caml << let is_man a = (List.assoc "gender" a = "M") >>

children(children[x] q) -> split(x,())
children(_ q) | children(_[_] q) -> children(q)

name(name[x] q) -> x
name(_ q) -> name(q)

sons(man[@a x] y,q) -> man[@a x] sons(y,q)
sons(_[_] y,q) | sons(_ y,q) -> sons(y,q)
sons((),q) -> q

daughters(woman[@a x] y,q) -> man[@a x] daughters(y,q)
daughters(_[_] y,q) | daughters(_ y,q) -> daughters(y,q)
daughters((),q) -> q

split(person[@a x] y,q) ->
  let tag : string = << if is_man a then "man" else "woman" >> in
  let q = split(y,q) in
  let c = children(x) in
  let c = sons[sons(c,())] daughters[daughters(c,())] in
  match name(x) with [ %n _ -> let a' = << ["name",n] >> in %tag[ @a' c ] q  ]

split(_ y,q) -> split(y,q)
split((),q) -> q
main(doc[x] _) -> split(x,())