/* $Id: LatexMathParser.java,v 1.3 2007/02/25 20:05:35 m31 Exp $ * * This file is part of the project "Hilbert II" - http://www.qedeq.org * * Copyright 2000-2007, Michael Meyling . * * "Hilbert II" is free software; you can redistribute * it and/or modify it under the terms of the GNU General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ package org.qedeq.kernel.parser; import java.util.ArrayList; import java.util.List; import org.qedeq.kernel.log.Trace; import org.qedeq.kernel.utility.TextInput; /* * TODO refactor * * Whitespace LaTeX form, could be eaten * \t * \r * \n * \\ * \\, * & * \\\\ * \\par * \\quad * \\qquad * * Separator only one allowed, before and after only whitespace is possible * , * | * $$ * Separator should be read as tokens. * * Problem: If some atom like is followed by "(" it should be taken as an * (function) operator. But if we start with readToken we don't see the "(" * character. * * Problem: Could whitespace be recognized? * Translating whitespace tokens into spaces is not easy, one has to know the * end of the whitespace token. * Possible solution: * function read token (LaTeX specific) * skip real whitespace (" ", "\t", "\r", "\n") * read char * case char * "\\" read characters or numbers (check LaTeX Syntax) * "{", "}", "(", ")" are also allowed * resulting string is token * LaTeX command definition modifies above: * Die meisten LATEX-Befehle haben eines der beiden folgenden Formate: Entweder sie beginnen * mit einem Backslash (\) und haben dann einen nur aus Buchstaben bestehenden Namen, der durch * ein oder mehrere Leerzeichen oder durch ein nachfolgendes Sonderzeichen oder eine Ziffer beendet * wird; oder sie bestehen aus einem Backslash und genau einem Sonderzeichen oder einer Ziffer. * Gross- und Kleinbuchstaben haben auch in Befehlsnamen verschiedene Bedeutung. Wenn man nach * einem Befehlsnamen eine Leerstelle erhalten will, muss man "{}" zur Beendigung des Befehlsnamens * oder einen eigenen Befehl f\u00fcr die Leerstelle verwenden. */ /** * Parse LaTeX term or formula data into {@link org.qedeq.kernel.parser.Term}s. * * @version $Revision: 1.3 $ * @author Michael Meyling */ public final class LatexMathParser extends MathParser { /** Characters with special LaTeX meaning. */ private static final String SPECIALCHARACTERS = "(),{}\\~%$&"; /** Counter for token whitespace lines. */ private int tokenWhiteSpaceLines; /** * Constructor. * * @param input Parse this input. * @param operators List of operators. */ public LatexMathParser(final TextInput input, final List operators) { super(new MementoTextInput(input), operators); } /** * Constructor. * * @param buffer Parse this input. * @param operators List of operators. */ public LatexMathParser(final StringBuffer buffer, final List operators) { this(new TextInput(buffer), operators); } protected final String readToken() { final String method = "readToken()"; Trace.begin(this, method); StringBuffer token = new StringBuffer(); tokenWhiteSpaceLines = 0; try { do { tokenWhiteSpaceLines += readPureWhitespace(); if (tokenWhiteSpaceLines > 1) { break; } if (eof()) { if (token.length() <= 0) { token = null; } break; } final int c = getChar(); if (Character.isDigit((char) c)) { token.append((char) readChar()); if (Character.isDigit((char) getChar())) { continue; } break; } if (SPECIALCHARACTERS.indexOf(c) >= 0) { switch (c) { case '&': case '%': case '~': case '$': // TODO mime 20060504 or break in this case? readChar(); continue; case '\\': final String t = readBackslashToken(); if (t.equals(" ") || t.equals("quad") || t.equals("qquad")) { continue; } token.append(t); if ('_' == getChar() || '^' == getChar()) { token.append((char) readChar()); continue; } break; case '{': readChar(); token.append("("); break; case '}': readChar(); token.append(")"); break; default: readChar(); token.append((char) c); if ('_' == getChar() || '^' == getChar()) { token.append((char) readChar()); continue; } } break; } token.append((char) readChar()); if ('_' == getChar() || '^' == getChar()) { token.append((char) readChar()); continue; } break; /* String operator = null; markPosition(); while (!eof() && (Character.isLetterOrDigit((char) getChar()) || '_' == getChar() || '^' == getChar())) { token.append((char) readChar()); if (null != getOperator(token.toString())) { operator = token.toString(); clearMark(); markPosition(); } } if (operator != null) { rewindPosition(); token.setLength(0); token.append(operator); } else { clearMark(); } */ } while (!eof()); Trace.param(this, method, "Read token", token); return (token != null ? token.toString() : null); } finally { Trace.end(this, method); } } private String readBackslashToken() { final String method = "readBackslashToken()"; Trace.begin(this, method); if (getChar() != '\\') { throw new IllegalArgumentException("\\ expected"); } readChar(); // read \ if (eof()) { Trace.param(this, method, "return", null); Trace.end(this, method); return null; } if (!Character.isLetter((char) getChar())) { Trace.param(this, method, "return", (char) getChar()); Trace.end(this, method); return "" + ((char) readChar()); } final StringBuffer buffer = new StringBuffer(); do { buffer.append((char) readChar()); } while (!eof() && Character.isLetter((char) getChar())); Trace.param(this, method, "return", buffer.toString()); Trace.end(this, method); return buffer.toString(); } private int readPureWhitespace() { int lines = 0; while (getChar() != -1 && Character.isWhitespace((char) getChar())) { if ('\n' == (char) getChar()) { lines++; } readChar(); } return lines; } protected final Operator getOperator(final String token) { Operator result = null; if (token == null) { return result; } for (int i = 0; i < getOperators().size(); i++) { if (token.equals(((Operator) getOperators().get(i)).getStartSymbol())) { result = (Operator) getOperators().get(i); break; } } return result; } protected final List getOperators(final String token) { final List result = new ArrayList(); if (token == null) { return result; } for (int i = 0; i < getOperators().size(); i++) { if (token.equals(((Operator) getOperators().get(i)).getStartSymbol())) { result.add(getOperators().get(i)); } } return result; } protected boolean eot(final String token) { return token == null || token.trim().length() == 0; } }