001 /* This file is part of the project "Hilbert II" - http://www.qedeq.org
002 *
003 * Copyright 2000-2013, Michael Meyling <mime@qedeq.org>.
004 *
005 * "Hilbert II" is free software; you can redistribute
006 * it and/or modify it under the terms of the GNU General Public
007 * License as published by the Free Software Foundation; either
008 * version 2 of the License, or (at your option) any later version.
009 *
010 * This program is distributed in the hope that it will be useful,
011 * but WITHOUT ANY WARRANTY; without even the implied warranty of
012 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
013 * GNU General Public License for more details.
014 */
015
016 package org.qedeq.kernel.bo.parser;
017
018 import java.util.ArrayList;
019 import java.util.List;
020
021 import org.qedeq.base.trace.Trace;
022
023 /*
024 * LATER mime 20080131: refactor
025 *
026 */
027
028 /**
029 * Parse term or formula data into {@link org.qedeq.kernel.bo.parser.Term}s.
030 * This parser uses simple ASCII text operators.
031 *
032 * @author Michael Meyling
033 */
034 public final class AsciiMathParser extends MathParser {
035
036 /** This class. */
037 private static final Class CLASS = AsciiMathParser.class;
038
039 /** Separators for tokens. */
040 private static final String SEPARATORS = "()[],{}";
041
042 /**
043 * Constructor.
044 */
045 public AsciiMathParser() {
046 super();
047 }
048
049 protected final String readToken() {
050 final String method = "readToken()";
051 int lines = 0;
052 while (getChar() != -1 && Character.isWhitespace((char) getChar())) {
053 if ('\n' == (char) getChar()) {
054 lines++;
055 }
056 readChar();
057 }
058 if (lines > 1) {
059 return "";
060 }
061 if (eof()) {
062 return null;
063 }
064 if (SEPARATORS.indexOf(getChar()) >= 0) {
065 Trace.param(CLASS, this, method, "Read token", "" + (char) getChar());
066 return "" + (char) readChar();
067 }
068 final StringBuffer token = new StringBuffer();
069 String operator = null;
070 markPosition();
071 while (!eof() && !Character.isWhitespace((char) getChar())
072 && SEPARATORS.indexOf(getChar()) < 0) {
073 token.append((char) readChar());
074 if (null != getOperator(token.toString())) {
075 operator = token.toString();
076 clearMark();
077 markPosition();
078 }
079 }
080 if (operator != null) {
081 rewindPosition();
082 token.setLength(0);
083 token.append(operator);
084 } else {
085 clearMark();
086 }
087 Trace.param(CLASS, this, method, "Read token", token);
088 return token.toString();
089 }
090
091 protected final Operator getOperator(final String token) {
092 Operator result = null;
093 if (token == null) {
094 return result;
095 }
096 for (int i = 0; i < getOperators().size(); i++) {
097 if (token.equals(((Operator) getOperators().get(i)).getStartSymbol())) {
098 result = (Operator) getOperators().get(i);
099 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 }
|