[swift-evolution] protocol-oriented integers (take 2)

[Xiaodi Wu]

You're quite right. Since the multiplicative inverse of any integer other
than 1 and -1 is not itself an integer, there isn't much one can do...


On Sun, Jan 15, 2017 at 08:41 Dave Abrahams <dabrahams at apple.com> wrote:

>
>
> on Sun Jan 15 2017, Xiaodi Wu <xiaodi.wu-AT-gmail.com> wrote:
>
>
>
> > Given that Arithmetic also provides for multiplication and division,
> might
>
> > it be wise then also to have .multiplicativeIdentity (or .one)?
>
>
>
> I'm always wary of adding requirements that don't have a demonstrated
>
> use-case in a generic algorithm.  What generic algorithm can use this
>
> value?
>
> >
>
> > On Sun, Jan 15, 2017 at 02:47 Dave Abrahams via swift-evolution <
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> > swift-evolution at swift.org> wrote:
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> >
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> >>
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> >> on Sat Jan 14 2017, Dave Abrahams <swift-evolution at swift.org> wrote:
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> >>
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> >> > That said, the ability to interpret integer literals as an arbitrary
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> >> > Arithmetic isn't used anywhere in the standard library, so I'd like to
>
> >> > consider undoing
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> >> >
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> >>
> https://github.com/apple/swift/commit/de5b03ddc41be9c5ca5e15d5709eb2be069286c1
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> >> > and moving ExpressibleByIntegerLiteral down the protocol hierarchy to
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> >> > BinaryInteger.
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> >>
>
> >> Oh, and I meant to add: maybe the right way for an arbitrary X modeling
>
> >> Arithmetic to spell zero (which is needed for negation) is something
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> >> like
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> >>
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> >>    X.additiveIdentity
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> >>
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> >> or
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> >>
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> >>    X.zero
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> >>
>
> >> in other words, via a requirement
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> >>
>
> >>    static var theNameWeChoose: Self { get }
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> >>
>
> >> --
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> >> -Dave
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> >>
>
> >> _______________________________________________
>
> >> swift-evolution mailing list
>
> >> swift-evolution at swift.org
>
> >> https://lists.swift.org/mailman/listinfo/swift-evolution
>
> >>
>
>
>
> --
>
> -Dave
>
>
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