mamba-org/mamba)
 
 
 If you are planning to use simdjson in a product, please work from one of our releases.
 
+
+
+
 Quick Start
 -----------
 
@@ -84,7 +86,7 @@ The simdjson library is easily consumable with a single .h and .cpp file.
    ```
 2. Create `quickstart.cpp`:
 
-```c++
+```cpp
 #include <iostream>
 #include "simdjson.h"
 using namespace simdjson;
@@ -119,6 +121,7 @@ Godbolt
 -------------
 
 Some users may want to browse code along with the compiled assembly. You want to check out the following lists of examples:
+* [C++26 reflection example](https://godbolt.org/z/K3Px64TqK)
 * [simdjson examples with errors handled through exceptions](https://godbolt.org/z/7G5qE4sr9)
 * [simdjson examples with errors without exceptions](https://godbolt.org/z/e9dWb9E4v)
 
@@ -227,6 +230,13 @@ Contributing to simdjson
 Head over to [CONTRIBUTING.md](CONTRIBUTING.md) for information on contributing to simdjson, and
 [HACKING.md](HACKING.md) for information on source, building, and architecture/design.
 
+
+Stars
+------
+
+[![Star History Chart](https://api.star-history.com/svg?repos=simdjson/simdjson&type=Date)](https://www.star-history.com/#simdjson/simdjson&Date)
+
+
 License
 -------
 

benchmark/CMakeLists.txt

@@ -35,13 +35,16 @@ if (TARGET benchmark::benchmark)
   endif()
 endif()
 
-if(SIMDJSON_STATIC_REFLECTION)
-  add_subdirectory(static_reflect)
-endif(SIMDJSON_STATIC_REFLECTION)
-
 
 include(CheckCXXCompilerFlag)
 check_cxx_compiler_flag("-std=c++20" SIMDJSON_COMPILER_SUPPORTS_CXX20)
-if(SIMDJSON_EXCEPTIONS AND SIMDJSON_COMPILER_SUPPORTS_CXX20)
-  add_subdirectory(from)
-endif()
+if(SIMDJSON_STATIC_REFLECTION)
+  add_subdirectory(static_reflect)
+else()
+  if(SIMDJSON_EXCEPTIONS AND SIMDJSON_COMPILER_SUPPORTS_CXX20)
+    add_subdirectory(from)
+    add_subdirectory(car_builder)
+  endif()
+endif(SIMDJSON_STATIC_REFLECTION)
+
+

benchmark/accessor_performance/README.md

@@ -0,0 +1,46 @@
+# Accessor Performance Benchmarks (C++26)
+
+These benchmarks compare the performance of runtime vs compile-time JSON accessors.
+For the comparison to be meaningful, you must build simdjson with support for
+C++26 reflexion. See the `p2996` repository in the main project directory.
+
+## Files
+
+- `accessor_benchmark.h` - Common benchmark framework and test data
+- `runtime_accessors.h` - Runtime `at_path()` benchmarks
+- `compile_time_accessors.h` - Compile-time `at_path_compiled()` benchmarks (requires C++26 reflection)
+
+## Benchmarks
+
+Each benchmark measures parsing + single field access:
+
+1. **accessor_simple** - Simple field: `.name`
+2. **accessor_nested** - Nested field: `.address.city`
+3. **accessor_deep** - Deep nested field: `.address.coordinates.lat`
+
+## Building (Linux/macOS)
+
+```bash
+cmake -B build -D SIMDJSON_STATIC_REFLECTION=ON -DSIMDJSON_DEVELOPER_MODE=ON
+cmake --build build --target=bench_ondemand
+```
+
+The `SIMDJSON_STATIC_REFLECTION` will be made unnecessary once mainstream compilers
+begin supporting C++26 sufficiently well.
+
+## Running (Linux/macOS)
+
+
+```bash
+# Run all accessor benchmarks
+./build/bench_ondemand --benchmark_filter="accessor"
+```
+
+## Results
+
+We find that compile-time accessors show performance improvements that scale with path depth:
+- Simple fields: ~1.2x faster
+- Nested fields: ~1.5x faster
+- Deep nested fields: ~1.8x faster
+
+The speedup comes from eliminating runtime path parsing and conversion overhead.

benchmark/accessor_performance/accessor_benchmark.h

@@ -0,0 +1,132 @@
+#pragma once
+
+#include "json_benchmark/file_runner.h"
+#include <string>
+
+namespace accessor_performance {
+
+using namespace json_benchmark;
+
+// Test JSON for accessor benchmarks
+static const char* TEST_JSON = R"({
+  "name": "Alice",
+  "age": 30,
+  "email": "alice@example.com",
+  "address": {
+    "street": "123 Main St",
+    "city": "Boston",
+    "state": "MA",
+    "zip": 12345,
+    "coordinates": {
+      "lat": 42.3601,
+      "lon": -71.0589
+    }
+  },
+  "scores": [95, 87, 92, 88, 91],
+  "preferences": {
+    "theme": "dark",
+    "notifications": {
+      "email": true,
+      "push": false,
+      "sms": true
+    }
+  }
+})";
+
+// Struct definitions for compile-time validation
+#if SIMDJSON_STATIC_REFLECTION
+struct Coordinates {
+  double lat;
+  double lon;
+};
+
+struct Address {
+  std::string street;
+  std::string city;
+  std::string state;
+  int64_t zip;
+  Coordinates coordinates;
+};
+
+struct Notifications {
+  bool email;
+  bool push;
+  bool sms;
+};
+
+struct Preferences {
+  std::string theme;
+  Notifications notifications;
+};
+
+struct TestData {
+  std::string name;
+  int64_t age;
+  std::string email;
+  Address address;
+  std::vector<int64_t> scores;
+  Preferences preferences;
+};
+#endif // SIMDJSON_STATIC_REFLECTION
+
+// Single-access benchmark runner: measures ONE field access per iteration
+template<typename I>
+struct single_access_runner : public file_runner<I> {
+  std::string result_string;
+  int64_t result_int{};
+  double result_double{};
+  bool result_bool{};
+
+  bool setup(benchmark::State &state) {
+    this->json = simdjson::padded_string(TEST_JSON, strlen(TEST_JSON));
+    state.SetBytesProcessed(int64_t(state.iterations()) * int64_t(this->json.size()));
+    return true;
+  }
+
+  bool before_run(benchmark::State &state) {
+    if (!file_runner<I>::before_run(state)) { return false; }
+    result_string.clear();
+    result_int = 0;
+    result_double = 0.0;
+    result_bool = false;
+    return true;
+  }
+
+  bool run(benchmark::State &) {
+    return this->implementation.run(this->json, result_string, result_int, result_double, result_bool);
+  }
+
+  template<typename R>
+  bool diff(benchmark::State &state, single_access_runner<R> &reference) {
+    if (result_string != reference.result_string ||
+        result_int != reference.result_int ||
+        result_double != reference.result_double ||
+        result_bool != reference.result_bool) {
+      std::cerr << "Accessor benchmark results differ!" << std::endl;
+      return false;
+    }
+    return true;
+  }
+
+  size_t items_per_iteration() {
+    return 1;
+  }
+};
+
+// Benchmark template definitions
+struct runtime_at_path_simple;
+template<typename I> simdjson_inline static void accessor_simple(benchmark::State &state) {
+  run_json_benchmark<single_access_runner<I>, single_access_runner<runtime_at_path_simple>>(state);
+}
+
+struct runtime_at_path_nested;
+template<typename I> simdjson_inline static void accessor_nested(benchmark::State &state) {
+  run_json_benchmark<single_access_runner<I>, single_access_runner<runtime_at_path_nested>>(state);
+}
+
+struct runtime_at_path_deep;
+template<typename I> simdjson_inline static void accessor_deep(benchmark::State &state) {
+  run_json_benchmark<single_access_runner<I>, single_access_runner<runtime_at_path_deep>>(state);
+}
+
+} // namespace accessor_performance

benchmark/accessor_performance/compile_time_accessors.h

@@ -0,0 +1,56 @@
+#pragma once
+
+#if SIMDJSON_EXCEPTIONS && SIMDJSON_STATIC_REFLECTION
+
+#include "accessor_benchmark.h"
+
+namespace accessor_performance {
+
+using namespace simdjson;
+
+struct compile_time_at_path_simple {
+  ondemand::parser parser{};
+
+  bool run(simdjson::padded_string &json, std::string &result_str, int64_t&, double&, bool&) {
+    auto doc = parser.iterate(json);
+    std::string_view name;
+    auto r = ondemand::json_path::at_path_compiled<TestData, ".name">(doc);
+    if (r.get(name) != SUCCESS) return false;
+    result_str = name;
+    return true;
+  }
+};
+
+struct compile_time_at_path_nested {
+  ondemand::parser parser{};
+
+  bool run(simdjson::padded_string &json, std::string &result_str, int64_t&, double&, bool&) {
+    auto doc = parser.iterate(json);
+    std::string_view city;
+    auto r = ondemand::json_path::at_path_compiled<TestData, ".address.city">(doc);
+    if (r.get(city) != SUCCESS) return false;
+    result_str = city;
+    return true;
+  }
+};
+
+struct compile_time_at_path_deep {
+  ondemand::parser parser{};
+
+  bool run(simdjson::padded_string &json, std::string&, int64_t&, double &result_dbl, bool&) {
+    auto doc = parser.iterate(json);
+    double lat;
+    auto r = ondemand::json_path::at_path_compiled<TestData, ".address.coordinates.lat">(doc);
+    if (r.get(lat) != SUCCESS) return false;
+    result_dbl = lat;
+    return true;
+  }
+};
+
+BENCHMARK_TEMPLATE(accessor_simple, compile_time_at_path_simple)->UseManualTime();
+BENCHMARK_TEMPLATE(accessor_nested, compile_time_at_path_nested)->UseManualTime();
+BENCHMARK_TEMPLATE(accessor_deep, compile_time_at_path_deep)->UseManualTime();
+
+} // namespace accessor_performance
+
+#endif // SIMDJSON_EXCEPTIONS && SIMDJSON_STATIC_REFLECTION

benchmark/accessor_performance/runtime_accessors.h

@@ -0,0 +1,53 @@
+#pragma once
+
+#if SIMDJSON_EXCEPTIONS
+
+#include "accessor_benchmark.h"
+
+namespace accessor_performance {
+
+using namespace simdjson;
+
+struct runtime_at_path_simple {
+  ondemand::parser parser{};
+
+  bool run(simdjson::padded_string &json, std::string &result_str, int64_t&, double&, bool&) {
+    auto doc = parser.iterate(json);
+    std::string_view name;
+    if (doc.at_path(".name").get(name) != SUCCESS) return false;
+    result_str = name;
+    return true;
+  }
+};
+
+struct runtime_at_path_nested {
+  ondemand::parser parser{};
+
+  bool run(simdjson::padded_string &json, std::string &result_str, int64_t&, double&, bool&) {
+    auto doc = parser.iterate(json);
+    std::string_view city;
+    if (doc.at_path(".address.city").get(city) != SUCCESS) return false;
+    result_str = city;
+    return true;
+  }
+};
+
+struct runtime_at_path_deep {
+  ondemand::parser parser{};
+
+  bool run(simdjson::padded_string &json, std::string&, int64_t&, double &result_dbl, bool&) {
+    auto doc = parser.iterate(json);
+    double lat;
+    if (doc.at_path(".address.coordinates.lat").get(lat) != SUCCESS) return false;
+    result_dbl = lat;
+    return true;
+  }
+};
+
+BENCHMARK_TEMPLATE(accessor_simple, runtime_at_path_simple)->UseManualTime();
+BENCHMARK_TEMPLATE(accessor_nested, runtime_at_path_nested)->UseManualTime();
+BENCHMARK_TEMPLATE(accessor_deep, runtime_at_path_deep)->UseManualTime();
+
+} // namespace accessor_performance
+
+#endif // SIMDJSON_EXCEPTIONS

benchmark/bench_ondemand.cpp

@@ -148,4 +148,9 @@ SIMDJSON_POP_DISABLE_WARNINGS
 #include "large_amazon_cellphones/simdjson_dom.h"
 #include "large_amazon_cellphones/simdjson_ondemand.h"
 
+#include "accessor_performance/runtime_accessors.h"
+#if SIMDJSON_STATIC_REFLECTION
+#include "accessor_performance/compile_time_accessors.h"
+#endif
+
 BENCHMARK_MAIN();

benchmark/car_builder/CMakeLists.txt

@@ -0,0 +1,14 @@
+# Executable
+add_executable(benchmark_car_builder benchmark_car_builder.cpp)
+
+# Compile for C++20.
+target_compile_features(benchmark_car_builder PRIVATE cxx_std_20)
+
+# Check if -march=native is supported
+include(CheckCXXCompilerFlag)
+check_cxx_compiler_flag("-march=native" SIMDJSON_SUPPORTS_MARCH_NATIVE)
+if(SIMDJSON_SUPPORTS_MARCH_NATIVE)
+  target_compile_options(benchmark_car_builder PRIVATE -march=native)
+endif()
+
+target_include_directories(benchmark_car_builder PRIVATE ${CMAKE_CURRENT_LIST_DIR}/..)

benchmark/car_builder/benchmark_car_builder.cpp

@@ -0,0 +1,127 @@
+#include "event_counter.h"
+#include <random>
+#include <vector>
+
+#include <simdjson.h>
+
+event_collector collector;
+
+struct Car {
+  std::string make;
+  std::string model;
+  int64_t year; // We deliberately do not include the tire pressure.
+};
+
+std::vector<Car> generate_random_cars(size_t count) {
+  static const std::vector<std::string> makes = {"Toyota", "Honda", "Ford",
+                                                 "BMW", "Mazda"};
+  static const std::vector<std::string> models = {"Camry", "Civic", "Focus",
+                                                  "320i", "3"};
+  static thread_local std::mt19937 rng{std::random_device{}()};
+  std::uniform_int_distribution<int> make_dist(0, makes.size() - 1);
+  std::uniform_int_distribution<int> model_dist(0, models.size() - 1);
+  std::uniform_int_distribution<int64_t> year_dist(2000, 2025);
+  std::uniform_real_distribution<double> pressure_dist(30.0, 45.0);
+
+  std::vector<Car> cars;
+  cars.reserve(count);
+  for (size_t i = 0; i < count; ++i) {
+    Car car;
+    car.make = makes[make_dist(rng)];
+    car.model = models[model_dist(rng)];
+    car.year = year_dist(rng);
+    cars.push_back(std::move(car));
+  }
+  return cars;
+}
+
+std::string_view serialize(simdjson::builder::string_builder &sb,
+                           const std::vector<Car> &cars) {
+  sb.clear();
+  sb.start_array();
+  for (const auto &car : cars) {
+    sb.start_object();
+    sb.append_key_value("make", car.make);
+    sb.append_comma();
+    sb.append_key_value("model", car.model);
+    sb.append_comma();
+    sb.append_key_value("year", car.year);
+    sb.end_object();
+  }
+  sb.end_array();
+  std::string_view result;
+  if (sb.view().get(result)) {
+    return ""; // unexpected (error)
+  }
+  return result;
+}
+
+double pretty_print(const std::string &name, size_t num_chars,
+                    std::pair<event_aggregate, size_t> result) {
+  const auto &agg = result.first;
+  size_t N = result.second;
+  num_chars *= N;
+  printf("%-40s : %8.2f ns %8.2f GB/s", name.c_str(),
+         agg.elapsed_ns() / num_chars, num_chars / agg.elapsed_ns());
+  if (collector.has_events()) {
+    printf(" %8.2f GHz %8.2f cycles/char %8.2f ins./char %8.2f i/c",
+           agg.cycles() / agg.elapsed_ns(), agg.cycles() / num_chars,
+           agg.instructions() / num_chars, agg.instructions() / agg.cycles());
+  }
+  printf("\n");
+  return num_chars / agg.elapsed_ns();
+}
+
+template <class function_type>
+std::pair<event_aggregate, size_t>
+bench(const function_type &&function, size_t min_repeat = 100,
+      size_t min_time_ns = 40'000'000, size_t max_repeat = 10000000) {
+  size_t N = min_repeat;
+  if (N == 0) {
+    N = 1;
+  }
+  event_aggregate warm_aggregate{};
+  for (size_t i = 0; i < N; i++) {
+    std::atomic_thread_fence(std::memory_order_acquire);
+    collector.start();
+    function();
+    std::atomic_thread_fence(std::memory_order_release);
+    event_count allocate_count = collector.end();
+    warm_aggregate << allocate_count;
+    if ((i + 1 == N) && (warm_aggregate.total_elapsed_ns() < min_time_ns) &&
+        (N < max_repeat)) {
+      N *= 10;
+    }
+  }
+  event_aggregate aggregate{};
+  for (size_t i = 0; i < 10; i++) {
+    std::atomic_thread_fence(std::memory_order_acquire);
+    collector.start();
+    for (size_t i = 0; i < N; i++) {
+      function();
+    }
+    std::atomic_thread_fence(std::memory_order_release);
+    event_count allocate_count = collector.end();
+    aggregate << allocate_count;
+  }
+  return {aggregate, N};
+}
+
+void run_benchmarks() {
+  std::vector<Car> source = generate_random_cars(100000);
+  simdjson::builder::string_builder sb;
+  size_t volume = serialize(sb, source).size();
+
+  pretty_print("string_builder", volume, bench([&source, &sb]() -> size_t {
+                 return serialize(sb, source).size();
+               }));
+}
+
+int main() {
+  for (size_t trial = 0; trial < 3; trial++) {
+    printf("Trial %zu:\n", trial + 1);
+    run_benchmarks();
+    printf("\n");
+  }
+  return EXIT_SUCCESS;
+}

benchmark/distinct_user_id/yyjson.h

@@ -44,7 +44,10 @@ struct yyjson_base {
 
 struct yyjson : yyjson_base {
   bool run(simdjson::padded_string &json, std::vector<uint64_t> &result) {
-    return yyjson_base::run(yyjson_read(json.data(), json.size(), 0), result);
+    yyjson_doc *doc = yyjson_read(json.data(), json.size(), 0);
+    bool b = yyjson_base::run(doc, result);
+    yyjson_doc_free(doc);
+    return b;
   }
 };
 BENCHMARK_TEMPLATE(distinct_user_id, yyjson)->UseManualTime();
@@ -52,11 +55,15 @@ BENCHMARK_TEMPLATE(distinct_user_id, yyjson)->UseManualTime();
 #if SIMDJSON_COMPETITION_ONDEMAND_INSITU
 struct yyjson_insitu : yyjson_base {
   bool run(simdjson::padded_string &json, std::vector<uint64_t> &result) {
-    return yyjson_base::run(yyjson_read_opts(json.data(), json.size(), YYJSON_READ_INSITU, 0, 0), result);
+    yyjson_doc *doc = yyjson_read_opts(json.data(), json.size(), YYJSON_READ_INSITU, 0, 0);
+    bool b = yyjson_base::run(doc, result);
+    yyjson_doc_free(doc);
+    return b;
   }
 };
 BENCHMARK_TEMPLATE(distinct_user_id, yyjson_insitu)->UseManualTime();
 #endif // SIMDJSON_COMPETITION_ONDEMAND_INSITU
+
 } // namespace distinct_user_id
 
 #endif // SIMDJSON_COMPETITION_YYJSON

benchmark/find_tweet/yyjson.h

@@ -36,18 +36,26 @@ struct yyjson_base {
 
 struct yyjson : yyjson_base {
   bool run(simdjson::padded_string &json, uint64_t find_id, std::string_view &result) {
-    return yyjson_base::run(yyjson_read(json.data(), json.size(), 0), find_id, result);
+    yyjson_doc *doc = yyjson_read(json.data(), json.size(), 0);
+    bool b = yyjson_base::run(doc, find_id, result);
+    yyjson_doc_free(doc);
+    return b;
   }
 };
 BENCHMARK_TEMPLATE(find_tweet, yyjson)->UseManualTime();
+
 #if SIMDJSON_COMPETITION_ONDEMAND_INSITU
 struct yyjson_insitu : yyjson_base {
   bool run(simdjson::padded_string &json, uint64_t find_id, std::string_view &result) {
-    return yyjson_base::run(yyjson_read_opts(json.data(), json.size(), YYJSON_READ_INSITU, 0, 0), find_id, result);
+    yyjson_doc *doc = yyjson_read_opts(json.data(), json.size(), YYJSON_READ_INSITU, 0, 0);
+    bool b = yyjson_base::run(doc, find_id, result);
+    yyjson_doc_free(doc);
+    return b;
   }
 };
 BENCHMARK_TEMPLATE(find_tweet, yyjson_insitu)->UseManualTime();
 #endif // SIMDJSON_COMPETITION_ONDEMAND_INSITU
+
 } // namespace find_tweet
 
 #endif // SIMDJSON_COMPETITION_YYJSON

benchmark/from/CMakeLists.txt

@@ -2,8 +2,9 @@
 add_executable(from_benchmark from_benchmark.cpp)
 
 # Compile for C++20.
-target_compile_features(from_benchmark PRIVATE cxx_std_20)
-
+if(CMAKE_CXX_STANDARD LESS 20)
+  target_compile_features(from_benchmark PRIVATE cxx_std_20)
+endif()
 # Check if -march=native is supported
 include(CheckCXXCompilerFlag)
 check_cxx_compiler_flag("-march=native" SIMDJSON_SUPPORTS_MARCH_NATIVE)

benchmark/json2msgpack/yyjson.h

@@ -100,6 +100,7 @@ struct yyjson : yyjson2msgpack {
            std::string_view &result) {
     yyjson_doc *doc = yyjson_read(json.data(), json.size(), 0);
     result = to_msgpack(doc, reinterpret_cast<uint8_t*>(buffer));
+    yyjson_doc_free(doc);
     return true;
   }
 };
@@ -113,6 +114,7 @@ struct yyjson_insitu : yyjson2msgpack {
     yyjson_doc *doc =
         yyjson_read_opts(json.data(), json.size(), YYJSON_READ_INSITU, 0, 0);
     result = to_msgpack(doc, reinterpret_cast<uint8_t*>(buffer));
+    yyjson_doc_free(doc);
     return true;
   }
 };
@@ -120,4 +122,4 @@ BENCHMARK_TEMPLATE(json2msgpack, yyjson_insitu)->UseManualTime();
 #endif // SIMDJSON_COMPETITION_ONDEMAND_INSITU
 } // namespace json2msgpack
 
-#endif // SIMDJSON_COMPETITION_YYJSON
+#endif // SIMDJSON_COMPETITION_YYJSON

benchmark/kostya/yyjson.h

@@ -49,18 +49,26 @@ struct yyjson_base {
 
 struct yyjson : yyjson_base {
   bool run(simdjson::padded_string &json, std::vector<point> &result) {
-    return yyjson_base::run(yyjson_read(json.data(), json.size(), 0), result);
+    yyjson_doc *doc = yyjson_read(json.data(), json.size(), 0);
+    bool b = yyjson_base::run(doc, result);
+    yyjson_doc_free(doc);
+    return b;
   }
 };
 BENCHMARK_TEMPLATE(kostya, yyjson)->UseManualTime();
+
 #if SIMDJSON_COMPETITION_ONDEMAND_INSITU
 struct yyjson_insitu : yyjson_base {
   bool run(simdjson::padded_string &json, std::vector<point> &result) {
-    return yyjson_base::run(yyjson_read_opts(json.data(), json.size(), YYJSON_READ_INSITU, 0, 0), result);
+    yyjson_doc *doc = yyjson_read_opts(json.data(), json.size(), YYJSON_READ_INSITU, 0, 0);
+    bool b = yyjson_base::run(doc, result);
+    yyjson_doc_free(doc);
+    return b;
   }
 };
 BENCHMARK_TEMPLATE(kostya, yyjson_insitu)->UseManualTime();
 #endif // SIMDJSON_COMPETITION_ONDEMAND_INSITU
+
 } // namespace kostya
 
 #endif // SIMDJSON_COMPETITION_YYJSON

benchmark/large_random/yyjson.h

@@ -47,18 +47,26 @@ struct yyjson_base {
 
 struct yyjson : yyjson_base {
   bool run(simdjson::padded_string &json, std::vector<point> &result) {
-    return yyjson_base::run(yyjson_read(json.data(), json.size(), 0), result);
+    yyjson_doc *doc = yyjson_read(json.data(), json.size(), 0);
+    bool b = yyjson_base::run(doc, result);
+    yyjson_doc_free(doc);
+    return b;
   }
 };
 BENCHMARK_TEMPLATE(large_random, yyjson)->UseManualTime();
+
 #if SIMDJSON_COMPETITION_ONDEMAND_INSITU
 struct yyjson_insitu : yyjson_base {
   bool run(simdjson::padded_string &json, std::vector<point> &result) {
-    return yyjson_base::run(yyjson_read_opts(json.data(), json.size(), YYJSON_READ_INSITU, 0, 0), result);
+    yyjson_doc *doc = yyjson_read_opts(json.data(), json.size(), YYJSON_READ_INSITU, 0, 0);
+    bool b = yyjson_base::run(doc, result);
+    yyjson_doc_free(doc);
+    return b;
   }
 };
 BENCHMARK_TEMPLATE(large_random, yyjson_insitu)->UseManualTime();
 #endif // SIMDJSON_COMPETITION_ONDEMAND_INSITU
+
 } // namespace large_random
 
 #endif // SIMDJSON_COMPETITION_YYJSON

benchmark/partial_tweets/yyjson.h

@@ -62,19 +62,26 @@ struct yyjson_base {
 
 struct yyjson : yyjson_base {
   bool run(simdjson::padded_string &json, std::vector<tweet<std::string_view>> &result) {
-    return yyjson_base::run(yyjson_read(json.data(), json.size(), 0), result);
+    yyjson_doc *doc = yyjson_read(json.data(), json.size(), 0);
+    bool b = yyjson_base::run(doc, result);
+    yyjson_doc_free(doc);
+    return b;
   }
 };
 BENCHMARK_TEMPLATE(partial_tweets, yyjson)->UseManualTime();
+
 #if SIMDJSON_COMPETITION_ONDEMAND_INSITU
 struct yyjson_insitu : yyjson_base {
   bool run(simdjson::padded_string &json, std::vector<tweet<std::string_view>> &result) {
-    return yyjson_base::run(yyjson_read_opts(json.data(), json.size(), YYJSON_READ_INSITU, 0, 0), result);
+    yyjson_doc *doc = yyjson_read_opts(json.data(), json.size(), YYJSON_READ_INSITU, 0, 0);
+    bool b = yyjson_base::run(doc, result);
+    yyjson_doc_free(doc);
+    return b;
   }
 };
 BENCHMARK_TEMPLATE(partial_tweets, yyjson_insitu)->UseManualTime();
 #endif // SIMDJSON_COMPETITION_ONDEMAND_INSITU
+
 } // namespace partial_tweets
 
 #endif // SIMDJSON_COMPETITION_YYJSON
-

benchmark/static_reflect/CMakeLists.txt

@@ -6,38 +6,42 @@ CPMAddPackage(
   EXCLUDE_FROM_ALL YES
 )
 
+option(SIMDJSON_USE_RUST "Build the static_reflect benchmark" OFF)
 
-
-if(NOT WIN32)
-# We want the check whether Rust is available before trying to build a crate.
-CPMAddPackage(
-  NAME corrosion
-  GITHUB_REPOSITORY corrosion-rs/corrosion
-  VERSION 0.4.4
-  DOWNLOAD_ONLY ON
-  OPTIONS "Rust_FIND_QUIETLY OFF"
-)
-include("${corrosion_SOURCE_DIR}/cmake/FindRust.cmake")
-endif()
-
-if(RUST_FOUND)
-  message(STATUS "Rust found: " ${Rust_VERSION} )
-  add_subdirectory("${corrosion_SOURCE_DIR}" "${PROJECT_BINARY_DIR}/_deps/corrosion" EXCLUDE_FROM_ALL)
-  # Important: we want to build in release mode!
-  corrosion_import_crate(MANIFEST_PATH "serde-benchmark/Cargo.toml" NO_LINKER_OVERRIDE PROFILE release)
-else()
-  message(STATUS "Rust/Cargo is unavailable." )
-  message(STATUS "We will not benchmark serde-benchmark." )
-  if (${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
-    message(STATUS "Under macOS, you may be able to install rust with")
-    message(STATUS "curl https://sh.rustup.rs -sSf | sh")
-  elseif(CMAKE_SYSTEM_NAME STREQUAL "Linux")
-    message(STATUS "Under Linux, you may be able to install rust with a command such as")
-    message(STATUS "apt-get install cargo" )
-    message(STATUS "or" )
-    message(STATUS "curl https://sh.rustup.rs -sSf | sh")
+if(SIMDJSON_USER_RUST)
+  if(NOT WIN32)
+  # We want the check whether Rust is available before trying to build a crate.
+  CPMAddPackage(
+    NAME corrosion
+    GITHUB_REPOSITORY corrosion-rs/corrosion
+    VERSION 0.4.4
+    DOWNLOAD_ONLY ON
+    OPTIONS "Rust_FIND_QUIETLY OFF"
+  )
+  include("${corrosion_SOURCE_DIR}/cmake/FindRust.cmake")
   endif()
-endif()
+
+  if(RUST_FOUND)
+    message(STATUS "Rust found: " ${Rust_VERSION} )
+    add_subdirectory("${corrosion_SOURCE_DIR}" "${PROJECT_BINARY_DIR}/_deps/corrosion" EXCLUDE_FROM_ALL)
+    # Important: we want to build in release mode!
+    corrosion_import_crate(MANIFEST_PATH "serde-benchmark/Cargo.toml" NO_LINKER_OVERRIDE PROFILE release)
+  else()
+    message(STATUS "Rust/Cargo is unavailable." )
+    message(STATUS "We will not benchmark serde-benchmark." )
+    if (${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
+      message(STATUS "Under macOS, you may be able to install rust with")
+      message(STATUS "curl https://sh.rustup.rs -sSf | sh")
+    elseif(CMAKE_SYSTEM_NAME STREQUAL "Linux")
+      message(STATUS "Under Linux, you may be able to install rust with a command such as")
+      message(STATUS "apt-get install cargo" )
+      message(STATUS "or" )
+      message(STATUS "curl https://sh.rustup.rs -sSf | sh")
+    endif()
+  endif()
+else(SIMDJSON_USER_RUST)
+  message(STATUS "We will not benchmark serde-benchmark." )
+endif(SIMDJSON_USER_RUST)
 
 # Add the benchmark executable targets
 add_subdirectory(twitter_benchmark)

benchmark/top_tweet/yyjson.h

@@ -51,18 +51,26 @@ struct yyjson_base {
 
 struct yyjson : yyjson_base {
   bool run(simdjson::padded_string &json, int64_t max_retweet_count, top_tweet_result<StringType> &result) {
-    return yyjson_base::run(yyjson_read(json.data(), json.size(), 0), max_retweet_count, result);
+    yyjson_doc *doc = yyjson_read(json.data(), json.size(), 0);
+    bool b = yyjson_base::run(doc, max_retweet_count, result);
+    yyjson_doc_free(doc);
+    return b;
   }
 };
 BENCHMARK_TEMPLATE(top_tweet, yyjson)->UseManualTime();
+
 #if SIMDJSON_COMPETITION_ONDEMAND_INSITU
 struct yyjson_insitu : yyjson_base {
   bool run(simdjson::padded_string &json, int64_t max_retweet_count, top_tweet_result<StringType> &result) {
-    return yyjson_base::run(yyjson_read_opts(json.data(), json.size(), YYJSON_READ_INSITU, 0, 0), max_retweet_count, result);
+    yyjson_doc *doc = yyjson_read_opts(json.data(), json.size(), YYJSON_READ_INSITU, 0, 0);
+    bool b = yyjson_base::run(doc, max_retweet_count, result);
+    yyjson_doc_free(doc);
+    return b;
   }
 };
 BENCHMARK_TEMPLATE(top_tweet, yyjson_insitu)->UseManualTime();
 #endif // SIMDJSON_COMPETITION_ONDEMAND_INSITU
+
 } // namespace top_tweet
 
 #endif // SIMDJSON_COMPETITION_YYJSON

cmake/developer-options.cmake

@@ -4,7 +4,7 @@
 add_library(simdjson-internal-flags INTERFACE)
 if(NOT DEFINED CMAKE_POSITION_INDEPENDENT_CODE)
   # We default to ON for all targets, so that we can use the library in shared libraries.
-  set_target_properties(simdjson-internal-flags PROPERTIES POSITION_INDEPENDENT_CODE ON)
+  set_target_properties(simdjson-internal-flags PROPERTIES INTERFACE_POSITION_INDEPENDENT_CODE ON)
 endif(NOT DEFINED CMAKE_POSITION_INDEPENDENT_CODE)
 
 option(SIMDJSON_CHECK_EOF "Check for the end of the input buffer. The setting is unnecessary since we require padding of the inputs. You should expect tests to fail with this option turned on." OFF)
@@ -32,6 +32,9 @@ undefined behavior.")
     link_libraries(
         -fsanitize=address -fno-omit-frame-pointer -fno-sanitize-recover=all
     )
+  elseif (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
+    add_compile_options(-fsanitize=address)
+    link_libraries(-fsanitize=address)
   else()
     message(
         STATUS
@@ -171,6 +174,10 @@ else()
       -Werror -Wall -Wextra -Weffc++ -Wsign-compare -Wshadow -Wwrite-strings
       -Wpointer-arith -Winit-self -Wconversion -Wno-sign-conversion
   )
+  if(CMAKE_CXX_STANDARD VERSION_GREATER_EQUAL 20)
+    target_compile_options(simdjson-internal-flags INTERFACE -Wctad-maybe-unsupported)
+  endif()
+
 endif()
 
 option(SIMDJSON_GLIBCXX_ASSERTIONS "Set _GLIBCXX_ASSERTIONS" OFF)

cmake/toolchains-ci/riscv64-linux-gnu.cmake

@@ -0,0 +1,4 @@
+set(CMAKE_SYSTEM_NAME Linux)
+set(CMAKE_SYSTEM_PROCESSOR riscv64)
+
+set(CMAKE_CROSSCOMPILING_EMULATOR "qemu-riscv64-static")

doc/basics_doxygen.md

@@ -1,5 +1,8 @@
 We take our documentation seriously. Please start reading the documentation before you attempt to use simdjson. We hope you will enjoy reading us.
 
