[swift-evolution] [Proposal] Sealed classes by default

Tino Heth 2th at gmx.de
Mon Aug 15 04:51:51 CDT 2016

> Am 14.08.2016 um 14:59 schrieb Jean-Denis Muys via swift-evolution <swift-evolution at swift.org>:
> This decision is bad, not because it makes the default for classes to be unsubclassable

Seems that the prediction of the grief caused by SE-0117 in the long run was right ;-) — but be careful, the title doesn't reflect reality anymore:
As far as I understand, the default won't be changed at all.
It has been internal, and it will be internal.
The change is that changing the default to "public" will only make a class/method visible outside the current module, without the right to subclass/override.
So, basically, "public" is renamed to "open".
Imho this is still causing unnecessary trouble, as it breaks most libraries out there (more precisely: Third party code that relies on the old behavior), but in the future, you can just use "open" instead of "public", and little else will change — except that users of your framework may assume that "open" is an extension of "public", whereas you may follow the notion that "public" is an restriction of "open".

In the end, imho the whole topic has been decided in a very Solomonic way that disappoints both parties ;-), so I don't think it will be a reason for someone to fork Swift.
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