(***********************************************************************)
(*                                                                     *)
(*                         Applied Type System                         *)
(*                                                                     *)
(***********************************************************************)
(*
** ATS/Postiats - Unleashing the Potential of Types!
** Copyright (C) 2010-2015 Hongwei Xi, ATS Trustful Software, Inc.
** All rights reserved
**
** ATS is free software;  you can  redistribute it and/or modify it under
** the terms of  the GNU GENERAL PUBLIC LICENSE (GPL) as published by the
** Free Software Foundation; either version 3, or (at  your  option)  any
** later version.
**
** ATS 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  ATS;  see the  file COPYING.  If not, please write to the
** Free Software Foundation,  51 Franklin Street, Fifth Floor, Boston, MA
** 02110-1301, USA.
*)
(* ****** ****** *)
(*
** Source:
** $PATSHOME/prelude/SATS/CODEGEN/option_vt.atxt
** Time of generation: Thu Jan 11 11:00:08 2018
*)
(* ****** ****** *)
(* Author: Hongwei Xi *)
(* Authoremail: hwxi AT cs DOT bu DOT edu *)
(* Start time: February, 2012 *)
(* ****** ****** *)
sortdef vt0p = vt@ype

(* ****** ****** *)

#if(0)
//
// HX: these decls are available in [basic_dyn.sats]
//
stadef option_vt = option_vt0ype_bool_vtype
vtypedef Option_vt (a:vt0p) = [b:bool] option_vt (a, b)
//
#endif
(* ****** ****** *)
fun {a:vt0p} option_vt_some (x : a) :<!wrt> option_vt(a, true)

fun {a:vt0p} option_vt_none () :<!wrt> option_vt(a, false)

(* ****** ****** *)
fun {a:vt0p} option_vt_make_opt {b:bool} ( b : bool(b)
                                         , x : &opt(INV(a), b) >> a?
                                         ) :<!wrt> option_vt(a, b)

// end-of-fun
(* ****** ****** *)
fun option_vt_is_some {a:vt0p}{b:bool} (opt : !option_vt(INV(a), b)) :<>
  bool(b)

// end of [option_vt_is_some]
fun option_vt_is_none {a:vt0p}{b:bool} (opt : !option_vt(INV(a), b)) :<>
  bool(~b)

// end of [option_vt_is_none]
(* ****** ****** *)
//
fun {a:vt0p} option_vt_unsome (opt : option_vt(INV(a), true)) :<!wrt>
  (a)

fun {a:vt0p} option_vt_unnone (opt : option_vt(INV(a), false)) :<!wrt>
  void

//
(* ****** ****** *)
//
fun {a:t0p} option_vt_free (opt : Option_vt(INV(a))) :<!wrt> void

fun {a:t0p} option2bool_vt {b:bool} (opt : option_vt(INV(a), b)) :<!wrt>
  bool(b)

//
(* ****** ****** *)
//
fun {a:vt0p} fprint_option_vt {b:bool} ( out : FILEref
                                       , opt : !option_vt(INV(a), b)
                                       ) : void

//
overload fprint with fprint_option_vt

//
(* ****** ****** *)
//
// overloading for certain symbols
//
(* ****** ****** *)
overload iseqz with option_vt_is_none

overload isneqz with option_vt_is_some

(* ****** ****** *)
(* end of [option_vt.sats] *)