(************************************************************************)
(* This file is part of SKS.  SKS is free software; you can
   redistribute it and/or modify it under the terms of the GNU General
   Public License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
   USA *)
(***********************************************************************)

(** Allows for some python-like tricks, at the expense of some performance 
  and indirection *)
open StdLabels
open MoreLabels

module Array =
struct
  include Array
  let normalize ar i = if i < 0 then length ar + i else i
  let get ar i = get ar (normalize ar i)
  let slice start stop ar =
    let stop = if stop = 0 then length ar else stop in
    let pos = normalize ar start in
    let len = (normalize ar stop) - pos in
    sub ar ~pos ~len
end

module String =
struct
  include String
  let normalize str i = if i < 0 then length str + i else i
  let get str i = get str (normalize str i)
  let slice start stop str =
    let stop = if stop = 0 then length str else stop in
    let pos = normalize str start in
    let len = (normalize str stop) - pos in
    sub str ~pos ~len
end

let rec range ?(stride=1) ?(start=0) stop = 
  if start >= stop then []
  else start::(range ~stride ~start:(start+stride) stop)


let ( </> ) string (start,stop) = String.slice start stop string
let ( <|> ) ar (start,stop) = Array.slice start stop ar