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	"'Tom Oram'" <tom@scl.co.uk>
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Date: Wed, 26 Jun 2013 13:54:02 +0200
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Subject: AW: [PHP-DEV] RFC Proposal: New assign value operator
From: rstoll@tutteli.ch ("Robert Stoll")

As far as I see it, it is kind of an operator overload mechanism for the =
assign operator.
This can be useful for small utility classes such as Money, Email etc.

An example was given:
$price =3D new MoneyValue();
$price :=3D 29.99;

Instead of writing something like:
$price =3D new MoneyValue();
$price->setPrice(29.99);

The benefit is small, but can lead to better readable code. But since it =
is only for the assign operator and not for + - etc., for me the =
question remains open why not writing something like this directly:

$price =3D new MoneyValue(29.99);

-----Urspr=C3=BCngliche Nachricht-----
Von: Richard Quadling [mailto:rquadling@gmail.com]=20
Gesendet: Mittwoch, 26. Juni 2013 12:51
An: Tom Oram
Cc: PHP internals
Betreff: Re: [PHP-DEV] RFC Proposal: New assign value operator

On 25 June 2013 11:01, Tom Oram <tom@scl.co.uk> wrote:

> Hi everyone,
>
> I've got an idea for an RFC proposal and from reading the instructions =

> it looks like I should run it past you guys first.
>
> I have not made any contributions to PHP before although I have made=20
> some custom modifications in house in the past and while I'm no longer =

> familiar with the PHP code base I am confident I have the skills to=20
> implement this should it be accepted.
>
> What I want to propose is a new assignment operator which rather than=20
> setting the variable to completely new value it would update the value =

> while maintaining the type.
>
> The main motivation for this is for easy assignment to value objects=20
> aka assignment operator overloading via a magic method (prehaps called =

> __assign).
>
> Here is an example ( for now I will use the PASCAL style assignment=20
> operator :=3D as the new operator as it is a know assignment operator=20
> and currently not used in PHP):
>
> // For a class defined like so...
> class MoneyValue
> {
>     protected $amount;
>
>     public function __assign($value)
>     {
>         $this->amount =3D $value;
>     }
> }
>
> // The amount could then be assigned using the new operator like this
>
> $price =3D new MoneyValue();
>
> $price :=3D 29.99;
>
> While the primary focus would be for assignment operator overloading=20
> as I just displayed in the previous example, for consistency it could=20
> be used with scalar values to preserve type like so:
>
> // $str is now a string
>
> $str =3D 'Original String';
>
> // Using the new assignment variable would cast the value being=20
> assigned to the variable's type // (in this case a string). So
>
> $str :=3D 7;
>
> // Would be the equivalent to
> //
> // $str =3D (string) 7;
> //
> // $str =3D=3D=3D "7"
>
>
> Another quick example:
>
> $num =3D 5;
>
> $num :=3D '12';
>
> // Equivalent to
> //
> // $num =3D (int) '12';
> //
> // $num =3D=3D=3D 12;
>
> So what do you guys think?
>
> If I get a good response I'll look into how to create a proper RFC and =

> start trying to work out how to implement it.
>
> Many thanks and look forward to some responses, Tom
>

Hi.

I'm not going to comment on the merits as such, but I'd be interested in =
knowing what problem this RFC would solve?

Considering PHP has type juggling scalars, it would SEEM (I may have =
missed the point) that this could result in data loss when the enforced =
conversion results in 0/False/"".

$num =3D 8;
$num :=3D "data from user"; // 0

Unless that is the expected behaviour.

Where would this RFC change be used?

And having said all of that, I'm not against it, just want to see what =
it would be useful for that isn't already part of PHP's toolbox.

--
Richard Quadling
Twitter : @RQuadling
EE : http://e-e.com/M_248814.html
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