public CALC val(Object value, Class<? extends NumConverter> converter) {
        infix.add(new Num(value, converter));
        return getThis();
    }
public CALC val ( Object value , Class < ? extends NumConverter > converter ) { infix . add ( new Num ( value , converter ) ) ; return getThis ( ) ; }
Append value to expression

@param value custom type value
@param converter class for convert custom type to {@link Num}
@return