This is an educational tutorial that walks through implementing a complete JSON library from scratch in C. The project covers the full data lifecycle of JSON, including parsing text into structured in-memory representations, validating input against the specification, serializing data back into standard JSON output, and providing structured access to elements within parsed arrays and objects.
The implementation is built around a hand-written recursive descent parser that processes JSON text by matching grammar rules to build a structured data tree. Parsed values are stored in a tagged union representation with explicit type, number, string, array, and object fields, while memory is managed manually through explicit allocation and deallocation of value structures and string buffers. The library includes a compact serialization generator that produces JSON output by recursively walking the value tree and writing formatted text, along with a custom double-precision number parser that converts JSON number tokens into IEEE 754 double values.
The project covers JSON validation with clear syntax error reporting through a fixed set of integer error codes, and provides a structured query interface for retrieving and modifying elements within parsed arrays and objects. The documentation and source code are organized as a step-by-step tutorial, making the implementation accessible for learning how to build a JSON library from the ground up.