MoonMarkdown

A CommonMark spec-compliant Markdown to HTML parser written in pure MoonBit.

Why MoonMarkdown?

MoonBit ecosystem has @mizchi/markdown (fast but 38% spec-compatible) and Cmark.mbt (C FFI wrapper). MoonMarkdown is the first pure MoonBit implementation targeting full CommonMark compliance.

Features

• Block elements: ATX/Setext headings, paragraphs, fenced/indented code blocks, thematic breaks, blockquotes, ordered/unordered lists, HTML blocks, link reference definitions
• Inline elements: backslash escapes, code spans, emphasis (italic/bold/bold-italic), links, images, autolinks, HTML entities, hard/soft line breaks
• GFM extensions: tables (with alignment), task lists, strikethrough, bare URL autolinks
• HTML rendering: with entity escaping and customizable CSS classes
• CLI tool: convert Markdown files to HTML from command line
• Zero dependencies: pure MoonBit, compiles to Native/Wasm/JS

Installation

moon add wangyichao/moonmarkdown

Usage

Library API

// One-liner: parse + render
let html = @moonmarkdown.md_to_html("# Hello\n\n**bold** text")

// Two-step: parse then render
let ast = @moonmarkdown.parse(input)
let html = @moonmarkdown.render(ast)

CLI

# Convert file to stdout
moon run cmd/main -- input.md

# Pipe from stdin
echo "# Hello" | moon run cmd/main

Examples

Markdown	HTML Output
*italic*	<em>italic</em>
**bold**	<strong>bold</strong>
`code`	<code>code</code>
[link](url)	<a href="url">link</a>
| a | b |	<table>...</table>

Project Structure

moonmarkdown/
├── types/       # AST type definitions (Block, Inline)
├── util/        # Line scanner, character classification, HTML escape
├── block/       # Block-level parser
├── inline/      # Inline parser (emphasis, links, code spans)
├── render/      # HTML renderer
├── ext/         # GFM extensions (tables, task lists, strikethrough)
├── cmd/main/    # CLI entry point
├── tests/       # Test suite
└── docs/        # Competition materials

License

MIT