-* Basics: https://github.com/simdjson/simdjson/blob/master/doc/basics.md is an overview of how to use simdjson and its APIs.
-* iterate_many: https://github.com/simdjson/simdjson/blob/master/doc/iterate_many.md describes an interface providing features to work with files or streams containing multiple small JSON documents. As fast and convenient as possible.
-* Performance: https://github.com/simdjson/simdjson/blob/master/doc/performance.md shows some more advanced scenarios and how to tune for them.
+* [Basics](doc/basics.md) is an overview of how to use simdjson and its APIs.
+* [Builder](doc/builder.md) is an overview of how to efficiently write JSON strings using simdjson.
+* [Performance](doc/performance.md) shows some more advanced scenarios and how to tune for them.
+* [Implementation Selection](doc/implementation-selection.md) describes runtime CPU detection and
+  how you can work with it.
+* [API](https://simdjson.github.io/simdjson/) contains the automatically generated API documentation.

doc/builder.md

@@ -34,32 +34,33 @@ It has the following methods to add content to the string:
 - `append_null()`: Appends the string "null" to the JSON buffer.
 - `clear()`: Clears the contents of the JSON buffer, resetting the position to 0 while retaining the allocated capacity.
 - `escape_and_append(std::string_view input)`: Appends a string view to the JSON buffer after escaping special characters (e.g., quotes, backslashes) as required by JSON.
-- `escape_and_append_with_quotes(std::string_view input)` Appends a string view surrounded by double quotes (e.g., "input") to the JSON buffer after escaping special characters.
-Parameters:
+- `escape_and_append_with_quotes(std::string_view input)` Appends a string view surrounded by double quotes (e.g., "input") to the JSON buffer after escaping special characters. For constant strings, you may also do `escape_and_append_with_quotes<"mystring">()`.
 - `escape_and_append_with_quotes(char input)`: Appends a single character surrounded by double quotes (e.g., "c") to the JSON buffer after escaping it if necessary.
 - `append_raw(const char *c)`: Appends a null-terminated C string directly to the JSON buffer without escaping.
 - `append_raw(std::string_view input)`: Appends a string view directly to the JSON buffer without escaping.
 - `append_raw(const char *str, size_t len)`: Appends a specified number of characters from a C string directly to the JSON
+- `append_key_value(key,value)`: Appends a key and a value (`"json":somevalue`)
+- `append_key_value<"mykey">(value)`: Appends a key and a value (`"json":somevalue`), useful when the key is a compile-time constant (C++20).
 
-After writting the content, if you have reasons to believe that the content might violate UTF-8 conventions, you can check it as follows:
+After writing the content, if you have reasons to believe that the content might violate UTF-8 conventions, you can check it as follows:
 
 - `validate_unicode()`: Checks if the content in the JSON buffer is valid UTF-8. Returns: true if the content is valid UTF-8, false otherwise.
 
 You might need to do unicode validation if you have strings in your data structures containing
-malformed UTF-8.
+malformed UTF-8. Note that we do not automatically call `validate_unicode()`.
 
 Once you are satisfied, you can recover the string as follows:
 
 - `operator std::string()`: Converts the JSON buffer to an std::string. (Might throw if an error occurred.)
 - `operator std::string_view()`: Converts the JSON buffer to an std::string_view.  (Might throw if an error occurred.)
-- `view()`: Returns a view of the written JSON buffer as a `simdjson_result<std::string_view>`.
+- `view()`: Returns a view of the written JSON buffer as a `simdjson_result<std::string_view>` (C++20).
 
-The later method (`view()`) is recommended.
+The later method (`view()`) is recommended.  For performance reasons, we expect you to explicitly call `validate_unicode()` as needed (e.g., prior to calling `view()`).
 
 Example: string_builder
 ---------------------------
 
-```C++
+```cpp
 struct Car {
     std::string make;
     std::string model;
@@ -131,20 +132,20 @@ In all cases, the `std::string_view` instance depends the corresponding `string_
 
 
 
-If you have C++20, you can simplify the code, as the `std::vector<double>` is automatically
-supported.
+If you have C++20, you can simplify the code, as the `std::vector<double>` is automatically supported. Further, we can pass the keys (which are compile-time
+constant) as template parameter (for improved performance).
 
 ```cpp
     Car c = {"Toyota", "Corolla", 2017, {30.0,30.2,30.513,30.79}};
     simdjson::builder::string_builder sb;
     sb.start_object();
-    sb.append_key_value("make", c.make);
+    sb.append_key_value<"make">(c.make);
     sb.append_comma();
-    sb.append_key_value("model", c.model);
+    sb.append_key_value<"model">(c.model);
     sb.append_comma();
-    sb.append_key_value("year", c.year);
+    sb.append_key_value<"year">(c.year);
     sb.append_comma();
-    sb.append_key_value("tire_pressure", c.tire_pressure);
+    sb.append_key_value<"tire_pressure">(c.tire_pressure);
     sb.end_object();
     std::string_view p = sb.view();
 ```
@@ -175,9 +176,52 @@ std::vector<std::vector<double>> c = {{1.0, 2.0}, {3.0, 4.0}};
 std::string json = simdjson::to_json(c);
 ```
 
+We also have an overload for when you want to reuse the same `std::string` instance:
+
+
+```cpp
+std::vector<std::vector<double>> c = {{1.0, 2.0}, {3.0, 4.0}};
+std::string json;
+auto error = simdjson::to_json(c, json);
+if(error) { /* there was an error */ }
+```
+
+
 We do recommend that you create and reuse the `string_builder` instance for performance
 reasons.
 
+You can also add custom serialization functions using a `tag_invoke` function.
+For example, the following
+function will allow you to serialize instances of the type `Car`.
+
+```cpp
+#include <simdjson>
+
+struct Car {
+  std::string make;
+  std::string model;
+  int64_t year;
+  std::vector<float> tire_pressure;
+};
+
+namespace simdjson {
+
+template <typename builder_type>
+void tag_invoke(serialize_tag, builder_type &builder, const Car& car) {
+  builder.start_object();
+  builder.append_key_value("make", car.make);
+  builder.append_comma();
+  builder.append_key_value("model", car.model);
+  builder.append_comma();
+  builder.append_key_value("year", car.year);
+  builder.append_comma();
+  builder.append_key_value("tire_pressure", car.tire_pressure);
+  builder.end_object();
+}
+
+} // namespace simdjson
+```
+
 C++26 static reflection
 ------------------------
 
@@ -239,7 +283,38 @@ with the `simdjson::to_json` template function.
 If you know the output size, in bytes, of your JSON string, you may
 pass it as a second parameter (e.g., `simdjson::to_json(c, 31123)`).
 
+Sometimes you may want to reuse the same `std::string` instance. We
+have an overload for this purpose:
 
+```cpp
+Car c = {"Toyota", "Corolla", 2017, {30.0,30.2,30.513,30.79}};
+std::string s;
+auto error = simdjson::to_json(c, s);
+if(error) { /* there was an error */ }
+```
+
+You can then also add a third parameter for the expected output size in bytes.
+
+### Extracting just some fields
+In some instances, your class might have many fields that you do not want to serialize.
+You can achieve this result with the `simdjson::extract_from` template. In the following
+example, we serialize only the `year` and `price` fields on the `Car` instance.
+```cpp
+struct Car {
+    std::string make;
+    std::string model;
+    int year;
+    double price;
+    bool electric;
+};
+Car car{"Ford", "F-150", 2024, 55000.0, false};
+// Extract year and price
+std::string json_result = simdjson::extract_from<"year", "price">(car);
+// Alternatively:
+// std::string json_result;
+// auto error =  extract_from<"year", "price">(car).get(json_result);
+// if(error) { /* error handling */ }
+```
 
 ### Without `string_buffer` instance but with explicit error handling
 
@@ -248,9 +323,44 @@ pattern:
 
 ```cpp
   std::string json;
-  if(simdjson::to(c).get(json)) {
+  if(simdjson::to_json(c).get(json)) {
     // there was an error
   } else {
     // json contain the serialized JSON
   }
+```
+
+### Customization
+
+If you want to serialize a value in a custome way, you can do it with a
+`tag_invoke` specialization like the following example which will map
+the year attribute to a string.
+
+
+```cpp
+#include <simdjson>
+
+struct Car {
+  std::string make;
+  std::string model;
+  int64_t year;
+  std::vector<float> tire_pressure;
+};
+
+namespace simdjson {
+
+template <typename builder_type>
+void tag_invoke(serialize_tag, builder_type &builder, const Car& car) {
+  builder.start_object();
+  builder.append_key_value("make", car.make);
+  builder.append_comma();
+  builder.append_key_value("model", car.model);
+  builder.append_comma();
+  builder.append_key_value("year", std::to_string(car.year));
+  builder.append_comma();
+  builder.append_key_value("tire_pressure", car.tire_pressure);
+  builder.end_object();
+}
+
+} // namespace simdjson
 ```

doc/compile_time_accessors.md

@@ -0,0 +1,444 @@
+# Compile-Time JSONPath and JSON Pointer Accessors
+
+**Note:** This feature requires C++26 Static Reflection support (P2996) and is currently only available with experimental compilers. You must enable it with `-DSIMDJSON_STATIC_REFLECTION=ON` when building.
+
+## Overview
+
+simdjson provides compile-time JSONPath and JSON Pointer accessors that validate paths against struct definitions at compile time and generate optimized accessor code with zero runtime overhead. This combines the safety of compile-time type checking with the performance of pre-parsed, pre-validated access paths.
+
+## Requirements
+
+- C++26 compiler with Static Reflection support (P2996)
+- Experimental compiler flags:
+  - Clang with P2996 support: `-std=c++26 -freflection -fexpansion-statements`
+- Build configuration: `-DSIMDJSON_STATIC_REFLECTION=ON`
+
+## How It Works
+
+**Compile Time:**
+1. Path string is parsed and converted to access steps
+2. Path is validated against struct definition using reflection
+3. Field types are checked and verified
+4. Optimized accessor code is generated
+
+**Runtime:**
+- Direct navigation with no parsing
+- No validation overhead
+- No string comparisons for path components
+- Type-safe extraction
+
+## Two Usage Modes
+
+### Mode 1: With Type Validation (Recommended)
+
+When you provide a struct type, the compiler validates the entire path at compile time:
+
+```cpp
+struct User {
+  std::string name;
+  int age;
+  std::vector<std::string> emails;
+};
+
+const padded_string json = R"({
+  "name": "Alice",
+  "age": 30,
+  "emails": ["alice@example.com", "alice@work.com"]
+})"_padded;
+
+ondemand::parser parser;
+auto doc = parser.iterate(json);
+
+// Compile-time validation: checks that User has "name" field of type std::string
+std::string name;
+auto result = ondemand::json_path::at_path_compiled<User, ".name">(doc);
+result.get(name); // name = "Alice"
+
+// Compile-time validation: checks that "emails" is array-like with string elements
+std::string email;
+result = ondemand::json_path::at_path_compiled<User, ".emails[0]">(doc);
+result.get(email); // email = "alice@example.com"
+```
+
+**Benefits:**
+- **Compile-time errors** if path doesn't exist in struct
+- **Type safety** - verifies field types match expected types
+- **Refactoring protection** - renaming struct fields causes compile errors
+
+**What gets validated:**
+- Field existence
+- Field types
+- Array/container access validity
+- Nested struct navigation
+
+### Mode 2: Without Validation
+
+When you omit the struct type, the path is parsed at compile time but not validated:
+
+```cpp
+const padded_string json = R"({
+  "name": "Alice",
+  "age": 30,
+  "address": {"city": "Boston"}
+})"_padded;
+
+ondemand::parser parser;
+auto doc = parser.iterate(json);
+
+// No compile-time validation - path is only parsed
+std::string name;
+auto result = ondemand::json_path::at_path_compiled<".name">(doc);
+result.get(name); // name = "Alice"
+
+std::string_view city;
+result = ondemand::json_path::at_path_compiled<".address.city">(doc);
+result.get(city); // city = "Boston"
+```
+
+**Benefits:**
+- Works with dynamic/unknown JSON structures
+- Still benefits from compile-time path parsing
+- No runtime string parsing overhead
+
+**Use when:**
+- JSON structure is not known at compile time
+- Working with varied JSON schemas
+- Prototyping or exploratory parsing
+
+## JSONPath Syntax
+
+JSONPath uses dot notation and bracket notation for field access:
+
+### Supported Syntax
+
+| Syntax | Description | Example |
+|--------|-------------|---------|
+| `.field` | Dot notation for field access | `.name`, `.address.city` |
+| `["field"]` | Bracket notation with quotes | `["name"]`, `["address"]["city"]` |
+| `[index]` | Array index access | `[0]`, `[1]` |
+| Mixed | Combination of notations | `.emails[0]`, `["users"][0].name` |
+| `$` prefix | Optional root indicator | `$.name`, `$["name"]` |
+
+### Examples
+
+```cpp
+struct Address {
+  std::string city;
+  int zip;
+};
+
+struct Person {
+  std::string name;
+  int age;
+  Address address;
+  std::vector<std::string> emails;
+};
+
+// Dot notation
+at_path_compiled<Person, ".name">(doc)
+at_path_compiled<Person, ".address.city">(doc)
+
+// Bracket notation
+at_path_compiled<Person, "[\"name\"]">(doc)
+at_path_compiled<Person, "[\"address\"][\"city\"]">(doc)
+
+// Array access
+at_path_compiled<Person, ".emails[0]">(doc)
+at_path_compiled<Person, ".emails[1]">(doc)
+
+// Mixed notation
+at_path_compiled<Person, ".address[\"zip\"]">(doc)
+at_path_compiled<Person, "[\"emails\"][0]">(doc)
+
+// With root indicator
+at_path_compiled<Person, "$.name">(doc)
+at_path_compiled<Person, "$.address.city">(doc)
+```
+
+## JSON Pointer Syntax
+
+JSON Pointer (RFC 6901) uses slash-separated paths:
+
+### Supported Syntax
+
+| Syntax | Description | Example |
+|--------|-------------|---------|
+| `/field` | Field access | `/name`, `/address/city` |
+| `/index` | Array index | `/0`, `/1` |
+| `~0` | Escaped `~` | `/field~0name` → field~name |
+| `~1` | Escaped `/` | `/field~1name` → field/name |
+
+### Examples
+
+```cpp
+struct Car {
+  std::string make;
+  std::string model;
+  int64_t year;
+  std::vector<double> tire_pressure;
+};
+
+// Field access
+at_pointer_compiled<Car, "/make">(doc)
+at_pointer_compiled<Car, "/model">(doc)
+
+// Array access
+at_pointer_compiled<Car, "/tire_pressure/0">(doc)
+at_pointer_compiled<Car, "/tire_pressure/1">(doc)
+
+// Root pointer (returns whole document)
+at_pointer_compiled<Car, "">(doc)
+at_pointer_compiled<Car, "/">(doc)
+```
+
+## API Reference
+
+### JSONPath Functions
+
+```cpp
+// With type validation
+template<typename T, constevalutil::fixed_string Path, typename DocOrValue>
+simdjson_result<value> at_path_compiled(DocOrValue& doc_or_val);
+
+// Without validation
+template<constevalutil::fixed_string Path, typename DocOrValue>
+simdjson_result<value> at_path_compiled(DocOrValue& doc_or_val);
+```
+
+### JSON Pointer Functions
+
+```cpp
+// With type validation
+template<typename T, constevalutil::fixed_string Pointer, typename DocOrValue>
+simdjson_result<value> at_pointer_compiled(DocOrValue& doc_or_val);
+
+// Without validation
+template<constevalutil::fixed_string Pointer, typename DocOrValue>
+simdjson_result<value> at_pointer_compiled(DocOrValue& doc_or_val);
+```
+
+### Direct Field Extraction
+
+Extract values directly into variables with compile-time type checking:
+
+```cpp
+// JSONPath
+template<typename T, constevalutil::fixed_string Path>
+struct path_accessor {
+  template<typename DocOrValue, typename FieldType>
+  static error_code extract_field(DocOrValue& doc_or_val, FieldType& target);
+};
+
+// JSON Pointer
+template<typename T, constevalutil::fixed_string Pointer>
+struct pointer_accessor {
+  template<typename DocOrValue, typename FieldType>
+  static error_code extract_field(DocOrValue& doc_or_val, FieldType& target);
+};
+```
+
+**Example:**
+
+```cpp
+struct User {
+  std::string name;
+  int age;
+};
+
+ondemand::parser parser;
+auto doc = parser.iterate(json);
+
+// Extract directly into variable
+std::string name;
+ondemand::json_path::path_accessor<User, ".name">::extract_field(doc, name);
+
+int age;
+ondemand::json_path::pointer_accessor<User, "/age">::extract_field(doc, age);
+```
+
+The compiler verifies that the target variable type matches the field type at the path.
+
+## Complete Examples
+
+### Example 1: Validated Access
+
+```cpp
+#include "simdjson.h"
+using namespace simdjson;
+
+struct Car {
+  std::string make;
+  std::string model;
+  int64_t year;
+  std::vector<double> tire_pressure;
+};
+
+int main() {
+  const padded_string json = R"({
+    "make": "Toyota",
+    "model": "Camry",
+    "year": 2018,
+    "tire_pressure": [40.1, 39.9, 37.7, 40.4]
+  })"_padded;
+
+  ondemand::parser parser;
+  auto doc = parser.iterate(json);
+
+  // Type-validated access
+  std::string make;
+  auto result = ondemand::json_path::at_path_compiled<Car, ".make">(doc);
+  result.get(make); // make = "Toyota"
+
+  // Array access with validation
+  double pressure;
+  result = ondemand::json_path::at_path_compiled<Car, ".tire_pressure[1]">(doc);
+  result.get(pressure); // pressure = 39.9
+
+  return 0;
+}
+```
+
+### Example 2: Non-Validated Access
+
+```cpp
+#include "simdjson.h"
+using namespace simdjson;
+
+int main() {
+  const padded_string json = R"({
+    "user": {
+      "name": "Alice",
+      "preferences": {
+        "theme": "dark",
+        "notifications": true
+      }
+    }
+  })"_padded;
+
+  ondemand::parser parser;
+  auto doc = parser.iterate(json);
+
+  // No validation - works with any JSON structure
+  std::string_view theme;
+  auto result = ondemand::json_path::at_path_compiled<".user.preferences.theme">(doc);
+  result.get(theme); // theme = "dark"
+
+  bool notifications;
+  result = ondemand::json_path::at_path_compiled<".user.preferences.notifications">(doc);
+  result.get(notifications); // notifications = true
+
+  return 0;
+}
+```
+
+### Example 3: Direct Extraction
+
+```cpp
+#include "simdjson.h"
+using namespace simdjson;
+
+struct Person {
+  std::string name;
+  int age;
+  std::vector<std::string> emails;
+};
+
+int main() {
+  const padded_string json = R"({
+    "name": "Bob",
+    "age": 25,
+    "emails": ["bob@example.com", "bob@work.com"]
+  })"_padded;
+
+  ondemand::parser parser;
+  auto doc = parser.iterate(json);
+
+  // Extract with type validation
+  std::string name;
+  ondemand::json_path::path_accessor<Person, ".name">::extract_field(doc, name);
+  // name = "Bob"
+
+  int age;
+  ondemand::json_path::pointer_accessor<Person, "/age">::extract_field(doc, age);
+  // age = 25
+
+  std::string email;
+  ondemand::json_path::path_accessor<Person, ".emails[0]">::extract_field(doc, email);
+  // email = "bob@example.com"
+
+  return 0;
+}
+```
+
+## Error Handling
+
+Compile-time errors occur when:
+- Path doesn't exist in struct: `static_assert` failure
+- Field type mismatch: `static_assert` failure
+- Invalid array access on non-array field: `static_assert` failure
+
+Runtime errors occur when:
+- JSON structure doesn't match expected structure
+- Array index out of bounds
+- Type conversion failures
+
+```cpp
+struct User {
+  std::string name;
+  int age;
+};
+
+// Compile-time error: no "email" field in User
+// auto result = ondemand::json_path::at_path_compiled<User, ".email">(doc);
+
+// Compile-time error: age is not an array
+// auto result = ondemand::json_path::at_path_compiled<User, ".age[0]">(doc);
+
+// Runtime error if JSON doesn't have "name" field
+auto result = ondemand::json_path::at_path_compiled<User, ".name">(doc);
+std::string name;
+if (result.get(name) != SUCCESS) {
+  // Handle error
+}
+```
+
+## Performance
+
+Compile-time accessors provide:
+- **Zero path parsing overhead** - paths parsed at compile time
+- **Zero validation overhead** - validation done at compile time
+- **Direct field access** - no runtime path traversal
+- **Type-safe extraction** - no dynamic type checking
+
+Compared to runtime `at_path()` and `at_pointer()`:
+- Eliminates runtime path string parsing
+- Eliminates runtime path validation
+- Generates optimal code path directly
+
+## Limitations
+
+- Requires C++26 compiler with P2996 support (experimental)
+- Paths must be compile-time constants (string literals)
+- Cannot use runtime-computed paths
+- Limited to struct types that support reflection
+- Array indices must be compile-time constants in the path
+
+## When to Use
+
+**Use compile-time accessors when:**
+- You have well-defined struct types
+- JSON structure is known at compile time
+- You want maximum type safety
+- Performance is critical
+
+**Use runtime `at_path()`/`at_pointer()` when:**
+- JSON structure varies or is unknown
+- Paths are computed at runtime
+- Working with C++20 or earlier
+- Flexibility is more important than compile-time checks
+
+## See Also
+
+- [JSON Pointer](basics.md#json-pointer) - Runtime JSON Pointer support
+- [JSONPath](basics.md#jsonpath) - Runtime JSONPath support
+- [Static Reflection for Deserialization](basics.md#3-using-static-reflection-c26) - Using reflection for full struct deserialization

doc/dom.md

@@ -41,7 +41,7 @@ The Basics: Loading and Parsing JSON Documents using the DOM front-end
 The simdjson library offers a simple DOM tree API, which you can access by creating a
 `dom::parser` and calling the `load()` method:
 
-```c++
+```cpp
 dom::parser parser;
 dom::element doc = parser.load(filename); // load and parse a file
 ```
@@ -49,21 +49,21 @@ dom::element doc = parser.load(filename); // load and parse a file
 Or by creating a padded string (for efficiency reasons, simdjson requires a string with
 SIMDJSON_PADDING bytes at the end) and calling `parse()`:
 
-```c++
+```cpp
 dom::parser parser;
 dom::element doc = parser.parse("[1,2,3]"_padded); // parse a string, the _padded suffix creates a simdjson::padded_string instance
 ```
 
 You can copy your data directly on a `simdjson::padded_string` as follows:
 
-```c++
+```cpp
 const char * data = "my data"; // 7 bytes
 simdjson::padded_string my_padded_data(data, 7); // copies to a padded buffer
 ```
 
 Or as follows...
 
-```c++
+```cpp
 std::string data = "my data";
 simdjson::padded_string my_padded_data(data); // copies to a padded buffer
 ```
@@ -83,7 +83,7 @@ container-overflow checks, you may encounter sanitizer warnings.
 You can safely ignore these warnings. Or you can call `simdjson::pad(std::string&)` to pad the
 string with `SIMDJSON_PADDING` spaces: this function returns a `simdjson::padding_string_view` which can be be passed to the parser's iterator function:
 
-```c++
+```cpp
 std::string json = "[1]";
 dom::element doc = parser.parse(simdjson::pad(json));
 ```
@@ -117,7 +117,7 @@ Once you have an element, you can navigate it with idiomatic C++ iterators, oper
   dom::object and dom::array. An exception (`simdjson::simdjson_error`) is thrown if the cast is not possible.
 * **Extracting Values (without exceptions):** You can use a variant usage of `get()` with error codes to avoid exceptions. You first declare the variable of the appropriate type (`double`, `uint64_t`, `int64_t`, `bool`, `std::string_view`,
   `dom::object` and `dom::array`) and pass it by reference to `get()` which gives you back an error code: e.g.,
-  ```c++
+  ```cpp
   simdjson::error_code error;
   simdjson::padded_string numberstring = "1.2"_padded; // our JSON input ("1.2")
   simdjson::dom::parser parser;
@@ -129,7 +129,7 @@ Once you have an element, you can navigate it with idiomatic C++ iterators, oper
   The strings contain unescaped valid UTF-8 strings: no unmatched surrogate is allowed.
   Internally, numbers are stored as either 64-bit integers or 64-bit floating-point numbers.
   Thus it is possible to get the full 64-bit integer range (either signed or  unsigned).
-  By default, the string `-0` is parsed as the integer 0 as in Pytho or C++. If you set the macro
+  By default, the string `-0` is parsed as the integer 0 as in Python or C++. If you set the macro
   `SIMDJSON_MINUS_ZERO_AS_FLOAT` to `1` when building simdjson, you can get that `-0` is mapped to `-0.0`
   as in JavaScript. You can get the desired effect by building simdjson with cmake setting the
   `SIMDJSON_MINUS_ZERO_AS_FLOAT` to on: `cmake -B build -D SIMDJSON_MINUS_ZERO_AS_FLOAT=ON`.
@@ -152,7 +152,7 @@ Once you have an element, you can navigate it with idiomatic C++ iterators, oper
 
 The following code illustrates all of the above:
 
-```c++
+```cpp
 auto cars_json = R"( [
   { "make": "Toyota", "model": "Camry",  "year": 2018, "tire_pressure": [ 40.1, 39.9, 37.7, 40.4 ] },
   { "make": "Kia",    "model": "Soul",   "year": 2012, "tire_pressure": [ 30.1, 31.0, 28.6, 28.7 ] },
@@ -185,7 +185,7 @@ for (dom::object car : parser.parse(cars_json)) {
 
 Here is a different example illustrating the same ideas:
 
-```C++
+```cpp
 auto abstract_json = R"( [
     {  "12345" : {"a":12.34, "b":56.78, "c": 9998877}   },
     {  "12545" : {"a":11.44, "b":12.78, "c": 11111111}  }
@@ -207,7 +207,7 @@ for (dom::object obj : parser.parse(abstract_json)) {
 And another one:
 
 
-```C++
+```cpp
   auto abstract_json = R"(
     {  "str" : { "123" : {"abc" : 3.14 } } } )"_padded;
   dom::parser parser;
@@ -221,7 +221,7 @@ C++17 Support
 
 While the simdjson library can be used in any project using C++ 11 and above, field iteration has special support C++ 17's destructuring syntax. For example:
 
-```c++
+```cpp
 padded_string json = R"(  { "foo": 1, "bar": 2 }  )"_padded;
 dom::parser parser;
 dom::object object; // invalid until the get() succeeds
@@ -234,7 +234,7 @@ for (auto [key, value] : object) {
 
 For comparison, here is the C++ 11 version of the same code:
 
-```c++
+```cpp
 // C++ 11 version for comparison
 padded_string json = R"(  { "foo": 1, "bar": 2 }  )"_padded;
 dom::parser parser;
@@ -251,7 +251,7 @@ C++20 Support
 
 simdjson library also supports some C++20 feature including `std::ranges`:
 
-```c++
+```cpp
 auto cars_json = R"( [
   { "make": "Toyota", "model": "Camry",  "year": 2018, "tire_pressure": [ 40.1, 39.9, 37.7, 40.4 ] },
   { "make": "Kia",    "model": "Soul",   "year": 2012, "tire_pressure": [ 30.1, 31.0, 28.6, 28.7 ] },
@@ -270,7 +270,7 @@ JSON Pointer
 The simdjson library also supports [JSON pointer](https://tools.ietf.org/html/rfc6901) through the
 `at_pointer()` method, letting you reach further down into the document in a single call:
 
-```c++
+```cpp
 auto cars_json = R"( [
   { "make": "Toyota", "model": "Camry",  "year": 2018, "tire_pressure": [ 40.1, 39.9, 37.7, 40.4 ] },
   { "make": "Kia",    "model": "Soul",   "year": 2012, "tire_pressure": [ 30.1, 31.0, 28.6, 28.7 ] },
@@ -291,7 +291,7 @@ You can apply a JSON Pointer expression to any node and the path gets interprete
 
 Consider the following example:
 
-```c++
+```cpp
 auto cars_json = R"( [
   { "make": "Toyota", "model": "Camry",  "year": 2018, "tire_pressure": [ 40.1, 39.9, 37.7, 40.4 ] },
   { "make": "Kia",    "model": "Soul",   "year": 2012, "tire_pressure": [ 30.1, 31.0, 28.6, 28.7 ] },
@@ -313,11 +313,11 @@ JSONPath
 ------------
 
 
-The simdjson library supports a subset of [JSONPath](https://datatracker.ietf.org/doc/html/draft-normington-jsonpath-00) through the `at_path()` method, allowing you to reach further into the document in a single call. The subset of JSONPath that is implemented is the subset that is trivially convertible into the JSON Pointer format, using `.` to access a field and `[]` to access a specific index.
+The simdjson library supports a subset of [JSONPath](https://www.rfc-editor.org/rfc/rfc9535) (RFC 9535) through the `at_path()` method, allowing you to reach further into the document in a single call. The subset of JSONPath that is implemented is the subset that is trivially convertible into the JSON Pointer format, using `.` to access a field and `[]` to access a specific index.
 
