no BatHashtbl.for_all

[UnixJunkie]

This is inconsistent with many other modules: List, Map, Array.
And yes, sometimes you need to check something about all key-value pairs in a hashtbl...

[UnixJunkie]

exception Falsified

(* test if predicate holds for all key-value pairs *)
let ht_for_all ht p =
  try
    Ht.iter (fun k v ->
        if not (p k v) then
          raise Falsified
      ) ht;
    true
  with Falsified -> false

[UnixJunkie]

If we have a for_all, we probably should have an exists too.