The Scala 2.8.0 Beta 1 prerelease was released on January 27, 2010. I have finally begun converting my Scala code to 2.8. During the first pass of the conversion, I changed my code to get replace calls that are now deprecated or no longer supported. The second pass, however, has been more interesting.

Scala 2.8 adds many new features. So far, I’ve only managed to play with a few of them, but those few features I’ve tried really make a difference. For instance:

• Named and default arguments have allowed me to simplify some of my objects and classes, sometimes dramatically. Alternate constructors and overloaded methods often just go away, to be replaced by a single method with default parameter values. I really like this feature in other languages, like Python, and I’m thrilled that Scala finally has it.

• The new @tailrec annotation is fabulous. There are places in my code where I assumed tail call optimization was happening, but I hadn’t bothered to verify it by looking at the byte code. Using @tailrec, I’m quickly finding the ones where my assumptions were wrong, without having to disassemble the class files myself. This one simple feature is proving to be an incredible time-saver.

• The revamped Scala REPL is a joy to work with. The addition of tab completion alone has proved to be incredibly useful.

As I dig further into Scala 2.8, I fully expect to find other wonders. I am looking forward to digging more deeply into the redesigned collection libraries.