(***********************************************************************)
(*                                                                     *)
(*                         Applied Type System                         *)
(*                                                                     *)
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(*
** 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: Mon Sep  5 21:48:35 2016
*)

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

(* Author: Hongwei Xi *)
(* Authoremail: hwxi AT cs DOT bu DOT edu *)
(* Start time: February, 2012 *)

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

sortdef vt0p = viewt@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 ((*void*)):<!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) // endfun

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

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: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] *)