Header-only typed JSON mapping library built in the Hope ecosystem. It maps JSON to C++ structs (and back) using hope-core reflection and named field wrappers. The project naming/style follows the conventions used in glensand/hope.

hope-json is focused on:

• Strict and nullable field policies for predictable schema behavior.
• Compile-time typed wrappers around JSON primitives and arrays.
• Conversion between JSON text and aggregate C++ structs via load / store.
• Minimal setup with no runtime schema definitions.

• C++17 compiler
• CMake 3.11+ (project root) and 3.15+ (lib/)
• hope-core submodule (ext/hope-core)

git clone --recurse-submodules <repo-url>
cd hope-json
cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build
ctest --test-dir build -V

#include "hope/document.h"
#include "hope/types_macro.h"

struct profile final {
    SJSTRING(name);
    SJINT(age);
    NJREAL(score);
};

int main() {
    constexpr auto* json = R"({"name":"Gleb","age":30,"score":99.5})";

    auto object = hope::load<profile>(json);
    object.age = 31;

    const auto out = hope::store(object);
    return out.empty();
}

The library uses named wrappers for each struct field:

• Strict fields: SJINT, SJREAL, SJBOOL, SJSTRING, SJARRAY, SJOBJECT
• Nullable fields: NJINT, NJREAL, NJBOOL, NJSTRING, NJARRAY, NJOBJECT

Strict fields require valid JSON values. Nullable fields are optional and only serialized when present.

• lib/hope: public include path (#include "hope/...")
• test/: unit tests (GoogleTest)
• samples/document: usage example
• ext/hope-core: Hope reflection/type utilities dependency

• The project follows hope naming/style (hope::... namespace and hope/... headers).

Distributed under the MIT License.