Jac — a language grammar for highlight.js

Jac is the primary programming language of the Jaseci runtime, featuring Python-compatible syntax extended with Object-Spatial Programming constructs — walkers, nodes, and edges — for building agentic AI applications.

Features

Highlights all Jac language constructs including:

• Archetype declarations: walker, node, edge, obj, class, enum
• Ability declarations: can, def
• Access modifiers: pub, priv, protect, static, override, abs
• Object-Spatial keywords: visit, disengage, report, spawn, here, visitor, root
• Property declarations: has, glob
• Single-line # and block #* ... *# comments
• f-strings, triple-quoted strings, raw strings, bytes
• Numeric literals with underscores, hex, binary, octal

Installation

npm

npm install highlightjs-jac

CDN

<script src="https://unpkg.com/highlightjs-jac/dist/jac.min.js"></script>

Usage

Browser (CDN / static site)

Load after highlight.js — the grammar self-registers via the CDN build.

<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.11.1/styles/github.min.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.11.1/highlight.min.js"></script>
<script src="https://unpkg.com/highlightjs-jac/dist/jac.min.js"></script>
<script>hljs.highlightAll();</script>

Then mark your code blocks with the jac language class:

<pre><code class="language-jac">
walker MyWalker {
    can walk with `root entry {
        visit [-->];
    }
}
</code></pre>

Node.js / ESM bundler (Webpack, Rollup, Vite)

import hljs from 'highlight.js/lib/core';
import jac from 'highlightjs-jac';

hljs.registerLanguage('jac', jac);

const result = hljs.highlight('walker Foo { can walk; }', { language: 'jac' });
console.log(result.value);

Example

import:py from math { sqrt }

node Person {
    has name: str;
    has age: int = 0;
}

edge Knows {
    has since: int = 2020;
}

walker Greeter {
    can greet with Person entry {
        :g: msg = f"Hello, {here.name}!";
        report msg;
    }

    can travel with `root entry {
        visit [-->];
        disengage;
    }
}

Development

This package follows the highlight.js third-party language contribution guide.

To develop locally:

git clone https://github.com/jaseci-labs/highlightjs-jac
cd highlightjs-jac
npm install
npm run build

To run fixture tests with the highlight.js test harness, clone this repository inside a local highlight.js checkout under extra/highlightjs-jac and execute the highlight.js test commands.

License

BSD 3-Clause © Jaseci Labs

Links

• Jac language documentation
• Jaseci GitHub
• highlight.js
• highlight.js GitHub