Hi,
On Mon, Oct 15, 2012 at 6:02 PM, Clint Priest <[email protected]> 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.
This discussion makes we wonder about another aspect of the patch that
is unclear:
class A {
public $v = 2;
}
class B extends A {
public $v { get { .. }; set { .. } };
}
Will $b->v trigger the accessors, will it ignore them and access "v"
in the properties table, or is overriding existing properties using
accessors rejected during compilation?
Best,
>
> -Clint
>
> On Oct 15, 2012, at 9:37 AM, "Levi Morrison" <[email protected]> wrote:
>
>>> I *think* we are on the same page here, though I'm not sure what 'user' is
>>> referring to (user of interface "implementer") or (user of class B). In
>>> any case, I don't believe that your class B would be allowed at present,
>>> but if it is, then it should not be allowed because defining a property to
>>> satisfy the requirements of an accessor is not right.
>>
>> According to whom? In my opinion, not allowing a property to satisfy
>> the requirement of an accessor is wrong.
--
Etienne Kneuss
http://www.colder.ch
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