I want to write a function that works on any Scala type with a total ordering (i.e. I can use '<' on it). What's the syntax for that? The best I've come up with is
def lessThan[T <: Ordered[T]](x: T, Y: T) = x < y
That doesn't work, though, when I try using it from the REPL:
scala> lessThan(1, 2)
<console>:8: error: inferred type arguments [Int] do not conform to method lessThan's type parameter bounds [T <: Ordered[T]]
lessThan(1, 2)
^
scala> import runtime._
import runtime._
scala> lessThan(new RichInt(1), new RichInt(2))
<console>:8: error: inferred type arguments [scala.runtime.RichInt] do not conform to method lessThan's type parameter bounds [T <: Ordered[T]]
lessThan(new RichInt(1), new RichInt(2))
Essentially, I believe I want the equivalent of this Haskell code:
lessThan :: (Ord a) => a -> a -> Bool
lessThan x y = x < y
I'm using scala 2.7.3 on a Debian system.
What am I missing, and where?