replace with regex and callback in PHP

gistfile1.aw

<?php

function urlReplace($text, $replaceWith){
  // set the callback function
  $callback = function($match)use($replaceWith){
    $replaced0 =preg_replace('/\{0\}/', $match[0], $replaceWith);
    return preg_replace('/\{1\}/', toUpper($match[0]), $replaced0);
  };  
  var_dump($callback);
  return preg_replace_callback('/https?:\/\/\S+(?= |$)/',$callback, $text);
}


function toUpper($input){
  return strtoupper($input);
} 

// test
$s = "http://www.bitbucket.com here and  https://github.com there";
$result = urlReplace($s, '<a href={0}>{1}</a>');
echo $result;