Scala comparing generics? -


i writing generic binary search implementation , failing compile (compare not member of type parameter b) though b ordering , should converted implicitly ordered has compare method:

  /**    * generic binary search in (min,max) f achieve target goal    * o(log n)    *    * @param f function binary search on - monotonically increasing    * @param min starting minimum guess (must exclusive)    * @param max starting maximum guess (must exclusive)    * @param avg mid function (min+max)/2    * @param goal target achieve    * @tparam input type of f    * @tparam b output type of f    * @return some(x) such f(x) goal else none    */   import scala.math.ordering.implicits._    def binarysearch[a: ordering, b: ordering](f: => b, min: a, max: a, avg: (a, a) => a, goal: b): option[a] = {     if (min >= max) {       none     } else {       val mid = avg(min, max)       f(mid) compare goal match {         case  1 => binarysearch(f, min, mid, avg, goal)         case -1 => binarysearch(f, mid, max, avg, goal)         case  0 => some(mid)       }     }   }

try importing scala.math.ordered:

import scala.math.ordered._

it has implicit conversion of elements of type b ordered granted there ordering typeclass type b in scope.


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