jjson

Proof-of-concept library for Json serialization in C

This small library illustrates how Json serializer interfaces could be built in a readable and close-to-output way. Writing json in C normally means calling x_begin(context) and x_end(context)-style functions. This isn't hard or tricky to do - but the C normally looks looking nothing like the json output. In contrast to this - Json code in Python or Javascript actually looks like the expected output, which is a nice feature for ease of use and particularly for clarity of the code.

However, with a simple macro trick we can make this happen in C. This library is a proof of concept of this - at the moment not intendet for production use. I originally came across this macro trick in a snippet of GUI code (credit to Ryan of https://dion.systems/).

Example of usage

Expected output

{
  "id": 9000237,
  "address": {
    "street": "Creek Street",
    "street_number": 10
  },
  "an_array": [
    "value",
    100
  ]
}

jjson code

    // Initialize a json context/handle to your json document
    jj_ctx doc = {0};

    // Populate the document with data
    jj_root(&doc) {
        jj_num("id", 9000237);
        jj_obj("address") {
            jj_str("street", "Creek Street");
            jj_num("street_number", 10);
        };
        jj_arr("an_array") {
            jj_ustr("value"); // unnamed string
            jj_unum(100);
        };
    };
    
    // Serialize and print
    printf( jj_serialize(doc) );

Minified vs. Pretty json

All output is "pretty" by default. I.e. with spacing, newlines and indents. To output minified json - use the jj_serialize_minified function.

// Output pretty json
char *pretty = jj_serialize(doc);

// Output minified json
char *minified = jj_serialize_minified(doc);