footnote helper

example_in_order.php

<?php footnote(1) ?>
1st footnote
<?php end_footnote() ?>

<?php footnote(2) ?>
2nd footnote
<?php end_footnote() ?>

example_out_of_order.php

<?php footnote(2) ?>
2nd footnote
<?php end_footnote() ?>

<?php footnote(1) ?>
1st footnote
<?php end_footnote() ?>

FootnoteHelper.php

<?php

use_helper('Tag');

$footnotes = array();
$footnote_ptr = 0;

function footnote($reference)
{
	global $footnote_ptr;
	$footnote_ptr = $reference;
	ob_start();
}

function end_footnote()
{
	global $footnotes;
	global $footnote_ptr;
	$footnotes[$footnote_ptr] = ob_get_clean();
}

function get_footnotes()
{
	global $footnotes;
	ksort($footnotes);
	return $footnotes;
}

function link_to_footnote($reference, $options = array())
{
	return content_tag('sup', content_tag('a', $reference, array_merge(array('href' => "#footnote_$reference"), $options)));
}

usage.php

<dl class="footnotes">
	<?php foreach (get_footnotes() as $i => $note): ?>
		<dt id="footnote-<?= $i ?>"><?= ($i + 1) ?>:</dt>
		<dd><?= $note ?></dd>
	<?php endforeach ?>
</dl>