Markfive

Markfive is a lightweight markup language that compiles to semantic HTML. It looks similar to Markdown, but it covers many more HTML elements (<dfn>, <kbd>, <samp>, <cite>, <mark>, <time>, <ruby>, …), has first-class footnotes, tables with merged cells, MathML output and language-aware typography.

Syntax

Paragraphs and line breaks

Paragraphs are separated by blank lines. Unlike Markdown, every line break inside a paragraph is kept (rendered as <br>):

First line of a paragraph.
Second line of the same paragraph.

Another paragraph.

Inside a line, {/} inserts a line break (<br>) and {/?} a word-break opportunity (<wbr>).

A thematic break (<hr>) is a * * * line followed by a blank line.

Headings

A heading is a line underlined with at least three characters. The underline character sets the level:

Document title
**************

Chapter
=======

Subchapter
----------

Section
.......

Underline	Element
***	<h1>
===	<h2>
---	<h3>
...	<h4>

A heading must be followed by a blank line. A single line placed between the heading and the blank line becomes a subtitle and the pair is wrapped in <hgroup>:

Chapter 2
=========
Subtitle

Every heading of level 2 or lower opens a <section> that lasts until the next heading of the same or higher level. Each heading gets an id generated from its text (Chapter 2 → chapter_2); duplicates are made unique. Use --heading-shift=N to render all headings N levels lower.

Attributes

HTML attributes are written in braces:

{#id .class1.class2 lang=en title="Quoted value" data-foo='bar' hidden}

• #name sets the id,
• .name adds classes (several can be chained: .a.b),
• name=value sets an attribute (quote the value if it contains spaces),
• a bare name sets an empty attribute.

Block attributes go on their own line directly before the block:

{style="color: orange"}
A paragraph with a style.

{.compact}
- First item
- Second item

{#custom-id}
Heading with a custom id
------------------------

An attributes line at the very top of the file, followed by a blank line, applies to the whole document (e.g. {lang=fr} sets the language used for typography).

Block markers accept attributes right after the marker: ""{.note}, ``{.language-js}, ??{.box}, @main{#content}, -{.done} item, 1.{.done} item, |{.total} cell.

Inline attributes go right after the closing marker: *word*{lang=en}, [link](url){target=_blank}, ?[text]?{.highlight}.

Inline formatting

Markfive	HTML
*strong*	<strong>
~emphasis~	<em>
#bold#	<b>
/italic/	<i>
__underline__	<u>
--strikeout--	<s>
=highlight=	<mark>
''Title''	<cite>
:term:	<dfn>
:term:(Title)	<dfn title="Title">
`code`	<code>
>command>	<kbd>
<output<	<samp>
$x$	<var> (or MathML, see Math)
x^2^	<sup>
H_2_O	<sub>
?[text]?	<span>
[[Enter]]	key (<kbd class="mf-key">)
[[Ctrl]+[C]]	key combination
[|OK|]	button (<kbd class="mf-button"><samp>)
[|File|Save|]	menu path

Markers only work at word boundaries: the opening marker must not be preceded by a letter or digit and the closing marker must not be followed by one, so parag~raph stays literal. To format part of a word, wrap the content in brackets: #[J]#ava#[S]#cript. Superscript and subscript are the exception – they work inside words (km^2^), but content containing spaces must be bracketed: sli^[ce of text]^.

*strong*, ~emphasis~, =highlight= and ?[span]? can be nested in themselves: ~outer ~inner~ outer~.

Other inline HTML elements are written as @element[content]:

@abbr[HTML]{title="HyperText Markup Language"}
@small[fine print]
@del[removed] @ins[added]
@bdi[user name]
@ruby[漢 @rt[kan]]
@time[today](2025-07-30)
@data[five](5)

Supported elements are abbr, bdi, data, del, ins, rt, ruby, small and time. For time and data the value in parentheses becomes the datetime and value attribute respectively.

Links and images

[link text](https://example.com)
[link text](https://example.com){target=_blank}
&[alt text](image.png){.class}

If the alt text of an image contains formatting, the image is rendered as <object role="img"> with the formatted content as its fallback.

Notes

Footnotes are written inline and collected at the end of the document:

Some claim[*][Source of the claim.].

The number of asterisks selects an independent series of notes: [*] is numbered 1, 2, 3, [**] uses a, b, c and [***] uses A, B, C.

A note can be given an id and then referenced again:

First mention[*][The note.]{#src}. Second mention[*](#src).

