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Date: Thu, 17 Sep 2020 12:28:06 +0000
Message-ID: <CAJpLVh0K0Mkqa2RP9DLWNXbZJGqhrvJ4CTOWvAkz-7iGENWjYg@mail.gmail.com>
To: PHP internals <internals@lists.php.net>
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Subject: Namespace-private class properties
From: olleharstedt@gmail.com (=?UTF-8?Q?Olle_H=C3=A4rstedt?=)

(NB: This idea is NOT about namespace visibility for classes, interfaces or
traits (already discussed here: https://wiki.php.net/rfc/namespace-visibility).
It's about adding a *new* visibility qualifier, call it "internal", to
make properties
private inside a namespace. The purpose is to make composition less
fragile by not
exposing more than necessary.)

(NB: This feature exists in Swift, described here:
https://docs.swift.org/swift-book/LanguageGuide/AccessControl.html)

We have public, protected and private. Since PHP has no module system, we
have no qualifier to mark a class property as "private for this module".
One solution to this could be to add a new qualifier "internal", to make
properties public within the current namespace.

Use-cases:

* Split data and behaviour into different files and classes
* Safely skip getters and setters without risk of properties being abused
by client code

Tiny example:

```
namespace App\User;
class User {
  internal $username;
  internal $password;
}

namespace App\User\Services;
class ProcessUser {
  // Child namespace has access to internal properties,
  // but App\ has not.
}
```

Possible?

Olle