 Consider the following example:
 
-```c++
+```cpp
 auto cars_json = R"( [
   { "make": "Toyota", "model": "Camry",  "year": 2018, "tire_pressure": [ 40.1, 39.9, 37.7, 40.4 ] },
   { "make": "Kia",    "model": "Soul",   "year": 2012, "tire_pressure": [ 30.1, 31.0, 28.6, 28.7 ] },
@@ -336,7 +336,7 @@ cout << p << endl; // Prints 39.9
 
 We also support the `$` prefix. When you start a JSONPath expression with $, you are indicating that the path starts from the root of the JSON document. E.g.,
 
-```c++
+```cpp
 auto json = R"( { "c" :{ "foo": { "a": [ 10, 20, 30 ] }}, "d": { "foo2": { "a": [ 10, 20, 30 ] }} , "e": 120 })"_padded;
 dom::parser parser;
 dom::element doc;
@@ -428,7 +428,7 @@ Error Handling
 All simdjson APIs that can fail return `simdjson_result<T>`, which is a &lt;value, error_code&gt;
 pair. You can retrieve the value with .get(), like so:
 
-```c++
+```cpp
 dom::element doc;
 auto error = parser.parse(json).get(doc);
 if (error) { cerr << error << endl; exit(1); }
@@ -462,7 +462,7 @@ We can write a "quick start" example where we attempt to parse the following JSO
 Our program loads the file, selects value corresponding to key "search_metadata" which expected to be an object, and then
 it selects the key "count" within that object.
 
-```C++
+```cpp
 #include <iostream>
 #include "simdjson.h"
 
@@ -490,7 +490,7 @@ triggering exceptions. To do this, we use `["statuses"].at(0)["id"]`. We break t
 
 Observe how we use the `at` method when querying an index into an array, and not the bracket operator.
 
-```C++
+```cpp
 #include <iostream>
 #include "simdjson.h"
 
@@ -514,7 +514,7 @@ over the content of an array.
 
 This is how the example in "Using the Parsed JSON" could be written using only error code checking:
 
-```c++
+```cpp
 auto cars_json = R"( [
   { "make": "Toyota", "model": "Camry",  "year": 2018, "tire_pressure": [ 40.1, 39.9, 37.7, 40.4 ] },
   { "make": "Kia",    "model": "Soul",   "year": 2012, "tire_pressure": [ 30.1, 31.0, 28.6, 28.7 ] },
@@ -561,7 +561,7 @@ for (dom::element car_element : cars) {
 
 Here is another example:
 
-```C++
+```cpp
 auto abstract_json = R"( [
     {  "12345" : {"a":12.34, "b":56.78, "c": 9998877}   },
     {  "12545" : {"a":11.44, "b":12.78, "c": 11111111}  }
@@ -594,7 +594,7 @@ for (dom::element elem : array) {
 
 And another one:
 
-```C++
+```cpp
   auto abstract_json = R"(
     {  "str" : { "123" : {"abc" : 3.14 } } } )"_padded;
   dom::parser parser;
@@ -608,7 +608,7 @@ Notice how we can string several operations (`parser.parse(abstract_json)["str"]
 
 The next two functions will take as input a JSON document containing an array with a single element, either a string or a number. They return true upon success.
 
-```C++
+```cpp
 simdjson::dom::parser parser{};
 
 bool parse_double(const char *j, double &d) {
@@ -640,7 +640,7 @@ target_compile_definitions(simdjson PUBLIC SIMDJSON_EXCEPTIONS=OFF)
 
 Users more comfortable with an exception flow may choose to directly cast the `simdjson_result<T>` to the desired type:
 
-```c++
+```cpp
 dom::element doc = parser.parse(json); // Throws an exception if there was an error!
 ```
 
@@ -650,7 +650,7 @@ program from continuing if there was an error.
 
 If one is willing to trigger exceptions, it is possible to write simpler code:
 
-```C++
+```cpp
 #include <iostream>
 #include "simdjson.h"
 
@@ -671,7 +671,7 @@ inspect or walk over JSON elements. To do that, you can use iterators and the ty
 example, here's a quick and dirty recursive function that verbosely prints the JSON document as JSON
 (* ignoring nuances like trailing commas and escaping strings, for brevity's sake):
 
-```c++
+```cpp
 void print_json(dom::element element) {
   switch (element.type()) {
     case dom::element_type::ARRAY:
@@ -727,7 +727,7 @@ and reuse it. The simdjson library will allocate and retain internal buffers bet
 buffers hot in cache and keeping memory allocation and initialization to a minimum. In this manner,
 you can parse terabytes of JSON data without doing any new allocation.
 
-```c++
+```cpp
 dom::parser parser;
 
 // This initializes buffers and a document big enough to handle this JSON.
@@ -770,7 +770,7 @@ without bound:
 
 * You can set a *max capacity* when constructing a parser:
 
-  ```c++
+  ```cpp
   dom::parser parser(1000*1000); // Never grow past documents > 1MB
   for (web_request request : listen()) {
     dom::element doc;
@@ -786,7 +786,7 @@ without bound:
 * You can set a *fixed capacity* that never grows, as well, which can be excellent for
   predictability and reliability, since simdjson will never call malloc after startup!
 
-  ```c++
+  ```cpp
   dom::parser parser(0); // This parser will refuse to automatically grow capacity
   auto error = parser.allocate(1000*1000); // This allocates enough capacity to handle documents <= 1MB
   if (error) { cerr << error << endl; exit(1); }
@@ -817,7 +817,7 @@ When calling `parser.parse` on a pointer (e.g., `parser.parse(my_char_pointer, m
 Some users may not be able use our `padded_string` class or to load the data directly from disk (`parser.load`). They may need to pass data pointers to the library.  If these users wish to avoid temporary copies and corresponding temporary memory allocations, they may want to call `parser.parse` with the `realloc_if_needed` parameter set to false (e.g., `parser.parse(my_char_pointer, my_length_in_bytes, false)`). In such cases, they need to ensure that there are at least SIMDJSON_PADDING extra bytes at the end that can be safely accessed and read. They do not need to initialize the padded bytes to any value in particular. The following example is safe:
 
 
-```C++
+```cpp
 const char *json      = R"({"key":"value"})";
 const size_t json_len = std::strlen(json);
 std::unique_ptr<char[]> padded_json_copy{new char[json_len + SIMDJSON_PADDING]};

doc/implementation-selection.md

@@ -55,7 +55,7 @@ Inspecting the Detected Implementation
 
 You can check what implementation is running with `active_implementation`:
 
-```c++
+```cpp
 cout << "simdjson v" << SIMDJSON_VERSION << endl;
 cout << "Detected the best implementation for your machine: " << simdjson::get_active_implementation()->name();
 cout << "(" << simdjson::get_active_implementation()->description() << ")" << endl;
@@ -68,7 +68,7 @@ Querying Available Implementations
 
 You can list all available implementations, regardless of which one was selected:
 
-```c++
+```cpp
 for (auto implementation : simdjson::get_available_implementations()) {
   cout << implementation->name() << ": " << implementation->description() << endl;
 }
@@ -76,7 +76,7 @@ for (auto implementation : simdjson::get_available_implementations()) {
 
 And look them up by name:
 
-```c++
+```cpp
 cout << simdjson::get_available_implementations()["fallback"]->description() << endl;
 ```
 When an implementation is not available, the bracket call `simdjson::get_available_implementations()[name]`
@@ -93,7 +93,7 @@ Manually Selecting the Implementation
 If you're trying to do performance tests or see how different implementations of simdjson run, you
 can select the CPU architecture yourself:
 
-```c++
+```cpp
 // Use the fallback implementation, even though my machine is fast enough for anything
 simdjson::get_active_implementation() = simdjson::get_available_implementations()["fallback"];
 ```
@@ -102,7 +102,7 @@ You are responsible for ensuring that the requirements of the selected implement
 Furthermore, you should check that the implementation is available before setting it to `simdjson::get_active_implementation()`
 by comparing it with the null pointer.
 
-```c++
+```cpp
 auto my_implementation = simdjson::get_available_implementations()["haswell"];
 if (! my_implementation) { exit(1); }
 if (! my_implementation->supported_by_runtime_system()) { exit(1); }
@@ -114,7 +114,7 @@ Checking that an Implementation can Run on your System
 
 You should call `supported_by_runtime_system()` to compare the processor's features with the need of the implementation.
 
-```c++
+```cpp
 for (auto implementation : simdjson::get_available_implementations()) {
   if (implementation->supported_by_runtime_system()) {
     cout << implementation->name() << ": " << implementation->description() << endl;

doc/iterate_many.md

@@ -132,7 +132,7 @@ E.g., `[1,2]{"32":1}` is recognized as two documents.
 Some official formats **(non-exhaustive list)**:
 - [Newline-Delimited JSON (NDJSON)](https://github.com/ndjson/ndjson-spec/)
 - [JSON lines (JSONL)](http://jsonlines.org/)
-- [Record separator-delimited JSON (RFC 7464)](https://tools.ietf.org/html/rfc7464) <- Not supported by JsonStream!
+- [Record separator-delimited JSON (RFC 7464)](https://tools.ietf.org/html/rfc7464) <- Not supported by simdjson!
 - [More on Wikipedia...](https://en.wikipedia.org/wiki/JSON_streaming)
 
 API
@@ -140,7 +140,7 @@ API
 
 Example:
 
-```c++
+```cpp
 auto json = R"({ "foo": 1 } { "foo": 2 } { "foo": 3 } )"_padded;
 ondemand::parser parser;
 ondemand::document_stream docs = parser.iterate_many(json);
@@ -197,7 +197,7 @@ and `error()` to check if there were any error.
 Let us illustrate the idea with code:
 
 
-```C++
+```cpp
     auto json = R"([1,2,3]  {"1":1,"2":3,"4":4} [1,2,3]  )"_padded;
     simdjson::ondemand::parser parser;
     simdjson::ondemand::document_stream stream;
@@ -238,7 +238,7 @@ Some users may need to work with truncated streams. The simdjson may truncate do
 
 Consider the following example where a truncated document (`{"key":"intentionally unclosed string  `) containing 39 bytes has been left within the stream. In such cases, the first two whole documents are parsed and returned, and the `truncated_bytes()` method returns 39.
 
-```C++
+```cpp
     auto json = R"([1,2,3]  {"1":1,"2":3,"4":4} {"key":"intentionally unclosed string  )"_padded;
     simdjson::ondemand::parser parser;
     simdjson::ondemand::document_stream stream;
@@ -267,7 +267,7 @@ is effectively ignored, as it is set to at least the document size.
 
 Example:
 
-```C++
+```cpp
     auto json = R"( 1, 2, 3, 4, "a", "b", "c", {"hello": "world"} , [1, 2, 3])"_padded;
     ondemand::parser parser;
     ondemand::document_stream doc_stream;
@@ -314,7 +314,7 @@ the simdjson library.
 
 Consider a custom class `Car`:
 
-```C++
+```cpp
 struct Car {
   std::string make;
   std::string model;
@@ -328,7 +328,7 @@ You may support deserializing directly from a JSON value or document to your own
 by defining a single `tag_invoke` function:
 
 
-```C++
+```cpp
 namespace simdjson {
 // This tag_invoke MUST be inside simdjson namespace
 template <typename simdjson_value>
@@ -370,7 +370,7 @@ tag_invoke functions.
 Given a stream of JSON documents, you can add them to a data structure
 such as a `std::vector<Car>` like so if you support exceptions:
 
-```C++
+```cpp
   padded_string json =
       R"( { "make": "Toyota", "model": "Camry",  "year": 2018,
        "tire_pressure": [ 40.1, 39.9 ] }
@@ -391,7 +391,7 @@ such as a `std::vector<Car>` like so if you support exceptions:
 Otherwise you may use this longer version for explicit handling of errors:
 
 
-```C++
+```cpp
   std::vector<Car> cars;
   for(auto doc : stream) {
     Car c;

doc/ondemand_design.md

@@ -23,7 +23,7 @@ applications with a computation efficiency that is difficult to surpass.
 
 A code example illustrates our API from a programmer's point of view:
 
-```c++
+```cpp
 ondemand::parser parser;
 auto doc = parser.iterate(json);
 for (auto tweet : doc["statuses"]) {
@@ -109,7 +109,7 @@ The DOM approach was the only way to parse JSON documents up to version 0.6 of t
 Our DOM API looks similar to our On-Demand example, except
 it calls `parse` instead of `iterate`:
 
-```c++
+```cpp
 dom::parser parser;
 auto doc = parser.parse(json);
 for (auto tweet : doc["statuses"]) {
@@ -157,7 +157,7 @@ examples. To make it short enough to use as an example at all, it has heavily re
 a part of the problem (does not get user.screen_name), it has bugs (it does not handle sub-objects
 in a tweet at all), and it uses a theoretical, simple event-based API that minimizes ceremony.
 
-```c++
+```cpp
 struct twitter_callbacks {
   bool in_statuses;
   bool in_tweet;
@@ -284,14 +284,14 @@ To help visualize the algorithm, we'll walk through the example C++ given at the
 
    This declaration does not allocate any memory; that will happen in the next step.
 
-   ```c++
+   ```cpp
    ondemand::parser parser;
    ```
 
 2. We then start iterating the JSON document by allocating internal parser buffers, preprocessing
    the JSON, and initializing the iterator.
 
-   ```c++
+   ```cpp
    auto doc = parser.iterate(json);
    ```
 
@@ -337,14 +337,14 @@ To help visualize the algorithm, we'll walk through the example C++ given at the
 3. We iterate over the "statuses" field using a typical C++ iterator, reading past the initial
    `{ "statuses": [ {`.
 
-   ```c++
+   ```cpp
    for (ondemand::object tweet : doc["statuses"]) {
    ```
 
    This shorthand does a lot, and it is helpful to see what it expands to.
    Comments in front of each one explain what's going on:
 
-   ```c++
+   ```cpp
    // Validate that the top-level value is an object: check for {. Increase depth to 2 (root > field).
    ondemand::object top = doc.get_object();
 
@@ -396,7 +396,7 @@ To help visualize the algorithm, we'll walk through the example C++ given at the
 
 4. We get the `"text"` field as a string.
 
-   ```c++
+   ```cpp
    std::string_view text        = tweet["text"];
    ```
 
@@ -435,7 +435,7 @@ To help visualize the algorithm, we'll walk through the example C++ given at the
 
 4. We get the `"screen_name"` from the `"user"` object.
 
-   ```c++
+   ```cpp
       ondemand::object user        = tweet["user"];
       screen_name                  = user["screen_name"];
    ```
@@ -469,7 +469,7 @@ To help visualize the algorithm, we'll walk through the example C++ given at the
 
 5. We get `"retweet_count"` as an unsigned integer.
 
-   ```c++
+   ```cpp
    uint64_t         retweets    = tweet["retweet_count"];
    ```
 
@@ -513,7 +513,7 @@ To help visualize the algorithm, we'll walk through the example C++ given at the
 
 6. We loop to the next tweet.
 
-   ```c++
+   ```cpp
    for (ondemand::object tweet : doc["statuses"]) {
      ...
    }
@@ -521,7 +521,7 @@ To help visualize the algorithm, we'll walk through the example C++ given at the
 
    The relevant parts of the loop  are:
 
-   ```c++
+   ```cpp
    while (iter != statuses.end()) {
      ondemand::object tweet = *iter;
      ...
@@ -566,7 +566,7 @@ To help visualize the algorithm, we'll walk through the example C++ given at the
 
 8. The loop ends. Recall the relevant parts of the statuses loop:
 
-   ```c++
+   ```cpp
    while (iter != statuses.end()) {
      ondemand::object tweet = *iter;
      ...
@@ -610,7 +610,7 @@ When the user requests strings, we unescape them to a single string buffer much
 so that users enjoy the same string performance as the core simdjson. We do not write the length to the
 string buffer, however; that is stored in the `string_view` instance we return to the user.
 
-```C++
+```cpp
   ondemand::parser parser;
   auto doc = parser.iterate(json);
   std::set<std::string_view> default_users;
@@ -645,7 +645,7 @@ from the `unescaped_key()` method has a lifecycle tied to the `parser` instance:
 is destroyed or reused with another document, the `std::string_view` instance becomes invalid.
 
 
-```C++
+```cpp
 auto doc = parser.iterate(json);
 for(auto field : doc.get_object())  {
       std::string_view keyv = field.unescaped_key();
@@ -670,7 +670,7 @@ in production systems:
   Some care is needed when using the On-Demand API in scenarios where you need to access several sibling arrays or objects because
   only one object or array can be active at any one time. Let us consider the following example:
 
-```C++
+```cpp
     ondemand::parser parser;
     const padded_string json = R"({ "parent": {"child1": {"name": "John"} , "child2": {"name": "Daniel"}} })"_padded;
     auto doc = parser.iterate(json);
@@ -688,7 +688,7 @@ in production systems:
 
 A correct usage is given by the following example:
 
-```C++
+```cpp
     ondemand::parser parser;
     const padded_string json = R"({ "parent": {"child1": {"name": "John"} , "child2": {"name": "Daniel"}} })"_padded;
     auto doc = parser.iterate(json);
@@ -754,7 +754,7 @@ Some users wish to run at the best possible speed. Under recent Intel and AMD pr
 
 Given that the On-Demand API offer limited runtime dispatching, it matters that your code is compiled against a specific CPU target. You should verify that the code is compiled against the target you expect. Thankfully, the simdjson library will tell you exactly what it detects as an implementation: `icelake` (AVX512 x64 processors), `haswell` (AVX2 x64 processors), `westmere` (SSE4 x64 processors), `arm64` (64-bit ARM), `ppc64` (64-bit POWER), `lasx` (LoongArch), `lsx` (LoongArch),  `fallback` (others). Under x64 processors, many programmers will want to target `haswell` whereas under ARM, most programmers will want to target `arm64` (and it should do so automatically). The `fallback` is probably only good for testing purposes, not for deployment.
 
-```C++
+```cpp
   std::cout << simdjson::builtin_implementation()->name() << std::endl;
 ```
 

doc/parse_many.md

@@ -132,7 +132,7 @@ Whitespace Characters:
 Some official formats **(non-exhaustive list)**:
 - [Newline-Delimited JSON (NDJSON)](https://github.com/ndjson/ndjson-spec)
 - [JSON lines (JSONL)](http://jsonlines.org/)
-- [Record separator-delimited JSON (RFC 7464)](https://tools.ietf.org/html/rfc7464) <- Not supported by JsonStream!
+- [Record separator-delimited JSON (RFC 7464)](https://tools.ietf.org/html/rfc7464) <- Not supported by simdjson!
 - [More on Wikipedia...](https://en.wikipedia.org/wiki/JSON_streaming)
 
 API
@@ -184,7 +184,7 @@ You may also call the `source()` method to get a `std::string_view` instance on
 Let us illustrate the idea with code:
 
 
-```C++
+```cpp
     auto json = R"([1,2,3]  {"1":1,"2":3,"4":4} [1,2,3]  )"_padded;
     simdjson::dom::parser parser;
     simdjson::dom::document_stream stream;
@@ -225,7 +225,7 @@ Some users may need to work with truncated streams. The simdjson may truncate do
 
 Consider the following example where a truncated document (`{"key":"intentionally unclosed string  `) containing 39 bytes has been left within the stream. In such cases, the first two whole documents are parsed and returned, and the `truncated_bytes()` method returns 39.
 
-```C++
+```cpp
     auto json = R"([1,2,3]  {"1":1,"2":3,"4":4} {"key":"intentionally unclosed string  )"_padded;
     simdjson::dom::parser parser;
     simdjson::dom::document_stream stream;

doc/performance.md

@@ -47,7 +47,7 @@ and reuse it. The simdjson library will allocate and retain internal buffers bet
 buffers hot in cache and keeping memory allocation and initialization to a minimum. In this manner,
 you can parse terabytes of JSON data without doing any new allocation.
 
-```c++
+```cpp
 ondemand::parser parser;
 
 // This initializes buffers  big enough to handle this JSON.
@@ -71,14 +71,14 @@ Reusing string buffers
 
 We recommend against creating many `std::string` or `simdjson::padded_string` instances to store the JSON content in your application. [Creating many non-trivial objects is convenient but often surprisingly slow](https://lemire.me/blog/2020/08/08/performance-tip-constructing-many-non-trivial-objects-is-slow/). Instead, as much as possible, you should allocate (once or a few times) reusable memory buffers where you write your JSON content. If you have a buffer `json_str` (of type `char*`) allocated for  `capacity` bytes and you store a JSON document spanning `length` bytes, you can pass it to simdjson as follows:
 
-```c++
+```cpp
  auto doc = parser.iterate(padded_string_view(json_str, length, capacity));
 ```
 
 or simply
 
 
-```c++
+```cpp
  auto doc = parser.iterate(json_str, length, capacity);
 ```
 
@@ -89,7 +89,7 @@ Server Loops: Long-Running Processes and Memory Capacity
 The On-Demand approach also automatically expands its memory capacity when larger documents are parsed. However, for longer processes where very large files are processed (such as server loops), this capacity is not resized down. On-Demand also lets you adjust the maximal capacity that the parser can process:
 
 * You can set an upper bound (*max_capacity*) when construction the parser:
-```C++
+```cpp
     ondemand::parser parser(1000*1000);  // Never grows past documents > 1 MB
     auto doc = parser.iterate(json);
     for (web_request request : listen()) {
@@ -105,7 +105,7 @@ The On-Demand approach also automatically expands its memory capacity when large
 The capacity will grow as the parser encounters larger documents up to 1 MB.
 
 * You can also allocate a *fixed capacity* that will never grow:
-```C++
+```cpp
     ondemand::parser parser(1000*1000);
     parser.allocate(1000*1000)  // Fix the capacity to 1 MB
     auto doc = parser.iterate(json);
@@ -253,7 +253,7 @@ long page_size() {
 // page boundary.
 bool need_allocation(const char *buf, size_t len) {
   return ((reinterpret_cast<uintptr_t>(buf + len - 1) % page_size())
-    + simdjson::SIMDJSON_PADDING > static_cast<uintptr_t>(page_size()));
+    + simdjson::SIMDJSON_PADDING >= static_cast<uintptr_t>(page_size()));
 }
 
 simdjson::padded_string_view

fuzz/fuzz_minify.cpp

@@ -18,7 +18,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
     auto error = parser.parse(str).get(elem);
     if (error) { return 0; }
 
-    std::string minified=simdjson::minify(elem);
+    std::string minified = simdjson::minify(elem);
     (void)minified;
     return 0;
 }

include/simdjson/arm64/stringparsing_defs.h

@@ -17,7 +17,7 @@ using namespace simd;
 struct backslash_and_quote {
 public:
   static constexpr uint32_t BYTES_PROCESSED = 32;
-  simdjson_inline static backslash_and_quote copy_and_find(const uint8_t *src, uint8_t *dst);
+  simdjson_inline backslash_and_quote copy_and_find(const uint8_t *src, uint8_t *dst);
 
   simdjson_inline bool has_quote_first() { return ((bs_bits - 1) & quote_bits) != 0; }
   simdjson_inline bool has_backslash() { return bs_bits != 0; }

include/simdjson/base.h

@@ -10,6 +10,7 @@
 #include "simdjson/error.h"
 #include "simdjson/portability.h"
 #include "simdjson/concepts.h"
+#include "simdjson/constevalutil.h"
 
 /**
  * @brief The top level simdjson namespace, containing everything the library provides.

include/simdjson/concepts.h

@@ -122,11 +122,65 @@ concept optional_type = requires(std::remove_cvref_t<T> obj) {
     } -> std::convertible_to<typename std::remove_cvref_t<T>::value_type>;
   };
   { static_cast<bool>(obj) } -> std::same_as<bool>; // convertible to bool
+  { obj.reset() } noexcept -> std::same_as<void>;
 };
 
 
 
+// Types we serialize as JSON strings (not as containers)
+template <typename T>
+concept string_like =
+  std::is_same_v<std::remove_cvref_t<T>, std::string> ||
+  std::is_same_v<std::remove_cvref_t<T>, std::string_view> ||
+  std::is_same_v<std::remove_cvref_t<T>, const char*> ||
+  std::is_same_v<std::remove_cvref_t<T>, char*>;
+
+// Concept that checks if a type is a container but not a string (because
+// strings handling must be handled differently)
+// Now uses iterator-based approach for broader container support
+template <typename T>
+concept container_but_not_string =
+  std::ranges::input_range<T> && !string_like<T> && !concepts::string_view_keyed_map<T>;
+
+
+
+// Concept: Indexable container that is not a string or associative container
+// Accepts: std::vector, std::array, std::deque (have operator[], value_type, not string_like)
+// Rejects: std::string (string_like), std::list (no operator[]), std::map (has key_type)
+template<typename Container>
+concept indexable_container = requires {
+  typename Container::value_type;
+  requires !concepts::string_like<Container>;
+  requires !requires { typename Container::key_type; };  // Reject maps/sets
+  requires requires(Container& c, std::size_t i) {
+    { c[i] } -> std::convertible_to<typename Container::value_type>;
+  };
+};
+
+
+// Variable template to use with std::meta::substitute
+template<typename Container>
+constexpr bool indexable_container_v = indexable_container<Container>;
+
 } // namespace concepts
+
+
+/**
+ * We use tag_invoke as our customization point mechanism.
+ */
+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;
+    };
+
 } // namespace simdjson
 #endif // SIMDJSON_SUPPORTS_CONCEPTS
 #endif // SIMDJSON_CONCEPTS_H

include/simdjson/constevalutil.h

@@ -0,0 +1,75 @@
+#ifndef SIMDJSON_CONSTEVALUTIL_H
+#define SIMDJSON_CONSTEVALUTIL_H
+
+#include <string>
+#include <string_view>
+#include <array>
+
+namespace simdjson {
+namespace constevalutil {
+#if SIMDJSON_CONSTEVAL
+
+constexpr static std::array<uint8_t, 256> json_quotable_character = {
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+constexpr static std::array<std::string_view, 32> control_chars = {
+    "\\u0000", "\\u0001", "\\u0002", "\\u0003", "\\u0004", "\\u0005", "\\u0006",
+    "\\u0007", "\\b", "\\t",     "\\n",     "\\u000b", "\\f",     "\\r",
+    "\\u000e", "\\u000f", "\\u0010", "\\u0011", "\\u0012", "\\u0013", "\\u0014",
+    "\\u0015", "\\u0016", "\\u0017", "\\u0018", "\\u0019", "\\u001a", "\\u001b",
+    "\\u001c", "\\u001d", "\\u001e", "\\u001f"};
+// unoptimized, meant for compile-time execution
+consteval std::string consteval_to_quoted_escaped(std::string_view input) {
+  std::string out = "\"";
+  for (char c : input) {
+    if (json_quotable_character[uint8_t(c)]) {
+      if (c == '"') {
+        out.append("\\\"");
+      } else if (c == '\\') {
+        out.append("\\\\");
+      } else {
+        std::string_view v = control_chars[uint8_t(c)];
+        out.append(v);
+      }
+    } else {
+      out.push_back(c);
+    }
+  }
+  out.push_back('"');
+  return out;
+}
+#endif  // SIMDJSON_CONSTEVAL
+
+
+#if SIMDJSON_SUPPORTS_CONCEPTS
+template <std::size_t N>
+struct fixed_string {
+    constexpr fixed_string(const char (&str)[N])  {
+        for (std::size_t i = 0; i < N; ++i) {
+            data[i] = str[i];
+        }
+    }
+    char data[N];
+    constexpr std::string_view view() const { return {data, N - 1}; }
+};
+template <std::size_t N>
+fixed_string(const char (&)[N]) -> fixed_string<N>;
+
+template <fixed_string str>
+struct string_constant {
+    static constexpr std::string_view value = str.view();
+};
+#endif // SIMDJSON_SUPPORTS_CONCEPTS
+
+} // namespace constevalutil
+} // namespace simdjson
+#endif // SIMDJSON_CONSTEVALUTIL_H

include/simdjson/convert-inl.h

@@ -58,6 +58,12 @@ inline simdjson_result<T> auto_parser<parser_type>::result() noexcept(is_nothrow
   return m_doc.get<T>();
 }
 
+template <typename parser_type>
+template <typename T>
+simdjson_warn_unused simdjson_inline error_code auto_parser<parser_type>::get(T &value) && noexcept(is_nothrow_gettable<T>) {
+  return result<T>().get(value);
+}
+
 template <typename parser_type>
 inline simdjson_result<ondemand::array> auto_parser<parser_type>::array() noexcept {
   return result<ondemand::array>();
@@ -73,12 +79,7 @@ inline simdjson_result<ondemand::number> auto_parser<parser_type>::number() noex
   return result<ondemand::number>();
 }
 
-template <typename parser_type>
-template <typename T>
-inline auto_parser<parser_type>::operator simdjson_result<T>() noexcept(is_nothrow_gettable<T>) {
-  return result<T>();
-}
-
+#if SIMDJSON_EXCEPTIONS
 template <typename parser_type>
 template <typename T>
 inline auto_parser<parser_type>::operator T() noexcept(false) {
@@ -87,6 +88,7 @@ inline auto_parser<parser_type>::operator T() noexcept(false) {
   }
   return m_doc.get<T>();
 }
+#endif // SIMDJSON_EXCEPTIONS
 
 template <typename parser_type>
 template <typename T>
@@ -109,13 +111,23 @@ inline T to_adaptor<T>::operator()(simdjson_result<ondemand::value> &val) const
 
 template <typename T>
 inline auto to_adaptor<T>::operator()(padded_string_view const str) const noexcept {
-  return auto_parser{str};
+  return auto_parser<ondemand::parser *>{str};
 }
 
 template <typename T>
 inline auto to_adaptor<T>::operator()(ondemand::parser &parser, padded_string_view const str) const noexcept {
   return auto_parser<ondemand::parser *>{parser, str};
 }
+
+template <typename T>
+inline auto to_adaptor<T>::operator()(std::string str) const noexcept {
+  return auto_parser<ondemand::parser *>{pad_with_reserve(str)};
+}
+
+template <typename T>
+inline auto to_adaptor<T>::operator()(ondemand::parser &parser, std::string str) const noexcept {
+  return auto_parser<ondemand::parser *>{parser, pad_with_reserve(str)};
+}
 } // namespace internal
 } // namespace convert
 } // namespace simdjson

include/simdjson/convert.h

@@ -46,16 +46,19 @@ public:
 
 	template <typename T>
 	simdjson_warn_unused simdjson_inline simdjson_result<T> result() noexcept(is_nothrow_gettable<T>);
+	template <typename T>
+	simdjson_warn_unused simdjson_inline error_code get(T &value) && noexcept(is_nothrow_gettable<T>);
+
 
 	simdjson_warn_unused simdjson_inline simdjson_result<ondemand::array> array() noexcept;
 	simdjson_warn_unused simdjson_inline simdjson_result<ondemand::object> object() noexcept;
 	simdjson_warn_unused simdjson_inline simdjson_result<ondemand::number> number() noexcept;
 
-	template <typename T>
-	simdjson_warn_unused simdjson_inline explicit(false) operator simdjson_result<T>() noexcept(is_nothrow_gettable<T>);
 
+#if SIMDJSON_EXCEPTIONS
 	template <typename T>
 	simdjson_warn_unused simdjson_inline explicit(false) operator T() noexcept(false);
+#endif // SIMDJSON_EXCEPTIONS
 
 	template <typename T>
 	simdjson_warn_unused simdjson_inline std::optional<T> optional() noexcept(is_nothrow_gettable<T>);
@@ -72,7 +75,14 @@ struct to_adaptor {
 	T operator()(simdjson_result<ondemand::value> &val) const noexcept;
 	auto operator()(padded_string_view const str) const noexcept;
 	auto operator()(ondemand::parser &parser, padded_string_view const str) const noexcept;
+	// The std::string is padded with reserve to ensure there is enough space for padding.
+	// Some sanitizers may not like this, so you can use simdjson::pad instead.
+	// simdjson::from(simdjson::pad(str))
+	auto operator()(std::string str) const noexcept;
+	auto operator()(ondemand::parser &parser, std::string str) const noexcept;
 };
+// deduction guide
+auto_parser(padded_string_view const str) -> auto_parser<ondemand::parser*>;
 } // namespace internal
 } // namespace convert
 

include/simdjson/dom/array.h

@@ -111,7 +111,7 @@ public:
   inline simdjson_result<element> at_pointer(std::string_view json_pointer) const noexcept;
 
