[Ur] Simple type level function Name -> Name - are there funnier examples?

[Marc Weber]

This is fun:

  con change_name :: Name -> Name = fn _ => #Boo
  con n2 :: Name = change_name #Arbitrary
  val my_rec_abc : $[n2=int] = { Boo = 1 }
  val my_rec_abc : {Boo : int} = my_rec_abc

however something more funny does no longer work:

con change_name_toggle :: Name -> Name = fn name =>
    case name of
          #Boo => #Bar
          |#Bar => #Boo

So is there any way (more than one) to implement such function?

What else can be done with names? There are no operations such as
"prefix them with db_" or such, are there?

I'm trying to come up with samples for each line of the manual ..

Marc Weber