scala-2.9

Is there a method in Akka (or in the standard library in Scala 2.10) to convert a Future[A] which might fail into a Future[Either[Exception,A]] ? I know that you can write f.map(Right(_)).recover { case e:Exception => Left(e) } It just seems to be such a common task that I wonder whether I have overlooked something. I'm interested in answers for Scala 2.9/Akka and Scala 2.10. The primary reason why this method is missing is that it does not really have good semantics: the static type Future[Either[Throwable, T]] does not ensure that that future cannot fail, hence the type change does not gain

I started working my way through the Scala Koans , which is organized around a suite of unit tests with blanks that one needs to fill in. (This idea was modeled after a similar Ruby Koans project.) You start the sbt tool running a test, and it admonishes: [info] + ***************************************** [info] + [info] + [info] + [info] + Please meditate on koan "None equals None" of suite "AboutEmptyValues" [info] + [info] + [info] + [info] + ***************************************** ...and so you go look at this unit test and it says: test("None equals None") { assert(None === __) } ...and

I am trying to program the coin change problem in Scala using recursion. The code that i have written is as follows. def countChange(money: Int, coins: List[Int]): Int = { def ways(change: List[Int], size: Int, capacity: Int): Int = { if(capacity == 0) 1 if((capacity < 0) || (size <= 0)) 0 //println and readLine to check and control each recursive call. println("calling ways(",change, change.length-1, capacity,") + ways(",change, change.length, capacity - change(change.length - 1),")") readLine() // ways(change, change.length-1, capacity) + ways(change, change.length, capacity - change(change

I want a program I'm building to be able to report its own version at runtime (e.g. scala myprog.jar --version ). Traditionally in a maven project, I'd use resource filtering (pom.xml -> file.properties -> read value at runtime). I know there's sbt-filter-plugin to emulate this functionality, but I'm curious if there's a more standard / preferred / clever way of doing this in SBT. tl;dr how can I read the version number defined in build.sbt at runtime? Update... https://github.com/ritschwumm/xsbt-reflect (mentioned above) is Obsolete, but there is this cool SBT release tool that can

For reading files in Scala, there is Source.fromFile("file.txt").mkString Is there an equivalent and concise way to write a string to file? Most languages support something like that. My favorite is Groovy: def f = new File("file.txt") // Read def s = f.text // Write f.text = "file contents" I'd like to use the code for programs ranging from a single line to a short page of code. Having to use your own library doesn't make sense here. I expect a modern language to let me write something to a file conveniently. There are posts similar to this, but they don't answer my exact question or are