   /**
-   * Recursive function which processes the json path of each child element
+   * Recursive function which processes the JSON path of each child element
    */
   inline void process_json_path_of_child_elements(std::vector<element>::iterator& current, std::vector<element>::iterator& end, const std::string_view& path_suffix, std::vector<element>& accumulator) const noexcept;
 
@@ -126,7 +126,7 @@ public:
    * JSONPath queries that trivially convertible to JSON Pointer queries: key
    * names and array indices.
    *
-   * https://datatracker.ietf.org/doc/html/draft-normington-jsonpath-00
+   * https://www.rfc-editor.org/rfc/rfc9535 (RFC 9535)
    *
    * @return The value associated with the given JSONPath expression, or:
    *         - INVALID_JSON_POINTER if the JSONPath to JSON Pointer conversion fails

include/simdjson/dom/document_stream.h

@@ -74,7 +74,7 @@ public:
   /**
    * Construct an uninitialized document_stream.
    *
-   *  ```c++
+   *  ```cpp
    *  document_stream docs;
    *  error = parser.parse_many(json).get(docs);
    *  ```

include/simdjson/dom/element.h

@@ -408,7 +408,7 @@ public:
    * JSONPath queries that trivially convertible to JSON Pointer queries: key
    * names and array indices.
    *
-   * https://datatracker.ietf.org/doc/html/draft-normington-jsonpath-00
+   * https://www.rfc-editor.org/rfc/rfc9535 (RFC 9535)
    *
    * @return The value associated with the given JSONPath expression, or:
    *         - INVALID_JSON_POINTER if the JSONPath to JSON Pointer conversion fails

include/simdjson/dom/object-inl.h

@@ -186,7 +186,7 @@ inline simdjson_result<std::vector<element>> object::at_path_with_wildcard(std::
   }
 
   if (i >= json_path.size() || (json_path[i] != '.' && json_path[i] != '[')) {
-    // expect json path to always start with $ but this isn't currently
+    // expect JSONPath expressions to always start with $ but this isn't currently
     // expected in jsonpathutil.h.
     return INVALID_JSON_POINTER;
   }

include/simdjson/dom/object.h

@@ -175,7 +175,7 @@ public:
   inline simdjson_result<element> at_pointer(std::string_view json_pointer) const noexcept;
 
   /**
-   * Recursive function which processes the json path of each child element
+   * Recursive function which processes the JSON path of each child element
    */
   inline void process_json_path_of_child_elements(std::vector<element>::iterator& current, std::vector<element>::iterator& end, const std::string_view& path_suffix, std::vector<element>& accumulator) const noexcept;
 
@@ -189,7 +189,7 @@ public:
    * JSONPath queries that trivially convertible to JSON Pointer queries: key
    * names and array indices.
    *
-   * https://datatracker.ietf.org/doc/html/draft-normington-jsonpath-00
+   * https://www.rfc-editor.org/rfc/rfc9535 (RFC 9535)
    *
    * @return The value associated with the given JSONPath expression, or:
    *         - INVALID_JSON_POINTER if the JSONPath to JSON Pointer conversion fails

include/simdjson/error-inl.h

@@ -67,8 +67,38 @@ simdjson_inline error_code simdjson_result_base<T>::error() const noexcept {
   return this->second;
 }
 
+
+template<typename T>
+simdjson_inline bool simdjson_result_base<T>::has_value() const noexcept {
+  return this->error() == SUCCESS;
+}
+
 #if SIMDJSON_EXCEPTIONS
 
+
+template<typename T>
+simdjson_inline T& simdjson_result_base<T>::operator*() &  noexcept(false) {
+  return this->value();
+}
+
+template<typename T>
+simdjson_inline T&& simdjson_result_base<T>::operator*() &&  noexcept(false) {
+  return std::forward<internal::simdjson_result_base<T>>(*this).value();
+}
+
+template<typename T>
+simdjson_inline T* simdjson_result_base<T>::operator->() noexcept(false) {
+  if (this->error()) { throw simdjson_error(this->error()); }
+  return &this->first;
+}
+
+
+template<typename T>
+simdjson_inline const T* simdjson_result_base<T>::operator->() const noexcept(false) {
+  if (this->error()) { throw simdjson_error(this->error()); }
+  return &this->first;
+}
+
 template<typename T>
 simdjson_inline T& simdjson_result_base<T>::value() & noexcept(false) {
   if (error()) { throw simdjson_error(error()); }
@@ -93,6 +123,7 @@ simdjson_inline simdjson_result_base<T>::operator T&&() && noexcept(false) {
 
 #endif // SIMDJSON_EXCEPTIONS
 
+
 template<typename T>
 simdjson_inline const T& simdjson_result_base<T>::value_unsafe() const& noexcept {
   return this->first;

include/simdjson/error.h

@@ -108,6 +108,10 @@ namespace internal {
 /**
  * The result of a simdjson operation that could fail.
  *
+ * IMPORTANT: For the ondemand API, we use implementation_simdjson_result_base<T> as a base class
+ * to avoid some compilation issue. Thus, if you modify this class, please ensure that the ondemand
+ * implementation_simdjson_result_base<T> is also modified.
+ *
  * Gives the option of reading error codes, or throwing an exception by casting to the desired result.
  *
  * This is a base class for implementations that want to add functions to the result type for
@@ -168,8 +172,27 @@ struct simdjson_result_base : protected std::pair<T, error_code> {
    */
   simdjson_inline error_code error() const noexcept;
 
+  /**
+   * Whether there is a value.
+   */
+  simdjson_inline bool has_value() const noexcept;
 #if SIMDJSON_EXCEPTIONS
 
+  /**
+   * Dereference operator to access the contained value.
+   *
+   * @throw simdjson_error if there was an error.
+   */
+  simdjson_inline T& operator*() &  noexcept(false);
+  simdjson_inline T&& operator*() &&  noexcept(false);
+  /**
+   * Arrow operator to access members of the contained value.
+   *
+   * @throw simdjson_error if there was an error.
+   */
+  simdjson_inline T* operator->() noexcept(false);
+  simdjson_inline const T* operator->() const noexcept(false);
+
   /**
    * Get the result value.
    *
@@ -253,6 +276,7 @@ struct simdjson_result_base : protected std::pair<T, error_code> {
  */
 template<typename T>
 struct simdjson_result : public internal::simdjson_result_base<T> {
+
   /**
    * @private Create a new empty result with error = UNINITIALIZED.
    */
@@ -306,8 +330,11 @@ struct simdjson_result : public internal::simdjson_result_base<T> {
    */
   simdjson_inline error_code error() const noexcept;
 
-#if SIMDJSON_EXCEPTIONS
 
+
+#if SIMDJSON_EXCEPTIONS
+  using internal::simdjson_result_base<T>::operator*;
+  using internal::simdjson_result_base<T>::operator->;
   /**
    * Get the result value.
    *

include/simdjson/fallback/stringparsing_defs.h

@@ -13,7 +13,7 @@ namespace {
 struct backslash_and_quote {
 public:
   static constexpr uint32_t BYTES_PROCESSED = 1;
-  simdjson_inline static backslash_and_quote copy_and_find(const uint8_t *src, uint8_t *dst);
+  simdjson_inline backslash_and_quote copy_and_find(const uint8_t *src, uint8_t *dst);
 
   simdjson_inline bool has_quote_first() { return c == '"'; }
   simdjson_inline bool has_backslash() { return c == '\\'; }

include/simdjson/generic/implementation_simdjson_result_base-inl.h

@@ -29,12 +29,41 @@ simdjson_warn_unused simdjson_inline error_code implementation_simdjson_result_b
 }
 
 template<typename T>
-simdjson_inline error_code implementation_simdjson_result_base<T>::error() const noexcept {
+simdjson_warn_unused simdjson_inline error_code implementation_simdjson_result_base<T>::error() const noexcept {
   return this->second;
 }
 
+
+template<typename T>
+simdjson_warn_unused simdjson_inline bool implementation_simdjson_result_base<T>::has_value() const noexcept {
+  return this->error() == SUCCESS;
+}
+
 #if SIMDJSON_EXCEPTIONS
 
+template<typename T>
+simdjson_inline T& implementation_simdjson_result_base<T>::operator*() &  noexcept(false) {
+  return this->value();
+}
+
+template<typename T>
+simdjson_inline T&& implementation_simdjson_result_base<T>::operator*() &&  noexcept(false) {
+  return std::forward<implementation_simdjson_result_base<T>>(*this).value();
+}
+
+template<typename T>
+simdjson_inline T* implementation_simdjson_result_base<T>::operator->() noexcept(false) {
+  if (this->error()) { throw simdjson_error(this->error()); }
+  return &this->first;
+}
+
+
+template<typename T>
+simdjson_inline const T* implementation_simdjson_result_base<T>::operator->() const noexcept(false) {
+  if (this->error()) { throw simdjson_error(this->error()); }
+  return &this->first;
+}
+
 template<typename T>
 simdjson_inline T& implementation_simdjson_result_base<T>::value() & noexcept(false) {
   if (error()) { throw simdjson_error(error()); }

include/simdjson/generic/implementation_simdjson_result_base.h

@@ -67,12 +67,17 @@ struct implementation_simdjson_result_base {
    *
    * @param value The variable to assign the value to. May not be set if there is an error.
    */
-  simdjson_inline error_code get(T &value) && noexcept;
+  simdjson_warn_unused simdjson_inline error_code get(T &value) && noexcept;
 
   /**
    * The error.
    */
-  simdjson_inline error_code error() const noexcept;
+  simdjson_warn_unused simdjson_inline error_code error() const noexcept;
+
+  /**
+   * Whether there is a value.
+   */
+  simdjson_warn_unused simdjson_inline bool has_value() const noexcept;
 
 #if SIMDJSON_EXCEPTIONS
 
@@ -81,6 +86,16 @@ struct implementation_simdjson_result_base {
    *
    * @throw simdjson_error if there was an error.
    */
+  simdjson_inline T& operator*() &  noexcept(false);
+  simdjson_inline T&& operator*() &&  noexcept(false);
+  /**
+   * Arrow operator to access members of the contained value.
+   *
+   * @throw simdjson_error if there was an error.
+   */
+  simdjson_inline T* operator->() noexcept(false);
+  simdjson_inline const T* operator->() const noexcept(false);
+
   simdjson_inline T& value() & noexcept(false);
 
   /**

include/simdjson/generic/numberparsing.h

@@ -361,7 +361,7 @@ simdjson_inline bool is_digit(const uint8_t c) {
   return static_cast<uint8_t>(c - '0') <= 9;
 }
 
-simdjson_inline error_code parse_decimal_after_separator(simdjson_unused const uint8_t *const src, const uint8_t *&p, uint64_t &i, int64_t &exponent) {
+simdjson_warn_unused simdjson_inline error_code parse_decimal_after_separator(simdjson_unused const uint8_t *const src, const uint8_t *&p, uint64_t &i, int64_t &exponent) {
   // we continue with the fiction that we have an integer. If the
   // floating point number is representable as x * 10^z for some integer
   // z that fits in 53 bits, then we will be able to convert back the
@@ -389,7 +389,7 @@ simdjson_inline error_code parse_decimal_after_separator(simdjson_unused const u
   return SUCCESS;
 }
 
-simdjson_inline error_code parse_exponent(simdjson_unused const uint8_t *const src, const uint8_t *&p, int64_t &exponent) {
+simdjson_warn_unused simdjson_inline error_code parse_exponent(simdjson_unused const uint8_t *const src, const uint8_t *&p, int64_t &exponent) {
   // Exp Sign: -123.456e[-]78
   bool neg_exp = ('-' == *p);
   if (neg_exp || '+' == *p) { p++; } // Skip + as well
@@ -478,7 +478,7 @@ static error_code slow_float_parsing(simdjson_unused const uint8_t * src, double
 
 /** @private */
 template<typename W>
-simdjson_inline error_code write_float(const uint8_t *const src, bool negative, uint64_t i, const uint8_t * start_digits, size_t digit_count, int64_t exponent, W &writer) {
+simdjson_warn_unused simdjson_inline error_code write_float(const uint8_t *const src, bool negative, uint64_t i, const uint8_t * start_digits, size_t digit_count, int64_t exponent, W &writer) {
   // If we frequently had to deal with long strings of digits,
   // we could extend our code by using a 128-bit integer instead
   // of a 64-bit integer. However, this is uncommon in practice.
@@ -541,13 +541,13 @@ simdjson_inline error_code write_float(const uint8_t *const src, bool negative,
 //
 // Our objective is accurate parsing (ULP of 0) at high speed.
 template<typename W>
-simdjson_inline error_code parse_number(const uint8_t *const src, W &writer);
+simdjson_warn_unused simdjson_inline error_code parse_number(const uint8_t *const src, W &writer);
 
 // for performance analysis, it is sometimes  useful to skip parsing
 #ifdef SIMDJSON_SKIPNUMBERPARSING
 
 template<typename W>
-simdjson_inline error_code parse_number(const uint8_t *const, W &writer) {
+simdjson_warn_unused simdjson_inline error_code parse_number(const uint8_t *const, W &writer) {
   writer.append_s64(0);        // always write zero
   return SUCCESS;              // always succeeds
 }
@@ -573,7 +573,7 @@ simdjson_unused simdjson_inline simdjson_result<number_type> get_number_type(con
 //
 // Our objective is accurate parsing (ULP of 0) at high speed.
 template<typename W>
-simdjson_inline error_code parse_number(const uint8_t *const src, W &writer) {
+simdjson_warn_unused simdjson_inline error_code parse_number(const uint8_t *const src, W &writer) {
   //
   // Check for minus sign
   //

include/simdjson/generic/ondemand/amalgamated.h

@@ -14,6 +14,9 @@
 #include "simdjson/generic/ondemand/raw_json_string.h"
 #include "simdjson/generic/ondemand/parser.h"
 
+// JSON builder - needed for extract_into functionality
+#include "simdjson/generic/ondemand/json_string_builder.h"
+
 // All other declarations
 #include "simdjson/generic/ondemand/array.h"
 #include "simdjson/generic/ondemand/array_iterator.h"
@@ -45,9 +48,10 @@
 #include "simdjson/generic/ondemand/token_iterator-inl.h"
 #include "simdjson/generic/ondemand/value_iterator-inl.h"
 
-// JSON builder, ideally they should not be part of the ondemand directory
-// but it is convenient for now to have them here.
-#include "simdjson/generic/ondemand/json_string_builder.h"
+// JSON builder inline definitions
 #include "simdjson/generic/ondemand/json_string_builder-inl.h"
 #include "simdjson/generic/ondemand/json_builder.h"
 
+// JSON path accessor (compile-time) - must be after inline definitions
+#include "simdjson/generic/ondemand/compile_time_accessors.h"
+

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

@@ -85,7 +85,7 @@ simdjson_inline simdjson_result<array_iterator> array::begin() noexcept {
 simdjson_inline simdjson_result<array_iterator> array::end() noexcept {
   return array_iterator(iter);
 }
-simdjson_inline error_code array::consume() noexcept {
+simdjson_warn_unused simdjson_warn_unused simdjson_inline error_code array::consume() noexcept {
   auto error = iter.json_iter().skip_child(iter.depth()-1);
   if(error) { iter.abandon(); }
   return error;

include/simdjson/generic/ondemand/array.h

@@ -107,7 +107,7 @@ public:
    * JSONPath queries that trivially convertible to JSON Pointer queries: key
    * names and array indices.
    *
-   * https://datatracker.ietf.org/doc/html/draft-normington-jsonpath-00
+   * https://www.rfc-editor.org/rfc/rfc9535 (RFC 9535)
    *
    * @return The value associated with the given JSONPath expression, or:
    *         - INVALID_JSON_POINTER if the JSONPath to JSON Pointer conversion fails
@@ -141,7 +141,7 @@ public:
    * @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)
+  simdjson_warn_unused simdjson_inline error_code get(T &out)
      noexcept(custom_deserializable<T, array> ? nothrow_custom_deserializable<T, array> : true) {
     static_assert(custom_deserializable<T, array>);
     return deserialize(*this, out);
@@ -166,7 +166,7 @@ protected:
   /**
    * Go to the end of the array, no matter where you are right now.
    */
-  simdjson_inline error_code consume() noexcept;
+  simdjson_warn_unused simdjson_inline error_code consume() noexcept;
 
   /**
    * Begin array iteration.
@@ -252,7 +252,7 @@ public:
     return first.get<T>();
   }
   template<typename T>
-  simdjson_inline error_code get(T& out) noexcept {
+  simdjson_warn_unused simdjson_inline error_code get(T& out) noexcept {
     if (error()) { return error(); }
     if constexpr (std::is_same_v<T, SIMDJSON_IMPLEMENTATION::ondemand::array>) {
       out = first;

