We made a slight update of the documentation.
These rules have already been available in 0.4 , but they were not described in the documentation.
1) If you have textfields where you expect the user to enter a float number (e.g. 0.49) you would expect 0,49 in a german form.
So for validating values with decimal mark, you can give all numeric rules a second parameter, which specifies the expected decimal mark.
$rule_BedSize = new NetefxValidatorRule("BedSize", "SMALLEREQUAL", array('2.15',','), "We have no beds longer than 2,15 meters.");
2) for a CheckboxSetField you can validate min_number_checkboxes_checked and max_number_checkboxes_checked.
Check the section "FUNCTION rule: using library functions or writing own functions" in the documentation for an example usage.