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Date: Wed, 28 Jun 2017 20:07:23 -0300
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To: Kalle Sommer Nielsen <kalle@php.net>
Cc: PHP Internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary="001a11475b6e67755305530d4012"
Subject: Re: [PHP-DEV] Final variables
From: david.proweb@gmail.com (David Rodrigues)

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=E2=80=8B
Walter Parker <walterp@gmail.com>
=E2=80=8B wrote:=E2=80=8B
> =E2=80=8B
Constant may not have been the right word (or idea), but I agree with
Kalle. We should use readonly as the keyword here and not final as the
keyword. We can keep the same scoping rules so the following would work:
>=E2=80=8B
=E2=80=8B> function randomNumber() {
=E2=80=8B>=E2=80=8B
  *readonly *$number =3D mt_rand();
=E2=80=8B
=E2=80=8BI agree that "readonly" is a better keyword, but we have to points=
 here:
1. "final" is used on some language (Java, C++ I guess);
2. "final" keyword does exists on PHP with a "similar" behaviour;

If we can implements "readonly" is good too, because turn it more implicit.



2017-06-28 15:46 GMT-03:00 David Rodrigues <david.proweb@gmail.com>:

> 2017-06-28 13:59 GMT-03:00 Kalle Sommer Nielsen <kalle@php.net>:
>
>> Hi David
>>
>> It seems like what you are looking for here is actually a constant[1].
>> However constants do not support non scalar types, such as array or
>> objects, what would really solve it on the objects side of things
>> would be the introduction of a "readonly" keyword or similar, like
>> that of C#[2]
>>
> =E2=80=8B=E2=80=8B
>
> =E2=80=8BNot on reality.=E2=80=8B :(
>
> The "final" keyworks make a "local scope" variable value "blocked to
> rewrite" after instantiate it.
> Okay, it sounds like a "const", and it is, but "not as we known it".
>
> While constants are class member (or globals), a final variable is just a
> variable blocked to rewrite, and it could be initialized with a new data
> content every time that the context is called (eg. a function).
>
> For instance (note that the parameter is "final", then I can't modify the
> parameter variable, but it can receives a new value each time that I call
> this function):
>
> function write(final $message) { echo $message; }
> write("Hello");
> write("World");
> // Write "Hello World" on ouput.
>
> Or then:
>
> function randomNumber() {
>   final $number =3D mt_rand();
>   echo $number;
>
>   // $number =3D mt_rand_again(); // <-- will not be allowed!
> }
> randomNumber();
> =E2=80=8B // Write "0.123"
> randomNumber();
> =E2=80=8B // Write "0.456"
> =E2=80=8B
>
>
>
>>
>> [1] http://php.net/constants
>> [2] https://docs.microsoft.com/en-us/dotnet/csharp/language-refe
>> rence/keywords/readonly
>>
>
> --
> David Rodrigues
>



--=20
David Rodrigues

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