How to write asInstanceOfOpt[T] where T <: Any

Question

There\'s a handy implementation of asInstanceOfOpt, a safe version of asInstanceOf, given in the answer to How to write "asInstanceOfOption"

Answer 1

You could use shapeless's Typeable from Miles Sabin:

Type casting using type parameter

It handles primitives and boxing:

scala> import shapeless._; import syntax.typeable._
import shapeless._
import syntax.typeable._

scala> 1.cast[Int]
res1: Option[Int] = Some(1)

scala> 1.cast[String]
res2: Option[String] = None

scala> "hello".cast[String]
res4: Option[String] = Some(hello)

scala> "foo".cast[Int]
res5: Option[Int] = None

You can see the source here to see how it's written:

https://github.com/milessabin/shapeless/blob/master/core/src/main/scala/shapeless/typeable.scala