-- iteration 9g: skillhost's grammar on the 9b surface. count(query) for
-- COUNT(*), backlink-emptiness for a correlated NOT EXISTS. No new grammar.
@table(name: "skills", index: [name], index: [parent])
class Skill {
  name: Text
  parent: ?ref Skill
  children: backlink Skill.parent
}
fn main() {
  let git = insert Skill { name: "git", parent: nil }
  insert Skill { name: "git-commit", parent: git }
  insert Skill { name: "docker", parent: nil }
  print_int(count(from x in Skill select x))
  for s in from x in Skill where len(x.children) == 0 order by x.name select x {
    print(s.name)
  }
}