glueckpress/wp-bootstrap-subheading.php

## wp-bootstrap-subheading.php
<?php

/**
 * Append a sub-heading to WordPress post titles
 *
 * Input: My title | my sub-title
 * Output: My title <small>my sub-title</small>
 *
 * The filter the_title() is used for posts/pages AND nav menus in WordPress.
 * In order to filter only post/page titles, not nav menu items, we need to
 * switch the title filter off when the menu class starts and back on when it ends.
 *
 * Toscho has created a life-saving example at WordPress StackExchange: http://bit.ly/Res0ci
 * I just had to switch the on/off statement and add the actual filter function.
 * Also added a filter for single_post_title() which is used by wp_title() to demonstrate how
 * to manipulate the <title> element within <head>. Outcomment/delete it as you see fit.
 */

add_filter( 'wp_nav_menu_args', 'gp121028_title_filter_switch' );
add_filter( 'wp_nav_menu', 'gp121028_title_filter_switch' );
add_filter( 'single_post_title', 'gp121028_filter_single_post_title' ); // for demo purposes only
/**
 * Switch title filter off when menu class starts and on when it ends.
 *
 * @param  mixed $input Array or string, we just pass it through.
 * @return mixed
 */
function gp121028_title_filter_switch( $input ) {
	$func = 'wp_nav_menu_args' == current_filter() ? 'remove_filter' : 'add_filter';
	$func( 'the_title', 'gp121028_filter_title' );
	return $input;
}

/**
 * Filter function for the_title()
 */
function gp121028_filter_title( $title ) {
	$substrings = explode( ' | ', $title );
	$title = ( ! empty( $substrings[0] ) ) ? $substrings[0] . '<small>' . $substrings[1] . '</small>' : $title;
    return $title;
}

/**
 * Filter function for single_post_title()
 */
function gp121028_filter_single_post_title( $title ) {
	$substrings = explode( ' | ', $title );
	$title = ( ! empty( $substrings[1] ) ) ? $substrings[0] . ' (' . $substrings[1] . ')': $title;
	return $title;
}
	<?php

	/**
	* Append a sub-heading to WordPress post titles
	*
	* Input: My title \| my sub-title
	* Output: My title <small>my sub-title</small>
	*
	* The filter the_title() is used for posts/pages AND nav menus in WordPress.
	* In order to filter only post/page titles, not nav menu items, we need to
	* switch the title filter off when the menu class starts and back on when it ends.
	*
	* Toscho has created a life-saving example at WordPress StackExchange: http://bit.ly/Res0ci
	* I just had to switch the on/off statement and add the actual filter function.
	* Also added a filter for single_post_title() which is used by wp_title() to demonstrate how
	* to manipulate the <title> element within <head>. Outcomment/delete it as you see fit.
	*/

	add_filter( 'wp_nav_menu_args', 'gp121028_title_filter_switch' );
	add_filter( 'wp_nav_menu', 'gp121028_title_filter_switch' );
	add_filter( 'single_post_title', 'gp121028_filter_single_post_title' ); // for demo purposes only
	/**
	* Switch title filter off when menu class starts and on when it ends.
	*
	* @param mixed $input Array or string, we just pass it through.
	* @return mixed
	*/
	function gp121028_title_filter_switch( $input ) {
	$func = 'wp_nav_menu_args' == current_filter() ? 'remove_filter' : 'add_filter';
	$func( 'the_title', 'gp121028_filter_title' );
	return $input;
	}

	/**
	* Filter function for the_title()
	*/
	function gp121028_filter_title( $title ) {
	$substrings = explode( ' \| ', $title );
	$title = ( ! empty( $substrings[0] ) ) ? $substrings[0] . '<small>' . $substrings[1] . '</small>' : $title;
	return $title;
	}

	/**
	* Filter function for single_post_title()
	*/
	function gp121028_filter_single_post_title( $title ) {
	$substrings = explode( ' \| ', $title );
	$title = ( ! empty( $substrings[1] ) ) ? $substrings[0] . ' (' . $substrings[1] . ')': $title;
	return $title;
	}