Lists

- Unordered item
- Another item
	- Nested item (indented with a tab)

1. Ordered item
2. Another item
5. Item with value 5

Numbers that don't continue the sequence are kept as the value attribute. A blank line between two items at the same level starts a new list.

To put several blocks in one item, leave the marker empty and indent the content:

1. Item 1
2.
	First paragraph of item 2.

	Second paragraph of item 2.
3. Item 3

Description lists

Terms start with : and descriptions with =:

: Apartment
	= An execution context grouping threads with COM objects.
: Flat
	= A deflated tire.

Alternatively, a line ending with a colon followed by an indented line forms a term-description pair:

Fuzzy logic:
	gradual transition between "perfect falsity" and "perfect truth"

Block quotes

""
	A quotation. It can contain

	several paragraphs and other blocks.

"" A one-line quotation.

Code, keyboard input and sample output

A code block (<pre><code>) starts with `` and its content is indented. Whitespace and indentation inside it are preserved:

``
	if n < 0:
		raise ValueError()

`` print('A one-line code block')

Lines starting with > form a keyboard input block (<pre><kbd>) and lines starting with < a sample output block (<pre><samp>):

> npm install
> npm start

< added 42 packages in 2s

Divs and other blocks

?? creates a <div> containing the indented blocks:

??{.box}
	A paragraph in a div.

	??{.inner}
		A nested div.

??{.one-liner} A one-line div.

??{.empty}

@header, @main, @footer, @aside, @address, @pre, @del and @ins create the corresponding HTML element around their indented content. Inside @pre whitespace is preserved.

@main
	Main content.

	@pre
		Pre    formatted
		       text

Tables

In a simple table each line is a row; ! starts a header cell and | a data cell:

! Name   ! Position
| Chao   | Intern
| Nguyễn | Worker

Each > after the cell marker makes the cell span one more column. A ^ after the marker merges the cell with the one above it (its content, if any, is appended to that cell):

! First name ! Last name ! Paid
| Bob        | Smith     | 600
|^           |^ p.v.     | 400
|> Total                 | 1000

In a complex table rows are separated with lines starting with |- (any further - and | characters are ignored, so they can be used to draw the grid) and every cell can be written on its own line:

|-------|--------|-----
! Title ! Author ! Year
|-------|--------|-----
| The Title
| Author
| 2015

Cell attributes go right after the cell marker: |{.highlight} 2025.

Math

Math is rendered to MathML with Temml. A display formula is a line starting with $$ (the closing $$ is optional); inline math is enclosed in single dollars:

$$ E = \frac{mc^2}{\sqrt{1-\frac{v^2}{c^2}}} $$

Here, $E$ is energy. Similar equation is $E=mc^2$.

An inline formula consisting only of letters ($x$) is rendered as a simple <var>.

LaTeX syntax is supported, extended with a few shortcuts:

• a / b is a fraction; parentheses around the numerator or denominator are dropped: (-b \pm \sqrt{b^2 - 4ac}) / 2a,
• √{x} and ∛{x} are square and cube roots,
• braces after a set operator are literal: S ⊂ {a, b, c}.

Comments

Comments are not rendered:

// A one-line comment.

//
	A commented-out block.

	- including a list

Variables

{{name}} is replaced with the value passed on the command line as --name=value. Undefined variables are replaced with an empty string.

Typography

Unless --no-typography is given, the following replacements are made outside of code:

Input	Output
"text", 'text'	quotation marks of the current language
...	…
---	— (em dash)
3--5	3–5 (en dash)
-15	−15 (minus sign)
5', 12''	5′, 12″ (primes)
1600 x 900	1600 × 900
<<text>>	«text»
<text>	‹text›
[<u, v>]	⟨u, v⟩ (angle brackets)

Angle brackets take precedence over <samp< and >kbd> markers, and their content can be formatted: [<*A*>]. A link whose text starts with < must escape it: [\<b>](https://example.com).

The language is taken from the nearest lang attribute (English by default), e.g. "text" becomes “text” in English, „text” with {lang=pl} and „text“ with {lang=de}. For French, narrow no-break spaces are added before ?, !, : and inside guillemets.

Escaping

A backslash before a marker makes it literal: \*not strong\*. A backslash at the beginning of a line prevents it from being interpreted as a block marker:

\- Not a list item
\* * *

Use \\ for a literal backslash followed by a working marker.

Usage

Building:

npm run build

Develop mode (faster builds, watching for changes):

npm run dev

Running test:

markfive test/test.mf

Writing test to HTML file:

markfive test/test.mf > test/test.part.html
markfive --preview test/test.mf > test/test.html