On 16/10/12 13:37, Clint Priest wrote:
On Mon, Oct 15, 2012 at 6:02 PM, Clint Priest<cpri...@zerocue.com> wrote:
> >Because fundamentally interfaces are designed to explain a way of
communicating and properties are symmetrical and non-
>observable.
> >
> >The implementing class cannot "know" when a property has changed.
>
>Do you agree that there is nothing that distinguishes
>
>class A {
> public $v;
>}
>
>from
>
>class B {
> private $_v;
> public $v { get { return $this->v; }; set($n) { $this->v = $n; }} }
>
>when it comes to a client of B reading and writing to $b->v ? That's the
entire point of accessors: being able to seamlessly intercept
>usages of properties with custom code.
>
>If you define an interface saying interface A { public $v { get;set;} } you
are only saying to the user: objects of type A will have a
>property $v that you can read and write to.
>Whether it is a set of accessors or a property belongs to the implementation
detail of the class implementing A, the user should not
>be able to see a difference when interacting with the class, as he will do it
through $obj->v and $obj->v = ...;
>
>I can understand why we might not want that in PHP in order to simplify the
implementation, but it we follow logical reasoning I
>can't see why we shouldn't implement that.
>
I'm not sure I understand what you're getting at here Etienne, this thread was
about interfaces but now you're talking about two classes...
From an interface standpoint, both classes implement the same property.
One as a literal property, the other as an accessor. The point being,
from the code consuming the class, a property and accessor are the same
thing. Interfaces are about contracts between an implementation and a
consumer, so the actual implementation is irrelevant. What matters is
how the implementation is accessed by the consumer. If it is via
property syntax, then it *is* a property, even though the actual
implementation might be a property, an accessor or (in theory) even
__get/__set.
Cheers,
David
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