Swift command line script using NSOperation.

SwiftCommandLineWithNSOperation.swift

#!/usr/bin/env xcrun swift

//
//  SwiftCommandLineWithNSOperation.swift
//  SwiftCommandLineWithNSOperation
//
//  Created by Richard Stelling on 27/11/2015.
//  Copyright © 2015 Richard Stelling. All rights reserved.
//

import Foundation

// Set up the NSOperationQueue, the higher you set maxConcurrentOperationCount
// the quicker all the operation will finish (up to 10)
var queue = NSOperationQueue()
queue.maxConcurrentOperationCount = 5 //Deadlock if this is = 1
queue.qualityOfService = .Utility

let start = NSDate()

let outterOp = NSBlockOperation {
    
    for i in 0..<10 {
        
        let op = NSBlockOperation {
            
            for j in 0..<5 {
                
                sleep(1)
                
                print("*", terminator: "")
                fflush(__stdoutp)
                
            }
        }
        
        queue.addOperation(op)
        
        print("|")
        sleep(2)
    }
}

queue.addOperation(outterOp)

// This will block until all our operation have compleated (or been canceled)
queue.waitUntilAllOperationsAreFinished()

let end = NSDate()

let delta = end.timeIntervalSinceDate(start)
print("\n\nOperation took \(floor(delta)) wall clock seconds")

exit(0)