Wordpress: breadcrumbs

breadcrumbs.php

<?php 
  /**
   * only works in pages, no categories support
   * */
  echo '<ul>';
  
  if ( is_page() && $post->post_parent ): // checking if the page has parent
    
    $parent_id  = $post->post_parent; 
    $breadcrumbs = array();
    
    while ( $parent_id ):
      
     $page = get_page( $parent_id );
     $breadcrumbs[] = '<a href="'.get_permalink( $page->ID ).'">'.get_the_title( $page->ID ).'</a>';
     $parent_id  = $page->post_parent;
     
    endwhile;
    
    $breadcrumbs = array_reverse( $breadcrumbs );
    
    for ( $i = 0; $i < count( $breadcrumbs ); $i++ ): 
      
      echo '<li>'.$breadcrumbs[$i].'</li>'; // print parent titles
      
    endfor;
    
    echo '<li>'.get_the_title().'</li>' ; // print current page title
    
  endif; 
  
  echo '</ul>';
?>