json-parse

A lightweight JSON parser and serializer for C++17. This library allows you to parse JSON strings, manipulate JSON objects and arrays, and serialize them back to JSON format. It includes robust error handling, support for nested structures, and a simple API for easy use.

Project Structure

json-parse/
├── example/               # Example programs demonstrating usage
│   ├── json.cpp
│   ├── parse.cpp
│   └── stringify.cpp
├── src/                   # Source headers
│   ├── JSON.h
│   ├── JSONNode.h
│   ├── Parser.h
│   ├── Serializer.h
│   └── Utils.h
├── tests/                 # Unit tests
│   ├── official_test.cpp
│   ├── test_json.cpp
│   ├── test_parser.cpp
│   └── test_stringify.cpp
├── Makefile               # Build system
├── json-parser.cpp        # Main executable
├── notes.md               # Notes and documentation
└── README.md              # This file

Features

• Parse JSON strings into C++ objects (JSON/JSONNode)
• Manipulate objects, arrays, and primitive types (int, double, bool, string)
• Serialize JSONNode objects back into JSON strings
• Supports nested objects and arrays
• Handles null, true, false, numbers, strings, arrays, and objects
• Robust error handling for malformed JSON
• Simple API inspired by JavaScript object access

Installation

Clone the repository:

git clone https://github.com/sakkshm/json-parse.git
cd json-parse

Build the project (requires C++17):

make

This will compile all tests and the main binary in bin/.

Usage

Parsing a JSON file

./bin/json-parser <path/to/file.json>

Using in C++ code

#include "src/JSON.h"
#include <iostream>

int main() {
    std::string jsonStr = R"({"name":"Saksham","age":20,"skills":["C++","Python"]})";
    JSONNode person = parse(jsonStr);

    std::cout << "Name: " << person["name"].asString() << "\n";
    std::cout << "Age: " << person["age"].asInt() << "\n";
    std::cout << "First skill: " << person["skills"][0].asString() << "\n";

    return 0;
}

Serializing a JSON object

JSON person;
person["name"] = "Saksham";
person["age"] = 20;
person["skills"] = std::vector<JSONNode>{"C++", "Python", "TS"};

std::cout << stringify(person) << std::endl;
// Output: {"name":"Saksham","age":20,"skills":["C++","Python","TS"]}

Tests

Run all tests:

make test

This will execute all binaries in bin/ prefixed with test_ and stop on the first failure.

API Overview

JSONNode Class

• Constructors: JSONNode(), JSONNode(int), JSONNode(double), JSONNode(const std::string&), JSONNode(bool), JSONNode(std::vector<JSONNode>)
• Type checks: isObject(), isArray(), isValue(), isNull()
• Accessors: operator[](std::string key), operator[](int index)
• Value getters: asInt(), asDouble(), asBool(), asString(), asArray()
• Helpers: keys(), contains(key), size(), empty()

Parser & Serializer

• JSONNode parse(const std::string &jsonStr) → Parse JSON string
• std::string stringify(const JSONNode &node) → Serialize JSONNode to string

Notes

• Maximum nesting depth: 32 levels (MAX_DEPTH)
• Trailing commas are not allowed in objects or arrays
• Robust against malformed JSON (throws std::runtime_error)

Examples

See example/ for:

• json.cpp → Building JSON objects programmatically
• parse.cpp → Parsing JSON strings
• stringify.cpp → Serializing JSON objects