[swift-evolution] [Review #3] SE-0117: Allow distinguishing between public access and public overridability

[Vladimir.S]

On 21.07.2016 18:33, Chris Lattner via swift-evolution wrote:
> Hello Swift community,
>
> The third review of "SE-0117: Allow distinguishing between public access and public overridability" begins now and runs through July 25. The proposal is available here:
>
> 	https://github.com/apple/swift-evolution/blob/master/proposals/0117-non-public-subclassable-by-default.md

+1 for *second* approach because :

* Simple mental model. It is adding `open` keyword for methods only. It is 
very easy to understand/remember just one *new* rule : only `open` 
methods/props could be overridden outside of the module. Easy to describe 
this to anyone new in Swift.
* More flexible. You still can subclass the `public` class. But you can't 
"hurt" the logic inside the module while you can have additional state and 
methods in new class for your own logic. So IMO second approach fixes the 
exact reason why we have this proposal *without* adding unnecessary 
limitations and additional complexity.
* As I understand, for second approach there is no this IMO strange 
limitation : "The superclass of an open class must be open." (while yes, 
this still exists: "The overridden declaration of an open override must be 
open.")
* I feel this approach more Swifty - free to subclass if you want for your 
logic but safe for internal module's logic.
* 'open class' adds complexity to access model, given we already have 
public, internal, private, fileprivate
* Second approach unifies the syntax : structs and classes will have the 
same syntax for public declaration (only difference : classes can have 
'open' for methods/props)

>
> 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
>
>
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