[swift-evolution] [Pitch] Add the DefaultConstructible protocol to the standard library

[Daniel Leping]

Actually T() would definitely do the job. Thanks for pointing. A can agree
it's a good replacement.

As for requiring to conform to a protocol - definitely worse solution. I
was thinking of DefaultConstructable as of automatically applied protocol
to anything that has init().

About "Zero" or "Identity" concept I personally tend to think of it as of a
singleton static property. Also keeping in mind everything said above in
the discussion these two are just different protocols. I.e. for Int "zero"
could be 0 and "identity" could be 1. Identity does not feel to be the
right name, though.

Also, for the "zeroable" types I would rather use nil.

On Tue, 27 Dec 2016 at 10:40 Braeden Profile via swift-evolution <
swift-evolution at swift.org> wrote:

> I forgot to reply to the email list here.
>
> On Dec 26, 2016, at 10:03 PM, Xiaodi Wu <xiaodi.wu at gmail.com> wrote:
>
> Did you mean to reply offlist?
>
> Basically, a factory would be:
>
> func make<T>(_: T.Type) -> T { return T() }
>
> but you need T to conform to a protocol that guarantees T.init(). You use
> it like:
>
> make(Foo.self)
>
> But one can write:
>
> func make<T>(_ f: @autoclosure () -> T) -> T { return f() }
>
> and use this like:
>
> make(Foo())
>
> (pardon typos; freehanding on iPad)
>
>
>
> On Mon, Dec 26, 2016 at 23:58 Braeden Profile <jhaezhyr12 at gmail.com>
> wrote:
>
> Actually, I’m a little lost at this point of exactly how you could build a
> function with this pattern.  Code, anyone?
>
>
> On Dec 26, 2016, at 9:57 PM, Xiaodi Wu <xiaodi.wu at gmail.com> wrote:
>
> With @autoclosure your user can simply write T() as an argument. It is
> very elegant and not complicated at all.
>
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