Remove Empty Paragraphs from Shortcodes, WordPress

empty_paragraphs.php

<?php
// http://webandphp.com/remove-markup-from-wordpress-shortcodes

/**
 * Removes mismatched </p> and <p> tags from a string
 * 
 * @author Jason Lengstorf <jason@copterlabs.com>
 */
function copter_remove_crappy_markup( $string )
{
    $patterns = array(
        '#^\s*</p>#',
        '#<p>\s*$#'
    );

    return preg_replace($patterns, '', $string);
}


// USE IN SHORTCODE. EXAMPLE:
function my_shortcode_highlight( $attr, $content )
{
    $clean = copter_remove_crappy_markup($content);
    return '<div class="highlight">' . $clean . '</div>';
}
add_shortcode('highlight', 'my_shortcode_highlight');