anchor.diff:    (blur)="onBlur()"
     #input
   />
  -{{value}} X {{valueStr}}
   ''',
       providers: const [
         CUSTOM_INPUT_FDOUBLE_VALUE_ACCESSOR,
  
positive.code:   double parseDouble(value) {
      if (value == null) return null;
      if (value is num) {
        return value;
      } else {
        return double.parse(value.toString().replaceAll(",","."), (_) => null);
      }
  
negative.code:   void writeValue(obj) {
      value = obj;
      if (!focused) {
        if (value == null) {
          _valueStr = "";
        } else {
  