1 /* This file is part of the project "Hilbert II" - http://www.qedeq.org" target="alexandria_uri">http://www.qedeq.org
2 *
3 * Copyright 2000-2014, Michael Meyling <mime@qedeq.org>.
4 *
5 * "Hilbert II" is free software; you can redistribute
6 * it and/or modify it under the terms of the GNU General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
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
16 package org.qedeq.kernel.bo.parser;
17
18 import java.util.ArrayList;
19 import java.util.List;
20
21 /**
22 * Parse term or formula data into {@link org.qedeq.kernel.bo.parser.Term}s.
23 * This parser uses simple ASCII text operators.
24 *
25 * @version $Revision: 1.1 $
26 * @author Michael Meyling
27 */
28 public class SimpleMathParser extends MathParser {
29
30 /** Characters that are always tokens itself. */
31 private static final String SEPARATORS = "()[],{}";
32
33 /**
34 * Constructor.
35 */
36 public SimpleMathParser() {
37 super();
38 /*
39 operators.add(new Operator("~", "NOT", 110, 1, 1, 1));
40 operators.add(new Operator("-", "NOT", 110, 1, 1, 1));
41 operators.add(new Operator("&", "AND", 100, 0, 2));
42 operators.add(new Operator("|", "OR", 90, 0, 2));
43 // operators.put("v", new Operator("v", "OR", 90, 0, 2));
44 operators.add(new Operator("->", "IMPL", 80, 0, 2, 2));
45 operators.add(new Operator("=>", "IMPL", 80, 0, 2, 2));
46 operators.add(new Operator("<->", "EQUI", 80, 0, 2));
47 operators.add(new Operator("<=>", "EQUI", 80, 0, 2));
48 operators.add(new Operator("all", "ALL", 40, 1, 2, 3));
49 operators.add(new Operator("exists", "EXISTS", 40, 1, 2, 3));
50 operators.add(new Operator("in", "IN", 200, 0, 2, 2));
51 operators.add(new Operator("=", "EQUAL", 200, 0, 2));
52 operators.add(new Operator("{", ",", "}", "SET", 200, 0));
53 operators.add(new Operator("{", ":", "}", "SETPROP", 200, 2, 2));
54 */
55 }
56
57 protected final String readToken() {
58 int lines = 0;
59 while (getChar() != -1 && Character.isWhitespace((char) getChar())) {
60 if ('\n' == (char) getChar()) {
61 lines++;
62 }
63 readChar();
64 }
65 if (lines > 1) {
66 return "";
67 }
68 if (eof()) {
69 return null;
70 }
71 if (SEPARATORS.indexOf(getChar()) >= 0) {
72 return "" + (char) readChar();
73 }
74 final StringBuffer token = new StringBuffer();
75 while (!eof() && !Character.isWhitespace((char) getChar())
76 && SEPARATORS.indexOf(getChar()) < 0) {
77 token.append((char) readChar());
78 if (null != getOperator(token.toString())) {
79 if (getChar() >= 0) {
80 final char c = (char) getChar();
81 if (null != getOperator(token.toString() + c)) {
82 continue;
83 }
84 }
85 break;
86 }
87 }
88 return token.toString();
89 }
90
91 protected final Operator getOperator(final String token) {
92 Operator result = null;
93 if (token == null) {
94 return result;
95 }
96 for (int i = 0; i < getOperators().size(); i++) {
97 if (token.equals(((Operator) getOperators().get(i)).getStartSymbol())) {
98 result = (Operator) getOperators().get(i);
99 break;
100 }
101 }
102 return result;
103 }
104
105 protected final List getOperators(final String token) {
106 final List result = new ArrayList();
107 if (token == null) {
108 return result;
109 }
110 for (int i = 0; i < getOperators().size(); i++) {
111 if (token.equals(((Operator) getOperators().get(i)).getStartSymbol())) {
112 result.add(getOperators().get(i));
113 }
114 }
115 return result;
116 }
117
118 protected boolean eot(final String token) {
119 return token == null || token.trim().length() == 0;
120 }
121
122 }