Simple Parsing use strtok

<?php
function summarize($paragraph, $limit){
$tok = strtok($paragraph, " ");
$text="";
$words='0';
while($tok){
$text .= " ".$tok;
$words++;
if(($words >= $limit) && ((substr($tok, -1) == "!")||(substr($tok, -1) == ".")))
break;
$tok = strtok(" ");
}
return ltrim($text);
}
?>