1 package io.jawk.intermediate;
2
3 /*-
4 * ╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲
5 * Jawk
6 * ჻჻჻჻჻჻
7 * Copyright (C) 2006 - 2026 MetricsHub
8 * ჻჻჻჻჻჻
9 * This program is free software: you can redistribute it and/or modify
10 * it under the terms of the GNU Lesser General Public License as
11 * published by the Free Software Foundation, either version 3 of the
12 * License, or (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Lesser Public License for more details.
18 *
19 * You should have received a copy of the GNU General Lesser Public
20 * License along with this program. If not, see
21 * <http://www.gnu.org/licenses/lgpl-3.0.html>.
22 * ╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱
23 */
24
25 /**
26 * A pointer to a tuple within the list of tuples.
27 * Addresses are used for jumps, especially in reaction to
28 * conditional checks (i.e., if false, jump to else block, etc.).
29 * <p>
30 * Addresses have the following properties:
31 * <ul>
32 * <li>A name (label).
33 * <li>An index into the tuple queue.
34 * </ul>
35 * An address may not necessarily have an index assigned upon creation.
36 * However, upon tuple traversal, all address indexes must
37 * point to a valid tuple.
38 * <p>
39 * All addresses should have a meaningful label.
40 *
41 * @author Danny Daglas
42 */
43 public class Address implements java.io.Serializable {
44
45 private static final long serialVersionUID = 109610985341478678L;
46
47 /** Human-readable label used when rendering or debugging this address. */
48 private final String lbl;
49
50 /** Tuple index currently bound to this address, or {@code -1} when unresolved. */
51 private int idx = -1;
52
53 /**
54 * Creates an unresolved address with the supplied label.
55 *
56 * @param lbl Label to associate with this jump target
57 */
58 public Address(String lbl) {
59 this.lbl = lbl;
60 }
61
62 /**
63 * The label of the address.
64 * It is particularly useful when dumping tuples to an output stream.
65 *
66 * @return The label of the tuple.
67 */
68 public String label() {
69 return lbl;
70 }
71
72 /**
73 * Set the tuple index of this address.
74 * This can be deferred anytime after creation of the address,
75 * but the index must be assigned prior to traversing the tuples.
76 *
77 * @param index The tuple location within the tuple list (queue)
78 * for this address.
79 */
80 public void assignIndex(int index) {
81 this.idx = index;
82 }
83
84 /**
85 * <p>
86 * index.
87 * </p>
88 *
89 * @return The index into the tuple queue/array.
90 */
91 public int index() {
92 return idx;
93 }
94
95 @Override
96 public String toString() {
97 return label();
98 }
99 }