How to use

toggleSign

method

in

org.matheclipse.parser.client.ast.NumberNode

private final ASTNode parsePrefixOperator(final PrefixOperator prefixOperator) {
  getNextToken();
  final ASTNode temp = parseLookaheadOperator(prefixOperator.getPrecedence());
  if ("PreMinus".equals(prefixOperator.getFunctionName()) && temp instanceof NumberNode) {
    // special cases for negative numbers
    ((NumberNode) temp).toggleSign();
    return temp;
  }
  return prefixOperator.createFunction(fFactory, temp);
}

private ASTNode parsePrimary() {
  if (fToken == TT_OPERATOR) {
    if (fOperatorString.equals(".")) {
      fCurrentChar = '.';
      return getNumber(false);
    }
    final PrefixOperator prefixOperator = determinePrefixOperator();
    if (prefixOperator != null) {
      getNextToken();
      final ASTNode temp = parseLookaheadOperator(prefixOperator.getPrecedence());
      if (prefixOperator.getFunctionName().equals("PreMinus")) {
        // special cases for negative numbers
        if (temp instanceof NumberNode) {
          ((NumberNode) temp).toggleSign();
          return temp;
        }
      }
      return prefixOperator.createFunction(fFactory, temp);
    }
    throwSyntaxError("Operator: " + fOperatorString + " is no prefix operator.");
  }
  return getPart();
}

/**
 * Parses the primary.
 * 
 * @return the AST node
 */
private ASTNode parsePrimary() {
  if ( fToken == TT_OPERATOR ) {
    final PrefixOperator prefixOperator = determinePrefixOperator();
    if ( prefixOperator != null ) {
      getNextToken();
      final ASTNode temp = parseLookaheadOperator( prefixOperator.getPrecedence() );
      if ( prefixOperator.getFunctionName().equals( "PreMinus" ) ) {
        // special cases for negative numbers
        if ( temp instanceof NumberNode ) {
          ((NumberNode) temp).toggleSign();
          return temp;
        }
      }
      return prefixOperator.createFunction( fFactory, temp );
    }
    throwSyntaxError( "Operator: " + fOperatorString + " is no prefix operator." );
  }
  return getPart();
}