This only works on Scala 2.8, but it does work:
scala> def pythagoras[T](a: T, b: T, sqrt: T => T)(implicit n: Numeric[T]) = {
| import n.mkNumericOps
| sqrt(a*a + b*b)
| }
pythagoras: [T](a: T,b: T,sqrt: (T) => T)(implicit n: Numeric[T])T
scala> def intSqrt(n: Int) = Math.sqrt(n).toInt
intSqrt: (n: Int)Int
scala> pythagoras(3,4, intSqrt)
res0: Int = 5
More generally speaking, the trait Numeric
is effectively a reference on how to solve this type of problem. See also Ordering
.