Using a Closure as a While Loop's Condition

Question

I want to use a closure as a condition for a while loop. This is what I have:

var x: Int = 0
var closure = {() -> Bool in return x > 10}
while closure {
    x += 1
    println(x) // never prints
}

It never prints anything. If I change it to closure(), it doesn't work either.

Any help would be appreciated.

Answer 1

There are two problems here.

Firstly, as written, your code won't even compile. You need to change while closure to while closure().

Second, the bigger problem, your closure logic is wrong. x > 10 never returns true because x is never greater than 10. Flip the sign over and it'll work.

Swift 2

var x = 0
var closure = { () -> Bool in return x < 10 }
while closure() {
    ++x
    print(x)
}

Swift 1.2

var x = 0
var closure = { () -> Bool in return x < 10 }
while closure() {
    ++x
    println(x)
}