MultiMarkdown

MultiMarkdown (MMD) is a CommonMark superset created by Fletcher Penney that adds metadata blocks, footnotes, superscript/subscript, highlight, strikethrough, and table captions.

Package: relational-text/multimarkdownNamespace: org.multimarkdown.facet

Functions

import { from, to } from 'relational-text/registry'

from('multimarkdown', input: string): Document

Parse a MultiMarkdown string into a RelationalText Document.

const doc = from('multimarkdown', `Title: My Document
Author: Alice

## Introduction

This has ^superscript^ and ~subscript~ and ==highlight== and ~~strikethrough~~.

See the footnote.[^note]

[^note]: Footnote content here.
`)

Supports:

• Metadata block (key-value pairs before the first blank line) — each key stored as a metadata block with { key, value } attrs
• Footnote refs ([^key]) and definitions ([^key]: text)
• Standard CommonMark headings, code blocks, blockquotes, lists, HR, paragraphs
• Inline marks: **strong**, *italic*, _italic_, ~~strikethrough~~, ==highlight==, ^superscript^, ~subscript~, `code`

to('multimarkdown', doc: Document): string

Render a RelationalText Document to MultiMarkdown.

const mmd = to('multimarkdown', doc)

Metadata blocks are assembled at the top of the output, separated from the body by a blank line. Automatically applies lenses targeting org.multimarkdown.facet via lensGraph.autoTransform().

ensureMultiMarkdownLexicon(): void

Explicitly register the MultiMarkdown lexicon. Called automatically by from('multimarkdown', ...) / to('multimarkdown', ...) on first use.

Feature Mapping

Inline Marks

MultiMarkdown syntax	Feature name	RT hub name
**text**	strong	bold
*text* / _text_	emphasis	italic
~~text~~	strikethrough	strikethrough
==text==	highlight	highlight
^text^	superscript	superscript
~text~	subscript	subscript
`text`	code-span	code
[text](url)	link	link
	image	image
[^key]	footnote-ref	—

Block Elements

MultiMarkdown syntax	Feature name	Attrs
# … ######	heading	{ level: 1–6 }
```lang ```	code-block	{ language?: string }
> text	blockquote-marker	—
- text	bullet-list-marker / list-item-text	—
1. text	ordered-list-marker / list-item-text	—
---	horizontal-rule	—
[^key]: text	footnote-def	{ key }
Key: Value (metadata)	metadata	{ key, value }

Examples

Import

import { from } from 'relational-text/registry'

const doc = from('multimarkdown', `Title: My Note
Tags: science

## Findings

The result is x^2^ with ==highlighted== text and ~subscript~.

See note.[^1]

[^1]: The footnote text.
`)

Export

import { from, to } from 'relational-text/registry'

const doc = from('markdown', '## Heading\n\n**bold** and _italic_')
const mmd = to('multimarkdown', doc)
// "## Heading\n\n**bold** and *italic*"

Cross-format

import { from, to } from 'relational-text/registry'

const doc = from('multimarkdown', '## Title\n\nHello **world** with ==highlight==.')
const html = to('html', doc)
// '<h2>Title</h2>\n<p>Hello <strong>world</strong> with <mark>highlight</mark>.</p>\n'

Notes

• The metadata block is only recognized at the very start of the document, before any blank line. Each line must be a Key: Value pair; the block ends at the first blank line.
• Footnote refs ([^key]) and defs ([^key]: text) are stored and round-tripped. Cross-format conversions to formats without footnote support will drop them.
• highlight (==text==) maps to RT hub highlight, which in turn maps to HTML <mark>.
• The multimarkdown-to-relationaltext lens maps the common subset to RT hub names, including highlight→highlight.