HolGen (pronounced whole-gen) is an MIT licensed code generation tool developed alongside a game that I'm working on, that generates json loaders (using rapidjson) and Lua exporters for your data structures in C++. It has a C-like DSL allowing you to express your data structure along with your usage intent, and it generates C++ classes and CMake files.

PS: The project is not yet ready for its prime time; please don't use it in production unless you're OK with frequent changes. Once the project reaches 1.0, I'll make sure not to make backwards incompatible changes between minor versions.

Compile holgen cli application and put it in your PATH. Holgen is smart enough that it won't overwrite your files if the contents are identical, so you can integrate it with your build system and regenerate without triggering unnecessary rebuilds. Or if you're lazy, just create a bash script like this that you execute manually:

#!/usr/bin/env bash

holgen holgen/schemas libs/schemas project_r::schemas project_r_schemas ../ProjectRSchemas.h

CLI will change over time (getopts will be supported eventually), currently the usage is:

holgen [schema dir] [output dir] [namespace] [cmake project name] [common header file to include where you can configure error handling]

In the examples directory, you can see the schemas under < id >/schemas and the generated output in [example id] /output. There's a main project that includes all the projects in order to showcase its usage. The project is under examples/usage, and each example has an examples/usage/example< id >.cpp file making use of the generated code.

Check out this schema and its usage to see the basic syntax, structs, enums and fields. This example uses a single schema file for simplicity, but holgen cli will read all schema files under the provided directory.

This schema and its usage shows some field annotations to customize your getters/setters along with defining functions that can be called from C++ or Lua.

If you need to determine the type of a variable in runtime and store different types of objects in the same c++ container, variants will be useful! They're more or less like std::variant. See how to use it here.

If you're building an RPG, you'll have many weapons, armors, characters, and you'll want to be systematic in your usage. In that case DataManager is for you! It recursively loads all your data from a directory, assigns IDs, creates field based indices so that you can reference your resources using their name in json. Check out how it's used.