Generic `Shape` coproduct types reversed in section 2.4

[SamDM]

Near the end of section 2.4 there is the following example:

  sealed trait Shape
  final case class Rectangle(width: Double, height: Double) extends Shape
  final case class Circle(radius: Double) extends Shape

  val gen = Generic[Shape]

gen is supposed to be:

Generic[Shape]{type Repr = Rectangle :+: Circle :+: CNil} = ...

But when I try it, it is (note that Rectangle and Circle are in reversed order):

Generic[Shape]{type Repr = Circle :+: Rectangle :+: CNil} = ...

I am going through the book to learn about shapeless, I don't know if this is intended behavior of shapeless and a bug in the documentation or the other way around. Or does this only happen on my system? If this is a bug in shapeless I'll open an issue there (unless someone beats me to it).

I'm using scala 2.12.3 and shapeless 2.3.2, I'm compiling with sbt.

[SamDM]

Some more experimenting showed that the types are sorted by alphabet instead of order of occurence

[davegurnell]

Ah! Good to know. Thanks for the detective work! This must be intentional but I didn’t know it was the case. On Mon, 11 Dec 2017 at 23:21, Sam De Meyer [email protected] wrote:

Some more experimenting showed that the Types are sorted by alphabet instead of order of occurence

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