static <A> S pnlStructToString(final Collection<A> l) {
  ret hijackPrint(r { pnlStruct(l) });
}

static <A> Iterable<A> pnlStructToString(Iterable<A> l) {
  ret hijackPrint(r { pnlStruct(l) });
}

static <A> A[] pnlStructToString(A[] l) {
  ret hijackPrint(r { pnlStruct(l) });
}

static <A, B> Map<A, B> pnlStructToString(Map<A, B> map) {
  ret hijackPrint(r { pnlStruct(map) });
}