1 /*
2 * Copyright (c) 2001, Zoltan Farkas All Rights Reserved.
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 */
18
19 package net.sf.zel.instr.var;
20
21 import net.sf.zel.instr.Instruction;
22 import net.sf.zel.vm.ExecutionContext;
23 import net.sf.zel.vm.Variable;
24
25
26
27 /**
28 * @author zoly
29 */
30 public final class VREF extends Instruction
31 {
32 private static final long serialVersionUID = 480559631770514926L;
33
34 private VREF(){};
35
36 public void execute(final ExecutionContext context)
37 {
38 final java.lang.Number nr = (java.lang.Number) context.popSyncStackVal();
39 final Variable var = (Variable) context.popSyncStackVal();
40 context.stack.pop();
41 if (var == null)
42 {
43 context.stack.push(null);
44 } else
45 {
46 context.stack.push(var.getReferenceChain().get(nr.intValue()));
47 }
48 context.ip++;
49 }
50 /**
51 * instance
52 */
53 public static final Instruction instance = new VREF();
54 }