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import Foundation
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GeneratorType is a type of SequenceType.
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In order to conform, set the Element
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typealias and implement the next
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method.
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class Incrementing : GeneratorType {
typealias Element = Int
var counter = 0
func next() -> Element? {
return counter++
}
}
var count = Incrementing()
count.next()! // 0
count.next()! // 1
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for loops work with any SequenceType type.
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A SequenceType has a generate method that
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returns a GeneratorType.
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class Fibonacci : SequenceType {
func generate() -> GeneratorOf<Int> {
var current = 0
var next = 1
return GeneratorOf<Int> {
var returnVal = current
current = next
next += returnVal
return returnVal
}
}
}
var fibSequence = Fibonacci()
for i in fibSequence {
if i > 50 {
break
}
print("\(i) ") // 0 1 1 2 3 5 8 13 21 34
}
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