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Date: Tue, 5 Apr 2016 21:09:20 +0200
Message-ID: <CABdc3WpB2_nzF45a9qo64q3yUZmGpAdU=S9PUtDAejNiz72hQQ@mail.gmail.com>
To: Robert Stoll <php@tutteli.ch>
Cc: Marco Pivetta <ocramius@gmail.com>, PHP Internals List <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=001a11c3bc5a27d257052fc1951f
Subject: Re: [PHP-DEV] Final properties
From: michal@brzuchalski.com (=?UTF-8?Q?Micha=C5=82_Brzuchalski?=)

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Hi Robert, Marco and Chris,

now I see your point. Lastly I've found in DZone newsletter about Java
putting `var` and `val` keywords, interesting is the second which is going
to be used in case of immutable "variables" like a "values" (that's where
`val` came from) see here http://openjdk.java.net/jeps/286 at "Syntax
Choices" section. Checked C# for such feature and found out that there is
something like `sealed` keyword which prevents from changing reference and
also `readonly` keyword which states for property read only everywhere
except class constructor (interesting isn't it?).

I also read about "Immutable modifier" discussion and IMHO it looks like
it's about time to get such feature.

I also agree that `final` keyword may be not so good choice for
immutability, I've checked Scala, Kotlin and Swift about final properties
and it looks like there it is used to unable to override property
accedentally, and putting additional `override` (see
https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swif=
t_Programming_Language/Inheritance.html)
section "Overriding" says:
"To override a characteristic that would otherwise be inherited, you prefix
your overriding definition with the `override` keyword. Doing so clarifies
that you intend to provide an override and have not provided a matching
definition by mistake. Overriding by accident can cause unexpected
behavior, and any overrides without the override keyword are diagnosed as
an error when your code is compiled."

Considerring all of that thoughts I think that `final` keyword in
properties declaration whould be awesome with Typed Properties
https://wiki.php.net/rfc/typed-properties keeping to not override the Type
Hint declaration.

I'll try my best to continue implementation of somehow immutable variables
as they would be great at ValueObjects impl.
The choice for proprietary keyword could be a subject of discuccion.

Cheers,
--
Micha=C5=82


2016-04-05 20:08 GMT+02:00 Robert Stoll <php@tutteli.ch>:

> Hi Marco,
> >
> > I am aware of what `final` means in other languages, it just seems that
> everyone then needs to translate back and forth
> > from `final` to `immutable`. In addition to that, `final` has different
> meaning in inheritance (re-used keyword), so this adds
> > to the confusion for people unfamiliar with the feature.
>
> I think immutable is also not ideal because to me, it sounds like the
> whole object is immutable even though only the property is. I do not know=
 a
> better solution than final though
>
> Cheers,
> Robert
>
>
>

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