bundles/extlib/extlib-1.5.2/global.ml

   1 (*
   2  * Global - Mutable global variable
   3  * Copyright (C) 2003 Nicolas Cannasse
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version,
   9  * with the special exception on linking described in file LICENSE.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *)
  20
  21 exception Global_not_initialized of string
  22
  23 type 'a t = ('a option ref * string)
  24
  25 let empty name = ref None,name
  26
  27 let name = snd
  28
  29 let set (r,_) v = r := Some v
  30
  31 let get (r,name) =
  32         match !r with
  33         | None -> raise (Global_not_initialized name)
  34         | Some v -> v
  35
  36 let undef (r,_) = r := None
  37
  38 let isdef (r,_) = !r <> None
  39
  40 let opt (r,_) = !r