note 99236 deleted from class.arrayaccess by googleguy
| From: | googleguy@php.net | Date: | Sun, 25 Nov 2012 05:54:22 +0000 |
| Subject: | note 99236 deleted from class.arrayaccess by googleguy | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-192137@lists.php.net to get a copy of this message | ||
Note Submitter: uramihsayibok, gmail, com
----
EDITOR NOTE: You can return by reference in offsetGet as of PHP 5.3.4.
If you find yourself facing the dreaded "Indirect modification of overloaded element of $class
has no effect" then don't worry too much: there's a clever solution. While you
*CANNOT* return by-reference with offsetGet, you can return objects which _also_ implement
ArrayAccess...
Example:
<?php
// sanity and error checking omitted for brevity
// note: it's a good idea to implement arrayaccess + countable + an
// iterator interface (like iteratoraggregate) as a triplet
class RecursiveArrayAccess implements ArrayAccess {
private $data = array();
// necessary for deep copies
public function __clone() {
foreach ($this->data as $key => $value) if ($value instanceof self) $this[$key] = clone
$value;
}
public function __construct(array $data = array()) {
foreach ($data as $key => $value) $this[$key] = $value;
}
public function offsetSet($offset, $data) {
if (is_array($data)) $data = new self($data);
if ($offset === null) { // don't forget this!
$this->data[] = $data;
} else {
$this->data[$offset] = $data;
}
}
public function toArray() {
$data = $this->data;
foreach ($data as $key => $value) if ($value instanceof self) $data[$key] =
$value->toArray();
return $data;
}
// as normal
public function offsetGet($offset) { return $this->data[$offset]; }
public function offsetExists($offset) { return isset($this->data[$offset]); }
public function offsetUnset($offset) { unset($this->data); }
}
$a = new RecursiveArrayAccess();
$a[0] = array(1=>"foo", 2=>array(3=>"bar",
4=>array(5=>"bz")));
// oops. typo
$a[0][2][4][5] = "baz";
//var_dump($a);
//var_dump($a->toArray());
// isset and unset work too
//var_dump(isset($a[0][2][4][5])); // equivalent to $a[0][2][4]->offsetExists(5)
//unset($a[0][2][4][5]); // equivalent to $a[0][2][4]->offsetUnset(5);
// if __clone wasn't implemented then cloning would produce a shallow copy, and
$b = clone $a;
$b[0][2][4][5] = "xyzzy";
// would affect $a's data too
//echo $a[0][2][4][5]; // still "baz"
?>