code: public String evaluate(Map symbolTable)
  	throws RslEvaluationException {
  	if (concatValue == null) {
  	    return value;
  	} else {
  	    StringBuffer buf = new StringBuffer(value);
  	    buf.append(concatValue.evaluate(symbolTable));
  	    return buf.toString();
  	}
      }
docs: Evaluates the value with the specified
  symbol table.
  In this case the function just returns the
  string representation of the actual value.
  No symbol table lookups are performed.
  
  @param symbolTable the symbol table to evaluate
  the value against.
  @return an evaluated string.
  @exception RslEvaluationException If an error occured during
  rsl evaluation.