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Date: Tue, 30 Nov 2010 15:01:17 +0000
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To: president@basnetworks.net
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Subject: Re: [PHP-DEV] RFC: C-sharp style property get/set syntax for PHP
From: rquadling@gmail.com (Richard Quadling)

On 30 November 2010 12:48,  <president@basnetworks.net> wrote:
> Hi Richard,
>
>
>
>> I'd really like this feature to be part of PHP.
>>
>> I don't particularly like the use of what looks like a closure for the
>> set/get.
>
> While it looks like a closure, it may not necessarily be one. =C2=A0What =
I have
> presented in my RFC is a syntax, but I make little assumption about how i=
t
> would be implemented, as that would be out stepping my expertise.
>
> In C#, when a property gets compiled it is actually turned into two norma=
l
> class methods in a special namespace. =C2=A0Looking at a compiled C# libr=
ary
> with reflector will reveal this underlying implementation. =C2=A0So when =
a call
> to a property is compiled in C#, it is simple replaced with a call to a
> method. =C2=A0The properties themselves are nothing more than syntactic s=
ugar.
>
> Since PHP is interpreted instead of compiled, this may not be an ideal
> solution, but I couldn't guess as to what would be a better method.
> Preferably something that re-uses the existing class method
> interpretation.
>
>
>> I used to code in Delphi and I always like the way in which their
>> properties were defined.
>>
>> Essentially, the setter and getter are normal methods which are cherry
>> picked for a property [1].
>>
>> <?php
>> class TimePeriod
>> {
>> =C2=A0 =C2=A0 protected $seconds;
>>
>> =C2=A0 =C2=A0 public property Hours read getHours write setHours;
>>
>> =C2=A0 =C2=A0 protected function getHours()
>> =C2=A0 =C2=A0 {
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0 return $this->seconds / 3600;
>> =C2=A0 =C2=A0 }
>>
>> =C2=A0 =C2=A0 protected function setHours()
>> =C2=A0 =C2=A0 {
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0 $this->seconds =3D $value * 3600;
>> =C2=A0 =C2=A0 }
>>
>> =C2=A0 =C2=A0 // This property is read-only
>> =C2=A0 =C2=A0 public property Minutes read getMinutes;
>>
>> =C2=A0 =C2=A0 protected function getMinutes()
>> =C2=A0 =C2=A0 {
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0 return $this->seconds / 60;
>> =C2=A0 =C2=A0 }
>>
>> =C2=A0 =C2=A0 public property Milliseconds read getMilliseconds write
>> setMilliseconds;
>>
>> =C2=A0 =C2=A0 public function getMilliseconds()
>> =C2=A0 =C2=A0 {
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0 // This method is public
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0 return $this->seconds * 60;
>> =C2=A0 =C2=A0 }
>>
>> =C2=A0 =C2=A0 protected function setMilliseconds()
>> =C2=A0 =C2=A0 {
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0 // This method is protected
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0 $this->seconds =3D $value * 3600;
>> =C2=A0 =C2=A0 }
>> }
>>
>> For me, the advantage here is that I can independently the methods
>> from the property. If I want to force a subclass to implement a
>> setter/getter, then I can abstract the function in the base class.
>> Sure, some may say that I should be using an interface. I disagree as
>> I probably don't want the methods to be public. Protected or even
>> private and/or final.
>
> In the syntax I provided in my RFC, it is certainly possible to define a
> property with only a get or only a set method (these are implicit
> read-only and write-only properties). =C2=A0Furthermore, it is also possi=
ble to
> set the visibility of the get and set methods individually, as well as
> making either one final, static or (and I forgot to mention this in the
> RFC) abstract. =C2=A0But the advantage of my syntax, is not only can thes=
e
> things be set individually, but they can also be set just once for the
> pair, by specifying them on the property itself. =C2=A0This makes for cle=
aner
> and more readable code.
>
> My syntax also gives several other advantages over the delphi syntax. =C2=
=A0It
> is more logical, as it makes the property look more like a class variable
> than a class method. =C2=A0This makes sense because you call it like a
> variable. =C2=A0Additionally, because the get/set methods need to be cont=
ained
> within the body of the property definition, you immediately know if a
> property has both a get and a set method at a quick glance - you do not
> have to hunt through the class to see if there is another definition
> somewhere else.
>
>
>> The classic example is one of shapes. Every shape has a public $area
>> property, but the value would be provided by an abstract protected
>> TShape::getArea(); method. I can also finalise them, so, for example,
>> a triangle shape could have a final protected getArea() method and all
>> sub classes of triangles (scalene, isosceles, equilateral) would not
>> implement their own getArea() method.
>
> This is possible with the syntax I provided. =C2=A0I would suggest readin=
g more
> about the C# syntax, which my suggested syntax is based off of, as it wil=
l
> explain all of your questions.
>
> http://msdn.microsoft.com/en-us/library/x9fsa0sw%28VS.80%29.aspx
>
> - Dennis
>
>

Thanks for your reply.


Fundamentally, a big +1 from my little voice on having setters/getters in P=
HP.


The issue of documentation is probably that the documentation tools
would have to adapt. As things stand PHPDoc doesn't support
namespaces, so setters/getters would just be added to the WIBNI list.


With regard to the value supplied to the set method, would it make
more sense for PHP to be ...

        set($value) { $this->seconds =3D $value * 3600; }

or

        set { $this->seconds =3D __SETVALUE__ * 3600; }

Having $value without a clear indication of where it comes from
doesn't read quite right.

$value is way to generic to be magically created. __SETVALUE__ (or
__SOMETHINGELSE__) is clear in this regard.




Richard.

--=20
Richard Quadling
Twitter : EE : Zend
@RQuadling : e-e.com/M_248814.html : bit.ly/9O8vFY