Wordpress - Get the post terms

functions.php

<?php

/**
 * Get the terms of specific post in a list
 * @param  object $p      The post
 * @param  array  $params An array of params
 * @return string         The HTML result
 */
function get_post_terms($p, $params = array()) {
  $defaults = array(
    'class' => 'term-item',
    'separator' => ', ',
    'taxonomy' => 'category',
    'links' => true,
    'args' => array()
  );
  $options = array_merge($defaults, $params);

  $elements = array();
  $p->cats = wp_get_post_terms($p->ID, $options['taxonomy'], $options['args']);

  foreach ($p->cats as $c) {
    $cat = get_category($c);

    if ($options['links']) {
      $elements[] = "<a href=\"" . get_category_link($cat->term_id) . "\" class=\"" . $options['class'] . "\">" . $cat->name . "</a>";
    }
    else {
      $elements[] = "<span class=\"" . $options['class'] . "\">" . $cat->name . "</span>";
    }
  }

  return implode($options['separator'], $elements);
}

/**
 * Example of use:
 * 
 * <?php echo get_post_terms($post, array('taxonomy' => 'fields', 'links' => false, 'class' => 'term__item', 'separator' => ' | ')); ?>
 */