ows / commonmark-sup-sub-extensions

3.0.0-RC2 2026-10-30 12:32 UTC

Requires

• php: >=8.3
• league/commonmark: ^2.10.2

Requires (Dev)

• phpstan/phpstan: ^2.2.15
• phpunit/phpunit: ^10.5.64

GPL-2.0-or-later

• parser
• markdown
• commonmark

Published on Packagist.org on 2026-10-30 12:35 UTC

README

This library adds support of superscript and subscript (<sup> and <sub> HTML tags) to league/commonmark.

Versions compatibility

• 3.x is compatible with league/commonmark 2.x (2.10.2+) and requires PHP 8.3+ (recommended version)
• 2.x is compatible with league/commonmark 1.x
• 1.x is compatible with league/commonmark 0.17.x and 0.18.x and will no longer be supported

Installation

This project can be installed via Composer:

$ composer require ows/commonmark-sup-sub-extensions

Usage

use League\CommonMark\Environment\Environment;
use League\CommonMark\Extension\CommonMark\CommonMarkCoreExtension;
use League\CommonMark\MarkdownConverter;
use Ows\CommonMark\SupSubExtension\SupExtension;
use Ows\CommonMark\SupSubExtension\SubExtension;

$environment = new Environment();
$environment->addExtension(new CommonMarkCoreExtension());
$environment->addExtension(new SupExtension());
$environment->addExtension(new SubExtension());

$converter = new MarkdownConverter($environment);
echo $converter->convert('10^2^ H~2~O');

See league/commonmark extensions documentation.

Note: SubExtension cannot be used together with the StrikethroughExtension (also included in GithubFlavoredMarkdownExtension), as both use the ~ delimiter.

Syntax

Code:

10^2^
10~2~

Result:

10<sup>2</sup>
10<sub>2</sub>

As in Pandoc, spaces are not allowed between delimiters: use   instead (P~a cat~). Spaces inside nested elements are allowed (^[a link](https://example.com)^).