include/simdjson/generic/ondemand/compile_time_accessors.h

@@ -0,0 +1,938 @@
+/**
+ * Compile-time JSON Path and JSON Pointer accessors using C++26 reflection (P2996)
+ *
+ * This file validates JSON paths/pointers against struct definitions at compile time
+ * and generates optimized accessor code with zero runtime overhead.
+ *
+ * ## How It Works
+ *
+ * **Compile Time**: Path is parsed, validated against struct, types are checked
+ * **Runtime**: Direct navigation with no parsing or validation overhead
+ *
+ * Example:
+ * ```cpp
+ * struct User { std::string name; std::vector<std::string> emails; };
+ *
+ * std::string email;
+ * path_accessor<User, ".emails[0]">::extract_field(doc, email);
+ *
+ * // Compile time validates:
+ * // 1. User has "emails" field
+ * // 2. "emails" is array-like
+ * // 3. Element type is std::string
+ * // 4. static_assert(^^std::string == ^^std::string)
+ *
+ * // Runtime just navigates:
+ * // doc.get_object().find_field("emails").get_array().at(0).get(email)
+ * ```
+ *
+ * ## Key Reflection APIs
+ *
+ * - `^^Type`: Reflect operator, converts type to std::meta::info
+ * - `std::meta::nonstatic_data_members_of(type)`: Get all fields of a struct
+ * - `std::meta::identifier_of(member)`: Get field name as string_view
+ * - `std::meta::type_of(member)`: Get reflected type of a field
+ * - `std::meta::is_array_type(type)`: Check if C-style array
+ * - `std::meta::remove_extent(array)`: Extract element type from array
+ * - `std::meta::members_of(type)`: Get all members including typedefs
+ * - `std::meta::is_type(member)`: Check if member is a type (vs field)
+ *
+ * All operations execute at compile time in consteval contexts.
+ */
+#ifndef SIMDJSON_GENERIC_ONDEMAND_COMPILE_TIME_ACCESSORS_H
+
+#ifndef SIMDJSON_CONDITIONAL_INCLUDE
+#define SIMDJSON_GENERIC_ONDEMAND_COMPILE_TIME_ACCESSORS_H
+
+#endif // SIMDJSON_CONDITIONAL_INCLUDE
+
+// Arguably, we should just check SIMDJSON_STATIC_REFLECTION since it
+// is unlikely that we will have reflection support without concepts support.
+#if SIMDJSON_SUPPORTS_CONCEPTS && SIMDJSON_STATIC_REFLECTION
+
+#include <string_view>
+#include <cstddef>
+#include <array>
+
+namespace simdjson {
+namespace SIMDJSON_IMPLEMENTATION {
+namespace ondemand {
+/***
+ * JSONPath implementation for compile-time access
+ * RFC 9535 JSONPath: Query Expressions for JSON, https://www.rfc-editor.org/rfc/rfc9535
+ */
+namespace json_path {
+
+// Note: value type must be fully defined before this header is included
+// This is ensured by including this in amalgamated.h after value-inl.h
+
+using ::simdjson::SIMDJSON_IMPLEMENTATION::ondemand::value;
+
+// Path step types
+enum class step_type {
+  field,        // .field_name or ["field_name"]
+  array_index   // [index]
+};
+
+// Represents a single step in a JSON path
+template<std::size_t N>
+struct path_step {
+  step_type type;
+  char key[N];  // Field name (empty for array indices)
+  std::size_t index;  // Array index (0 for field access)
+
+  constexpr path_step(step_type t, const char (&k)[N], std::size_t idx = 0)
+    : type(t), index(idx) {
+    for (std::size_t i = 0; i < N; ++i) {
+      key[i] = k[i];
+    }
+  }
+
+  constexpr std::string_view key_view() const {
+    return {key, N - 1};
+  }
+};
+
+// Helper to create field step
+template<std::size_t N>
+consteval auto make_field_step(const char (&name)[N]) {
+  return path_step<N>(step_type::field, name, 0);
+}
+
+// Helper to create array index step
+consteval auto make_index_step(std::size_t idx) {
+  return path_step<1>(step_type::array_index, "", idx);
+}
+
+// Parse state for compile-time JSON path parsing
+struct parse_result {
+  bool success;
+  std::size_t pos;
+  std::string_view error_msg;
+};
+
+// Compile-time JSON path parser
+// Supports subset: .field, ["field"], [index], nested combinations
+template<constevalutil::fixed_string Path>
+struct json_path_parser {
+  static constexpr std::string_view path_str = Path.view();
+
+  // Skip leading $ if present
+  static consteval std::size_t skip_root() {
+    if (!path_str.empty() && path_str[0] == '$') {
+      return 1;
+    }
+    return 0;
+  }
+
+  // Count the number of steps in the path at compile time
+  static consteval std::size_t count_steps() {
+    std::size_t count = 0;
+    std::size_t i = skip_root();
+
+    while (i < path_str.size()) {
+      if (path_str[i] == '.') {
+        // Field access: .field
+        ++i;
+        if (i >= path_str.size()) break;
+
+        // Skip field name
+        while (i < path_str.size() && path_str[i] != '.' && path_str[i] != '[') {
+          ++i;
+        }
+        ++count;
+      } else if (path_str[i] == '[') {
+        // Array or bracket notation
+        ++i;
+        if (i >= path_str.size()) break;
+
+        if (path_str[i] == '"' || path_str[i] == '\'') {
+          // Field access: ["field"] or ['field']
+          char quote = path_str[i];
+          ++i;
+          while (i < path_str.size() && path_str[i] != quote) {
+            ++i;
+          }
+          if (i < path_str.size()) ++i; // skip closing quote
+          if (i < path_str.size() && path_str[i] == ']') ++i;
+        } else {
+          // Array index: [0], [123]
+          while (i < path_str.size() && path_str[i] != ']') {
+            ++i;
+          }
+          if (i < path_str.size()) ++i; // skip ]
+        }
+        ++count;
+      } else {
+        ++i;
+      }
+    }
+
+    return count;
+  }
+
+  // Parse a field name at compile time
+  static consteval std::size_t parse_field_name(std::size_t start, char* out, std::size_t max_len) {
+    std::size_t len = 0;
+    std::size_t i = start;
+
+    while (i < path_str.size() && path_str[i] != '.' && path_str[i] != '[' && len < max_len - 1) {
+      out[len++] = path_str[i++];
+    }
+    out[len] = '\0';
+    return i;
+  }
+
+  // Parse an array index at compile time
+  static consteval std::pair<std::size_t, std::size_t> parse_array_index(std::size_t start) {
+    std::size_t index = 0;
+    std::size_t i = start;
+
+    while (i < path_str.size() && path_str[i] >= '0' && path_str[i] <= '9') {
+      index = index * 10 + (path_str[i] - '0');
+      ++i;
+    }
+
+    return {i, index};
+  }
+};
+
+// Compile-time path accessor generator
+template<typename T, constevalutil::fixed_string Path>
+struct path_accessor {
+  using value = ::simdjson::SIMDJSON_IMPLEMENTATION::ondemand::value;
+
+  static constexpr auto parser = json_path_parser<Path>();
+  static constexpr std::size_t num_steps = parser.count_steps();
+  static constexpr std::string_view path_view = Path.view();
+
+  // Compile-time accessor generation
+  // If T is a struct, validates the path at compile time
+  // If T is void, skips validation
+  template<typename DocOrValue>
+  static inline simdjson_result<value> access(DocOrValue& doc_or_val) noexcept {
+    // Validate path at compile time if T is a struct
+    if constexpr (std::is_class_v<T>) {
+      constexpr bool path_valid = validate_path();
+      static_assert(path_valid, "JSON path does not match struct definition");
+    }
+
+    // Parse the path at compile time to build access steps
+    return access_impl<parser.skip_root()>(doc_or_val.get_value());
+  }
+
+  // Extract value at path directly into target with compile-time type validation
+  // Example: std::string name; path_accessor<User, ".name">::extract_field(doc, name);
+  template<typename DocOrValue, typename FieldType>
+  static inline error_code extract_field(DocOrValue& doc_or_val, FieldType& target) noexcept {
+    static_assert(std::is_class_v<T>, "extract_field requires T to be a struct type for validation");
+
+    // Validate path exists in struct definition
+    constexpr bool path_valid = validate_path();
+    static_assert(path_valid, "JSON path does not match struct definition");
+
+    // Get the type at the end of the path
+    constexpr auto final_type = get_final_type();
+
+    // Verify target type matches the field type
+    static_assert(final_type == ^^FieldType, "Target type does not match the field type at the path");
+
+    // All validation done at compile time - just navigate and extract
+    auto json_value = access_impl<parser.skip_root()>(doc_or_val.get_value());
+    if (json_value.error()) return json_value.error();
+
+    return json_value.get(target);
+  }
+
+private:
+  // Get the final type by walking the path through the struct type
+  template<typename U = T>
+  static consteval std::enable_if_t<std::is_class_v<U>, std::meta::info> get_final_type() {
+    auto current_type = ^^T;
+    std::size_t i = parser.skip_root();
+
+    while (i < path_view.size()) {
+      if (path_view[i] == '.') {
+        // .field syntax
+        ++i;
+        std::size_t field_start = i;
+        while (i < path_view.size() && path_view[i] != '.' && path_view[i] != '[') {
+          ++i;
+        }
+
+        std::string_view field_name = path_view.substr(field_start, i - field_start);
+
+        auto members = std::meta::nonstatic_data_members_of(
+          current_type, std::meta::access_context::unchecked()
+        );
+
+        for (auto mem : members) {
+          if (std::meta::identifier_of(mem) == field_name) {
+            current_type = std::meta::type_of(mem);
+            break;
+          }
+        }
+
+      } else if (path_view[i] == '[') {
+        ++i;
+        if (i >= path_view.size()) break;
+
+        if (path_view[i] == '"' || path_view[i] == '\'') {
+          // ["field"] syntax
+          char quote = path_view[i];
+          ++i;
+          std::size_t field_start = i;
+          while (i < path_view.size() && path_view[i] != quote) {
+            ++i;
+          }
+
+          std::string_view field_name = path_view.substr(field_start, i - field_start);
+          if (i < path_view.size()) ++i; // skip quote
+          if (i < path_view.size() && path_view[i] == ']') ++i;
+
+          auto members = std::meta::nonstatic_data_members_of(
+            current_type, std::meta::access_context::unchecked()
+          );
+
+          for (auto mem : members) {
+            if (std::meta::identifier_of(mem) == field_name) {
+              current_type = std::meta::type_of(mem);
+              break;
+            }
+          }
+
+        } else {
+          // [index] syntax - extract element type
+          while (i < path_view.size() && path_view[i] >= '0' && path_view[i] <= '9') {
+            ++i;
+          }
+          if (i < path_view.size() && path_view[i] == ']') ++i;
+
+          current_type = get_element_type_reflected(current_type);
+        }
+      } else {
+        ++i;
+      }
+    }
+
+    return current_type;
+  }
+
+private:
+  // Walk path and extract directly into final field using compile-time reflection
+  template<std::meta::info CurrentType, std::size_t PathPos, typename TargetType>
+  static inline error_code extract_with_reflection(simdjson_result<value> current, TargetType& target_ref) noexcept {
+    if (current.error()) return current.error();
+
+    // Base case: end of path - extract into target
+    if constexpr (PathPos >= path_view.size()) {
+      return current.get(target_ref);
+    }
+    // Field access: .field_name
+    else if constexpr (path_view[PathPos] == '.') {
+      constexpr auto field_info = parse_next_field(PathPos);
+      constexpr std::string_view field_name = std::get<0>(field_info);
+      constexpr std::size_t next_pos = std::get<1>(field_info);
+
+      constexpr auto member_info = find_member_by_name(CurrentType, field_name);
+      static_assert(member_info != ^^void, "Field not found in struct");
+
+      constexpr auto member_type = std::meta::type_of(member_info);
+
+      auto obj_result = current.get_object();
+      if (obj_result.error()) return obj_result.error();
+      auto obj = obj_result.value_unsafe();
+      auto field_value = obj.find_field_unordered(field_name);
+
+      if constexpr (next_pos >= path_view.size()) {
+        return field_value.get(target_ref);
+      } else {
+        return extract_with_reflection<member_type, next_pos>(field_value, target_ref);
+      }
+    }
+    // Bracket notation: [index] or ["field"]
+    else if constexpr (path_view[PathPos] == '[') {
+      constexpr auto bracket_info = parse_bracket(PathPos);
+      constexpr bool is_field = std::get<0>(bracket_info);
+      constexpr std::size_t next_pos = std::get<2>(bracket_info);
+
+      if constexpr (is_field) {
+        constexpr std::string_view field_name = std::get<1>(bracket_info);
+        constexpr auto member_info = find_member_by_name(CurrentType, field_name);
+        static_assert(member_info != ^^void, "Field not found in struct");
+        constexpr auto member_type = std::meta::type_of(member_info);
+
+        auto obj_result = current.get_object();
+        if (obj_result.error()) return obj_result.error();
+        auto obj = obj_result.value_unsafe();
+        auto field_value = obj.find_field_unordered(field_name);
+
+        if constexpr (next_pos >= path_view.size()) {
+          return field_value.get(target_ref);
+        } else {
+          return extract_with_reflection<member_type, next_pos>(field_value, target_ref);
+        }
+      } else {
+        constexpr std::size_t index = std::get<3>(bracket_info);
+        constexpr auto elem_type = get_element_type_reflected(CurrentType);
+        static_assert(elem_type != ^^void, "Could not determine array element type");
+
+        auto arr_result = current.get_array();
+        if (arr_result.error()) return arr_result.error();
+        auto arr = arr_result.value_unsafe();
+        auto elem_value = arr.at(index);
+
+        if constexpr (next_pos >= path_view.size()) {
+          return elem_value.get(target_ref);
+        } else {
+          return extract_with_reflection<elem_type, next_pos>(elem_value, target_ref);
+        }
+      }
+    }
+    // Skip unexpected characters and continue
+    else {
+      return extract_with_reflection<CurrentType, PathPos + 1>(current, target_ref);
+    }
+  }
+
+  // Find member by name in reflected type
+  static consteval std::meta::info find_member_by_name(std::meta::info type_refl, std::string_view name) {
+    auto members = std::meta::nonstatic_data_members_of(type_refl, std::meta::access_context::unchecked());
+    for (auto mem : members) {
+      if (std::meta::identifier_of(mem) == name) {
+        return mem;
+      }
+    }
+  }
+
+  // Generate compile-time accessor code by walking the path
+  template<std::size_t PathPos>
+  static inline simdjson_result<value> access_impl(simdjson_result<value> current) noexcept {
+    if (current.error()) return current;
+
+    if constexpr (PathPos >= path_view.size()) {
+      return current;
+    } else if constexpr (path_view[PathPos] == '.') {
+      constexpr auto field_info = parse_next_field(PathPos);
+      constexpr std::string_view field_name = std::get<0>(field_info);
+      constexpr std::size_t next_pos = std::get<1>(field_info);
+
+      auto obj_result = current.get_object();
+      if (obj_result.error()) return obj_result.error();
+
+      auto obj = obj_result.value_unsafe();
+      auto next_value = obj.find_field_unordered(field_name);
+
+      return access_impl<next_pos>(next_value);
+
+    } else if constexpr (path_view[PathPos] == '[') {
+      constexpr auto bracket_info = parse_bracket(PathPos);
+      constexpr bool is_field = std::get<0>(bracket_info);
+      constexpr std::size_t next_pos = std::get<2>(bracket_info);
+
+      if constexpr (is_field) {
+        constexpr std::string_view field_name = std::get<1>(bracket_info);
+
+        auto obj_result = current.get_object();
+        if (obj_result.error()) return obj_result.error();
+
+        auto obj = obj_result.value_unsafe();
+        auto next_value = obj.find_field_unordered(field_name);
+
+        return access_impl<next_pos>(next_value);
+
+      } else {
+        constexpr std::size_t index = std::get<3>(bracket_info);
+
+        auto arr_result = current.get_array();
+        if (arr_result.error()) return arr_result.error();
+
+        auto arr = arr_result.value_unsafe();
+        auto next_value = arr.at(index);
+
+        return access_impl<next_pos>(next_value);
+      }
+    } else {
+      return access_impl<PathPos + 1>(current);
+    }
+  }
+
+  // Parse next field name
+  static consteval auto parse_next_field(std::size_t start) {
+    std::size_t i = start + 1;
+    std::size_t field_start = i;
+    while (i < path_view.size() && path_view[i] != '.' && path_view[i] != '[') {
+      ++i;
+    }
+    std::string_view field_name = path_view.substr(field_start, i - field_start);
+    return std::make_tuple(field_name, i);
+  }
+
+  // Parse bracket notation: returns (is_field, field_name, next_pos, index)
+  static consteval auto parse_bracket(std::size_t start) {
+    std::size_t i = start + 1; // skip '['
+
+    if (i < path_view.size() && (path_view[i] == '"' || path_view[i] == '\'')) {
+      // Field access
+      char quote = path_view[i];
+      ++i;
+      std::size_t field_start = i;
+      while (i < path_view.size() && path_view[i] != quote) {
+        ++i;
+      }
+      std::string_view field_name = path_view.substr(field_start, i - field_start);
+      if (i < path_view.size()) ++i; // skip closing quote
+      if (i < path_view.size() && path_view[i] == ']') ++i;
+
+      return std::make_tuple(true, field_name, i, std::size_t(0));
+    } else {
+      // Array index
+      std::size_t index = 0;
+      while (i < path_view.size() && path_view[i] >= '0' && path_view[i] <= '9') {
+        index = index * 10 + (path_view[i] - '0');
+        ++i;
+      }
+      if (i < path_view.size() && path_view[i] == ']') ++i;
+
+      return std::make_tuple(false, std::string_view{}, i, index);
+    }
+  }
+
+public:
+  // Check if reflected type is array-like (C-style array or indexable container)
+  // Uses reflection to test: 1) std::meta::is_array_type() for C arrays
+  //                          2) std::meta::substitute() to test concepts::indexable_container concept
+  static consteval bool is_array_like_reflected(std::meta::info type_reflection) {
+    if (std::meta::is_array_type(type_reflection)) {
+      return true;
+    }
+
+    if (std::meta::can_substitute(^^concepts::indexable_container_v, {type_reflection})) {
+      return std::meta::extract<bool>(std::meta::substitute(^^concepts::indexable_container_v, {type_reflection}));
+    }
+    return false;
+  }
+
+  // Extract element type from reflected array or container
+  // For C arrays: uses std::meta::remove_extent()
+  // For containers: finds value_type member using std::meta::members_of()
+  static consteval std::meta::info get_element_type_reflected(std::meta::info type_reflection) {
+    if (std::meta::is_array_type(type_reflection)) {
+      return std::meta::remove_extent(type_reflection);
+    }
+
+    auto members = std::meta::members_of(type_reflection, std::meta::access_context::unchecked());
+    for (auto mem : members) {
+      if (std::meta::is_type(mem)) {
+        auto name = std::meta::identifier_of(mem);
+        if (name == "value_type") {
+          return mem;
+        }
+      }
+    }
+    return ^^void;
+  }
+
+private:
+  // Check if type has member with given name
+  template<typename Type>
+  static consteval bool has_member(std::string_view member_name) {
+    constexpr auto members = std::meta::nonstatic_data_members_of(^^Type, std::meta::access_context::unchecked());
+    for (auto mem : members) {
+      if (std::meta::identifier_of(mem) == member_name) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  // Get type of member by name
+  template<typename Type>
+  static consteval auto get_member_type(std::string_view member_name) {
+    constexpr auto members = std::meta::nonstatic_data_members_of(^^Type, std::meta::access_context::unchecked());
+    for (auto mem : members) {
+      if (std::meta::identifier_of(mem) == member_name) {
+        return std::meta::type_of(mem);
+      }
+    }
+    return ^^void;
+  }
+
+  // Check if non-reflected type is array-like
+  template<typename Type>
+  static consteval bool is_container_type() {
+    using BaseType = std::remove_cvref_t<Type>;
+    if constexpr (requires { typename BaseType::value_type; }) {
+      return true;
+    }
+    if constexpr (std::is_array_v<BaseType>) {
+      return true;
+    }
+    return false;
+  }
+
+  // Extract element type from non-reflected container
+  template<typename Type>
+  using extract_element_type = std::conditional_t<
+    requires { typename std::remove_cvref_t<Type>::value_type; },
+    typename std::remove_cvref_t<Type>::value_type,
+    std::conditional_t<
+      std::is_array_v<std::remove_cvref_t<Type>>,
+      std::remove_extent_t<std::remove_cvref_t<Type>>,
+      void
+    >
+  >;
+
+  // Validate path matches struct definition
+  static consteval bool validate_path() {
+    if constexpr (!std::is_class_v<T>) {
+      return true;
+    }
+
+    auto current_type = ^^T;
+    std::size_t i = parser.skip_root();
+
+    while (i < path_view.size()) {
+      if (path_view[i] == '.') {
+        ++i;
+        std::size_t field_start = i;
+        while (i < path_view.size() && path_view[i] != '.' && path_view[i] != '[') {
+          ++i;
+        }
+
+        std::string_view field_name = path_view.substr(field_start, i - field_start);
+
+        bool found = false;
+        auto members = std::meta::nonstatic_data_members_of(current_type, std::meta::access_context::unchecked());
+
+        for (auto mem : members) {
+          if (std::meta::identifier_of(mem) == field_name) {
+            current_type = std::meta::type_of(mem);
+            found = true;
+            break;
+          }
+        }
+
+        if (!found) {
+          return false;
+        }
+
+      } else if (path_view[i] == '[') {
+        ++i;
+        if (i >= path_view.size()) return false;
+
+        if (path_view[i] == '"' || path_view[i] == '\'') {
+          char quote = path_view[i];
+          ++i;
+          std::size_t field_start = i;
+          while (i < path_view.size() && path_view[i] != quote) {
+            ++i;
+          }
+
+          std::string_view field_name = path_view.substr(field_start, i - field_start);
+          if (i < path_view.size()) ++i;
+          if (i < path_view.size() && path_view[i] == ']') ++i;
+
+          bool found = false;
+          auto members = std::meta::nonstatic_data_members_of(current_type, std::meta::access_context::unchecked());
+
+          for (auto mem : members) {
+            if (std::meta::identifier_of(mem) == field_name) {
+              current_type = std::meta::type_of(mem);
+              found = true;
+              break;
+            }
+          }
+
+          if (!found) {
+            return false;
+          }
+
+        } else {
+          while (i < path_view.size() && path_view[i] >= '0' && path_view[i] <= '9') {
+            ++i;
+          }
+
+          if (i < path_view.size() && path_view[i] == ']') ++i;
+
+          if (!is_array_like_reflected(current_type)) {
+            return false;
+          }
+
+          auto new_type = get_element_type_reflected(current_type);
+
+          if (new_type == ^^void) {
+            return false;
+          }
+
+          current_type = new_type;
+        }
+      } else {
+        ++i;
+      }
+    }
+
+    return true;
+  }
+};
+
+// Compile-time path accessor with validation
+template<typename T, constevalutil::fixed_string Path, typename DocOrValue>
+inline simdjson_result<::simdjson::SIMDJSON_IMPLEMENTATION::ondemand::value> at_path_compiled(DocOrValue& doc_or_val) noexcept {
+  using accessor = path_accessor<T, Path>;
+  return accessor::access(doc_or_val);
+}
+
+// Overload without type parameter (no validation)
+template<constevalutil::fixed_string Path, typename DocOrValue>
+inline simdjson_result<::simdjson::SIMDJSON_IMPLEMENTATION::ondemand::value> at_path_compiled(DocOrValue& doc_or_val) noexcept {
+  using accessor = path_accessor<void, Path>;
+  return accessor::access(doc_or_val);
+}
+
+// ============================================================================
+// JSON Pointer Compile-Time Support (RFC 6901)
+// ============================================================================
+
+// JSON Pointer parser: /field/0/nested (slash-separated)
+template<constevalutil::fixed_string Pointer>
+struct json_pointer_parser {
+  static constexpr std::string_view pointer_str = Pointer.view();
+
+  // Unescape token: ~0 -> ~, ~1 -> /
+  static consteval void unescape_token(std::string_view src, char* dest, std::size_t& out_len) {
+    out_len = 0;
+    for (std::size_t i = 0; i < src.size(); ++i) {
+      if (src[i] == '~' && i + 1 < src.size()) {
+        if (src[i + 1] == '0') {
+          dest[out_len++] = '~';
+          ++i;
+        } else if (src[i + 1] == '1') {
+          dest[out_len++] = '/';
+          ++i;
+        } else {
+          dest[out_len++] = src[i];
+        }
+      } else {
+        dest[out_len++] = src[i];
+      }
+    }
+  }
+
+  // Check if token is numeric
+  static consteval bool is_numeric(std::string_view token) {
+    if (token.empty()) return false;
+    if (token[0] == '0' && token.size() > 1) return false;
+    for (char c : token) {
+      if (c < '0' || c > '9') return false;
+    }
+    return true;
+  }
+
+  // Parse numeric token to index
+  static consteval std::size_t parse_index(std::string_view token) {
+    std::size_t result = 0;
+    for (char c : token) {
+      result = result * 10 + (c - '0');
+    }
+    return result;
+  }
+
+  // Count tokens in pointer
+  static consteval std::size_t count_tokens() {
+    if (pointer_str.empty() || pointer_str == "/") return 0;
+
+    std::size_t count = 0;
+    std::size_t pos = pointer_str[0] == '/' ? 1 : 0;
+
+    while (pos < pointer_str.size()) {
+      ++count;
+      std::size_t next_slash = pointer_str.find('/', pos);
+      if (next_slash == std::string_view::npos) break;
+      pos = next_slash + 1;
+    }
+
+    return count;
+  }
+
+  // Get Nth token
+  static consteval std::string_view get_token(std::size_t token_index) {
+    std::size_t pos = pointer_str[0] == '/' ? 1 : 0;
+    std::size_t current_token = 0;
+
+    while (current_token < token_index) {
+      std::size_t next_slash = pointer_str.find('/', pos);
+      pos = next_slash + 1;
+      ++current_token;
+    }
+
+    std::size_t token_end = pointer_str.find('/', pos);
+    if (token_end == std::string_view::npos) token_end = pointer_str.size();
+
+    return pointer_str.substr(pos, token_end - pos);
+  }
+};
+
+// JSON Pointer accessor
+template<typename T, constevalutil::fixed_string Pointer>
+struct pointer_accessor {
+  using parser = json_pointer_parser<Pointer>;
+  static constexpr std::string_view pointer_view = Pointer.view();
+  static constexpr std::size_t token_count = parser::count_tokens();
+
+  // Validate pointer against struct definition
+  static consteval bool validate_pointer() {
+    if constexpr (!std::is_class_v<T>) {
+      return true;
+    }
+
+    auto current_type = ^^T;
+    std::size_t pos = pointer_view[0] == '/' ? 1 : 0;
+
+    while (pos < pointer_view.size()) {
+      // Extract token up to next /
+      std::size_t token_end = pointer_view.find('/', pos);
+      if (token_end == std::string_view::npos) token_end = pointer_view.size();
+
+      std::string_view token = pointer_view.substr(pos, token_end - pos);
+
+      if (parser::is_numeric(token)) {
+        if (!path_accessor<T, Pointer>::is_array_like_reflected(current_type)) {
+          return false;
+        }
+        current_type = path_accessor<T, Pointer>::get_element_type_reflected(current_type);
+      } else {
+        bool found = false;
+        auto members = std::meta::nonstatic_data_members_of(current_type, std::meta::access_context::unchecked());
+
+        for (auto mem : members) {
+          if (std::meta::identifier_of(mem) == token) {
+            current_type = std::meta::type_of(mem);
+            found = true;
+            break;
+          }
+        }
+
+        if (!found) return false;
+      }
+
+      pos = token_end + 1;
+    }
+
+    return true;
+  }
+
+  // Recursive accessor
+  template<std::size_t TokenIndex>
+  static inline simdjson_result<value> access_impl(simdjson_result<value> current) noexcept {
+    if constexpr (TokenIndex >= token_count) {
+      return current;
+    } else {
+      constexpr std::string_view token = parser::get_token(TokenIndex);
+
+      if constexpr (parser::is_numeric(token)) {
+        constexpr std::size_t index = parser::parse_index(token);
+        auto arr = current.get_array().value_unsafe();
+        auto next_value = arr.at(index);
+        return access_impl<TokenIndex + 1>(next_value);
+      } else {
+        auto obj = current.get_object().value_unsafe();
+        auto next_value = obj.find_field_unordered(token);
+        return access_impl<TokenIndex + 1>(next_value);
+      }
+    }
+  }
+
+  // Access JSON value at pointer
+  template<typename DocOrValue>
+  static inline simdjson_result<value> access(DocOrValue& doc_or_val) noexcept {
+    if constexpr (std::is_class_v<T>) {
+      constexpr bool pointer_valid = validate_pointer();
+      static_assert(pointer_valid, "JSON Pointer does not match struct definition");
+    }
+
+    if (pointer_view.empty() || pointer_view == "/") {
+      if constexpr (requires { doc_or_val.get_value(); }) {
+        return doc_or_val.get_value();
+      } else {
+        return doc_or_val;
+      }
+    }
+
+    simdjson_result<value> current = doc_or_val.get_value();
+    return access_impl<0>(current);
+  }
+
+  // Extract value at pointer directly into target with type validation
+  template<typename DocOrValue, typename FieldType>
+  static inline error_code extract_field(DocOrValue& doc_or_val, FieldType& target) noexcept {
+    static_assert(std::is_class_v<T>, "extract_field requires T to be a struct type for validation");
+
+    constexpr bool pointer_valid = validate_pointer();
+    static_assert(pointer_valid, "JSON Pointer does not match struct definition");
+
+    constexpr auto final_type = get_final_type();
+    static_assert(final_type == ^^FieldType, "Target type does not match the field type at the pointer");
+
+    simdjson_result<value> current_value = doc_or_val.get_value();
+    auto json_value = access_impl<0>(current_value);
+    if (json_value.error()) return json_value.error();
+
+    return json_value.get(target);
+  }
+
+private:
+  // Get final type by walking pointer through struct
+  template<typename U = T>
+  static consteval std::enable_if_t<std::is_class_v<U>, std::meta::info> get_final_type() {
+    auto current_type = ^^T;
+    std::size_t pos = pointer_view[0] == '/' ? 1 : 0;
+
+    while (pos < pointer_view.size()) {
+      std::size_t token_end = pointer_view.find('/', pos);
+      if (token_end == std::string_view::npos) token_end = pointer_view.size();
+
+      std::string_view token = pointer_view.substr(pos, token_end - pos);
+
+      if (parser::is_numeric(token)) {
+        current_type = path_accessor<T, "">::get_element_type_reflected(current_type);
+      } else {
+        auto members = std::meta::nonstatic_data_members_of(current_type, std::meta::access_context::unchecked());
+
+        for (auto mem : members) {
+          if (std::meta::identifier_of(mem) == token) {
+            current_type = std::meta::type_of(mem);
+            break;
+          }
+        }
+      }
+
+      pos = token_end + 1;
+    }
+
+    return current_type;
+  }
+};
+
+// Compile-time JSON Pointer accessor with validation
+template<typename T, constevalutil::fixed_string Pointer, typename DocOrValue>
+inline simdjson_result<::simdjson::SIMDJSON_IMPLEMENTATION::ondemand::value> at_pointer_compiled(DocOrValue& doc_or_val) noexcept {
+  using accessor = pointer_accessor<T, Pointer>;
+  return accessor::access(doc_or_val);
+}
+
+// Overload without type parameter (no validation)
+template<constevalutil::fixed_string Pointer, typename DocOrValue>
+inline simdjson_result<::simdjson::SIMDJSON_IMPLEMENTATION::ondemand::value> at_pointer_compiled(DocOrValue& doc_or_val) noexcept {
+  using accessor = pointer_accessor<void, Pointer>;
+  return accessor::access(doc_or_val);
+}
+
+} // namespace json_path
+} // namespace ondemand
+} // namespace SIMDJSON_IMPLEMENTATION
+} // namespace simdjson
+
+#endif // SIMDJSON_SUPPORTS_CONCEPTS && SIMDJSON_STATIC_REFLECTION
+#endif // SIMDJSON_GENERIC_ONDEMAND_COMPILE_TIME_ACCESSORS_H
+

include/simdjson/generic/ondemand/deserialize.h

@@ -7,55 +7,8 @@
 #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

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

@@ -141,7 +141,7 @@ simdjson_inline simdjson_result<std::string_view> document::get_string(bool allo
   return get_root_value_iterator().get_root_string(true, allow_replacement);
 }
 template <typename string_type>
-simdjson_inline error_code document::get_string(string_type& receiver, bool allow_replacement) noexcept {
+simdjson_warn_unused simdjson_inline error_code document::get_string(string_type& receiver, bool allow_replacement) noexcept {
   return get_root_value_iterator().get_root_string(receiver, true, allow_replacement);
 }
 simdjson_inline simdjson_result<std::string_view> document::get_wobbly_string() noexcept {
@@ -167,15 +167,15 @@ 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 error_code document::get(array& out) & noexcept { return get_array().get(out); }
-template<> simdjson_inline error_code document::get(object& out) & noexcept { return get_object().get(out); }
-template<> simdjson_inline error_code document::get(raw_json_string& out) & noexcept { return get_raw_json_string().get(out); }
-template<> simdjson_inline error_code document::get(std::string_view& out) & noexcept { return get_string(false).get(out); }
-template<> simdjson_inline error_code document::get(double& out) & noexcept { return get_double().get(out); }
-template<> simdjson_inline error_code document::get(uint64_t& out) & noexcept { return get_uint64().get(out); }
-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<> simdjson_warn_unused simdjson_inline error_code document::get(array& out) & noexcept { return get_array().get(out); }
+template<> simdjson_warn_unused simdjson_inline error_code document::get(object& out) & noexcept { return get_object().get(out); }
+template<> simdjson_warn_unused simdjson_inline error_code document::get(raw_json_string& out) & noexcept { return get_raw_json_string().get(out); }
+template<> simdjson_warn_unused simdjson_inline error_code document::get(std::string_view& out) & noexcept { return get_string(false).get(out); }
+template<> simdjson_warn_unused simdjson_inline error_code document::get(double& out) & noexcept { return get_double().get(out); }
+template<> simdjson_warn_unused simdjson_inline error_code document::get(uint64_t& out) & noexcept { return get_uint64().get(out); }
+template<> simdjson_warn_unused simdjson_inline error_code document::get(int64_t& out) & noexcept { return get_int64().get(out); }
+template<> simdjson_warn_unused simdjson_inline error_code document::get(bool& out) & noexcept { return get_bool().get(out); }
+template<> simdjson_warn_unused simdjson_inline error_code document::get(value& out) & noexcept { return get_value().get(out); }
 
 template<> simdjson_deprecated simdjson_inline simdjson_result<raw_json_string> document::get() && noexcept { return get_raw_json_string(); }
 template<> simdjson_deprecated simdjson_inline simdjson_result<std::string_view> document::get() && noexcept { return get_string(false); }
@@ -245,7 +245,7 @@ simdjson_inline simdjson_result<value> document::operator[](const char *key) & n
   return start_or_resume_object()[key];
 }
 
-simdjson_inline error_code document::consume() noexcept {
+simdjson_warn_unused simdjson_inline error_code document::consume() noexcept {
   bool scalar = false;
   auto error = is_scalar().get(scalar);
   if(error) { return error; }
@@ -347,6 +347,54 @@ simdjson_inline simdjson_result<value> document::at_path(std::string_view json_p
   }
 }
 
+
+
+#if SIMDJSON_SUPPORTS_CONCEPTS && SIMDJSON_STATIC_REFLECTION
+
+template<constevalutil::fixed_string... FieldNames, typename T>
+  requires(std::is_class_v<T> && (sizeof...(FieldNames) > 0))
+simdjson_warn_unused simdjson_inline error_code document::extract_into(T& out) & noexcept {
+  // Helper to check if a field name matches any of the requested fields
+  auto should_extract = [](std::string_view field_name) constexpr -> bool {
+    return ((FieldNames.view() == field_name) || ...);
+  };
+
+  // Iterate through all members of T using reflection
+  template for (constexpr auto mem : std::define_static_array(
+      std::meta::nonstatic_data_members_of(^^T, std::meta::access_context::unchecked()))) {
+
+    if constexpr (!std::meta::is_const(mem) && std::meta::is_public(mem)) {
+      constexpr std::string_view key = std::define_static_string(std::meta::identifier_of(mem));
+
+      // Only extract this field if it's in our list of requested fields
+      if constexpr (should_extract(key)) {
+        // Try to find and extract the field
+        if constexpr (concepts::optional_type<decltype(out.[:mem:])>) {
+          // For optional fields, it's ok if they're missing
+          auto field_result = find_field_unordered(key);
+          if (!field_result.error()) {
+            auto error = field_result.get(out.[:mem:]);
+            if (error && error != NO_SUCH_FIELD) {
+              return error;
+            }
+          } else if (field_result.error() != NO_SUCH_FIELD) {
+            return field_result.error();
+          } else {
+            out.[:mem:].reset();
+          }
+        } else {
+          // For required fields (in the requested list), fail if missing
+          SIMDJSON_TRY((*this)[key].get(out.[:mem:]));
+        }
+      }
+    }
+  };
+
+  return SUCCESS;
+}
+
+#endif // SIMDJSON_SUPPORTS_CONCEPTS && SIMDJSON_STATIC_REFLECTION
+
 } // namespace ondemand
 } // namespace SIMDJSON_IMPLEMENTATION
 } // namespace simdjson
@@ -454,7 +502,7 @@ simdjson_inline simdjson_result<std::string_view> simdjson_result<SIMDJSON_IMPLE
   return first.get_string(allow_replacement);
 }
 template <typename string_type>
-simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document>::get_string(string_type& receiver, bool allow_replacement) noexcept {
+simdjson_warn_unused simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document>::get_string(string_type& receiver, bool allow_replacement) noexcept {
   if (error()) { return error(); }
   return first.get_string(receiver, allow_replacement);
 }
@@ -490,12 +538,12 @@ simdjson_deprecated simdjson_inline simdjson_result<T> simdjson_result<SIMDJSON_
   return std::forward<SIMDJSON_IMPLEMENTATION::ondemand::document>(first).get<T>();
 }
 template<typename T>
-simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document>::get(T &out) & noexcept {
+simdjson_warn_unused simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document>::get(T &out) & noexcept {
   if (error()) { return error(); }
   return first.get<T>(out);
 }
 template<typename T>
-simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document>::get(T &out) && noexcept {
+simdjson_warn_unused simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document>::get(T &out) && noexcept {
   if (error()) { return error(); }
   return std::forward<SIMDJSON_IMPLEMENTATION::ondemand::document>(first).get<T>(out);
 }
@@ -505,8 +553,8 @@ template<> simdjson_deprecated simdjson_inline simdjson_result<SIMDJSON_IMPLEMEN
   if (error()) { return error(); }
   return std::forward<SIMDJSON_IMPLEMENTATION::ondemand::document>(first);
 }
-template<> simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document>::get<SIMDJSON_IMPLEMENTATION::ondemand::document>(SIMDJSON_IMPLEMENTATION::ondemand::document &out) & noexcept = delete;
-template<> simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document>::get<SIMDJSON_IMPLEMENTATION::ondemand::document>(SIMDJSON_IMPLEMENTATION::ondemand::document &out) && noexcept {
+template<> simdjson_warn_unused simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document>::get<SIMDJSON_IMPLEMENTATION::ondemand::document>(SIMDJSON_IMPLEMENTATION::ondemand::document &out) & noexcept = delete;
+template<> simdjson_warn_unused simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document>::get<SIMDJSON_IMPLEMENTATION::ondemand::document>(SIMDJSON_IMPLEMENTATION::ondemand::document &out) && noexcept {
   if (error()) { return error(); }
   out = std::forward<SIMDJSON_IMPLEMENTATION::ondemand::document>(first);
   return SUCCESS;
@@ -624,6 +672,15 @@ simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> simdjs
   return first.at_path(json_path);
 }
 
+#if SIMDJSON_STATIC_REFLECTION
+template<constevalutil::fixed_string... FieldNames, typename T>
+  requires(std::is_class_v<T> && (sizeof...(FieldNames) > 0))
+simdjson_warn_unused simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document>::extract_into(T& out) & noexcept {
+  if (error()) { return error(); }
+  return first.extract_into<FieldNames...>(out);
+}
+#endif // SIMDJSON_STATIC_REFLECTION
+
 } // namespace simdjson
 
 
@@ -658,7 +715,7 @@ simdjson_inline simdjson_result<double> document_reference::get_double() noexcep
 simdjson_inline simdjson_result<double> document_reference::get_double_in_string() noexcept { return doc->get_root_value_iterator().get_root_double(false); }
 simdjson_inline simdjson_result<std::string_view> document_reference::get_string(bool allow_replacement) noexcept { return doc->get_root_value_iterator().get_root_string(false, allow_replacement); }
 template <typename string_type>
-simdjson_inline error_code document_reference::get_string(string_type& receiver, bool allow_replacement) noexcept { return doc->get_root_value_iterator().get_root_string(receiver, false, allow_replacement); }
+simdjson_warn_unused simdjson_inline error_code document_reference::get_string(string_type& receiver, bool allow_replacement) noexcept { return doc->get_root_value_iterator().get_root_string(receiver, false, allow_replacement); }
 simdjson_inline simdjson_result<std::string_view> document_reference::get_wobbly_string() noexcept { return doc->get_root_value_iterator().get_root_wobbly_string(false); }
 simdjson_inline simdjson_result<raw_json_string> document_reference::get_raw_json_string() noexcept { return doc->get_root_value_iterator().get_root_raw_json_string(false); }
 simdjson_inline simdjson_result<bool> document_reference::get_bool() noexcept { return doc->get_root_value_iterator().get_root_bool(false); }
@@ -711,7 +768,13 @@ simdjson_inline simdjson_result<value> document_reference::at_pointer(std::strin
 simdjson_inline simdjson_result<value> document_reference::at_path(std::string_view json_path) noexcept { return doc->at_path(json_path); }
 simdjson_inline simdjson_result<std::string_view> document_reference::raw_json() noexcept { return doc->raw_json();}
 simdjson_inline document_reference::operator document&() const noexcept { return *doc; }
-
+#if SIMDJSON_SUPPORTS_CONCEPTS && SIMDJSON_STATIC_REFLECTION
+template<constevalutil::fixed_string... FieldNames, typename T>
+  requires(std::is_class_v<T> && (sizeof...(FieldNames) > 0))
+simdjson_warn_unused simdjson_inline error_code document_reference::extract_into(T& out) & noexcept {
+  return doc->extract_into<FieldNames...>(out);
+}
+#endif // SIMDJSON_SUPPORTS_CONCEPTS && SIMDJSON_STATIC_REFLECTION
 } // namespace ondemand
 } // namespace SIMDJSON_IMPLEMENTATION
 } // namespace simdjson
@@ -808,7 +871,7 @@ simdjson_inline simdjson_result<std::string_view> simdjson_result<SIMDJSON_IMPLE
   return first.get_string(allow_replacement);
 }
 template <typename string_type>
-simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document_reference>::get_string(string_type& receiver, bool allow_replacement) noexcept {
+simdjson_warn_unused simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document_reference>::get_string(string_type& receiver, bool allow_replacement) noexcept {
   if (error()) { return error(); }
   return first.get_string(receiver, allow_replacement);
 }
@@ -843,12 +906,12 @@ simdjson_inline simdjson_result<T> simdjson_result<SIMDJSON_IMPLEMENTATION::onde
   return std::forward<SIMDJSON_IMPLEMENTATION::ondemand::document_reference>(first).get<T>();
 }
 template <class T>
-simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document_reference>::get(T &out) & noexcept {
+simdjson_warn_unused simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document_reference>::get(T &out) & noexcept {
   if (error()) { return error(); }
   return first.get<T>(out);
 }
 template <class T>
-simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document_reference>::get(T &out) && noexcept {
+simdjson_warn_unused simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document_reference>::get(T &out) && noexcept {
   if (error()) { return error(); }
   return std::forward<SIMDJSON_IMPLEMENTATION::ondemand::document_reference>(first).get<T>(out);
 }
@@ -865,13 +928,13 @@ simdjson_inline simdjson_result<bool> simdjson_result<SIMDJSON_IMPLEMENTATION::o
   return first.is_string();
 }
 template <>
-simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document_reference>::get(SIMDJSON_IMPLEMENTATION::ondemand::document_reference &out) & noexcept {
+simdjson_warn_unused simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document_reference>::get(SIMDJSON_IMPLEMENTATION::ondemand::document_reference &out) & noexcept {
   if (error()) { return error(); }
   out = first;
   return SUCCESS;
 }
 template <>
-simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document_reference>::get(SIMDJSON_IMPLEMENTATION::ondemand::document_reference &out) && noexcept {
+simdjson_warn_unused simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document_reference>::get(SIMDJSON_IMPLEMENTATION::ondemand::document_reference &out) && noexcept {
   if (error()) { return error(); }
   out = first;
   return SUCCESS;
@@ -959,7 +1022,14 @@ simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> simdjs
   }
   return first.at_path(json_path);
 }
-
+#if SIMDJSON_STATIC_REFLECTION
+template<constevalutil::fixed_string... FieldNames, typename T>
+  requires(std::is_class_v<T> && (sizeof...(FieldNames) > 0))
+simdjson_warn_unused simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document_reference>::extract_into(T& out) & noexcept {
+  if (error()) { return error(); }
+  return first.extract_into<FieldNames...>(out);
+}
+#endif // SIMDJSON_STATIC_REFLECTION
 } // namespace simdjson
 
