在Swift中导入扩展文件

我在Swift中为UIView创建了一个扩展.任何人都知道如何将该文件导入我的UIViewController？

我想在控制器文件中导入扩展文件,这样我就可以重用扩展文件了.例如,像这样的结构:

UIViewExtension.swift

import UIKit

extension UIView {
    var myVar : Float {
        get {
            return myVar
        }
        set (newMyVar) {
            myVar = newMyVar
        }
    }
}

ViewController.swift

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        var squareView: UIView = UIView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))

        squareView.myVar = 50

        self.view.addSubview(squareView)
        println("Offset: \(squareView.myVar)")
    }
}

这是编译器给出的错误:

Command /Applications/Xcode6-Beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift failed with exit code 254