Short example which demonstrates how simply typeclass instance derivation could be done with the help of shapeless.
For this particular example, structural comparison operation derivation is done for sealed trait family.
I.e. for any sealed trait family like:
sealed trait Color
sealed trait PredefColor extends Color
case object Red extends PredefColor
case object Green extends PredefColor
case object Blue extends PredefColor
case class RGB(r: Int, g: Int, b: Int) extends Color
case class RGBA(r: Int, g: Int, b: Int, a: Int) extends Color
case class HSV(h: Int, s: Int, v: Int) extends ColorWe derive
val comparer = GenericComparer[Color]Which allows to determine structural difference between two objects belonging to the same family.
Done by Ivan Kamyshan, 2019.