Calling a function by type parameter in Scala

scala-call-func-type-param.md

Let's say you have a Scala function which takes type parameter:

  def myFunc[K]: T

Let's say I have several functions like that. Right now, if K could be one of several different values, I'd need some code like the following:

  kType match {
    case KIsInt =>  myFunc[Int]
    case KIsLong => myFunc[Long]
  }

I'd like a generic wrapper function that can switch on kType and call different functions. Is this possible? Something like this.

  def kFuncCall[T](kType: KType)(callFunc: [K] => T): T = {
    kType match {
      case KIsLong    => callFunc[Long]
      case KIsInt     => callFunc[Int]
    }

Interesting... I'm doing horrible things with typeclasses and types in https://github.com/gclaramunt/scala-reggen but at the end I resort to casting :(

The first thing it comes to mind is if you know you'll need a typeclass instance you can (again) add it to KType and use it explicitly: callFunc[kType.K](kType.typeClassOfK)

trait KType { 
  type K
  type TypeClassOfK <: SomeTypeClass
 }

case class KIsInt() extends KType { 
  type K=Int 
  type TypeClassOfK = TypeClassForInt
}

is not the most elegant way but I think it will work
(maybe is time to mine Scalaz for more sophisticated techniques, :) )

@gclaramunt thanks. I tried looking in Shapeless but didn't find anything that would help. Maybe Scalaz. :)