CodeBattle: "Given a sentence, sort characters in each word alphabetically."

description.txt

Examples:

"Eey fo Entw, adn Eot fo Fgor, Loow fo Abt, adn Egnotu fo Dgo."  == solution("Eye of Newt, and Toe of Frog, Wool of Bat, and Tongue of Dog.")

solution.php

<?php
function solution($sentence){
	return $sentence = preg_replace_callback(
		"/(\w+)/",
		 function(array $matches) {;
			$letters = str_split($matches[0]);
			natcasesort($letters);

			$string = implode('', $letters);
			if (preg_match('/[A-Z]/', $string)) {
				$string = ucfirst(strtolower($string));
			}
			return $string;
		 },
		 $sentence
	);
}