How to catch an invalid array index offset as a native exception in PHP

test_undefined_offset_exception.php

<?php

/**
 * this class shows how to override default PHP handler to catch undefined index errors
 * and throw it as native exceptions, much more convenient way to work with object
 * oriented programs.
 *
 * @author Moisés Maciá <[email protected]>
 * @see http://codeup.net
 */

class A
{
  public function __construct()
  {
    // override default error handler with our own closure that will detect
    // undefined offsets in arrays
    set_error_handler(function($errno, $errstr, $errfile, $errline) {
      // we are only interested in 'undefined index/offset' errors
      if (strpos($errstr, 'Undefined offset') !== false) {
        throw new OutOfRangeException($errstr, 0);
      }

      return true; // error bublling to PHP's default handler
    });
  }

  public function __destruct()
  {
    // very important, restore the default error handler whe finish
    restore_error_handler();
  }

  public function m()
  {
    $matrix[1][1] = 'dfsdf';
    $matrix[1][0] = 'dfsdf';
    $matrix[0][1] = 'dfsdf';


    try {
      echo $matrix[0][0]; // this offset doesn't exists!
    }
    catch(OutOfRangeException $e) {
      echo "exception catched!\n";
    }
  }
}

$a = new A();
$a->m(); // out -> Exception catched!

unset($a);

$matrix = array();
echo $matrix[0][0]; // out -> default PHP error message