How can I programmatically find Swift's version?

Question

I know I can find the version of Swift I\'m running right now reverting to a Terminal and typing:

xcrun swift --version
Swift version 1.1 (swift-600.0.57.4)
         


        

Answer 1

Finally got a workaround to do this. I'm using the constants prefixed with __ you can observe in your Playground. This would have been easier with some level of reflection, but...

__IPHONE_OS_VERSION_MAX_ALLOWED is 80200, meaning __IPHONE_8_2 for Xcode 6.2 (Swift 1.1) but its value is 80300 (__IPHONE_8_3) in Xcode 6.3 (Swift 1.2)

func isSwift12() -> Bool {
  return __IPHONE_OS_VERSION_MAX_ALLOWED == 80300
}

isSwift12()

So now in your library you can fail fast and tell your user Swift's version is not correct using this:

assert(isSwift12(), "Need Swift 12")

Swift will give you a nice:

assertion failed: Need Swift 12: file , line 20

UPDATE WWDC 2015 - Swift 2.0

As stated in Apple's Swift blog, in Swift 2.0 we have #available blocks to check for certain OS versions in our code. An example should be:

if #available(OSX 10.11, *) {
    monochromeFilter!.setValue(CIColor(red: 0.5, green: 0.5, blue: 0.5), forKey:kCIInputColorKey)
} else {
    // Fallback on earlier versions
}