The declaration of indexesOfObjectsPassingTest: looks like this in Swift,
func indexesOfObjectsPassingTest(predicate: ((AnyObject!, Int, CMutablePointer<ObjCBool>) -> Bool)!) -> NSIndexSet!
I've tried all sorts of permutations to get this to work, but I'm stumped, particularly with how you deal with this piece, CMutablePointer<ObjCBool>) -> Bool)!. I found it confusing enough, when I was first learning blocks in objective-c, how you translate from the declaration to actual use of a method, and the syntax of Swift is at least as confusing.
Best How To :
This code is working in the Playground for me ;) Hope it helps a bit
Extra Function-Definition
import Cocoa
let list = [2, 3, 4, 5, 6, 7, 8]
func test (object: AnyObject!, index: Int, stop: CMutablePointer<ObjCBool>) -> Bool
{
let number = object as Int
return (number % 2 == 0) //for even numbers
}
let result: NSIndexSet = (list as NSArray).indexesOfObjectsPassingTest(test)
println("\(result.lastIndex)") //prints "6" (because 8%2=0)
Inline-Closure
I transformed my above example to work with an inline-closure (described in the Swift-eBook). The parameter-list and return-type is separated by the term in.
import Cocoa
let list = [2, 3, 4, 5, 6, 7, 8]
let result: NSIndexSet = (list as NSArray).indexesOfObjectsPassingTest({
(object: AnyObject!, index: Int, stop: CMutablePointer<ObjCBool>) -> Bool in
let number = object as Int
return (number % 2 == 0) //for even numbers
})
println("\(result.lastIndex)") //prints "6" (because 8%2=0)
