Development

Introducing try-catch from Apple Swift 2, with sandbox on web by IBM Bluemix

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Apple Swift is a programming language for iOS application development at the beginning. It can be found on Mac’s Xcode.

Now Apple Swift 2 is hosted on IBM Bluemix’s website (http://swiftlang.ng.bluemix.net). The Swift version  is 2.2-dev as of today,

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Swift version 2.2-dev (LLVM 46be9ff861, Clang 4deb154edc, Swift 778f82939c)
Target: x86_64-unknown-linux-gnu

There are many language features introduced in Swift 2. Let’s begin with the elegant try-catch feature from a sample code,

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/* Basic fibonacci function in swift.
   Demostrates func calls and recursion.
*/

func fibonacci(i: Int) throws -> Int  {
    if i <= 2 {
        return 1
    } else {
        return **try** fibonacci(i - 1) + fibonacci(i - 2)
    }
}

do {
  try print(fibonacci(22))
  /* do something that doesn't throw in the middle
  */
  // the keyword reminds you below function will throw
  try print(fibonacci(11))
} catch {
  print("error")
}

The function doesn’t really throw any thing but you can see the function calls that throw are prefixed with try.

The evolution speed of Swift language seems a little bit faster than Google’s Go language on this feature.

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