Smarty : Variable Modifiers ( count_sentences )

This is used to count the number of sentences in a variable.
Example : count_sentences

<?php
$smarty->assign('articleTitle','Two Soviet Ships Collide - One Dies. Enraged Cow Injures Farmer with Axe.'
);
?>

Where template is:

{$articleTitle}
{$articleTitle|count_sentences}

Will output:

Two Soviet Ships Collide - One Dies. Enraged Cow Injures Farmer with Axe.
2