Jacson

Jacson is a simple Json parsing library and query engine in C (in ~1100 LoC).

Warning

This project is just a simple json parser with simple query engine. Don't use this library for real programs.

Features

• By not using recursion Jacson can handle deeply nested structures.
• Simple Public API

Build

To build Jacson, you need a C compiler (gcc or clang), cmake and make installed on your system.

git clone --depth=1 --branch=main https://github.com/thehxdev/jacson

cd jacson

mkdir -p build && cmake -B build -S .

cmake --build build

Then you can use libjacson.a file for your projects in build directory and header files in include directory. Or use test program in build directory to parse a json file and query data from that.

Take a look at test/test.c file to see how to use Jacson as a library.

Query Syntax

Jacson has very simple query syntax to get data from AST (Parsed json data).

• Use . to seperate different parts of query.
• Use [N] syntax to show an array's index where N is a positive integer or 0.

Example

Consider this json data:

{
    "message": "Hello World!",
    "status": 200,
    "ok": true,
    "arr": [
        true,
        false,
        56,
        12.841,
        {
            "name": "thehxdev"
        },
        null
    ]
}

To get thehxdev string, you can use arr.[4].name query string.

Note

Use test program in build directory to parse and query json files. Execute it with no arguments to get a help message.

Architecture:

Jacson architecture

+------------------+
|   Raw Json Data  |
+---------+--------+
          |         
+---------v--------+
|     Tokenizer    |
+---------+--------+
          |         
+---------v--------+
|     Validator    |
+---------+--------+
          |         
+---------v--------+
|      Parser      |
+------------------+

TODO

List of improvements and features to add:

• Free all memory used by Jacson (without recursion)
• Query engine for getting data from AST
• Handle control characters in json strings
• Unicode (utf-8) support
• Handle control characters in query strings
• Change or add data to AST
• Better and more advanced query engine
• Documentation for Jacson's public API
• Error handling and reporting errors to top-level callers
• More advanced json syntax validation
• Lazy evaluation capabilities
• Write tests for each module