[swift-evolution] Shorthand unwrap proposal

[James Campbell]

So I have a real-life situation in an application, which does what you
mention:

This code is for a camera app, on a `didSet` it removes a device if set
from the capture session, and if there is a new one set it adds it to the
capture session.

The add and remove methods indeed don't take optionals.

So this is the code before:

var audioDevice: AVCaptureDeviceInput? = nil {



        willSet {

            if let audioDevice = audioDevice {

               captureSession?.removeInput(audioDevice)

            }

        }



        didSet {

            if audioDevice = audioDevice {

               captureSession?.addInput(audioDevice)

            }

        }

    }


and after:

var audioDevice: AVCaptureDeviceInput? = nil {



        willSet {

            audioDevice.unwrap {

                self.captureSession?.removeInput($0)

            }

        }



        didSet {

            audioDevice.unwrap {

                self.captureSession?.addInput($0)

            }

        }

    }


The last two saved me a lot of typing in these cases and I feel like it is
more clear what is going on due to the `unwrap` method being clear in it's
intent and the lack of `audioDevice` being repeated multiple times.

*___________________________________*

*James⎥Head of Trolls*

*james at supmenow.com <james at supmenow.com>⎥supmenow.com <http://supmenow.com>*

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On 23 June 2016 at 17:11, Sean Heber <sean at fifthace.com> wrote:

> I’m a bit tore on this myself. I see the appeal, but let’s say we had such
> a function. If you wanted to use it with an named parameter it’d look like
> this:
>
> myReallyLongOptionalName.unwrap { string in
>   doSomethingWith(string)
> }
>
> And that is actually *more* characters than the current approach:
>
> if let string = myReallyLongOptionalName {
>   doSomethingWith(string)
> }
>
> However it’d be a big win especially when you can skip $0 and the braces
> entirely such as:
>
> myReallyLongOptionalName.unwrap(doSomethingWith)
>
> Of course if we were dealing with methods, you could write this like:
>
> myReallyLongOptionalName?.doSomething()
>
> And that is probably hard to beat.
>
> So I think the problem really only presents itself when you have an
> optional that you need to unwrap and use as a parameter to something that
> does not take an optional.
>
> I don’t have a solution - just trying to clarify the situation. :)
>
> l8r
> Sean
>
>
> > On Jun 23, 2016, at 10:36 AM, James Campbell via swift-evolution <
> swift-evolution at swift.org> wrote:
> >
> > I was wondering if people would be open to adding an unwrap method to
> the Optional type,  I already have a method like this which shortens code
> for me.
> >
> > So this:
> >
> > let myReallyLongOptionalName: String? = "Hey"
> >
> > if let string = myReallyLongOptionalName {
> >   doSomethingWith(string)
> > }
> >
> > Could become"
> >
> > let myReallyLongOptionalName: String? = "Hey"
> >
> > myReallyLongOptionalName.unwrap {
> >   doSomethingWith($0)
> > }
> >
> > The block would only be fired if myReallyLongOptionalName has a value.
> >
> > ___________________________________
> >
> > James⎥Head of Trolls
> >
> > james at supmenow.com⎥supmenow.com
> >
> > Sup
> >
> > Runway East >
> >
> > 10 Finsbury Square
> >
> > London
> >
> > > EC2A 1AF
> >
> > _______________________________________________
> > swift-evolution mailing list
> > swift-evolution at swift.org
> > https://lists.swift.org/mailman/listinfo/swift-evolution
>
>
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