/interpreter/tags/at2dist090708/src/edu/vub/at/exceptions/signals/SignalEscape.java

 1/**
 2 * AmbientTalk/2 Project
 3 * SignalEscape.java created on 31-okt-2006 at 12:31:43
 4 * (c) Programming Technology Lab, 2006 - 2007
 5 * Authors: Tom Van Cutsem & Stijn Mostinckx
 6 * 
 7 * Permission is hereby granted, free of charge, to any person
 8 * obtaining a copy of this software and associated documentation
 9 * files (the "Software"), to deal in the Software without
10 * restriction, including without limitation the rights to use,
11 * copy, modify, merge, publish, distribute, sublicense, and/or
12 * sell copies of the Software, and to permit persons to whom the
13 * Software is furnished to do so, subject to the following
14 * conditions:
15 *
16 * The above copyright notice and this permission notice shall be
17 * included in all copies or substantial portions of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
20 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
21 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
22 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
23 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
24 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
25 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
26 * OTHER DEALINGS IN THE SOFTWARE.
27 */
28package edu.vub.at.exceptions.signals;
29
30import edu.vub.at.objects.ATClosure;
31import edu.vub.at.objects.ATObject;
32
33/**
34 * A SignalEscape signal exception is raised whenever the 'quit' function of an escape block
35 * is invoked. It causes control of the interpreter to return to the invocation of the escape block.
36 * In other words, SignalEscape 'abuses' the Java exception handling mechanism to perform a non-local return.
37 * 
38 * @author tvcutsem
39 */
40public class SignalEscape extends Signal {
41	
42	private static final long serialVersionUID = -4808396148074816408L;
43	
44	/** The block which the escape command jumps out of */
45	public ATClosure originatingBlock;
46	
47	/** the value being return via the escape function */
48	public ATObject returnedValue;
49	
50	/**
51	 * Constructor creating an Escape signal to prematurely exit a block and return a specific value.
52	 * @param originatingBlock the current block one is jumping from.
53	 * @param returnedValue the value being returned.
54	 */
55	public SignalEscape(ATClosure originatingBlock, ATObject returnedValue) {
56		this.originatingBlock = originatingBlock;
57		this.returnedValue = returnedValue;
58	}
59
60}