public Term getValue() {
   ActivePlainDocument activeDocument = (ActivePlainDocument) getDocument();
   try {
     // return new PrologReal(new Double(activeDocument.getTextOrBacktrack()));
     String text = activeDocument.getTextOrBacktrack();
     BigInteger number = Converters.stringToStrictInteger(text);
     return new PrologInteger(number);
   } catch (Backtracking b) {
     return new PrologString(activeDocument.getText());
   } catch (TermIsNotAnInteger e) {
     return new PrologString(activeDocument.getText());
   }
 }