Implementing recursive generator for simple tree structure in Swift

Question

I have a simple tree structure in memory based on an XML document and I am trying to write a recursive generator to support SequenceType, but I am stuck on how

Answer 1

Here is a recursive post-order generator. Can't say I'd recommend actually using it though. @MartinR's answer seems a bit more practical

 public func generate() -> AnyGenerator {
    var childGenerator:AnyGenerator?
    var childArrayGenerator:IndexingGenerator<[XMLNode]>? = self.childNodes.generate()
    var returnedSelf = false

    return anyGenerator {
        if let next = childGenerator?.next() {
            return next
        }
        if let child = childArrayGenerator?.next() {
            childGenerator = child.generate()
            return childGenerator?.next()

        } else if !returnedSelf {

            returnedSelf = true
            return self

        } else {

            return nil
        }
    }
}