How do I refer to a variable in a function?

Question

How would I call the sun object I have made in a function (hello) from another function (collide)?

func collide() {
        if (CGRectIntersectsRect(player.frame, **sun.frame**)) {
            [EndGame];
        }

 func hello() {
        let sun = SKSpriteNode(imageNamed: "Sun")
}

You can't since the `sun` variable only lives within the scope of the `hello()` function. You might want to make the `sun` variable a class variable — rckoenes, Feb 05 '15 at 08:47
@RayToal I tried it having 'hello' return sun sprite but then i got a "missing argument for parameter 'completion' in call" — bandoy123, Feb 05 '15 at 08:50
Probably a function/method confusion. See [this answer](http://stackoverflow.com/questions/24050844/swift-missing-argument-label-xxx-in-call). — Ray Toal, Feb 05 '15 at 08:52

score 4 · Answer 1 · answered Feb 05 '15 at 08:49

You can't - the sun variable is local to the hello function, and it doesn't exist outside its scope.

If collide is invoked from hello, you can just pass it as an argument:

func collide(sun: SKSpriteNode) {
    if (CGRectIntersectsRect(player.frame, sun.frame)) {
        [EndGame];
    }
}

func hello() {
    let sun = SKSpriteNode(imageNamed: "Sun")
    ...
    collide(sun)
}

Otherwise if, as I think, these are instance methods of a class, just turn the sun variable into an instance property:

class Test {
    private var sun: SKSpriteNode?

    func collide(sun: SKSpriteNode) {
        if let sun = self.sun {
            if (CGRectIntersectsRect(player.frame, sun.frame)) {
                [EndGame];
            }
        }
    }

    func hello() {
        self.sun = SKSpriteNode(imageNamed: "Sun")
    }
}

score 1 · Answer 2 · answered Feb 05 '15 at 10:38

In addition to Antonio's answer, you can search an SKNode's children using a unique name.

For example.

let sun = SKSpriteNode(imageNamed:"Sun")
sun.name = "sun"
self.addChild(sun)

You can get it back by

if let sun =  self.childNodeWithName("sun")
{
    //use sun here
}

childNodeWithName returns an optional SKNode?.

How do I refer to a variable in a function?

2 Answers2