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iOS Build an Interactive Story App with Swift 2 Creating a Story Creating an Adventure

Andrea Miotto
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Andrea Miotto
iOS Development Techdegree Graduate 23,357 Points
Posted by Andrea Miotto
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Andrea Miotto
iOS Development Techdegree Graduate 23,357 Points

Result of call to 'addChoice(title:page:) is unused

Maybe I have a new versione of Xcode, but addChoice() return a Page type. When we call addChoice() like this:

homeward.addChoice(title: "Head back to Mars", page: touchdown)

I have the warning:

Result of call to 'addChoice(title:page:) is unused

Is there a better way? I don't like to have warnings :P

1 Answer

Michael Hulet
Michael Hulet
47,912 Points
Michael Hulet
Michael Hulet
47,912 Points

If it's warning you that you don't use the result, you can silence that warning by assigning it to an underscore constant, like this:

let _ = homeward.addChoice(title: "Head back to Mars", page: touchdown)

That'll tell Swift that you really don't want to use the result of calling that function, and it doesn't need to warn you about it. That being said, the _ constant/variable is basically just a garbage can. You can assign to it all you want, but you can never read from it in a normal app

Michael Hulet
Michael Hulet
47,912 Points
Michael Hulet
Michael Hulet
47,912 Points

Nope. Swift doesn't actually keep track of what's in the _ variable. When you assign to it, you're just tossing whatever you're assigning to it into computational oblivion