Profile a block of code in Swift 2.0

Profiling.swift

import Foundation

public func profiling<R>(label: String, @noescape _ block: () -> R) -> R { 
    NSLog("*** %@...", label) 
    let start = NSDate() 
    defer { 
        let end = NSDate() 
        NSLog("*** %@ took %5.3g seconds", label, end.timeIntervalSinceDate(start)) 
    } 
    return block() 
}

let result: Int? = profiling("heavy computation") {
    NSLog("Really computing hard now")
    return Int("123")
}

// 2015-06-09 22:32:48.811 repl_swift[39408:2024531] *** heavy computation...
// 2015-06-09 22:32:48.811 repl_swift[39408:2024531] Really computing hard now
// 2015-06-09 22:32:48.812 repl_swift[39408:2024531] *** heavy computation took 0.000195 seconds

Simple but useful way of reasonably profiling. If you want to do it more accurately, you would profile with no block and subtract from the original.