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| Re: ArrayAccess interface, Traversable interface and foreach [message #185988 is a reply to message #185987] |
Fri, 23 May 2014 20:35   |
Jerry Stuckle
Messages: 2598
Registered: September 2010
Karma: 0
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Senior Member |
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On 5/23/2014 2:22 PM, kurtk(at)pobox(dot)com wrote:
> The documentation for ArrayAccess (at http://www.php.net/manual/en/class.arrayaccess.php) doesn't show it implementing Traversable. Nevertheless, you can still use any class you write that implements ArrayAccess in a foreach loop.
>
> This seems like an oversight in the documentation--unless I am missing something?
>
Not an oversight, IMHO. I think it's impossible for the document
writers to cover *every* possible usage.
That's why there are usage notes, contributed by users like yourself,
who have found other usages which are valuable (or do not work).
You can always add your own note to the documentation to show how it's
done; in fact I would encourage it.
--
==================
Remove the "x" from my email address
Jerry Stuckle
jstucklex(at)attglobal(dot)net
==================
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| Re: ArrayAccess interface, Traversable interface and foreach [message #185991 is a reply to message #185990] |
Sat, 24 May 2014 12:37 |
Christoph Michael Bec
Messages: 207
Registered: June 2013
Karma: 0
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Senior Member |
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Jerry Stuckle wrote:
> On 5/24/2014 6:05 AM, Christoph Michael Becker wrote:
>> kurtk(at)pobox(dot)com wrote:
>>
>>> The documentation for ArrayAccess (at
>>> http://www.php.net/manual/en/class.arrayaccess.php) doesn't show it
>>> implementing Traversable. Nevertheless, you can still use any class
>>> you write that implements ArrayAccess in a foreach loop.
>>>
>>> This seems like an oversight in the documentation--unless I am
>>> missing something?
>>
>> You can use any object (whether it is an instance of a class that
>> implements Traversable or not) in a foreach loop, see
>> <http://www.php.net/manual/en/control-structures.foreach.php>.
>>
>
> But that is an entirely different access to what Kurt is talking about.
>
> Kurt is discussing how to transverse an array within an object; your
> page discusses how to transverse public data members in an object. But
> good OO practices says all data members should be private.
To traverse an array which is a member of an object $o with foreach($o
....), the object's class has to implement IteratorAggregate or Iterator,
not ArrayAccess.
--
Christoph M. Becker
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| Re: ArrayAccess interface, Traversable interface and foreach [message #185996 is a reply to message #185989] |
Tue, 27 May 2014 18:59 |
Adam Harvey
Messages: 25
Registered: September 2010
Karma: 0
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Junior Member |
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On Sat, 24 May 2014 12:05:02 +0200, Christoph Michael Becker wrote:
> kurtk(at)pobox(dot)com wrote:
>
>> This seems like an oversight in the documentation--unless I am missing
>> something?
>
> You can use any object (whether it is an instance of a class that
> implements Traversable or not) in a foreach loop, see
> <http://www.php.net/manual/en/control-structures.foreach.php>.
Yep, this is why objects that implement ArrayAccess still work with
foreach without implementing Traversable.
ArrayAccess and Traversable are technically different things: Traversable
provides a way to control iteration, whereas ArrayAccess is only for
array-style dereferencing via $object['key']. In practice, classes that
need to imitate arrays will need to implement both (probably by extending
a class such as ArrayObject that implements both interfaces).
Adam
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