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object Test extends App {
import scala.collection.generic.{ CanBuildFrom, FromRepr, HasElem }
def typed[T](t : => T) {}
class FilterMapImpl[A, Repr](val r : Repr)(implicit hasElem : HasElem[Repr, A]) {
def filterMap[B, That](f : A => Option[B])(implicit cbf : CanBuildFrom[Repr, B, That]) : That = r.flatMap(f(_).toSeq)
}
implicit def filterMap[Repr : FromRepr](r : Repr) = new FilterMapImpl(r)
val l = List(1, 2, 3, 4, 5)
val fml = l.filterMap(i => if(i % 2 == 0) Some(i) else None)
typed[List[Int]](fml)
println(fml)
val a = Array(1, 2, 3, 4, 5)
val fma = a.filterMap(i => if(i % 2 == 0) Some(i) else None)
typed[Array[Int]](fma)
println(fma.deep)
val s = "Hello World"
val fms1 = s.filterMap(c => if(c >= 'A' && c <= 'Z') Some(c) else None)
typed[String](fms1)
println(fms1)
val fms2 = s.filterMap(c =>if(c % 2 == 0) Some(c.toInt) else None)
typed[IndexedSeq[Int]](fms2)
println(fms2)
}
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