The constructors of PHP's ArrayIterator and ArrayObject have a flags parameter that is documented in ArrayObject::setFlags() as follows:
ArrayObject::STD_PROP_LISTProperties of the object have their normal functionality when accessed as list (var_dump, foreach, etc.).
ArrayObject::ARRAY_AS_PROPSEntries can be accessed as properties (read and write).
The documentation of ArrayIterator::setFlags() is similar (the difference being difference erroneous).
Now, I understand the second flag quite well, it allows property access with -> as well as array access with []:
$a = new ArrayIterator(array('foo'=>1), ArrayObject::ARRAY_AS_PROPS);
var_dump($a['foo']);
var_dump($a->foo);
int(1)
int(1)
But I cannot wrap my head around ArrayObject::STD_PROP_LIST. As far as I tested it, var_dump and foreach behave exactly the same with or without this flag. What am I missing here?
As stated in the comments in the PHP manual the flag causes the properties, instead of the array values to be visible in var_dump.
Credits for this go to the commenter in the PHP manual:
<?php
$a = new ArrayObject(array(), ArrayObject::STD_PROP_LIST);
$a['arr'] = 'array data';
$a->prop = 'prop data';
$b = new ArrayObject();
$b['arr'] = 'array data';
$b->prop = 'prop data';
// ArrayObject Object
// (
// [prop] => prop data
// )
print_r($a);
// ArrayObject Object
// (
// [arr] => array data
// )
print_r($b);
?>
This behaviour probably changed within never versions of PHP, as my version (5.4.6) of PHP always shows both: Properties and array values:
ArrayObject Object
(
[prop] => prop data
[storage:ArrayObject:private] => Array
(
[arr] => array data
)
)
ArrayObject Object
(
[prop] => prop data
[storage:ArrayObject:private] => Array
(
[arr] => array data
)
)