KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > Texpinfix


1 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
2  * Copyright (C) 2001 Gerwin Klein <lsf@jflex.de> *
3  * Copyright (C) 2001 Bernhard Rumpe <rumpe@in.tum.de> *
4  * All rights reserved. *
5  * *
6  * This program is free software; you can redistribute it and/or modify *
7  * it under the terms of the GNU General Public License. See the file *
8  * COPYRIGHT for more information. *
9  * *
10  * This program is distributed in the hope that it will be useful, *
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of *
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
13  * GNU General Public License for more details. *
14  * *
15  * You should have received a copy of the GNU General Public License along *
16  * with this program; if not, write to the Free Software Foundation, Inc., *
17  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA *
18  * *
19  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
20
21
22 /**
23  * AST node for infix expressions
24  */
25 class Texpinfix extends Texp implements AST {
26   Texp exp1, exp2; // left and right sub expression
27 char kind; // kind ('+', '-', '*', '/')
28
29   public Texpinfix(Texp e1, char k, Texp e2) {
30     exp1=e1;
31     kind=k;
32     exp2=e2;
33   }
34
35   public String JavaDoc toString() {
36     return("("+exp1+kind+exp2+")");
37   }
38
39   public void checkcontext(SymTab st) { // context conditions
40 exp1.checkcontext(st);
41     exp2.checkcontext(st);
42   }
43
44   public void prepInterp(SymTab st) { // set pointers und indices
45 exp1.prepInterp(st);
46     exp2.prepInterp(st);
47   }
48
49   public int interpret(int[] in, int[] par) {
50     int e1 = exp1.interpret(in,par);
51     int e2 = exp2.interpret(in,par);
52
53     switch (kind) {
54     case '+': return(e1+e2);
55     case '-': return(e1-e2);
56     case '*': return(e1*e2);
57     case '/': return(e1/e2);
58     }
59
60     return -1; // error
61 }
62 }
63
64
65
Popular Tags