How to use org.eclipse.jface.text.rules

private boolean skipWhitespace(ICharacterScanner scanner) {
  while (fWhitespaceDetector.isWhitespace((char) scanner.read())) {
    // do nothing
  }
  scanner.unread();
  return true;
}

@Override
protected boolean endSequenceDetected(ICharacterScanner scanner) {
  fCount++;
  if (scanner.read() == '}')
    return fCount > 2;
  scanner.unread();
  return super.endSequenceDetected(scanner);
}

@Override
public IToken evaluate(ICharacterScanner scanner, boolean resume) {
  if (fColumn == UNDEFINED)
    return doEvaluate(scanner, resume);
  int c= scanner.read();
  scanner.unread();
  if (c == fStartSequence[0])
    return (fColumn == scanner.getColumn() ? doEvaluate(scanner, resume) : Token.UNDEFINED);
  return Token.UNDEFINED;
}

  public IToken evaluate(ICharacterScanner scanner) {
    int pos = scanner.getColumn();
    if (pos != 0){
      scanner.unread();
      char first = (char)scanner.read();
      if (first == '.')
        return Token.UNDEFINED;
    }
    return super.evaluate(scanner);
  }
}

public IToken nextToken() {
  fTokenOffset= fOffset;
  fColumn= UNDEFINED;
  if (fRules != null) {
    for (int i= 0; i < fRules.length; i++) {
      IToken token= (fRules[i].evaluate(this));
      if (!token.isUndefined())
        return token;
    }
  }
  if (read() == EOF)
    return Token.EOF;
  return fDefaultReturnToken;
}

@Override
public int getTokenLength() {
  if (fOffset < fRangeEnd)
    return fOffset - getTokenOffset();
  return fRangeEnd - getTokenOffset();
}

/**
 * Calls {@link #initialize()} if the receiver is not yet initialized.
 */
protected final void checkInitialization() {
  if (!fIsInitialized)
    initialize();
}

@Override
public boolean documentChanged(DocumentEvent e) {
  if (fIsInitialized) {
    IRegion region= documentChanged2(e);
    return (region != null);
  }
  return false;
}

@Override
public boolean documentChanged(DocumentEvent e) {
  IRegion region= documentChanged2(e);
  return (region != null);
}

public IToken evaluate(ICharacterScanner scanner, boolean resume) {
  if (fColumn == UNDEFINED)
    return doEvaluate(scanner, resume);
  int c= scanner.read();
  scanner.unread();
  if (c == fStartSequence[0])
    return (fColumn == scanner.getColumn() ? doEvaluate(scanner, resume) : Token.UNDEFINED);
  return Token.UNDEFINED;
}

private boolean skipWhitespace(ICharacterScanner scanner) {
  while (fWhitespaceDetector.isWhitespace((char) scanner.read())) {
    // do nothing
  }
  scanner.unread();
  return true;
}

@Override
protected boolean endSequenceDetected(ICharacterScanner scanner) {
  fCount++;
  if (scanner.read() == '}')
    return fCount > 2;
  scanner.unread();
  return super.endSequenceDetected(scanner);
}

public IToken nextToken() {
  fTokenOffset= fOffset;
  fColumn= UNDEFINED;
  if (fRules != null) {
    for (int i= 0; i < fRules.length; i++) {
      IToken token= (fRules[i].evaluate(this));
      if (!token.isUndefined())
        return token;
    }
  }
  if (read() == EOF)
    return Token.EOF;
  return fDefaultReturnToken;
}

@Override
public IToken evaluate(ICharacterScanner scanner, boolean resume) {
  if (fColumn == UNDEFINED)
    return doEvaluate(scanner, resume);
  int c= scanner.read();
  scanner.unread();
  if (c == fStartSequence[0])
    return (fColumn == scanner.getColumn() ? doEvaluate(scanner, resume) : Token.UNDEFINED);
  return Token.UNDEFINED;
}

private boolean skipWhitespace(ICharacterScanner scanner) {
  while (fWhitespaceDetector.isWhitespace((char) scanner.read())) {
    // do nothing
  }
  scanner.unread();
  return true;
}

@Override
protected boolean endSequenceDetected(ICharacterScanner scanner) {
  fCount++;
  if (scanner.read() == '}')
    return fCount > 2;
  scanner.unread();
  return super.endSequenceDetected(scanner);
}

@Override
public IToken nextToken() {
  fTokenOffset= fOffset;
  fColumn= UNDEFINED;
  if (fRules != null) {
    for (int i= 0; i < fRules.length; i++) {
      IToken token= (fRules[i].evaluate(this));
      if (!token.isUndefined())
        return token;
    }
  }
  if (read() == EOF)
    return Token.EOF;
  return fDefaultReturnToken;
}

public IToken evaluate(ICharacterScanner scanner, boolean resume) {
  if (fColumn == UNDEFINED)
    return doEvaluate(scanner, resume);
  int c= scanner.read();
  scanner.unread();
  if (c == fStartSequence[0])
    return (fColumn == scanner.getColumn() ? doEvaluate(scanner, resume) : Token.UNDEFINED);
  return Token.UNDEFINED;
}

private boolean skipWhitespace(ICharacterScanner scanner) {
  while (fWhitespaceDetector.isWhitespace((char) scanner.read())) {
    // do nothing
  }
  scanner.unread();
  return true;
}

protected boolean endSequenceDetected(ICharacterScanner scanner) {
  fCount++;
  if (scanner.read() == '}')
    return fCount > 2;
  scanner.unread();
  return super.endSequenceDetected(scanner);
}