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Date: Wed, 9 Jun 2021 17:05:26 +0700
Message-ID: <CAEZPtU61cfg4thuHOWOcpVFQo7pjZzgHr3QckiYqC9i=U6exOA@mail.gmail.com>
To: Nikita Popov <nikita.ppv@gmail.com>
Cc: PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] Readonly properties
From: pierre.php@gmail.com (Pierre Joye)

Hi Nikita,

On Fri, Jun 4, 2021 at 10:19 PM Nikita Popov <nikita.ppv@gmail.com> wrote:
>
> Hi internals,
>
> I'd like to open the discussion on readonly properties:
> https://wiki.php.net/rfc/readonly_properties_v2

Very good work, thank you :)

> This proposal is similar to the
> https://wiki.php.net/rfc/write_once_properties RFC that has been declined
> previously. One significant difference is that the new RFC limits the scope
> of initializing assignments. I think a key mistake of the previous RFC was
> the confusing "write-once" framing, which is both technically correct and
> quite irrelevant.
>
> Please see the rationale section (
> https://wiki.php.net/rfc/readonly_properties_v2#rationale) for how this
> proposal relates to other RFCs and alternatives.

About this paragraph in
https://wiki.php.net/rfc/readonly_properties_v2#rationale:

" The addition of readonly properties neither precludes nor
discourages the addition of asymmetric property visibility."

To me this sentence is the meaning of a readonly property, not an
immutable property, as in writeable once property, in constructor.

This RFC is perfect given its goal but the property attribute "readonly".

How would you define a property only readable from outside the scope
but writeable inside the scope of its class (->status f.e.)?

This is PHP and we always have our ways. That being said, the keyword
"readonly" is really about what is defined as "asymmetric property
visibility" in many other languages. Rust uses annotation, .net via
either  readonly and they use an init setter to make it immutable in
v9 (public DateTime RecordedAt { get; init; }), other like java or
scala relies on setting a property getters only.

Given this, I wonder if it would not be easier to have actual per
property getter/setter as an addition or replacement to the current
(kind of horrible) get/set($name, $value).  This would all cases in
one shot, a more complicated shot but much more powerful. For the
record, I am totally not a fan of the 'manual" get/setMyProperty ;)

In any case, I would at least put a second thought on the name "readonly".

ps: sorry if this question has been discussed in previous RFCs,
pointers appreciated as I did not find it :)

Best,
-- 
Pierre