anyObjectPassingTest.swift

//: Playground - noun: a place where people can play

import Cocoa

var aSet = Set<Int>()
aSet.insert(1)
aSet.insert(2)
aSet.insert(3)

// The rest of this code doesn't even remotely work.

typealias TestBlock = (obj: AnyObject) -> Bool

extension Set {

	func anyObjectPassingTest(testBlock: TestBlock) -> AnyObject? {
		
		for oneObject in self {
			if testBlock(oneObject) {
				return oneObject
			}
		}
		
		return nil
	}
}

let x = aSet.anyObjectPassingTest { (obj) -> Bool in
	return obj % 2 == 0
}

print(x)

@natecook1000: The second solution is pretty nifty. Finds the first element. I assume it stops iterating the collection there. Then returns it. There's (from a casual understanding) an extra pointer deference there for the return self[index] but who cares and that's a nice way of expressing it. You're totally right that it should match the indexOf method. I'd missed @NoEscape at some point. DIdn't know that was a thing! Thanks.