 #endif // SIMDJSON_GENERIC_ONDEMAND_DOCUMENT_INL_H

include/simdjson/generic/ondemand/document.h

@@ -117,7 +117,7 @@ public:
    * @returns INCORRECT_TYPE if the JSON value is not a string. Otherwise, we return SUCCESS.
    */
   template <typename string_type>
-  simdjson_inline error_code get_string(string_type& receiver, bool allow_replacement = false) noexcept;
+  simdjson_warn_unused simdjson_inline error_code get_string(string_type& receiver, bool allow_replacement = false) noexcept;
   /**
    * Cast this JSON value to a string.
    *
@@ -228,7 +228,7 @@ public:
    * @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) &
+  simdjson_warn_unused simdjson_inline error_code get(T &out) &
 #if SIMDJSON_SUPPORTS_CONCEPTS
     noexcept(custom_deserializable<T, document> ? nothrow_custom_deserializable<T, document> : true)
 #else
@@ -407,7 +407,7 @@ public:
    * The following code reads z, then y, then x, and thus will not retrieve x or y if fed the
    * JSON `{ "x": 1, "y": 2, "z": 3 }`:
    *
-   * ```c++
+   * ```cpp
    * simdjson::ondemand::parser parser;
    * auto obj = parser.parse(R"( { "x": 1, "y": 2, "z": 3 } )"_padded);
    * double z = obj.find_field("z");
@@ -701,7 +701,7 @@ public:
    * JSONPath queries that trivially convertible to JSON Pointer queries: key
    * names and array indices.
    *
-   * https://datatracker.ietf.org/doc/html/draft-normington-jsonpath-00
+   * https://www.rfc-editor.org/rfc/rfc9535 (RFC 9535)
    *
    * Key values are matched exactly, without unescaping or Unicode normalization.
    * We do a byte-by-byte comparison. E.g.
@@ -725,11 +725,41 @@ public:
    * the JSON document.
    */
   simdjson_inline simdjson_result<std::string_view> raw_json() noexcept;
+
+#if SIMDJSON_STATIC_REFLECTION
+  /**
+   * Extract only specific fields from the JSON object into a struct.
+   *
+   * This allows selective deserialization of only the fields you need,
+   * potentially improving performance by skipping unwanted fields.
+   *
+   * Example:
+   * ```cpp
+   * struct Car {
+   *   std::string make;
+   *   std::string model;
+   *   int year;
+   *   double price;
+   * };
+   *
+   * Car car;
+   * doc.extract_into<"make", "model">(car);
+   * // Only 'make' and 'model' fields are extracted from JSON
+   * ```
+   *
+   * @tparam FieldNames Compile-time string literals specifying which fields to extract
+   * @param out The output struct to populate with selected fields
+   * @returns SUCCESS on success, or an error code if a required field is missing or has wrong type
+   */
+  template<constevalutil::fixed_string... FieldNames, typename T>
+    requires(std::is_class_v<T> && (sizeof...(FieldNames) > 0))
+  simdjson_warn_unused simdjson_inline error_code extract_into(T& out) & noexcept;
+#endif // SIMDJSON_STATIC_REFLECTION
 protected:
   /**
    * Consumes the document.
    */
-  simdjson_inline error_code consume() noexcept;
+  simdjson_warn_unused simdjson_inline error_code consume() noexcept;
 
   simdjson_inline document(ondemand::json_iterator &&iter) noexcept;
   simdjson_inline const uint8_t *text(uint32_t idx) const noexcept;
@@ -782,7 +812,7 @@ public:
   simdjson_inline simdjson_result<double> get_double_in_string() noexcept;
   simdjson_inline simdjson_result<std::string_view> get_string(bool allow_replacement = false) noexcept;
   template <typename string_type>
-  simdjson_inline error_code get_string(string_type& receiver, bool allow_replacement = false) noexcept;
+  simdjson_warn_unused simdjson_inline error_code get_string(string_type& receiver, bool allow_replacement = false) noexcept;
   simdjson_inline simdjson_result<std::string_view> get_wobbly_string() noexcept;
   simdjson_inline simdjson_result<raw_json_string> get_raw_json_string() noexcept;
   simdjson_inline simdjson_result<bool> get_bool() noexcept;
@@ -826,7 +856,7 @@ public:
    * @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) &
+  simdjson_warn_unused simdjson_inline error_code get(T &out) &
 #if SIMDJSON_SUPPORTS_CONCEPTS
     noexcept(custom_deserializable<T, document> ? nothrow_custom_deserializable<T, document_reference> : true)
 #else
@@ -861,6 +891,11 @@ public:
   /** @overload template<typename T> error_code get(T &out) & noexcept */
   template<typename T> simdjson_inline error_code get(T &out) && noexcept;
   simdjson_inline simdjson_result<std::string_view> raw_json() noexcept;
+#if SIMDJSON_STATIC_REFLECTION
+  template<constevalutil::fixed_string... FieldNames, typename T>
+    requires(std::is_class_v<T> && (sizeof...(FieldNames) > 0))
+  simdjson_warn_unused simdjson_inline error_code extract_into(T& out) & noexcept;
+#endif // SIMDJSON_STATIC_REFLECTION
   simdjson_inline operator document&() const noexcept;
 #if SIMDJSON_EXCEPTIONS
   template <class T>
@@ -929,7 +964,7 @@ public:
   simdjson_inline simdjson_result<double> get_double_in_string() noexcept;
   simdjson_inline simdjson_result<std::string_view> get_string(bool allow_replacement = false) noexcept;
   template <typename string_type>
-  simdjson_inline error_code get_string(string_type& receiver, bool allow_replacement = false) noexcept;
+  simdjson_warn_unused simdjson_inline error_code get_string(string_type& receiver, bool allow_replacement = false) noexcept;
   simdjson_inline simdjson_result<std::string_view> get_wobbly_string() noexcept;
   simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::raw_json_string> get_raw_json_string() noexcept;
   simdjson_inline simdjson_result<bool> get_bool() noexcept;
@@ -942,6 +977,9 @@ public:
   template<typename T> simdjson_inline error_code get(T &out) & noexcept;
   template<typename T> simdjson_inline error_code get(T &out) && noexcept;
 #if SIMDJSON_EXCEPTIONS
+
+  using SIMDJSON_IMPLEMENTATION::implementation_simdjson_result_base<SIMDJSON_IMPLEMENTATION::ondemand::document>::operator*;
+  using SIMDJSON_IMPLEMENTATION::implementation_simdjson_result_base<SIMDJSON_IMPLEMENTATION::ondemand::document>::operator->;
   template <class T, typename std::enable_if<std::is_same<T, SIMDJSON_IMPLEMENTATION::ondemand::document>::value == false>::type>
   explicit simdjson_inline operator T() noexcept(false);
   simdjson_inline operator SIMDJSON_IMPLEMENTATION::ondemand::array() & noexcept(false);
@@ -981,6 +1019,11 @@ public:
 
   simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> at_pointer(std::string_view json_pointer) noexcept;
   simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> at_path(std::string_view json_path) noexcept;
+#if SIMDJSON_STATIC_REFLECTION
+  template<constevalutil::fixed_string... FieldNames, typename T>
+    requires(std::is_class_v<T> && (sizeof...(FieldNames) > 0))
+  simdjson_warn_unused simdjson_inline error_code extract_into(T& out) & noexcept;
+#endif // SIMDJSON_STATIC_REFLECTION
 };
 
 
@@ -1007,7 +1050,7 @@ public:
   simdjson_inline simdjson_result<double> get_double_in_string() noexcept;
   simdjson_inline simdjson_result<std::string_view> get_string(bool allow_replacement = false) noexcept;
   template <typename string_type>
-  simdjson_inline error_code get_string(string_type& receiver, bool allow_replacement = false) noexcept;
+  simdjson_warn_unused simdjson_inline error_code get_string(string_type& receiver, bool allow_replacement = false) noexcept;
   simdjson_inline simdjson_result<std::string_view> get_wobbly_string() noexcept;
   simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::raw_json_string> get_raw_json_string() noexcept;
   simdjson_inline simdjson_result<bool> get_bool() noexcept;
@@ -1058,6 +1101,11 @@ public:
 
   simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> at_pointer(std::string_view json_pointer) noexcept;
   simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> at_path(std::string_view json_path) noexcept;
+#if SIMDJSON_STATIC_REFLECTION
+  template<constevalutil::fixed_string... FieldNames, typename T>
+    requires(std::is_class_v<T> && (sizeof...(FieldNames) > 0))
+  simdjson_warn_unused simdjson_inline error_code extract_into(T& out) & noexcept;
+#endif // SIMDJSON_STATIC_REFLECTION
 };
 
 

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

@@ -312,7 +312,10 @@ inline void document_stream::next_document() noexcept {
   // Always set depth=1 at the start of document
   doc.iter._depth = 1;
   // consume comma if comma separated is allowed
-  if (allow_comma_separated) { doc.iter.consume_character(','); }
+  if (allow_comma_separated) {
+    error_code ignored = doc.iter.consume_character(',');
+    static_cast<void>(ignored); // ignored on purpose
+  }
   // Resets the string buffer at the beginning, thus invalidating the strings.
   doc.iter._string_buf_loc = parser->string_buf.get();
   doc.iter._root = doc.iter.position();

include/simdjson/generic/ondemand/document_stream.h

@@ -81,7 +81,7 @@ public:
   /**
    * Construct an uninitialized document_stream.
    *
-   *  ```c++
+   *  ```cpp
    *  document_stream docs;
    *  auto error = parser.iterate_many(json).get(docs);
    *  ```

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

@@ -114,7 +114,7 @@ simdjson_inline simdjson_result<std::string_view> simdjson_result<SIMDJSON_IMPLE
 }
 
 template<typename string_type>
-simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::field>::unescaped_key(string_type &receiver, bool allow_replacement) noexcept {
+simdjson_warn_unused simdjson_inline error_code simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::field>::unescaped_key(string_type &receiver, bool allow_replacement) noexcept {
   if (error()) { return error(); }
   return first.unescaped_key(receiver, allow_replacement);
 }

include/simdjson/generic/ondemand/json_builder.h

@@ -13,7 +13,7 @@
 
 #include <charconv>
 #include <cstring>
-#include <experimental/meta>
+#include <meta>
 #include <memory>
 #include <optional>
 #include <string_view>
@@ -25,30 +25,21 @@ namespace simdjson {
 namespace SIMDJSON_IMPLEMENTATION {
 namespace builder {
 
-// Concept that checks if a type is a container but not a string (because
-// strings handling must be handled differently)
-template <typename T>
-concept container_but_not_string =
-    requires(T a) {
-      { a.size() } -> std::convertible_to<std::size_t>;
-      {
-        a[std::declval<std::size_t>()]
-      }; // check if elements are accessible for the subscript operator
-    } && !std::is_same_v<T, std::string> &&
-    !std::is_same_v<T, std::string_view> && !std::is_same_v<T, const char *>;
-
 template <class T>
-  requires(container_but_not_string<T>)
+  requires(concepts::container_but_not_string<T> && !require_custom_serialization<T>)
 constexpr void atom(string_builder &b, const T &t) {
-  if (t.size() == 0) {
+  auto it = t.begin();
+  auto end = t.end();
+  if (it == end) {
     b.append_raw("[]");
     return;
   }
   b.append('[');
-  atom(b, t[0]);
-  for (size_t i = 1; i < t.size(); ++i) {
+  atom(b, *it);
+  ++it;
+  for (; it != end; ++it) {
     b.append(',');
-    atom(b, t[i]);
+    atom(b, *it);
   }
   b.append(']');
 }
@@ -63,6 +54,7 @@ constexpr void atom(string_builder &b, const T &t) {
 }
 
 template <concepts::string_view_keyed_map T>
+  requires(!require_custom_serialization<T>)
 constexpr void atom(string_builder &b, const T &m) {
   if (m.empty()) {
     b.append_raw("{}");
@@ -89,12 +81,9 @@ template<typename number_type,
 constexpr void atom(string_builder &b, const number_type t) {
   b.append(t);
 }
-#if SIMDJSON_CONSTEVAL
-consteval std::string consteval_to_quoted_escaped(std::string_view input);
-#endif
 
 template <class T>
-  requires(std::is_class_v<T> && !container_but_not_string<T> &&
+  requires(std::is_class_v<T> && !concepts::container_but_not_string<T> &&
            !concepts::string_view_keyed_map<T> &&
            !concepts::optional_type<T> &&
            !concepts::smart_pointer<T> &&
@@ -102,14 +91,14 @@ template <class T>
            !std::is_same_v<T, std::string> &&
            !std::is_same_v<T, std::string_view> &&
            !std::is_same_v<T, const char*> &&
-           !std::is_same_v<T, char>)
+           !std::is_same_v<T, char> && !require_custom_serialization<T>)
 constexpr void atom(string_builder &b, const T &t) {
   int i = 0;
   b.append('{');
-  [:expand(std::meta::nonstatic_data_members_of(^^T, std::meta::access_context::unchecked())):] >> [&]<auto dm>() {
+  template for (constexpr auto dm : std::define_static_array(std::meta::nonstatic_data_members_of(^^T, std::meta::access_context::unchecked()))) {
     if (i != 0)
       b.append(',');
-    constexpr auto key = std::define_static_string(consteval_to_quoted_escaped(std::meta::identifier_of(dm)));
+    constexpr auto key = std::define_static_string(constevalutil::consteval_to_quoted_escaped(std::meta::identifier_of(dm)));
     b.append_raw(key);
     b.append(':');
     atom(b, t.[:dm:]);
@@ -120,6 +109,7 @@ constexpr void atom(string_builder &b, const T &t) {
 
 // Support for optional types (std::optional, etc.)
 template <concepts::optional_type T>
+  requires(!require_custom_serialization<T>)
 constexpr void atom(string_builder &b, const T &opt) {
   if (opt) {
     atom(b, opt.value());
@@ -130,6 +120,7 @@ constexpr void atom(string_builder &b, const T &opt) {
 
 // Support for smart pointers (std::unique_ptr, std::shared_ptr, etc.)
 template <concepts::smart_pointer T>
+  requires(!require_custom_serialization<T>)
 constexpr void atom(string_builder &b, const T &ptr) {
   if (ptr) {
     atom(b, *ptr);
@@ -140,24 +131,19 @@ constexpr void atom(string_builder &b, const T &ptr) {
 
 // Support for enums - serialize as string representation using expand approach from P2996R12
 template <typename T>
-  requires(std::is_enum_v<T>)
+  requires(std::is_enum_v<T> && !require_custom_serialization<T>)
 void atom(string_builder &b, const T &e) {
 #if SIMDJSON_STATIC_REFLECTION
-  std::string_view result = "<unnamed>";
-  [:expand(std::meta::enumerators_of(^^T)):] >> [&]<auto enum_val>{
+  constexpr auto enumerators = std::define_static_array(std::meta::enumerators_of(^^T));
+  template for (constexpr auto enum_val : enumerators) {
+    constexpr auto enum_str = std::define_static_string(constevalutil::consteval_to_quoted_escaped(std::meta::identifier_of(enum_val)));
     if (e == [:enum_val:]) {
-      result = std::meta::identifier_of(enum_val);
+      b.append_raw(enum_str);
+      return;
     }
   };
-
-  if (result != "<unnamed>") {
-    b.append_raw("\"");
-    b.append_raw(result);
-    b.append_raw("\"");
-  } else {
-    // Fallback to integer if enum value not found
-    atom(b, static_cast<std::underlying_type_t<T>>(e));
-  }
+  // Fallback to integer if enum value not found
+  atom(b, static_cast<std::underlying_type_t<T>>(e));
 #else
   // Fallback: serialize as integer if reflection not available
   atom(b, static_cast<std::underlying_type_t<T>>(e));
@@ -166,10 +152,10 @@ void atom(string_builder &b, const T &e) {
 
 // Support for appendable containers that don't have operator[] (sets, etc.)
 template <concepts::appendable_containers T>
-  requires(!container_but_not_string<T> && !concepts::string_view_keyed_map<T> &&
+  requires(!concepts::container_but_not_string<T> && !concepts::string_view_keyed_map<T> &&
            !concepts::optional_type<T> && !concepts::smart_pointer<T> &&
            !std::is_same_v<T, std::string> &&
-           !std::is_same_v<T, std::string_view> && !std::is_same_v<T, const char*>)
+           !std::is_same_v<T, std::string_view> && !std::is_same_v<T, const char*> && !require_custom_serialization<T>)
 constexpr void atom(string_builder &b, const T &container) {
   if (container.empty()) {
     b.append_raw("[]");
@@ -204,32 +190,35 @@ void append(string_builder &b, const T &t) {
 }
 
 template <concepts::optional_type T>
+  requires(!require_custom_serialization<T>)
 void append(string_builder &b, const T &t) {
   atom(b, t);
 }
 
 template <concepts::smart_pointer T>
+  requires(!require_custom_serialization<T>)
 void append(string_builder &b, const T &t) {
   atom(b, t);
 }
 
 template <concepts::appendable_containers T>
-  requires(!container_but_not_string<T> && !concepts::string_view_keyed_map<T> &&
+  requires(!concepts::container_but_not_string<T> && !concepts::string_view_keyed_map<T> &&
            !concepts::optional_type<T> && !concepts::smart_pointer<T> &&
            !std::is_same_v<T, std::string> &&
-           !std::is_same_v<T, std::string_view> && !std::is_same_v<T, const char*>)
+           !std::is_same_v<T, std::string_view> && !std::is_same_v<T, const char*> && !require_custom_serialization<T>)
 void append(string_builder &b, const T &t) {
   atom(b, t);
 }
 
 template <concepts::string_view_keyed_map T>
+  requires(!require_custom_serialization<T>)
 void append(string_builder &b, const T &t) {
   atom(b, t);
 }
 
 // works for struct
 template <class Z>
-  requires(std::is_class_v<Z> && !container_but_not_string<Z> &&
+  requires(std::is_class_v<Z> && !concepts::container_but_not_string<Z> &&
            !concepts::string_view_keyed_map<Z> &&
            !concepts::optional_type<Z> &&
            !concepts::smart_pointer<Z> &&
@@ -237,14 +226,14 @@ template <class Z>
            !std::is_same_v<Z, std::string> &&
            !std::is_same_v<Z, std::string_view> &&
            !std::is_same_v<Z, const char*> &&
-           !std::is_same_v<Z, char>)
+           !std::is_same_v<Z, char> && !require_custom_serialization<Z>)
 void append(string_builder &b, const Z &z) {
   int i = 0;
   b.append('{');
-  [:expand(std::meta::nonstatic_data_members_of(^^Z, std::meta::access_context::unchecked())):] >> [&]<auto dm>() {
+  template for (constexpr auto dm : std::define_static_array(std::meta::nonstatic_data_members_of(^^Z, std::meta::access_context::unchecked()))) {
     if (i != 0)
       b.append(',');
-    constexpr auto key = std::define_static_string(consteval_to_quoted_escaped(std::meta::identifier_of(dm)));
+    constexpr auto key = std::define_static_string(constevalutil::consteval_to_quoted_escaped(std::meta::identifier_of(dm)));
     b.append_raw(key);
     b.append(':');
     atom(b, z.[:dm:]);
@@ -253,25 +242,35 @@ void append(string_builder &b, const Z &z) {
   b.append('}');
 }
 
-// works for container
+// works for container that have begin() and end() iterators
 template <class Z>
-  requires(container_but_not_string<Z>)
+  requires(concepts::container_but_not_string<Z> && !require_custom_serialization<Z>)
 void append(string_builder &b, const Z &z) {
-  if (z.size() == 0) {
+  auto it = z.begin();
+  auto end = z.end();
+  if (it == end) {
     b.append_raw("[]");
     return;
   }
   b.append('[');
-  atom(b, z[0]);
-  for (size_t i = 1; i < z.size(); ++i) {
+  atom(b, *it);
+  ++it;
+  for (; it != end; ++it) {
     b.append(',');
-    atom(b, z[i]);
+    atom(b, *it);
   }
   b.append(']');
 }
 
 template <class Z>
-simdjson_result<std::string> to_json_string(const Z &z, size_t initial_capacity = 1024) {
+  requires (require_custom_serialization<Z>)
+void append(string_builder &b, const Z &z) {
+  b.append(z);
+}
+
+
+template <class Z>
+simdjson_warn_unused simdjson_result<std::string> to_json_string(const Z &z, size_t initial_capacity = string_builder::DEFAULT_INITIAL_CAPACITY) {
   string_builder b(initial_capacity);
   append(b, z);
   std::string_view s;
@@ -280,8 +279,8 @@ simdjson_result<std::string> to_json_string(const Z &z, size_t initial_capacity
 }
 
 template <class Z>
-simdjson_error to_json(const Z &z, std::string &s) {
-  string_builder b;
+simdjson_warn_unused simdjson_error to_json(const Z &z, std::string &s, size_t initial_capacity = string_builder::DEFAULT_INITIAL_CAPACITY) {
+  string_builder b(initial_capacity);
   append(b, z);
   std::string_view view;
   if(auto e = b.view().get(view); e) { return e; }
@@ -294,13 +293,88 @@ string_builder& operator<<(string_builder& b, const Z& z) {
   append(b, z);
   return b;
 }
+
+// extract_from: Serialize only specific fields from a struct to JSON
+template<constevalutil::fixed_string... FieldNames, typename T>
+  requires(std::is_class_v<T> && (sizeof...(FieldNames) > 0))
+void extract_from(string_builder &b, const T &obj) {
+  // Helper to check if a field name matches any of the requested fields
+  auto should_extract = [](std::string_view field_name) constexpr -> bool {
+    return ((FieldNames.view() == field_name) || ...);
+  };
+
+  b.append('{');
+  bool first = true;
+
+  // Iterate through all members of T using reflection
+  template for (constexpr auto mem : std::define_static_array(
+      std::meta::nonstatic_data_members_of(^^T, std::meta::access_context::unchecked()))) {
+
+    if constexpr (std::meta::is_public(mem)) {
+      constexpr std::string_view key = std::define_static_string(std::meta::identifier_of(mem));
+
+      // Only serialize this field if it's in our list of requested fields
+      if constexpr (should_extract(key)) {
+        if (!first) {
+          b.append(',');
+        }
+        first = false;
+
+        // Serialize the key
+        constexpr auto quoted_key = std::define_static_string(constevalutil::consteval_to_quoted_escaped(std::meta::identifier_of(mem)));
+        b.append_raw(quoted_key);
+        b.append(':');
+
+        // Serialize the value
+        atom(b, obj.[:mem:]);
+      }
+    }
+  };
+
+  b.append('}');
+}
+
+template<constevalutil::fixed_string... FieldNames, typename T>
+  requires(std::is_class_v<T> && (sizeof...(FieldNames) > 0))
+simdjson_warn_unused simdjson_result<std::string> extract_from(const T &obj, size_t initial_capacity = string_builder::DEFAULT_INITIAL_CAPACITY) {
+  string_builder b(initial_capacity);
+  extract_from<FieldNames...>(b, obj);
+  std::string_view s;
+  if(auto e = b.view().get(s); e) { return e; }
+  return std::string(s);
+}
+
 } // namespace builder
 } // namespace SIMDJSON_IMPLEMENTATION
 // Alias the function template to 'to' in the global namespace
 template <class Z>
-simdjson_result<std::string> to_json(const Z &z, size_t initial_capacity = 1024) {
-  return SIMDJSON_IMPLEMENTATION::builder::to_json_string(z, initial_capacity);
+simdjson_warn_unused simdjson_result<std::string> to_json(const Z &z, size_t initial_capacity = SIMDJSON_IMPLEMENTATION::builder::string_builder::DEFAULT_INITIAL_CAPACITY) {
+  SIMDJSON_IMPLEMENTATION::builder::string_builder b(initial_capacity);
+  SIMDJSON_IMPLEMENTATION::builder::append(b, z);
+  std::string_view s;
+  if(auto e = b.view().get(s); e) { return e; }
+  return std::string(s);
 }
+template <class Z>
+simdjson_warn_unused simdjson_error to_json(const Z &z, std::string &s, size_t initial_capacity = SIMDJSON_IMPLEMENTATION::builder::string_builder::DEFAULT_INITIAL_CAPACITY) {
+  SIMDJSON_IMPLEMENTATION::builder::string_builder b(initial_capacity);
+  SIMDJSON_IMPLEMENTATION::builder::append(b, z);
+  std::string_view view;
+  if(auto e = b.view().get(view); e) { return e; }
+  s.assign(view);
+  return SUCCESS;
+}
+// Global namespace function for extract_from
+template<constevalutil::fixed_string... FieldNames, typename T>
+  requires(std::is_class_v<T> && (sizeof...(FieldNames) > 0))
+simdjson_warn_unused simdjson_result<std::string> extract_from(const T &obj, size_t initial_capacity = SIMDJSON_IMPLEMENTATION::builder::string_builder::DEFAULT_INITIAL_CAPACITY) {
+  SIMDJSON_IMPLEMENTATION::builder::string_builder b(initial_capacity);
+  SIMDJSON_IMPLEMENTATION::builder::extract_from<FieldNames...>(b, obj);
+  std::string_view s;
+  if(auto e = b.view().get(s); e) { return e; }
+  return std::string(s);
+}
+
 } // namespace simdjson
 
 #endif // SIMDJSON_STATIC_REFLECTION

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

@@ -344,7 +344,7 @@ simdjson_inline uint8_t *&json_iterator::string_buf_loc() noexcept {
   return _string_buf_loc;
 }
 
-simdjson_inline error_code json_iterator::report_error(error_code _error, const char *message) noexcept {
+simdjson_warn_unused simdjson_inline error_code json_iterator::report_error(error_code _error, const char *message) noexcept {
   SIMDJSON_ASSUME(_error != SUCCESS && _error != UNINITIALIZED && _error != INCORRECT_TYPE && _error != NO_SUCH_FIELD);
   logger::log_error(*this, message);
   error = _error;
@@ -388,7 +388,7 @@ simdjson_inline void json_iterator::reenter_child(token_position position, depth
   _depth = child_depth;
 }
 
-simdjson_inline error_code json_iterator::consume_character(char c) noexcept {
+simdjson_warn_unused simdjson_inline error_code json_iterator::consume_character(char c) noexcept {
   if (*peek() == c) {
     return_current_and_advance();
     return SUCCESS;
@@ -411,7 +411,7 @@ simdjson_inline void json_iterator::set_start_position(depth_t depth, token_posi
 #endif
 
 
-simdjson_inline error_code json_iterator::optional_error(error_code _error, const char *message) noexcept {
+simdjson_warn_unused simdjson_inline error_code json_iterator::optional_error(error_code _error, const char *message) noexcept {
   SIMDJSON_ASSUME(_error == INCORRECT_TYPE || _error == NO_SUCH_FIELD);
   logger::log_error(*this, message);
   return _error;

include/simdjson/generic/ondemand/json_iterator.h

@@ -238,14 +238,14 @@ public:
    * @param error The error to report. Must not be SUCCESS, UNINITIALIZED, INCORRECT_TYPE, or NO_SUCH_FIELD.
    * @param message An error message to report with the error.
    */
-  simdjson_inline error_code report_error(error_code error, const char *message) noexcept;
+  simdjson_warn_unused simdjson_inline error_code report_error(error_code error, const char *message) noexcept;
 
   /**
    * Log error, but don't stop iteration.
    * @param error The error to report. Must be INCORRECT_TYPE, or NO_SUCH_FIELD.
    * @param message An error message to report with the error.
    */
-  simdjson_inline error_code optional_error(error_code error, const char *message) noexcept;
+  simdjson_warn_unused simdjson_inline error_code optional_error(error_code error, const char *message) noexcept;
 
   /**
    * Take an input in json containing max_len characters and attempt to copy it over to tmpbuf, a buffer with
@@ -265,7 +265,7 @@ public:
 
   simdjson_inline void reenter_child(token_position position, depth_t child_depth) noexcept;
 
-  simdjson_inline error_code consume_character(char c) noexcept;
+  simdjson_warn_unused  simdjson_inline error_code consume_character(char c) noexcept;
 #if SIMDJSON_DEVELOPMENT_CHECKS
   simdjson_inline token_position start_position(depth_t depth) const noexcept;
   simdjson_inline void set_start_position(depth_t depth, token_position position) noexcept;

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

@@ -42,24 +42,25 @@ namespace simdjson {
 namespace SIMDJSON_IMPLEMENTATION {
 namespace builder {
 
-static SIMDJSON_CONSTEXPR_LAMBDA std::array<uint8_t, 256> json_quotable_character = {
-  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
-  1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+static SIMDJSON_CONSTEXPR_LAMBDA std::array<uint8_t, 256>
+    json_quotable_character = {
+        1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+        1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
 
 /**
 
-A possible SWAR implementation of has_json_escapable_byte. It is not used because
-it is slower than the current implementation. It is kept here for reference (to show
-that we tried it).
+A possible SWAR implementation of has_json_escapable_byte. It is not used
+because it is slower than the current implementation. It is kept here for
+reference (to show that we tried it).
 
 inline bool has_json_escapable_byte(uint64_t x) {
   uint64_t is_ascii = 0x8080808080808080ULL & ~x;
@@ -76,7 +77,7 @@ SIMDJSON_CONSTEXPR_LAMBDA simdjson_inline bool
 simple_needs_escaping(std::string_view v) {
   for (char c : v) {
     // a table lookup is faster than a series of comparisons
-    if(json_quotable_character[static_cast<uint8_t>(c)]) {
+    if (json_quotable_character[static_cast<uint8_t>(c)]) {
       return true;
     }
   }
@@ -117,7 +118,8 @@ simdjson_inline bool fast_needs_escaping(std::string_view view) {
   __m128i running = _mm_setzero_si128();
   for (; i + 15 < view.size(); i += 16) {
 
-    __m128i word = _mm_loadu_si128(reinterpret_cast<const __m128i *>(view.data() + i));
+    __m128i word =
+        _mm_loadu_si128(reinterpret_cast<const __m128i *>(view.data() + i));
     running = _mm_or_si128(running, _mm_cmpeq_epi8(word, _mm_set1_epi8(34)));
     running = _mm_or_si128(running, _mm_cmpeq_epi8(word, _mm_set1_epi8(92)));
     running = _mm_or_si128(
@@ -125,8 +127,8 @@ simdjson_inline bool fast_needs_escaping(std::string_view view) {
                                 _mm_setzero_si128()));
   }
   if (i < view.size()) {
-    __m128i word =
-        _mm_loadu_si128(reinterpret_cast<const __m128i *>(view.data() + view.length() - 16));
+    __m128i word = _mm_loadu_si128(
+        reinterpret_cast<const __m128i *>(view.data() + view.length() - 16));
     running = _mm_or_si128(running, _mm_cmpeq_epi8(word, _mm_set1_epi8(34)));
     running = _mm_or_si128(running, _mm_cmpeq_epi8(word, _mm_set1_epi8(92)));
     running = _mm_or_si128(
@@ -141,7 +143,6 @@ simdjson_inline bool fast_needs_escaping(std::string_view view) {
 }
 #endif
 
-
 SIMDJSON_CONSTEXPR_LAMBDA inline size_t
 find_next_json_quotable_character(const std::string_view view,
                                   size_t location) noexcept {
@@ -155,12 +156,17 @@ find_next_json_quotable_character(const std::string_view view,
 }
 
 SIMDJSON_CONSTEXPR_LAMBDA static std::string_view control_chars[] = {
-    "\\x0000", "\\x0001", "\\x0002", "\\x0003", "\\x0004", "\\x0005", "\\x0006",
-    "\\x0007", "\\x0008", "\\t",     "\\n",     "\\x000b", "\\f",     "\\r",
-    "\\x000e", "\\x000f", "\\x0010", "\\x0011", "\\x0012", "\\x0013", "\\x0014",
-    "\\x0015", "\\x0016", "\\x0017", "\\x0018", "\\x0019", "\\x001a", "\\x001b",
-    "\\x001c", "\\x001d", "\\x001e", "\\x001f"};
+    "\\u0000", "\\u0001", "\\u0002", "\\u0003", "\\u0004", "\\u0005", "\\u0006",
+    "\\u0007", "\\b",     "\\t",     "\\n",     "\\u000b", "\\f",     "\\r",
+    "\\u000e", "\\u000f", "\\u0010", "\\u0011", "\\u0012", "\\u0013", "\\u0014",
+    "\\u0015", "\\u0016", "\\u0017", "\\u0018", "\\u0019", "\\u001a", "\\u001b",
+    "\\u001c", "\\u001d", "\\u001e", "\\u001f"};
 
+// All Unicode characters may be placed within the quotation marks, except for
+// the characters that MUST be escaped: quotation mark, reverse solidus, and the
+// control characters (U+0000 through U+001F). There are two-character sequence
+// escape representations of some popular characters:
+// \", \\, \b, \f, \n, \r, \t.
 SIMDJSON_CONSTEXPR_LAMBDA void escape_json_char(char c, char *&out) {
   if (c == '"') {
     memcpy(out, "\\\"", 2);
@@ -201,29 +207,6 @@ inline size_t write_string_escaped(const std::string_view input, char *out) {
   return out - initout;
 }
 
