/interpreter/tags/at2-build270707/src/edu/vub/at/objects/ATFraction.java

 1/**
 2 * AmbientTalk/2 Project
 3 * ATFraction.java created on 26-jul-2006 at 15:17:23
 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.objects;
29
30import edu.vub.at.exceptions.InterpreterException;
31
32
33/**
34 * ATFraction is the public interface to a native AmbientTalk fraction (a floating point value).
35 * 
36 * @author tvc
37 */
38public interface ATFraction extends ATNumeric {
39
40
41	//arithmetic operations
42	/**
43	 * Returns the fraction plus 1.
44	 *
45	 * @return an ATFraction resulting of adding 1 to the receiver.
46	 */	
47	public ATFraction base_inc() throws InterpreterException;
48	
49	/**
50	 * Returns the fraction minus 1.
51	 *
52	 * @return an ATFraction resulting of subtracting 1 to the receiver.
53	 */	
54	public ATFraction base_dec() throws InterpreterException;
55	
56	/**
57	 * Returns the absolute value of a fraction.
58	 * <p>
59	 * More specifically: 
60	 * <ul>
61	 * <li>If the receiver >= 0, the receiver is returned. 
62	 * <li>If the receiver < 0, the negation of the receiver is returned. 
63	 * </ul>
64	 * 
65	 * @return the absolute value of the receiver.
66	 */	
67	public ATFraction base_abs() throws InterpreterException;
68	
69	// base-level interface
70	
71	/**
72	 * Returns the closest number to the fraction.
73	 * <p>
74	 * More specifically, rounding a number is equivalent to <code> (fraction + 0.5).floor() </code>
75	 *
76	 * @return an ATNumber resulting of rounding the receiver to the closest number value.
77	 */	
78	public ATNumber base_round() throws InterpreterException;
79	
80	/**
81	 * Returns the closest number to positive infinity that is smaller than the fraction.
82	 *
83	 * @return the closest number to positive infinity that is smaller than the fraction.
84	 */	
85	public ATNumber base_floor() throws InterpreterException;
86	
87	/**
88	 * Returns the closest number to negative infinity that is greater than the fraction.
89	 *
90	 * @return the closest number to negative infinity that is greater than the fraction.
91	 */	
92	public ATNumber base_ceiling() throws InterpreterException;
93	
94}