[swift-users] Flatmap initializer inconsistency
swift at hpwooten.com
Tue May 2 18:48:30 CDT 2017
Yep, that explanation makes sense to me. It's picking the one that fits exactly.
Thanks for the help, everyone.
On Mon, May 1, 2017 at 11:48 PM, Zhao Xin <owenzx at gmail.com> wrote:
> That is because for `Optional` the `flatMap` is `func flatMap<U>(_
> transform: (Wrapped) throws -> U?) rethrows -> U?` and for `Int`, only
> `init?(exactly value: Double)` fits the situation. `init(_ value: Double)`
> doesn't return nil. So there is no ambiguity.
> On Tue, May 2, 2017 at 4:20 AM, Saagar Jha <saagar at saagarjha.com> wrote:
>> Well, the question still remains about why the compiler chose
>> init(exactly:) over init(). Shouldn’t there at least a warning of ambiguity?
>> Saagar Jha
>> On May 1, 2017, at 12:11, Zhao Xin via swift-users <swift-users at swift.org>
>> In my test, compiler thought you use `init?(exactly value: Double)`, which
>> returns nil. So this is not a bug.
>> On Tue, May 2, 2017 at 1:39 AM, Halen Wooten via swift-users
>> <swift-users at swift.org> wrote:
>>> I'm seeing a weird issue with using an initializer in flatMap. Here's
>>> an example:
>>> let time: TimeInterval? = 662.82582598600004
>>> let intTimeFlatmap = time.flatMap(Int.init) // nil
>>> let intTime = Int(time!) // 662
>>> I would expect for the flatMap call to return an optional Int with the
>>> proper value of 662. Is there something I'm misunderstanding, or is
>>> this a swift bug?
>>> swift-users mailing list
>>> swift-users at swift.org
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>> swift-users at swift.org
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