-#if SIMDJSON_CONSTEVAL
-// unoptimized, meant for compile-time execution
-consteval std::string consteval_to_quoted_escaped(std::string_view input) {
-  std::string out = "\"";
-  for (char c : input) {
-    if (json_quotable_character[uint8_t(c)]) {
-      if (c == '"') {
-        out.append("\\\"");
-      } else if (c == '\\') {
-        out.append("\\\\");
-      } else {
-        std::string_view v = control_chars[uint8_t(c)];
-        out.append(v);
-      }
-    } else {
-      out.push_back(c);
-    }
-  }
-  out.push_back('"');
-  return out;
-}
-#endif // SIMDJSON_CONSTEVAL
-
 simdjson_inline string_builder::string_builder(size_t initial_capacity)
     : buffer(new(std::nothrow) char[initial_capacity]), position(0),
       capacity(buffer.get() != nullptr ? initial_capacity : 0),
@@ -302,10 +285,13 @@ simdjson_inline void string_builder::clear() noexcept {
 
 namespace internal {
 
-// We could specialize further for 32-bit integers.
-simdjson_really_inline int int_log2(uint32_t x) { return (63 - leading_zeroes(x | 1)); }
+template <typename number_type, typename = typename std::enable_if<
+                                    std::is_unsigned<number_type>::value>::type>
+simdjson_really_inline int int_log2(number_type x) {
+  return 63 - leading_zeroes(uint64_t(x) | 1);
+}
 
-simdjson_really_inline int fast_digit_count(uint32_t x) {
+simdjson_really_inline int fast_digit_count_32(uint32_t x) {
   static uint64_t table[] = {
       4294967296,  8589934582,  8589934582,  8589934582,  12884901788,
       12884901788, 12884901788, 17179868184, 17179868184, 17179868184,
@@ -317,9 +303,7 @@ simdjson_really_inline int fast_digit_count(uint32_t x) {
   return uint32_t((x + table[int_log2(x)]) >> 32);
 }
 
-simdjson_really_inline int int_log2(uint64_t x) { return 63 - leading_zeroes(x | 1); }
-
-simdjson_really_inline int fast_digit_count(uint64_t x) {
+simdjson_really_inline int fast_digit_count_64(uint64_t x) {
   static uint64_t table[] = {9,
                              99,
                              999,
@@ -350,26 +334,31 @@ simdjson_really_inline size_t digit_count(number_type v) noexcept {
   static_assert(sizeof(number_type) == 8 || sizeof(number_type) == 4 ||
                     sizeof(number_type) == 2 || sizeof(number_type) == 1,
                 "We only support 8-bit, 16-bit, 32-bit and 64-bit numbers");
-  return fast_digit_count(v);
+  SIMDJSON_IF_CONSTEXPR(sizeof(number_type) <= 4) {
+    return fast_digit_count_32(static_cast<uint32_t>(v));
+  }
+  else {
+    return fast_digit_count_64(static_cast<uint64_t>(v));
+  }
 }
 static const char decimal_table[200] = {
-  0x30, 0x30, 0x30, 0x31, 0x30, 0x32, 0x30, 0x33, 0x30, 0x34, 0x30, 0x35,
-  0x30, 0x36, 0x30, 0x37, 0x30, 0x38, 0x30, 0x39, 0x31, 0x30, 0x31, 0x31,
-  0x31, 0x32, 0x31, 0x33, 0x31, 0x34, 0x31, 0x35, 0x31, 0x36, 0x31, 0x37,
-  0x31, 0x38, 0x31, 0x39, 0x32, 0x30, 0x32, 0x31, 0x32, 0x32, 0x32, 0x33,
-  0x32, 0x34, 0x32, 0x35, 0x32, 0x36, 0x32, 0x37, 0x32, 0x38, 0x32, 0x39,
-  0x33, 0x30, 0x33, 0x31, 0x33, 0x32, 0x33, 0x33, 0x33, 0x34, 0x33, 0x35,
-  0x33, 0x36, 0x33, 0x37, 0x33, 0x38, 0x33, 0x39, 0x34, 0x30, 0x34, 0x31,
-  0x34, 0x32, 0x34, 0x33, 0x34, 0x34, 0x34, 0x35, 0x34, 0x36, 0x34, 0x37,
-  0x34, 0x38, 0x34, 0x39, 0x35, 0x30, 0x35, 0x31, 0x35, 0x32, 0x35, 0x33,
-  0x35, 0x34, 0x35, 0x35, 0x35, 0x36, 0x35, 0x37, 0x35, 0x38, 0x35, 0x39,
-  0x36, 0x30, 0x36, 0x31, 0x36, 0x32, 0x36, 0x33, 0x36, 0x34, 0x36, 0x35,
-  0x36, 0x36, 0x36, 0x37, 0x36, 0x38, 0x36, 0x39, 0x37, 0x30, 0x37, 0x31,
-  0x37, 0x32, 0x37, 0x33, 0x37, 0x34, 0x37, 0x35, 0x37, 0x36, 0x37, 0x37,
-  0x37, 0x38, 0x37, 0x39, 0x38, 0x30, 0x38, 0x31, 0x38, 0x32, 0x38, 0x33,
-  0x38, 0x34, 0x38, 0x35, 0x38, 0x36, 0x38, 0x37, 0x38, 0x38, 0x38, 0x39,
-  0x39, 0x30, 0x39, 0x31, 0x39, 0x32, 0x39, 0x33, 0x39, 0x34, 0x39, 0x35,
-  0x39, 0x36, 0x39, 0x37, 0x39, 0x38, 0x39, 0x39,
+    0x30, 0x30, 0x30, 0x31, 0x30, 0x32, 0x30, 0x33, 0x30, 0x34, 0x30, 0x35,
+    0x30, 0x36, 0x30, 0x37, 0x30, 0x38, 0x30, 0x39, 0x31, 0x30, 0x31, 0x31,
+    0x31, 0x32, 0x31, 0x33, 0x31, 0x34, 0x31, 0x35, 0x31, 0x36, 0x31, 0x37,
+    0x31, 0x38, 0x31, 0x39, 0x32, 0x30, 0x32, 0x31, 0x32, 0x32, 0x32, 0x33,
+    0x32, 0x34, 0x32, 0x35, 0x32, 0x36, 0x32, 0x37, 0x32, 0x38, 0x32, 0x39,
+    0x33, 0x30, 0x33, 0x31, 0x33, 0x32, 0x33, 0x33, 0x33, 0x34, 0x33, 0x35,
+    0x33, 0x36, 0x33, 0x37, 0x33, 0x38, 0x33, 0x39, 0x34, 0x30, 0x34, 0x31,
+    0x34, 0x32, 0x34, 0x33, 0x34, 0x34, 0x34, 0x35, 0x34, 0x36, 0x34, 0x37,
+    0x34, 0x38, 0x34, 0x39, 0x35, 0x30, 0x35, 0x31, 0x35, 0x32, 0x35, 0x33,
+    0x35, 0x34, 0x35, 0x35, 0x35, 0x36, 0x35, 0x37, 0x35, 0x38, 0x35, 0x39,
+    0x36, 0x30, 0x36, 0x31, 0x36, 0x32, 0x36, 0x33, 0x36, 0x34, 0x36, 0x35,
+    0x36, 0x36, 0x36, 0x37, 0x36, 0x38, 0x36, 0x39, 0x37, 0x30, 0x37, 0x31,
+    0x37, 0x32, 0x37, 0x33, 0x37, 0x34, 0x37, 0x35, 0x37, 0x36, 0x37, 0x37,
+    0x37, 0x38, 0x37, 0x39, 0x38, 0x30, 0x38, 0x31, 0x38, 0x32, 0x38, 0x33,
+    0x38, 0x34, 0x38, 0x35, 0x38, 0x36, 0x38, 0x37, 0x38, 0x38, 0x38, 0x39,
+    0x39, 0x30, 0x39, 0x31, 0x39, 0x32, 0x39, 0x33, 0x39, 0x34, 0x39, 0x35,
+    0x39, 0x36, 0x39, 0x37, 0x39, 0x38, 0x39, 0x39,
 };
 } // namespace internal
 
@@ -405,7 +394,7 @@ simdjson_inline void string_builder::append(number_type v) noexcept {
       size_t dc = internal::digit_count(pv);
       char *write_pointer = buffer.get() + position + dc - 1;
       while (pv >= 100) {
-        memcpy(write_pointer - 1, &internal::decimal_table[(pv % 100)*2], 2);
+        memcpy(write_pointer - 1, &internal::decimal_table[(pv % 100) * 2], 2);
         write_pointer -= 2;
         pv /= 100;
       }
@@ -427,12 +416,12 @@ simdjson_inline void string_builder::append(number_type v) noexcept {
         pv = 0 - pv; // the 0 is for Microsoft
       }
       size_t dc = internal::digit_count(pv);
-      if (negative) {
-        buffer.get()[position++] = '-';
-      }
+      // by always writing the minus sign, we avoid the branch.
+      buffer.get()[position] = '-';
+      position += negative ? 1 : 0;
       char *write_pointer = buffer.get() + position + dc - 1;
       while (pv >= 100) {
-        memcpy(write_pointer - 1, &internal::decimal_table[(pv % 100)*2], 2);
+        memcpy(write_pointer - 1, &internal::decimal_table[(pv % 100) * 2], 2);
         write_pointer -= 2;
         pv /= 100;
       }
@@ -484,10 +473,17 @@ string_builder::escape_and_append_with_quotes(char input) noexcept {
   }
 }
 
-simdjson_inline void string_builder::escape_and_append_with_quotes(const char* input)  noexcept {
+simdjson_inline void
+string_builder::escape_and_append_with_quotes(const char *input) noexcept {
   std::string_view cinput(input);
   escape_and_append_with_quotes(cinput);
 }
+#if SIMDJSON_SUPPORTS_CONCEPTS
+template <constevalutil::fixed_string key>
+simdjson_inline void string_builder::escape_and_append_with_quotes() noexcept {
+  escape_and_append_with_quotes(constevalutil::string_constant<key>::value);
+}
+#endif
 
 simdjson_inline void string_builder::append_raw(const char *c) noexcept {
   size_t len = std::strlen(c);
@@ -512,6 +508,7 @@ simdjson_inline void string_builder::append_raw(const char *str,
 #if SIMDJSON_SUPPORTS_CONCEPTS
 // Support for optional types (std::optional, etc.)
 template <concepts::optional_type T>
+  requires(!require_custom_serialization<T>)
 simdjson_inline void string_builder::append(const T &opt) {
   if (opt) {
     append(*opt);
@@ -519,18 +516,25 @@ simdjson_inline void string_builder::append(const T &opt) {
     append_null();
   }
 }
+
 template <typename T>
-requires(std::is_convertible<T, std::string_view>::value ||
-std::is_same<T, const char*>::value )
+  requires(require_custom_serialization<T>)
+simdjson_inline void string_builder::append(const T &val) {
+  serialize(*this, val);
+}
+
+template <typename T>
+  requires(std::is_convertible<T, std::string_view>::value ||
+           std::is_same<T, const char *>::value)
 simdjson_inline void string_builder::append(const T &value) {
   escape_and_append_with_quotes(value);
 }
 #endif
 
 #if SIMDJSON_SUPPORTS_RANGES && SIMDJSON_SUPPORTS_CONCEPTS
-  // Support for range-based appending (std::ranges::view, etc.)
+// Support for range-based appending (std::ranges::view, etc.)
 template <std::ranges::range R>
-requires (!std::is_convertible<R, std::string_view>::value)
+  requires(!std::is_convertible<R, std::string_view>::value)
 simdjson_inline void string_builder::append(const R &range) noexcept {
   auto it = std::ranges::begin(range);
   auto end = std::ranges::end(range);
@@ -547,8 +551,8 @@ simdjson_inline void string_builder::append(const R &range) noexcept {
 
     // Append remaining items with preceding commas
     for (; it != end; ++it) {
-        append_comma();
-        append_key_value(it->first, it->second);
+      append_comma();
+      append_key_value(it->first, it->second);
     }
     end_object();
   } else {
@@ -564,11 +568,10 @@ simdjson_inline void string_builder::append(const R &range) noexcept {
 
     // Append remaining items with preceding commas
     for (; it != end; ++it) {
-        append_comma();
-        append(*it);
+      append_comma();
+      append(*it);
     }
     end_array();
-
   }
 }
 
@@ -576,7 +579,7 @@ simdjson_inline void string_builder::append(const R &range) noexcept {
 
 #if SIMDJSON_EXCEPTIONS
 simdjson_inline string_builder::operator std::string() const noexcept(false) {
-  return std::string(std::string_view());
+  return std::string(operator std::string_view());
 }
 
 simdjson_inline string_builder::operator std::string_view() const
@@ -605,70 +608,95 @@ simdjson_inline bool string_builder::validate_unicode() const noexcept {
   return simdjson::validate_utf8(buffer.get(), position);
 }
 
-simdjson_inline void string_builder::start_object()  noexcept {
+simdjson_inline void string_builder::start_object() noexcept {
   if (capacity_check(1)) {
     buffer.get()[position++] = '{';
   }
 }
 
-
-simdjson_inline void string_builder::end_object()  noexcept {
+simdjson_inline void string_builder::end_object() noexcept {
   if (capacity_check(1)) {
     buffer.get()[position++] = '}';
   }
 }
 
-
-simdjson_inline void string_builder::start_array()  noexcept {
+simdjson_inline void string_builder::start_array() noexcept {
   if (capacity_check(1)) {
     buffer.get()[position++] = '[';
   }
 }
 
-
-simdjson_inline void string_builder::end_array()  noexcept {
+simdjson_inline void string_builder::end_array() noexcept {
   if (capacity_check(1)) {
     buffer.get()[position++] = ']';
   }
 }
 
-
-simdjson_inline void string_builder::append_comma()  noexcept {
+simdjson_inline void string_builder::append_comma() noexcept {
   if (capacity_check(1)) {
     buffer.get()[position++] = ',';
   }
 }
 
-
-simdjson_inline void string_builder::append_colon()  noexcept {
+simdjson_inline void string_builder::append_colon() noexcept {
   if (capacity_check(1)) {
     buffer.get()[position++] = ':';
   }
 }
 
-template<typename key_type, typename value_type>
-simdjson_inline void string_builder::append_key_value(key_type key, value_type value) noexcept {
-  static_assert(
-    std::is_same<key_type, const char*>::value ||
-    std::is_convertible<key_type, std::string_view>::value,
-    "Unsupported key type");
+template <typename key_type, typename value_type>
+simdjson_inline void
+string_builder::append_key_value(key_type key, value_type value) noexcept {
+  static_assert(std::is_same<key_type, const char *>::value ||
+                    std::is_convertible<key_type, std::string_view>::value,
+                "Unsupported key type");
   escape_and_append_with_quotes(key);
   append_colon();
   SIMDJSON_IF_CONSTEXPR(std::is_same<value_type, std::nullptr_t>::value) {
     append_null();
-  } else SIMDJSON_IF_CONSTEXPR(std::is_same<value_type, char>::value) {
+  }
+  else SIMDJSON_IF_CONSTEXPR(std::is_same<value_type, char>::value) {
     escape_and_append_with_quotes(value);
-  } else SIMDJSON_IF_CONSTEXPR(std::is_convertible<value_type, std::string_view>::value) {
+  }
+  else SIMDJSON_IF_CONSTEXPR(
+      std::is_convertible<value_type, std::string_view>::value) {
     escape_and_append_with_quotes(value);
-  } else SIMDJSON_IF_CONSTEXPR(std::is_same<value_type, const char*>::value) {
+  }
+  else SIMDJSON_IF_CONSTEXPR(std::is_same<value_type, const char *>::value) {
     escape_and_append_with_quotes(value);
-  } else {
+  }
+  else {
     append(value);
   }
 }
 
+#if SIMDJSON_SUPPORTS_CONCEPTS
+template <constevalutil::fixed_string key, typename value_type>
+simdjson_inline void
+string_builder::append_key_value(value_type value) noexcept {
+  escape_and_append_with_quotes<key>();
+  append_colon();
+  SIMDJSON_IF_CONSTEXPR(std::is_same<value_type, std::nullptr_t>::value) {
+    append_null();
+  }
+  else SIMDJSON_IF_CONSTEXPR(std::is_same<value_type, char>::value) {
+    escape_and_append_with_quotes(value);
+  }
+  else SIMDJSON_IF_CONSTEXPR(
+      std::is_convertible<value_type, std::string_view>::value) {
+    escape_and_append_with_quotes(value);
+  }
+  else SIMDJSON_IF_CONSTEXPR(std::is_same<value_type, const char *>::value) {
+    escape_and_append_with_quotes(value);
+  }
+  else {
+    append(value);
+  }
+}
+#endif
+
 } // namespace builder
 } // namespace SIMDJSON_IMPLEMENTATION
 } // namespace simdjson
 
-#endif // SIMDJSON_GENERIC_STRING_BUILDER_INL_H
+#endif // SIMDJSON_GENERIC_STRING_BUILDER_INL_H

include/simdjson/generic/ondemand/json_string_builder.h

@@ -10,9 +10,40 @@
 #endif // SIMDJSON_CONDITIONAL_INCLUDE
 
 namespace simdjson {
+
+
+#if SIMDJSON_SUPPORTS_CONCEPTS
+
 namespace SIMDJSON_IMPLEMENTATION {
 namespace builder {
+  class string_builder;
+}}
 
+template <typename T, typename = void>
+struct has_custom_serialization : std::false_type {};
+
+inline constexpr struct serialize_tag {
+  template <typename T>
+    requires custom_deserializable<T>
+  constexpr void operator()(SIMDJSON_IMPLEMENTATION::builder::string_builder& b, T& obj) const{
+    return tag_invoke(*this, b, obj);
+  }
+
+
+} serialize{};
+template <typename T>
+struct has_custom_serialization<T, std::void_t<
+    decltype(tag_invoke(serialize, std::declval<SIMDJSON_IMPLEMENTATION::builder::string_builder&>(), std::declval<T&>()))
+>> : std::true_type {};
+
+template <typename T>
+constexpr bool require_custom_serialization = has_custom_serialization<T>::value;
+#else
+struct has_custom_serialization : std::false_type {};
+#endif // SIMDJSON_SUPPORTS_CONCEPTS
+
+namespace SIMDJSON_IMPLEMENTATION {
+namespace builder {
 /**
  * A builder for JSON strings representing documents. This is a low-level
  * builder that is not meant to be used directly by end-users. Though it
@@ -24,7 +55,9 @@ namespace builder {
  */
 class string_builder {
 public:
-  simdjson_inline string_builder(size_t initial_capacity = 1024);
+  simdjson_inline string_builder(size_t initial_capacity = DEFAULT_INITIAL_CAPACITY);
+
+  static constexpr size_t DEFAULT_INITIAL_CAPACITY = 1024;
 
   /**
    * Append number (includes Booleans). Booleans are mapped to the strings
@@ -33,7 +66,7 @@ public:
    * represents the number.
    */
   template<typename number_type,
-         typename = typename std::enable_if<std::is_arithmetic<number_type>::value>::type>
+    typename = typename std::enable_if<std::is_arithmetic<number_type>::value>::type>
   simdjson_inline void append(number_type v) noexcept;
 
   /**
@@ -62,7 +95,10 @@ public:
    * There is no UTF-8 validation.
    */
   simdjson_inline void escape_and_append_with_quotes(std::string_view input)  noexcept;
-
+#if SIMDJSON_SUPPORTS_CONCEPTS
+  template<constevalutil::fixed_string key>
+  simdjson_inline void escape_and_append_with_quotes()  noexcept;
+#endif
   /**
    * Append the character surrounded by double quotes, after escaping it.
    * There is no UTF-8 validation.
@@ -116,13 +152,21 @@ public:
    * The key is escaped and surrounded by double quotes.
    * The value is escaped if it is a string.
    */
-   template<typename key_type, typename value_type>
+  template<typename key_type, typename value_type>
   simdjson_inline void append_key_value(key_type key, value_type value) noexcept;
 #if SIMDJSON_SUPPORTS_CONCEPTS
+  template<constevalutil::fixed_string key, typename value_type>
+  simdjson_inline void append_key_value(value_type value) noexcept;
+
   // Support for optional types (std::optional, etc.)
   template <concepts::optional_type T>
+  requires(!require_custom_serialization<T>)
   simdjson_inline void append(const T &opt);
 
+  template <typename T>
+  requires(require_custom_serialization<T>)
+  simdjson_inline void append(const T &val);
+
   // Support for string-like types
   template <typename T>
   requires(std::is_convertible<T, std::string_view>::value ||
@@ -232,7 +276,7 @@ private:
 #if !SIMDJSON_STATIC_REFLECTION
 // fallback implementation until we have static reflection
 template <class Z>
-simdjson_result<std::string> to_json(const Z &z, size_t initial_capacity = 1024) {
+simdjson_warn_unused simdjson_result<std::string> to_json(const Z &z, size_t initial_capacity = simdjson::SIMDJSON_IMPLEMENTATION::builder::string_builder::DEFAULT_INITIAL_CAPACITY) {
   simdjson::SIMDJSON_IMPLEMENTATION::builder::string_builder b(initial_capacity);
   b.append(z);
   std::string_view s;
@@ -240,8 +284,20 @@ simdjson_result<std::string> to_json(const Z &z, size_t initial_capacity = 1024)
   if(e) { return e; }
   return std::string(s);
 }
+template <class Z>
+simdjson_warn_unused simdjson_error to_json(const Z &z, std::string &s, size_t initial_capacity = simdjson::SIMDJSON_IMPLEMENTATION::builder::string_builder::DEFAULT_INITIAL_CAPACITY) {
+  simdjson::SIMDJSON_IMPLEMENTATION::builder::string_builder b(initial_capacity);
+  b.append(z);
+  std::string_view sv;
+  auto e = b.view().get(sv);
+  if(e) { return e; }
+  s.assign(sv.data(), sv.size());
+  return simdjson::SUCCESS;
+}
 #endif
 
+#if SIMDJSON_SUPPORTS_CONCEPTS
+#endif // SIMDJSON_SUPPORTS_CONCEPTS
 
 } // namespace simdjson
 

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

@@ -9,6 +9,10 @@
 #include "simdjson/generic/ondemand/raw_json_string.h"
 #include "simdjson/generic/ondemand/json_iterator.h"
 #include "simdjson/generic/ondemand/value-inl.h"
+#if SIMDJSON_STATIC_REFLECTION
+#include "simdjson/generic/ondemand/json_string_builder.h"  // for constevalutil::fixed_string
+#include <meta>
+#endif
 #endif // SIMDJSON_CONDITIONAL_INCLUDE
 
 namespace simdjson {
@@ -66,7 +70,7 @@ simdjson_inline simdjson_result<object> object::start_root(value_iterator &iter)
   SIMDJSON_TRY( iter.start_root_object().error() );
   return object(iter);
 }
-simdjson_inline error_code object::consume() noexcept {
+simdjson_warn_unused simdjson_inline error_code object::consume() noexcept {
   if(iter.is_at_key()) {
     /**
      * whenever you are pointing at a key, calling skip_child() is
@@ -195,6 +199,52 @@ simdjson_inline simdjson_result<bool> object::reset() & noexcept {
   return iter.reset_object();
 }
 
+#if SIMDJSON_SUPPORTS_CONCEPTS && SIMDJSON_STATIC_REFLECTION
+
+template<constevalutil::fixed_string... FieldNames, typename T>
+  requires(std::is_class_v<T> && (sizeof...(FieldNames) > 0))
+simdjson_warn_unused simdjson_inline error_code object::extract_into(T& out) & noexcept {
+  // Helper to check if a field name matches any of the requested fields
+  auto should_extract = [](std::string_view field_name) constexpr -> bool {
+    return ((FieldNames.view() == field_name) || ...);
+  };
+
+  // Iterate through all members of T using reflection
+  template for (constexpr auto mem : std::define_static_array(
+      std::meta::nonstatic_data_members_of(^^T, std::meta::access_context::unchecked()))) {
+
+    if constexpr (!std::meta::is_const(mem) && std::meta::is_public(mem)) {
+      constexpr std::string_view key = std::define_static_string(std::meta::identifier_of(mem));
+
+      // Only extract this field if it's in our list of requested fields
+      if constexpr (should_extract(key)) {
+        // Try to find and extract the field
+        if constexpr (concepts::optional_type<decltype(out.[:mem:])>) {
+          // For optional fields, it's ok if they're missing
+          auto field_result = find_field_unordered(key);
+          if (!field_result.error()) {
+            auto error = field_result.get(out.[:mem:]);
+            if (error && error != NO_SUCH_FIELD) {
+              return error;
+            }
+          } else if (field_result.error() != NO_SUCH_FIELD) {
+            return field_result.error();
+          } else {
+            out.[:mem:].reset();
+          }
+        } else {
+          // For required fields (in the requested list), fail if missing
+          SIMDJSON_TRY((*this)[key].get(out.[:mem:]));
+        }
+      }
+    }
+  };
+
+  return SUCCESS;
+}
+
+#endif // SIMDJSON_SUPPORTS_CONCEPTS && SIMDJSON_STATIC_REFLECTION
+
 } // namespace ondemand
 } // namespace SIMDJSON_IMPLEMENTATION
 } // namespace simdjson

include/simdjson/generic/ondemand/object.h

@@ -5,6 +5,9 @@
 #include "simdjson/generic/ondemand/base.h"
 #include "simdjson/generic/implementation_simdjson_result_base.h"
 #include "simdjson/generic/ondemand/value_iterator.h"
+#if SIMDJSON_STATIC_REFLECTION && SIMDJSON_SUPPORTS_CONCEPTS
+#include "simdjson/generic/ondemand/json_string_builder.h"  // for constevalutil::fixed_string
+#endif
 #endif // SIMDJSON_CONDITIONAL_INCLUDE
 
 namespace simdjson {
@@ -31,7 +34,7 @@ public:
    * The following code reads z, then y, then x, and thus will not retrieve x or y if fed the
    * JSON `{ "x": 1, "y": 2, "z": 3 }`:
    *
-   * ```c++
+   * ```cpp
    * simdjson::ondemand::parser parser;
    * auto obj = parser.parse(R"( { "x": 1, "y": 2, "z": 3 } )"_padded);
    * double z = obj.find_field("z");
@@ -211,7 +214,7 @@ public:
    * @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)
+  simdjson_warn_unused simdjson_inline error_code get(T &out)
      noexcept(custom_deserializable<T, object> ? nothrow_custom_deserializable<T, object> : true) {
     static_assert(custom_deserializable<T, object>);
     return deserialize(*this, out);
@@ -231,12 +234,42 @@ public:
     SIMDJSON_TRY(get<T>(out));
     return out;
   }
+
+#if SIMDJSON_STATIC_REFLECTION
+  /**
+   * Extract only specific fields from the JSON object into a struct.
+   *
+   * This allows selective deserialization of only the fields you need,
+   * potentially improving performance by skipping unwanted fields.
+   *
+   * Example:
+   * ```cpp
+   * struct Car {
+   *   std::string make;
+   *   std::string model;
+   *   int year;
+   *   double price;
+   * };
+   *
+   * Car car;
+   * object.extract_into<"make", "model">(car);
+   * // Only 'make' and 'model' fields are extracted from JSON
+   * ```
+   *
+   * @tparam FieldNames Compile-time string literals specifying which fields to extract
+   * @param out The output struct to populate with selected fields
+   * @returns SUCCESS on success, or an error code if a required field is missing or has wrong type
+   */
+  template<constevalutil::fixed_string... FieldNames, typename T>
+    requires(std::is_class_v<T> && (sizeof...(FieldNames) > 0))
+  simdjson_warn_unused simdjson_inline error_code extract_into(T& out) & noexcept;
+#endif // SIMDJSON_STATIC_REFLECTION
 #endif // SIMDJSON_SUPPORTS_CONCEPTS
 protected:
   /**
    * Go to the end of the object, no matter where you are right now.
    */
-  simdjson_inline error_code consume() noexcept;
+  simdjson_warn_unused simdjson_inline error_code consume() noexcept;
   static simdjson_inline simdjson_result<object> start(value_iterator &iter) noexcept;
   static simdjson_inline simdjson_result<object> start_root(value_iterator &iter) noexcept;
   static simdjson_inline simdjson_result<object> started(value_iterator &iter) noexcept;
@@ -291,7 +324,7 @@ public:
     return first.get<T>();
   }
   template<typename T>
-  simdjson_inline error_code get(T& out) noexcept {
+  simdjson_warn_unused simdjson_inline error_code get(T& out) noexcept {
     if (error()) { return error(); }
     if constexpr (std::is_same_v<T, SIMDJSON_IMPLEMENTATION::ondemand::object>) {
       out = first;
@@ -300,6 +333,16 @@ public:
     }
     return SUCCESS;
   }
+
+#if SIMDJSON_STATIC_REFLECTION
+  // TODO: move this code into object-inl.h
+  template<constevalutil::fixed_string... FieldNames, typename T>
+    requires(std::is_class_v<T> && (sizeof...(FieldNames) > 0))
+  simdjson_warn_unused simdjson_inline error_code extract_into(T& out) noexcept {
+    if (error()) { return error(); }
+    return first.extract_into<FieldNames...>(out);
+  }
+#endif // SIMDJSON_STATIC_REFLECTION
 #endif // SIMDJSON_SUPPORTS_CONCEPTS
 };
 

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

@@ -15,8 +15,13 @@ namespace ondemand {
 
 simdjson_inline raw_json_string::raw_json_string(const uint8_t * _buf) noexcept : buf{_buf} {}
 
-simdjson_inline const char * raw_json_string::raw() const noexcept { return reinterpret_cast<const char *>(buf); }
+simdjson_inline const char * raw_json_string::raw() const noexcept {
+  return reinterpret_cast<const char *>(buf);
+}
 
+simdjson_inline char raw_json_string::operator[](size_t i) const noexcept {
+  return reinterpret_cast<const char *>(buf)[i];
+}
 
 simdjson_inline bool raw_json_string::is_free_from_unescaped_quote(std::string_view target) noexcept {
   size_t pos{0};
@@ -193,6 +198,10 @@ simdjson_inline simdjson_result<const char *> simdjson_result<SIMDJSON_IMPLEMENT
   if (error()) { return error(); }
   return first.raw();
 }
+simdjson_inline char simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::raw_json_string>::operator[](size_t i) const noexcept {
+  if (error()) { return error(); }
+  return first[i];
+}
 simdjson_inline simdjson_warn_unused simdjson_result<std::string_view> simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::raw_json_string>::unescape(SIMDJSON_IMPLEMENTATION::ondemand::json_iterator &iter, bool allow_replacement) const noexcept {
   if (error()) { return error(); }
   return first.unescape(iter, allow_replacement);

include/simdjson/generic/ondemand/raw_json_string.h

@@ -58,6 +58,12 @@ public:
    */
   simdjson_inline const char * raw() const noexcept;
 
+  /**
+   * Get the character at index i. This is unchecked.
+   * [0] when the string is of length 0 returns the final quote (").
+   */
+  simdjson_inline char operator[](size_t i) const noexcept;
+
   /**
    * This compares the current instance to the std::string_view target: returns true if
    * they are byte-by-byte equal (no escaping is done) on target.size() characters,
@@ -197,10 +203,10 @@ public:
   simdjson_inline ~simdjson_result() noexcept = default; ///< @private
 
   simdjson_inline simdjson_result<const char *> raw() const noexcept;
+  simdjson_inline char operator[](size_t) const noexcept;
   simdjson_inline simdjson_warn_unused simdjson_result<std::string_view> unescape(SIMDJSON_IMPLEMENTATION::ondemand::json_iterator &iter, bool allow_replacement) const noexcept;
   simdjson_inline simdjson_warn_unused simdjson_result<std::string_view> unescape_wobbly(SIMDJSON_IMPLEMENTATION::ondemand::json_iterator &iter) const noexcept;
 };
-
 } // namespace simdjson
 
 #endif // SIMDJSON_GENERIC_ONDEMAND_RAW_JSON_STRING_H

include/simdjson/generic/ondemand/std_deserialize.h

@@ -16,15 +16,12 @@
 #endif
 
 namespace simdjson {
-template <typename T>
-constexpr bool require_custom_serialization = false;
 
