(* Just some random utility functions *)

exception Error of string

let rec join str = function
  | [] -> ""
  | a::[] -> a
  | a::b::t -> join str ((a ^ str ^ b)::t)

let rec join_end str = function
  | [] -> ""
  | a::t -> a ^ str ^ (join_end str t)

let bonus_newline s = if s = "" then s else s ^ "\n"

let rec indent n = match n with
  0 -> ""
  | i -> "    " ^ (indent (i - 1));;

(* Split a list into two parts; the length of the first part is given. *)
let split_at_n l n =
  let rec split_2 l i f =
    match l with
    [] -> (f,[])
    | h::t -> if (i=0)
      then (f,h::t)
      else ( split_2 t (i-1) (f@[h]) )
  in
  split_2 l n []

let rec list_contains e = function
  | [] -> false
  | h::t -> if h = e then true else list_contains e t

let hash_keys_to_list hash =
  (* BatHashtbl.keys returns a BatEnum, let's turn it into a plain list *)
  BatEnum.fold (fun b a -> a::b) [] (BatHashtbl.keys hash)

let hash_to_pairs_list hash =
  BatEnum.fold (fun b a -> a::b) [] (BatHashtbl.enum hash)