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@gigiigig
Created June 29, 2017 10:16
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Change Return type of a function
{
trait Aux[T] {
type R
def apply(t: T): R
}
implicit val sa = new Aux[String] {
type R = Boolean
def apply(s: String): Boolean = s.isEmpty
}
implicit val ia = new Aux[Int] {
type R = String
def apply(i: Int): String = i.toString
}
def foo[T](t: T)(implicit aux: Aux[T]): aux.R = aux(t)
}
/*
@ val b: Boolean = foo("")
b: Boolean = true
@ val c: String = foo(2)
c: String = "2"
@ val c: Boolean = foo(4)
cmd4.sc:1: type mismatch;
found : ammonite.$sess.cmd0.ia.R
(which expands to) String
required: Boolean
val c: Boolean = foo(4)
^
Compilation Failed
*/
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