 //////////////////////////////
 // Number deserialization
 //////////////////////////////
 
 template <std::unsigned_integral T>
-  requires(!require_custom_serialization<T>)
 error_code tag_invoke(deserialize_tag, auto &val, T &out) noexcept {
   using limits = std::numeric_limits<T>;
 
@@ -38,7 +35,6 @@ error_code tag_invoke(deserialize_tag, auto &val, T &out) noexcept {
 }
 
 template <std::floating_point T>
-  requires(!require_custom_serialization<T>)
 error_code tag_invoke(deserialize_tag, auto &val, T &out) noexcept {
   double x;
   SIMDJSON_TRY(val.get_double().get(x));
@@ -47,7 +43,6 @@ error_code tag_invoke(deserialize_tag, auto &val, T &out) noexcept {
 }
 
 template <std::signed_integral T>
-  requires(!require_custom_serialization<T>)
 error_code tag_invoke(deserialize_tag, auto &val, T &out) noexcept {
   using limits = std::numeric_limits<T>;
 
@@ -77,7 +72,6 @@ error_code tag_invoke(deserialize_tag, auto &val, char &out) noexcept {
 
 // any string-like type (can be constructed from std::string_view)
 template <concepts::constructible_from_string_view T, typename ValT>
-  requires(!require_custom_serialization<T>)
 error_code tag_invoke(deserialize_tag, ValT &val, T &out) noexcept(std::is_nothrow_constructible_v<T, std::string_view>) {
   std::string_view str;
   SIMDJSON_TRY(val.get_string().get(str));
@@ -94,7 +88,6 @@ error_code tag_invoke(deserialize_tag, ValT &val, T &out) noexcept(std::is_nothr
  * doc.get<std::vector<int>>().
  */
 template <concepts::appendable_containers T, typename ValT>
-  requires(!require_custom_serialization<T>)
 error_code tag_invoke(deserialize_tag, ValT &val, T &out) noexcept(false) {
   using value_type = typename std::remove_cvref_t<T>::value_type;
   static_assert(
@@ -140,7 +133,6 @@ error_code tag_invoke(deserialize_tag, ValT &val, T &out) noexcept(false) {
  * string-keyed types.
  */
  template <concepts::string_view_keyed_map T, typename ValT>
- requires(!require_custom_serialization<T>)
 error_code tag_invoke(deserialize_tag, ValT &val, T &out) noexcept(false) {
   using value_type = typename std::remove_cvref_t<T>::mapped_type;
   static_assert(
@@ -222,7 +214,6 @@ error_code tag_invoke(deserialize_tag, SIMDJSON_IMPLEMENTATION::ondemand::docume
  * @return status of the conversion
  */
 template <concepts::smart_pointer T, typename ValT>
-  requires(!require_custom_serialization<T>)
 error_code tag_invoke(deserialize_tag, ValT &val, T &out) noexcept(nothrow_deserializable<typename std::remove_cvref_t<T>::element_type, ValT>) {
   using element_type = typename std::remove_cvref_t<T>::element_type;
 
@@ -248,12 +239,13 @@ error_code tag_invoke(deserialize_tag, ValT &val, T &out) noexcept(nothrow_deser
  * This CPO (Customization Point Object) will help deserialize into optional types.
  */
 template <concepts::optional_type T>
-  requires(!require_custom_serialization<T>)
 error_code tag_invoke(deserialize_tag, auto &val, T &out) noexcept(nothrow_deserializable<typename std::remove_cvref_t<T>::value_type, decltype(val)>) {
   using value_type = typename std::remove_cvref_t<T>::value_type;
 
   // Check if the value is null
-  if (val.is_null()) {
+  bool is_null_value;
+  SIMDJSON_TRY( val.is_null().get(is_null_value) );
+  if (is_null_value) {
     out.reset(); // Set to nullopt
     return SUCCESS;
   }
@@ -272,35 +264,9 @@ error_code tag_invoke(deserialize_tag, auto &val, T &out) noexcept(nothrow_deser
 template <typename T>
 constexpr bool user_defined_type = (std::is_class_v<T>
 && !std::is_same_v<T, std::string> && !std::is_same_v<T, std::string_view> && !concepts::optional_type<T> &&
-!concepts::appendable_containers<T> && !require_custom_serialization<T>);
+!concepts::appendable_containers<T>);
 
 
-// workaround from
-// https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2024/p2996r10.html#back-and-forth
-// for missing expansion statements
-namespace __impl {
-  template<auto... vals>
-  struct replicator_type {
-    template<typename F>
-      constexpr void operator>>(F body) const {
-        (body.template operator()<vals>(), ...);
-      }
-  };
-
-  template<auto... vals>
-  replicator_type<vals...> replicator = {};
-}
-
-template<typename R>
-consteval auto expand(R range) {
-  std::vector<std::meta::info> args;
-  for (auto r : range) {
-    args.push_back(reflect_constant(r));
-  }
-  return substitute(^^__impl::replicator, args);
-}
-// end of workaround
-
 template <typename T, typename ValT>
   requires(user_defined_type<T> && std::is_class_v<T>)
 error_code tag_invoke(deserialize_tag, ValT &val, T &out) noexcept {
@@ -310,19 +276,26 @@ error_code tag_invoke(deserialize_tag, ValT &val, T &out) noexcept {
   } else {
     SIMDJSON_TRY(val.get_object().get(obj));
   }
-  error_code e = simdjson::SUCCESS;
-
-  [:expand(std::meta::nonstatic_data_members_of(^^T, std::meta::access_context::unchecked())):] >> [&]<auto mem>() {
+  template for (constexpr auto mem : std::define_static_array(std::meta::nonstatic_data_members_of(^^T, std::meta::access_context::unchecked()))) {
     if constexpr (!std::meta::is_const(mem) && std::meta::is_public(mem)) {
       constexpr std::string_view key = std::define_static_string(std::meta::identifier_of(mem));
-      // Note: removed static assert as optional types are now handled generically
-      // as long we are succesful or the field is not found, we continue
-      if(e == simdjson::SUCCESS || e == simdjson::NO_SUCH_FIELD) {
-        e = obj[key].get(out.[:mem:]);
+      if constexpr (concepts::optional_type<decltype(out.[:mem:])>) {
+        // for optional members, it's ok if the key is missing
+        auto error = obj[key].get(out.[:mem:]);
+        if (error && error != NO_SUCH_FIELD) {
+          if(error == NO_SUCH_FIELD) {
+            out.[:mem:].reset();
+            continue;
+          }
+          return error;
+        }
+      } else {
+        // for non-optional members, the key must be present
+        SIMDJSON_TRY(obj[key].get(out.[:mem:]));
       }
     }
   };
-  return e;
+  return simdjson::SUCCESS;
 }
 
 // Support for enum deserialization - deserialize from string representation using expand approach from P2996R12
@@ -332,16 +305,15 @@ error_code tag_invoke(deserialize_tag, ValT &val, T &out) noexcept {
 #if SIMDJSON_STATIC_REFLECTION
   std::string_view str;
   SIMDJSON_TRY(val.get_string().get(str));
-
-  bool found = false;
-  [:expand(std::meta::enumerators_of(^^T)):] >> [&]<auto enum_val>{
-    if (!found && str == std::meta::identifier_of(enum_val)) {
+  constexpr auto enumerators = std::define_static_array(std::meta::enumerators_of(^^T));
+  template for (constexpr auto enum_val : enumerators) {
+    if (str == std::meta::identifier_of(enum_val)) {
       out = [:enum_val:];
-      found = true;
+      return SUCCESS;
     }
   };
 
-  return found ? SUCCESS : INCORRECT_TYPE;
+  return INCORRECT_TYPE;
 #else
   // Fallback: deserialize as integer if reflection not available
   std::underlying_type_t<T> int_val;
@@ -389,7 +361,9 @@ error_code tag_invoke(deserialize_tag, simdjson_value &val, std::shared_ptr<T> &
 // Unique pointers
 ////////////////////////////////////////
 error_code tag_invoke(deserialize_tag, auto &val, std::unique_ptr<bool> &out) noexcept {
-  if (val.is_null()) {
+  bool is_null_value;
+  SIMDJSON_TRY( val.is_null().get(is_null_value) );
+  if (is_null_value) {
     out.reset();
     return SUCCESS;
   }
@@ -402,7 +376,9 @@ error_code tag_invoke(deserialize_tag, auto &val, std::unique_ptr<bool> &out) no
 }
 
 error_code tag_invoke(deserialize_tag, auto &val, std::unique_ptr<int64_t> &out) noexcept {
-  if (val.is_null()) {
+  bool is_null_value;
+  SIMDJSON_TRY( val.is_null().get(is_null_value) );
+  if (is_null_value) {
     out.reset();
     return SUCCESS;
   }
@@ -415,7 +391,9 @@ error_code tag_invoke(deserialize_tag, auto &val, std::unique_ptr<int64_t> &out)
 }
 
 error_code tag_invoke(deserialize_tag, auto &val, std::unique_ptr<uint64_t> &out) noexcept {
-  if (val.is_null()) {
+  bool is_null_value;
+  SIMDJSON_TRY( val.is_null().get(is_null_value) );
+  if (is_null_value) {
     out.reset();
     return SUCCESS;
   }
@@ -428,7 +406,9 @@ error_code tag_invoke(deserialize_tag, auto &val, std::unique_ptr<uint64_t> &out
 }
 
 error_code tag_invoke(deserialize_tag, auto &val, std::unique_ptr<double> &out) noexcept {
-  if (val.is_null()) {
+  bool is_null_value;
+  SIMDJSON_TRY( val.is_null().get(is_null_value) );
+  if (is_null_value) {
     out.reset();
     return SUCCESS;
   }
@@ -441,7 +421,9 @@ error_code tag_invoke(deserialize_tag, auto &val, std::unique_ptr<double> &out)
 }
 
 error_code tag_invoke(deserialize_tag, auto &val, std::unique_ptr<std::string_view> &out) noexcept {
-  if (val.is_null()) {
+  bool is_null_value;
+  SIMDJSON_TRY( val.is_null().get(is_null_value) );
+  if (is_null_value) {
     out.reset();
     return SUCCESS;
   }
@@ -458,7 +440,9 @@ error_code tag_invoke(deserialize_tag, auto &val, std::unique_ptr<std::string_vi
 // Shared pointers
 ////////////////////////////////////////
 error_code tag_invoke(deserialize_tag, auto &val, std::shared_ptr<bool> &out) noexcept {
-  if (val.is_null()) {
+  bool is_null_value;
+  SIMDJSON_TRY( val.is_null().get(is_null_value) );
+  if (is_null_value) {
     out.reset();
     return SUCCESS;
   }
@@ -471,7 +455,9 @@ error_code tag_invoke(deserialize_tag, auto &val, std::shared_ptr<bool> &out) no
 }
 
 error_code tag_invoke(deserialize_tag, auto &val, std::shared_ptr<int64_t> &out) noexcept {
-  if (val.is_null()) {
+  bool is_null_value;
+  SIMDJSON_TRY( val.is_null().get(is_null_value) );
+  if (is_null_value) {
     out.reset();
     return SUCCESS;
   }
@@ -484,7 +470,9 @@ error_code tag_invoke(deserialize_tag, auto &val, std::shared_ptr<int64_t> &out)
 }
 
 error_code tag_invoke(deserialize_tag, auto &val, std::shared_ptr<uint64_t> &out) noexcept {
-  if (val.is_null()) {
+  bool is_null_value;
+  SIMDJSON_TRY( val.is_null().get(is_null_value) );
+  if (is_null_value) {
     out.reset();
     return SUCCESS;
   }
@@ -497,7 +485,9 @@ error_code tag_invoke(deserialize_tag, auto &val, std::shared_ptr<uint64_t> &out
 }
 
 error_code tag_invoke(deserialize_tag, auto &val, std::shared_ptr<double> &out) noexcept {
-  if (val.is_null()) {
+  bool is_null_value;
+  SIMDJSON_TRY( val.is_null().get(is_null_value) );
+  if (is_null_value) {
     out.reset();
     return SUCCESS;
   }
@@ -510,7 +500,9 @@ error_code tag_invoke(deserialize_tag, auto &val, std::shared_ptr<double> &out)
 }
 
 error_code tag_invoke(deserialize_tag, auto &val, std::shared_ptr<std::string_view> &out) noexcept {
-  if (val.is_null()) {
+  bool is_null_value;
+  SIMDJSON_TRY( val.is_null().get(is_null_value) );
+  if (is_null_value) {
     out.reset();
     return SUCCESS;
   }
@@ -532,7 +524,9 @@ error_code tag_invoke(deserialize_tag, auto &val, std::shared_ptr<std::string_vi
 ////////////////////////////////////////
 error_code tag_invoke(deserialize_tag, auto &val, std::unique_ptr<std::string> &out) noexcept {
   // Check if the value is null
-  if (val.is_null()) {
+  bool is_null_value;
+  SIMDJSON_TRY( val.is_null().get(is_null_value) );
+  if (is_null_value) {
     out.reset(); // Set to nullptr
     return SUCCESS;
   }
@@ -548,7 +542,9 @@ error_code tag_invoke(deserialize_tag, auto &val, std::unique_ptr<std::string> &
 
 error_code tag_invoke(deserialize_tag, auto &val, std::shared_ptr<std::string> &out) noexcept {
   // Check if the value is null
-  if (val.is_null()) {
+  bool is_null_value;
+  SIMDJSON_TRY( val.is_null().get(is_null_value) );
+  if (is_null_value) {
     out.reset(); // Set to nullptr
     return SUCCESS;
   }
@@ -564,7 +560,9 @@ error_code tag_invoke(deserialize_tag, auto &val, std::shared_ptr<std::string> &
 
 error_code tag_invoke(deserialize_tag, auto &val, std::unique_ptr<int> &out) noexcept {
   // Check if the value is null
-  if (val.is_null()) {
+  bool is_null_value;
+  SIMDJSON_TRY( val.is_null().get(is_null_value) );
+  if (is_null_value) {
     out.reset(); // Set to nullptr
     return SUCCESS;
   }

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

@@ -48,7 +48,7 @@ simdjson_inline simdjson_result<std::string_view> value::get_string(bool allow_r
   return iter.get_string(allow_replacement);
 }
 template <typename string_type>
-simdjson_inline error_code value::get_string(string_type& receiver, bool allow_replacement) noexcept {
+simdjson_warn_unused simdjson_inline error_code value::get_string(string_type& receiver, bool allow_replacement) noexcept {
   return iter.get_string(receiver, allow_replacement);
 }
 simdjson_inline simdjson_result<std::string_view> value::get_wobbly_string() noexcept {
@@ -90,15 +90,15 @@ template<> simdjson_inline simdjson_result<int64_t> value::get() noexcept { retu
 template<> simdjson_inline simdjson_result<bool> value::get() noexcept { return get_bool(); }
 
 
-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); }
+template<> simdjson_warn_unused simdjson_inline error_code value::get(array& out) noexcept { return get_array().get(out); }
+template<> simdjson_warn_unused simdjson_inline error_code value::get(object& out) noexcept { return get_object().get(out); }
+template<> simdjson_warn_unused simdjson_inline error_code value::get(raw_json_string& out) noexcept { return get_raw_json_string().get(out); }
+template<> simdjson_warn_unused simdjson_inline error_code value::get(std::string_view& out) noexcept { return get_string(false).get(out); }
+template<> simdjson_warn_unused simdjson_inline error_code value::get(number& out) noexcept { return get_number().get(out); }
+template<> simdjson_warn_unused simdjson_inline error_code value::get(double& out) noexcept { return get_double().get(out); }
+template<> simdjson_warn_unused simdjson_inline error_code value::get(uint64_t& out) noexcept { return get_uint64().get(out); }
+template<> simdjson_warn_unused simdjson_inline error_code value::get(int64_t& out) noexcept { return get_int64().get(out); }
+template<>  simdjson_warn_unused simdjson_inline error_code value::get(bool& out) noexcept { return get_bool().get(out); }
 
 #if SIMDJSON_EXCEPTIONS
 template <class T>

include/simdjson/generic/ondemand/value.h

@@ -65,7 +65,7 @@ public:
    * @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)
+  simdjson_warn_unused simdjson_inline error_code get(T &out)
 #if SIMDJSON_SUPPORTS_CONCEPTS
     noexcept(custom_deserializable<T, value> ? nothrow_custom_deserializable<T, value> : true)
 #else
@@ -79,7 +79,9 @@ public:
       using value_type = typename std::remove_cvref_t<T>::value_type;
 
       // Check if the value is null
-      if (is_null()) {
+      bool is_null_value;
+      SIMDJSON_TRY( is_null().get(is_null_value) );
+      if (is_null_value) {
         out.reset(); // Set to nullopt
         return SUCCESS;
       }
@@ -215,7 +217,7 @@ public:
    * @returns INCORRECT_TYPE if the JSON value is not a string. Otherwise, we return SUCCESS.
    */
   template <typename string_type>
-  simdjson_inline error_code get_string(string_type& receiver, bool allow_replacement = false) noexcept;
+  simdjson_warn_unused simdjson_inline error_code get_string(string_type& receiver, bool allow_replacement = false) noexcept;
 
   /**
    * Cast this JSON value to a "wobbly" string.
@@ -397,7 +399,7 @@ public:
    * The following code reads z, then y, then x, and thus will not retrieve x or y if fed the
    * JSON `{ "x": 1, "y": 2, "z": 3 }`:
    *
-   * ```c++
+   * ```cpp
    * simdjson::ondemand::parser parser;
    * auto obj = parser.parse(R"( { "x": 1, "y": 2, "z": 3 } )"_padded);
    * double z = obj.find_field("z");
@@ -736,7 +738,7 @@ public:
   simdjson_inline simdjson_result<double> get_double_in_string() noexcept;
   simdjson_inline simdjson_result<std::string_view> get_string(bool allow_replacement = false) noexcept;
   template <typename string_type>
-  simdjson_inline error_code get_string(string_type& receiver, bool allow_replacement = false) noexcept;
+  simdjson_warn_unused simdjson_inline error_code get_string(string_type& receiver, bool allow_replacement = false) noexcept;
   simdjson_inline simdjson_result<std::string_view> get_wobbly_string() noexcept;
   simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::raw_json_string> get_raw_json_string() noexcept;
   simdjson_inline simdjson_result<bool> get_bool() noexcept;
@@ -770,7 +772,7 @@ public:
    * The following code reads z, then y, then x, and thus will not retrieve x or y if fed the
    * JSON `{ "x": 1, "y": 2, "z": 3 }`:
    *
-   * ```c++
+   * ```cpp
    * simdjson::ondemand::parser parser;
    * auto obj = parser.parse(R"( { "x": 1, "y": 2, "z": 3 } )"_padded);
    * double z = obj.find_field("z");

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

@@ -41,7 +41,7 @@ simdjson_warn_unused simdjson_inline simdjson_result<bool> value_iterator::start
   if (*_json_iter->peek() == '}') {
     logger::log_value(*_json_iter, "empty object");
     _json_iter->return_current_and_advance();
-    end_container();
+    SIMDJSON_TRY(end_container());
     return false;
   }
   return true;
@@ -895,7 +895,7 @@ simdjson_inline void value_iterator::advance_scalar(const char *type) noexcept {
   _json_iter->ascend_to(depth()-1);
 }
 
-simdjson_inline error_code value_iterator::start_container(uint8_t start_char, const char *incorrect_type_message, const char *type) noexcept {
+simdjson_warn_unused simdjson_inline error_code value_iterator::start_container(uint8_t start_char, const char *incorrect_type_message, const char *type) noexcept {
   logger::log_start_value(*_json_iter, start_position(), depth(), type);
   // If we're not at the position anymore, we don't want to advance the cursor.
   const uint8_t *json;

include/simdjson/generic/ondemand/value_iterator.h

@@ -335,7 +335,7 @@ public:
   simdjson_warn_unused simdjson_inline simdjson_result<number> get_root_number(bool check_trailing) noexcept;
   simdjson_warn_unused simdjson_inline simdjson_result<bool> is_root_null(bool check_trailing) noexcept;
 
-  simdjson_inline error_code error() const noexcept;
+  simdjson_warn_unused simdjson_inline error_code error() const noexcept;
   simdjson_inline uint8_t *&string_buf_loc() noexcept;
   simdjson_inline const json_iterator &json_iter() const noexcept;
   simdjson_inline json_iterator &json_iter() noexcept;
@@ -419,8 +419,8 @@ protected:
   simdjson_inline const uint8_t *peek_non_root_scalar(const char *type) noexcept;
 
 
-  simdjson_inline error_code start_container(uint8_t start_char, const char *incorrect_type_message, const char *type) noexcept;
-  simdjson_inline error_code end_container() noexcept;
+  simdjson_warn_unused simdjson_inline error_code start_container(uint8_t start_char, const char *incorrect_type_message, const char *type) noexcept;
+  simdjson_warn_unused simdjson_inline error_code end_container() noexcept;
 
   /**
    * Advance to a place expecting a value (increasing depth).
@@ -430,8 +430,8 @@ protected:
    */
   simdjson_inline simdjson_result<const uint8_t *> advance_to_value() noexcept;
 
-  simdjson_inline error_code incorrect_type_error(const char *message) const noexcept;
-  simdjson_inline error_code error_unless_more_tokens(uint32_t tokens=1) const noexcept;
+  simdjson_warn_unused simdjson_inline error_code incorrect_type_error(const char *message) const noexcept;
+  simdjson_warn_unused simdjson_inline error_code error_unless_more_tokens(uint32_t tokens=1) const noexcept;
 
   simdjson_inline bool is_at_start() const noexcept;
   /**
@@ -468,7 +468,7 @@ protected:
   /** @copydoc error_code json_iterator::end_position() const noexcept; */
   simdjson_inline token_position end_position() const noexcept;
   /** @copydoc error_code json_iterator::report_error(error_code error, const char *message) noexcept; */
-  simdjson_inline error_code report_error(error_code error, const char *message) noexcept;
+  simdjson_warn_unused simdjson_inline error_code report_error(error_code error, const char *message) noexcept;
 
   friend class document;
   friend class object;

include/simdjson/haswell/stringparsing_defs.h

@@ -17,7 +17,7 @@ using namespace simd;
 struct backslash_and_quote {
 public:
   static constexpr uint32_t BYTES_PROCESSED = 32;
-  simdjson_inline static backslash_and_quote copy_and_find(const uint8_t *src, uint8_t *dst);
+  simdjson_inline backslash_and_quote copy_and_find(const uint8_t *src, uint8_t *dst);
 
   simdjson_inline bool has_quote_first() { return ((bs_bits - 1) & quote_bits) != 0; }
   simdjson_inline bool has_backslash() { return ((quote_bits - 1) & bs_bits) != 0; }

include/simdjson/icelake/stringparsing_defs.h

@@ -17,7 +17,7 @@ using namespace simd;
 struct backslash_and_quote {
 public:
   static constexpr uint32_t BYTES_PROCESSED = 64;
-  simdjson_inline static backslash_and_quote copy_and_find(const uint8_t *src, uint8_t *dst);
+  simdjson_inline backslash_and_quote copy_and_find(const uint8_t *src, uint8_t *dst);
 
   simdjson_inline bool has_quote_first() { return ((bs_bits - 1) & quote_bits) != 0; }
   simdjson_inline bool has_backslash() { return ((quote_bits - 1) & bs_bits) != 0; }

include/simdjson/lasx/stringparsing_defs.h

@@ -17,7 +17,7 @@ using namespace simd;
 struct backslash_and_quote {
 public:
   static constexpr uint32_t BYTES_PROCESSED = 32;
-  simdjson_inline static backslash_and_quote copy_and_find(const uint8_t *src, uint8_t *dst);
+  simdjson_inline backslash_and_quote copy_and_find(const uint8_t *src, uint8_t *dst);
 
   simdjson_inline bool has_quote_first() { return ((bs_bits - 1) & quote_bits) != 0; }
   simdjson_inline bool has_backslash() { return bs_bits != 0; }

include/simdjson/lsx/stringparsing_defs.h

@@ -17,7 +17,7 @@ using namespace simd;
 struct backslash_and_quote {
 public:
   static constexpr uint32_t BYTES_PROCESSED = 32;
-  simdjson_inline static backslash_and_quote copy_and_find(const uint8_t *src, uint8_t *dst);
+  simdjson_inline backslash_and_quote copy_and_find(const uint8_t *src, uint8_t *dst);
 
   simdjson_inline bool has_quote_first() { return ((bs_bits - 1) & quote_bits) != 0; }
   simdjson_inline bool has_backslash() { return bs_bits != 0; }
@@ -67,7 +67,7 @@ simdjson_inline escaping escaping::copy_and_find(const uint8_t *src, uint8_t *ds
   simd8<bool> is_backslash = (v == '\\');
   simd8<bool> is_control = (v < 32);
   return {
-    (is_backslash | is_quote | is_control).to_bitmask()
+    static_cast<uint64_t>((is_backslash | is_quote | is_control).to_bitmask())
   };
 }
 

include/simdjson/portability.h

@@ -45,6 +45,22 @@ using std::size_t;
 #define SIMDJSON_IS_ARM64 1
 #elif defined(__riscv) && __riscv_xlen == 64
 #define SIMDJSON_IS_RISCV64 1
+  #if __riscv_v_intrinsic >= 11000
+    #define SIMDJSON_HAS_RVV_INTRINSICS 1
+  #endif
+
+  #define SIMDJSON_HAS_ZVBB_INTRINSICS                                          \
+    0 // there is currently no way to detect this
+
+  #if SIMDJSON_HAS_RVV_INTRINSICS && __riscv_vector &&                          \
+      __riscv_v_min_vlen >= 128 && __riscv_v_elen >= 64
+    // RISC-V V extension
+    #define SIMDJSON_IS_RVV 1
+    #if SIMDJSON_HAS_ZVBB_INTRINSICS && __riscv_zvbb >= 1000000
+      // RISC-V Vector Basic Bit-manipulation
+      #define SIMDJSON_IS_ZVBB 1
+    #endif
+  #endif
 #elif defined(__loongarch_lp64)
 #define SIMDJSON_IS_LOONGARCH64 1
 #elif defined(__PPC64__) || defined(_M_PPC64)

include/simdjson/ppc64/stringparsing_defs.h

@@ -17,7 +17,7 @@ using namespace simd;
 struct backslash_and_quote {
 public:
   static constexpr uint32_t BYTES_PROCESSED = 32;
-  simdjson_inline static backslash_and_quote
+  simdjson_inline backslash_and_quote
   copy_and_find(const uint8_t *src, uint8_t *dst);
 
   simdjson_inline bool has_quote_first() {

include/simdjson/simdjson_version.h

@@ -4,7 +4,7 @@
 #define SIMDJSON_SIMDJSON_VERSION_H
 
 /** The version of simdjson being used (major.minor.revision) */
-#define SIMDJSON_VERSION "4.0.0"
+#define SIMDJSON_VERSION "4.1.0"
 
 namespace simdjson {
 enum {
@@ -15,7 +15,7 @@ enum {
   /**
    * The minor version (major.MINOR.revision) of simdjson being used.
    */
-  SIMDJSON_VERSION_MINOR = 0,
+  SIMDJSON_VERSION_MINOR = 1,
   /**
    * The revision (major.minor.REVISION) of simdjson being used.
    */

include/simdjson/westmere/stringparsing_defs.h

@@ -14,7 +14,7 @@ using namespace simd;
 struct backslash_and_quote {
 public:
   static constexpr uint32_t BYTES_PROCESSED = 32;
-  simdjson_inline static backslash_and_quote copy_and_find(const uint8_t *src, uint8_t *dst);
+  simdjson_inline backslash_and_quote copy_and_find(const uint8_t *src, uint8_t *dst);
 
   simdjson_inline bool has_quote_first() { return ((bs_bits - 1) & quote_bits) != 0; }
   simdjson_inline bool has_backslash() { return bs_bits != 0; }

p2996/README.md

@@ -78,3 +78,36 @@ You can modify the source code with your favorite editor and run again steps 5 (
 
 You can create a new docker shell at any time by running step 3 (bash script).
 
+## Using static reflection in your own projects
+
+You can import simdjson in your own CMake project. You can configure your project like so:
+
+```
+# Fetch simdjson from GitHub
+# Replace GIT_TAG by the commit you require.
+include(FetchContent)
+FetchContent_Declare(
+    simdjson
+    GIT_REPOSITORY https://github.com/simdjson/simdjson.git
+    GIT_TAG 015daad6a95a4f67c08ed5980d24b57be221c38f
+    CMAKE_ARGS -DSIMDJSON_STATIC_REFLECTION=ON
+)
+FetchContent_MakeAvailable(simdjson)
+
+##########
+# You may also use CPM.
+# https://github.com/cpm-cmake/CPM.cmake
+# CPMAddPackage(
+#    NAME simdjson
+#    GITHUB_REPOSITORY simdjson/simdjson
+#    GIT_TAG 015daad6a95a4f67c08ed5980d24b57be221c38f
+#    OPTIONS "SIMDJSON_STATIC_REFLECTION ON"
+# )
+target_link_libraries(webservice PRIVATE simdjson::simdjson)
+```
+
+Replace the `GIT_TAG` by the appropriate value.
+
+Once C++26 support will be officially available in mainstream compilers,
+we will simplify these instructions and it will no longer be needed
+to specify `SIMDJSON_STATIC_REFLECTION`.

scripts/javascript/generatelargejson.js

@@ -1,5 +1,5 @@
 
-var fs = require('fs');
+var fs = require('node:fs');
 
 var faker = require('faker');
 

singleheader/amalgamate.py

@@ -22,6 +22,9 @@ rules = """
 
 We refer your to the HACKING.md file for more information on how the project is organized.
 
+If you are trying to add a new implementation, you need to edit the amalgamate.py script
+to add your implementation to the IMPLEMENTATIONS list.
+
 To help understand the error, here are the rules for including files in simdjson:
 
 All implementation-specific files, including arm64.h, arm64/implementation.h and
@@ -480,11 +483,42 @@ AMAL_C = os.path.join(AMALGAMATE_OUTPUT_PATH, "simdjson.cpp")
 DEMOCPP = os.path.join(AMALGAMATE_OUTPUT_PATH, "amalgamate_demo.cpp")
 README = os.path.join(AMALGAMATE_OUTPUT_PATH, "README.md")
 
+def validate_implementations():
+    """Scan include/simdjson/*/implementation.h and compare with IMPLEMENTATIONS list."""
+    include_simdjson_path = os.path.join(PROJECTPATH, 'include', 'simdjson')
+    found_implementations = set()
+
+    if os.path.exists(include_simdjson_path):
+        for item in os.listdir(include_simdjson_path):
+            item_path = os.path.join(include_simdjson_path, item)
+            if os.path.isdir(item_path):
+                impl_h_path = os.path.join(item_path, 'implementation.h')
+                if os.path.exists(impl_h_path) and item != 'builtin':  # Ignore builtin
+                    found_implementations.add(item)
+
+    expected_implementations = set(IMPLEMENTATIONS)
+    if found_implementations != expected_implementations:
+        missing = expected_implementations - found_implementations
+        extra = found_implementations - expected_implementations
+        warning = "Warning: IMPLEMENTATIONS list does not match found implementations.\n"
+        if missing:
+            warning += f"Missing in filesystem: {sorted(missing)}\n"
+        if extra:
+            warning += f"Extra in filesystem: {sorted(extra)}\n"
+        print(warning)
+        return False
+    return True
+
 def read_version():
     with open(os.path.join(PROJECTPATH, 'include/simdjson/simdjson_version.h')) as f:
         return re.search(r'\d+\.\d+\.\d+', f.read()).group(0)
 
 version = read_version()
+if not validate_implementations():
+    print("Validation failed. Please update IMPLEMENTATIONS list in amalgamate.py.")
+    sys.exit(1)
+else:
+    print("implementation validated")
 Amalgamator.amalgamate(AMAL_H, "simdjson.h", ['include'], timestamp, version).validate_all_files_used('include')
 Amalgamator.amalgamate(AMAL_C, "simdjson.cpp", ['src', 'include'], timestamp, version).validate_all_files_used('src')