[Review #2] SE-0117: Default classes to be non-subclassable publicly&References=2C9B4C5A-52C2-4E0E-8B9E-6E5444629D85@apple.com&In-reply-to=2C9B4C5A-52C2-4E0E-8B9E-6E5444629D85@apple.com

tal · July 20, 2016, 1:54am

I have no concerns intrinsically to the behavior discussed but rather to
the complexity that this brings. Creating another type of access control
and possibly keyword just adds complexity to an already fairly complex
language. I’d probably be more onboard if it was merely final by default
for that reason alone.

Hello Swift community,

The second review of "SE-0117: Default classes to be non-subclassable

publicly" begins now and runs through July 22. The proposal is available
here:

github.com

apple/swift-evolution/blob/main/proposals/0117-non-public-subclassable-by-default.md

# Allow distinguishing between public access and public overridability

* Proposal: [SE-0117](0117-non-public-subclassable-by-default.md)
* Authors: [Javier Soto](https://github.com/JaviSoto), [John McCall](https://github.com/rjmccall)
* Review Manager: [Chris Lattner](http://github.com/lattner)
* Status: **Implemented (Swift 3)**
* Decision Notes: [Rationale](https://forums.swift.org/t/accepted-with-revision-se-0117-allow-distinguishing-between-public-access-and-public-overridability/3578)
* Implementation: [apple/swift#3882](https://github.com/apple/swift/pull/3882)
* Previous Revision: [1](https://github.com/apple/swift-evolution/blob/367086f18a5deaf8f9dfbe3f5a4846ef19addf38/proposals/0117-non-public-subclassable-by-default.md), [2](https://github.com/apple/swift-evolution/blob/2989538daa1640cfa6a56f80b5c7599967af0905/proposals/0117-non-public-subclassable-by-default.md), [3](https://github.com/apple/swift-evolution/blob/15c18d24adb7e701ae831b643e0803f1b6e601d9/proposals/0117-non-public-subclassable-by-default.md)

## Introduction

Since the first release of Swift, marking a class `public` has provided
two capabilities: it allows other modules to instantiate and use the
class, and it also allows other modules to define subclasses of it.
Similarly, marking a class member (a method, property, or subscript)
`public` has provided two capabilities: it allows other modules to
use the member, and it also allows those modules to override it.

This proposal suggests distinguishing these concepts.  It creates a new

This file has been truncated. show original

Reviews are an important part of the Swift evolution process. All reviews

should be sent to the swift-evolution mailing list at

https://lists.swift.org/mailman/listinfo/swift-evolution

or, if you would like to keep your feedback private, directly to the

review manager.

What goes into a review?

The goal of the review process is to improve the proposal under review

through constructive criticism and contribute to the direction of Swift.
When writing your review, here are some questions you might want to answer
in your review:

* What is your evaluation of the proposal?
* Is the problem being addressed significant enough to warrant a change

to Swift?

* Does this proposal fit well with the feel and direction of Swift?
* If you have used other languages or libraries with a similar feature,

how do you feel that this proposal compares to those?

* How much effort did you put into your review? A glance, a quick

reading, or an in-depth study?

More information about the Swift evolution process is available at

https://github.com/apple/swift-evolution/blob/master/process.md

Thank you,

-Chris Lattner
Review Manager

-Tal