1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
|
(*
* Copyright (c) 1997-1999, 2003 Massachusetts Institute of Technology
*
* This program 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
*
*)
(* $Id: expr.ml,v 1.14 2003/03/16 23:43:46 stevenj Exp $ *)
(* Here, we define the data type encapsulating a symbolic arithmetic
expression, and provide some routines for manipulating it. (See
also simplify.ml for functions to do symbolic simplifications.) *)
type expr =
Num of Number.number
| Var of Variable.variable
| Plus of expr list
| Times of expr * expr
| Uminus of expr
| Integer of int
type assignment = Assign of Variable.variable * expr
let rec find_vars x =
match x with
| Var y -> [y]
| Plus l -> List.flatten (List.map find_vars l)
| Times (a, b) -> (find_vars a) @ (find_vars b)
| Uminus a -> find_vars a
| _ -> []
|
