Example of using a "given Conversion" in Scala 3.

scala2-3-Conversion.scala

scala> import scala.language.implicitConversions
scala> case class Dollars(amount: Double):
     |   override def toString = f"$$$amount%.2f"
     | case class Percentage(amount: Double):
     |   override def toString = f"${(amount*100.0)}%.2f%%" 
     | case class Salary(gross: Dollars, taxes: Percentage):
     |   def net: Dollars = Dollars(gross.amount * (1.0 - taxes.amount))
// defined case class Dollars
// defined case class Percentage
// defined case class Salary
      
scala> given Conversion[Double,Dollars] = d => Dollars(d)
def given_Conversion_Double_Dollars: Conversion[Double, Dollars]

scala> given d2P: Conversion[Double,Percentage] = d => Percentage(d) 
def d2P: Conversion[Double, Percentage]

scala> val salary = Salary(100_000.0, 0.20)
scala> println(s"salary: $salary. Net pay: ${salary.net}") 
salary: Salary($100000.00,20.00%). Net pay: $80000.00