fun traverse(element) = {
   (element.foo#node.*foo#leaf map name: $)
}
ns foo http://demo.com
---
{
  result: {
    a: in0.root.store.&book,
    b: sizeOf(in0.root.store.&book),
    c: sizeOf(in0.root.store[?($$ ~= "book")]),
    d: traverse(in2.foo#node),
    e: in0.root.store.&book[&0]
  }
}
