<?php

add_action( 'init', function() {
	global $wp_rewrite;

	// Test the new method
	$regex = 'some/path/([^/]+)/?$';
	$redirect = 'index.php?some_var=$matches[1]&maybe_some_flag=1';

	add_rewrite_rule( $regex, array(
	  'some_var' => '$matches[1]', 
	  'maybe_some_flag' => 1
	) );

	var_dump( $wp_rewrite->extra_rules[$regex] == $redirect );

	// Test external rules
	$external_regex = 'other/path/([^/]+)/?$';
	$external_redirect = 'external.php?some_var=$matches[1]&maybe_some_flag=1';

	add_rewrite_rule( $external_regex, $external_redirect );

	var_dump( $wp_rewrite->non_wp_rules[ $external_regex ] == $external_redirect );
});