| 1 | /* This file is part of the project "Hilbert II" - 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 | } |