capital_eszett_dangit.php

<?php
/**
 * Capitalize ẞ Dangit
 *
 * @package     CapitalizeẞDangit
 * @author      Bernhard Kau
 * @license     GPLv3
 *
 * @wordpress-plugin
 * Plugin Name: Capitalize ẞ Dangit
 * Plugin URI:  https://kau-boys.com
 * Description: Introduces a helper function you can use to capitalize the letter ß when surrounded by capital letters
 * Version:     1.0.0
 * Author:      Bernhard Kau
 * Author URI:  https://kau-boys.com
 * License:     GPLv3
 * License URI: http://www.gnu.org/licenses/gpl-3.0
 */

/**
 * Capitalizes the letter ß when surrounded by capital letters
 *
 * @param string $text The text to be modified.
 *
 * @return string The modified text.
 */
function capital_ß_dangit( $text ) {
	return preg_replace( '/(\p{Lu})ß(\p{Lu})?/', '$1ẞ$2', $text );
}
add_filter( 'the_content', 'capital_ß_dangit', 11 );
add_filter( 'the_title', 'capital_ß_dangit', 11 );
add_filter( 'wp_title', 'capital_ß_dangit', 11 );
add_filter( 'comment_text', 'capital_ß_dangit', 31 );