Create pager for a related field

Below is an example wrapped in a shortcode.

If already in a PHP context, the content of the function attached to the shortcode can be used on its own as long as $atts values are set.

Example use would be:

[paged_relationship relationship_field="paged_relationship" relationship_post_type="example_post_type" limit="1"]

…where paged_relationship is the field name on the current object, example_post_type is the post type of the related content, and limit is the number of items to show for each page.

/**
 * Plugin Name: Pods —?Paged Relationship Shortcode
 * Description: Output a paged template based on relationship field. Usage: <code>[paged_relationship relationship_field="paged_relationship" relationship_post_type="example_post_type" limit="1"]</code> where <code>paged_relationship</code> is the field name on the current object, <code>example_post_type</code> is the post type of the related content, and <code>limit</code> is the number of items to show for each page.
 * Version: 1
 * Plugin URI: https://www.ads-software.com/support/topic/create-pager-for-a-related-field/
 */

// @see https://developer.www.ads-software.com/reference/functions/add_shortcode/
add_shortcode(
	'paged_relationship',
	function( $atts, $content, $tag ) {
		// @see https://docs.pods.io/code/pods/find/
		$pod = pods(
			$atts['relationship_post_type'],
			[
				'limit' => $atts['limit'],
				// @see https://www.php.net/manual/en/function.sprintf.php
				'where' => sprintf(
					// @see https://www.w3schools.com/mysql/mysql_in.asp
					't.ID IN( %s )',
					// @see https://www.php.net/manual/en/function.implode.php
					implode(
						', ',
						// @see https://www.php.net/manual/en/function.array-map
						array_map(
							'intval',
							(array) get_post_meta( get_the_ID(), $atts['relationship_field'], false )
						)
					)
				),
				'pagination' => 'true',
			]
		);
		
		// Shortcodes return output.
		// Output buffer, ob_* functions capture output for return.
		ob_start();
		
		echo '<ul>';
		
		// Output for each found item using Pods template syntax.
		// @see https://docs.pods.io/code/pods/template/
		echo $pod->template(
			null,
			'<li><a href="{@permalink}">{@post_title}</a></li>'
		);
		
		echo '</ul>';
		
		// Output pagination.
		// @see https://docs.pods.io/code/pods/pagination/
		echo $pod->pagination(
			[
				'type' => 'advanced',
			]
		);
		
		return ob_get_clean();
	}
);

The script can be installed as a plugin in wp-content/plugins, or activated using a Code Snippets plugin.

Please note the inline comments for additional options and documentation.