Add support for exclusive parameter groups (e.g. exactly_one_of) about grape HOT 2 OPEN

In your example when you use, it just acts like an include, so use :date_rage just imports start_date and end_date, there's no such parameter as date_range. Then you say one of date or date_range, then pass neither, and you get this error.

The feature you want is to say "either date, or a range (start and end)", however I don't think it can be expressed today with groups as you did, so this would be a (great) feature request.

Does this cover all the scenarios? Maybe write out a spec for this so if we can improve the DSL we know it still works?

params do
   optional :date
   optional :start_date
   optional :end_date
   mutually_exclusive :date, :start_date
   mutually_exclusive :date, :end_date
   at_least_one_of :date, :start_date
   at_least_one_of :date, :end_date
   all_or_none_of :start_date, :end_date
end

from grape.

That covers my scenario, though I chose a different approach (irrelevant to this question). Thank you for your input and hope this feature gets implemented!

from grape.