[swift-evolution] [swift-evolution-announce] Revision review: SE-104: Protocol-oriented integers

Nevin Brackett-Rozinsky nevin.brackettrozinsky at gmail.com
Fri Jul 21 10:11:50 CDT 2017

The updates look fine and reasonable to me.

That said, I think it is highly important that we have clarity regarding
what *is* the proper time, method, and process for raising issues with and
suggesting modifications to approved proposals. If there is one thing we
have learned recently it is that sometimes a proposed change sounds good
and gets approved (110, 25, etc.) which subsequently turns out to have
unintended detrimental consequences.

We are not infallible, and there will certainly be times in the future when
we think a change is good in theory, but then after experiencing it in
practice we recognize it has problems. When that happens—and happen it
will—we need to be able to correct our course. And it is far better to fix
such things before they are released to the wider world.

I don’t know if the issues Howard raises rise to that level. I haven’t
tested out the new integer protocols, so I am not in a position to weigh
the merits of the claim. Certainly in the abstract “signum” sounds like it
is asking for a property of the number, and not asking the number to do
something function-like, but I defer to those who use it in practice.

The point is, rather than shutting down discussion by saying “it has
already been approved” and “this is not the place for discussing that”, it
would greatly behoove the Swift Evolution process to have an established
method for recommending changes to already-approved proposals. We have this
time interval between when a proposal is accepted and when it appears in a
public release of the language, and it seems only natural to use it as a
beta-testing period.

That way we can fix problems we encounter before they become permanent, and
similarly we can make minor changes which are obvious improvements we
somehow overlooked during the initial review.


On Fri, Jul 21, 2017 at 7:50 AM, Xiaodi Wu via swift-evolution <
swift-evolution at swift.org> wrote:

> I understand you feel this way, but this thread is a formal review of
> specific amendments to SE-0104. Those amendments are, again, the following:
> * Reorganizing shift operators
> * Removing the ArithmeticOverflow type in favor of using a simple Bool
> * Changing BinaryInteger's initializers that convert from floating point
> values
> * Renaming BinaryInteger's init(extendingOrTruncating:)
> On Fri, Jul 21, 2017 at 02:08 Haravikk via swift-evolution <
> swift-evolution at swift.org> wrote:
>> On 21 Jul 2017, at 02:01, Xiaodi Wu via swift-evolution <
>> swift-evolution at swift.org> wrote:
>> Hi Howard,
>> The removal of BitwiseOperations is not under review here; that, like
>> signum(), has been considered twice and approved twice, and has not been
>> revised.
>> On Thu, Jul 20, 2017 at 19:36 Howard Lovatt via swift-evolution <
>> swift-evolution at swift.org> wrote:
>>> The revised version of the proposal can be found here:
>>>> https://github.com/apple/swift-evolution/blob/master/
>>>> proposals/0104-improved-integers.md
>>>> • What is your evaluation of the proposal?
>>> Overall +1. Two reservations:
>>>   1. Functions like `signum()` that return a property would read better
>>> as a property!
>>>   2. I have found `BitwiseOperations` useful as an extension to both
>>> Bool and Set and for a custom set type. Therefore would prefer its
>>> retention and even more preferably that Bool and Set implement it.
>>> • Is the problem being addressed significant enough to warrant a change
>>>> to Swift?
>>> Yes, generic representation of integers is useful.
>>>> • Does this proposal fit well with the feel and direction of Swift?
>>> Yes, particularly the re-arrangment of the protocol hierarchy is in
>>> keeping with the rest of the restructuring of the standard library.
>>>> • If you have used other languages or libraries with a similar feature,
>>>> how do you feel that this proposal compares to those?
>>> Yes, many languages I use allow generic numeric functions to be written
>>> and I write my own numeric functions and will therefore use these protocols.
>>>> • How much effort did you put into your review? A glance, a quick
>>>> reading, or an in-depth study?
>>> Quick read, but have pulled my hair out trying to write generic stuff in
>>> Swift as it stands now.
>> I agree with Howard on both points; In particular I've never agreed with
>> the removal of BitwiseOperations, and believe it to be a mistake. What's
>> the point of making Integers more protocol-oriented if you then go about
>> getting rid of useful protocols?
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