Is it possible to use the variable from an optional binding within the same conditional statement?

Question

if let popupButton = result?.control as? NSPopUpButto {
    if popupButton.numberOfItems <= 1 {
        // blahblah
    }
}

I want to avoid the double nested if.

if let popupButton = result?.control as? NSPopUpButton && popupButton.numberOfItems <= 1 {}

but I get the unresolved identifier compiler error if I do that.

Is there any way to make this condition on one line? Or because I'm using an optional binding, am I forced to make a nested if here?

score 5 · Accepted Answer · answered Jul 25 '17 at 20:49

5

You can do it this way:

if let popupButton = result?.control as? NSPopUpButton, popupButton.numberOfItems <= 1 {
    //blahblah
}

answered Jul 25 '17 at 20:49

Mo Abdul-Hameed

yup that did it! do you happen to know the term for the comma here? e.g, `&&` is a `conditional AND` – A O Jul 25 '17 at 20:51
I don't know if there is a term for it, but I just made a quick look on [Swift documentation on optional binding](https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/TheBasics.html#//apple_ref/doc/uid/TP40014097-CH5-ID333) and didn't find a term. – Mo Abdul-Hameed Jul 25 '17 at 20:55
5

the `,` is used to form a *multi-clause condition*. This used to be done with the `where` keyword; if you use `where` instead of the comma, the error message mentions using a `,` to form a multi-clause condition. So I guess that is Swift's term for it. – vacawama Jul 25 '17 at 20:55

1 Answers1