Swift 2.0 Guard Statement

guard.swift

// Like an if statement, guard executes statements based on a Boolean value of an expression. 
// Unlike an if statement, guard statements only run if the conditions are not met. 
// You can think of guard more like an Assert, but rather than crashing, you can gracefully exit.
    
    func fooGuardNonOptional(x: Int) {
        guard x > 0 else {
            // Value requirements not met, do something
            return
        }
        
        // Do stuff with x
    }
    
    func fooGuard(x: Int?) {
        guard let x = x where x > 0 else {
            // Value requirements not met, do something
            return
        }
        
        // Do stuff with x
        x.description
    }
    
    func fooGuardBlock(x: Int?, block: () -> Void) {
        guard let x = x where x > 0 else {
            // Value requirements not met, do something
            return
        }
    
        // Do stuff with x and call block()
        block()
}