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In-Reply-To: <f08c75e6-896a-cf92-f2e1-01468c043c07@nunninger.info>
Date: Tue, 10 Jan 2023 12:29:00 -0600
Message-ID: <CAJp_myUrQvqU2UTvy9BQa=onyzibGs6VTn9D_OdLK5kdh+tTDA@mail.gmail.com>
To: Thomas Nunninger <thomas@nunninger.info>
Cc: php internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC][Vote] Asymmetric Visibility
From: mweierophinney@gmail.com ("Matthew Weier O'Phinney")

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On Tue, Jan 10, 2023 at 11:19 AM Thomas Nunninger <thomas@nunninger.info>
wrote:

> I doubt, there would be any need for readonly if we would have had
> asymmetric visibility first. And (using asymmetric visibility) I assume,
> developers should be able to ensure that a property is 1. only
> initialized once, 2. inside the limited scope of a class, and 3. not
> overwritten during the lifetime of the object. I'd be interested in a
> use case where you would really like to ensure this on the engine level.
>
> To go one step further, I would even ask the heretical question if we
> should discourage/deprecate readonly once we have asymmetric visibility.
> ;-)
>

I disagree. They serve different use cases.

In the case of readonly, it's an easy way to also define _immutable_
classes.
Aviz doesn't provide that; in fact, it is a way to explicitly allow use
cases where changes can be made, while still providing direct access to a
property. Yes, you _could_ add logic to a class to prevent changes after
initialization... but marking a property as readonly does that for you, in
a way that is less error prone than userland logic.

-- 
Matthew Weier O'Phinney
mweierophinney@gmail.com
https://mwop.net/
he/him

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