(*
** Course: Concepts of Programming Languages (BU CAS CS 320)
** Semester: Summer I, 2009
** Instructor: Hongwei Xi (hwxi AT cs DOT bu DOT edu)
*)

//
// Author: Hongwei Xi (hwxi AT cs DOT bu DOT edu)
// Time: June, 2009
//

(* ****** ****** *)
//
// An interpreter for STFPL (a simple typed functional programming language)
// The code was originally written by Hongwei Xi in May 2005
//
(* ****** ****** *)

local
staload TR1 = "trans1_tc.sats"
(*
staload TR1 = "trans1_ti.sats"
*)
in
typedef v1ar = $TR1.v1ar
typedef v1arlst = $TR1.v1arlst
typedef e1xp = $TR1.e1xp
end

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

datatype v1al =
  | V1ALbool of bool
  | V1ALint of int
  | V1ALstr of string
  | V1ALtup of list0 v1al 
  | V1ALclo of (env, v1arlst, e1xp)
  | V1ALref of ref (v1al)

where env = list0 @(v1ar, v1al)

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

fun fprint_v1al (out: FILEref, v: v1al): void
fun fprint_v1allst (out: FILEref, vs: list0 v1al): void

fun print_v1al (v: v1al): void and prerr_v1al (v: v1al): void

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

fun interp1_exp (e: e1xp): v1al

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

(* end of [interp1.sats] *)