markdown-plus-plus

Markdown++

Markdown++ is an open documentation format built on CommonMark. It adds professional publishing features -- styles, variables, conditional content, cross-references, content assembly, metadata -- through HTML comment directives and inline tokens that are invisible to standard Markdown renderers.

Every Markdown++ file is a valid CommonMark document. No proprietary syntax, no custom file extension, no build step required to preview your content.

Quick look

<!-- style:Note -->
This paragraph is styled as a note in published output, but renders
as a normal paragraph in GitHub, VS Code, or any Markdown viewer.

<!-- condition:online -->
This content only appears in online output formats.
<!-- /condition -->

The current version is $product_version;, released $release_date;.

HTML comments are invisible to renderers. Inline tokens ($variable;) pass through as literal text. The extensions activate only when processed by a publishing tool.

What's in this repo

This is the home of the Markdown++ format standard -- its specification, examples, and tooling.

• spec/ -- The Markdown++ whitepaper explaining the format, its design rationale, and how it compares to DITA, FrameMaker, Word, and other documentation formats.
• examples/ -- Sample .md files demonstrating Markdown++ features.
• Syntax reference -- Complete reference for all extensions, rules, and validation codes.

Tools

Claude Code plugin

A Claude Code marketplace plugin for AI-assisted Markdown++ authoring.

/plugin marketplace add quadralay/markdown-plus-plus
/plugin install markdown-plus-plus@markdown-plus-plus

Feature	Description
Syntax reference	Authoritative reference for all extensions (variables, conditions, styles, aliases, includes, markers, multiline tables)
Validation	Python script to check syntax errors, unclosed conditions, invalid variables, malformed JSON markers, duplicate aliases, orphaned tags
Alias generation	Script to auto-generate unique aliases for headings
Best practices	Naming conventions, document structure patterns, common mistakes

Other tools

• asciidoctor-mdpp -- Convert AsciiDoc documents to Markdown++.

License

MIT