muh filters

which_bar.rb

WhichBar = 
    Filter::Lift
  | Filter::Singular.new(
      attribute: :open,
      value: true
    )
  | Filter::Collection.new(
      attribute: :people,
      aggregator: {
        klass: :compare,
        options: {
          attribute: :age,
          value: 21,
          comparator: :>=,
          reductor: :all?
        }
      }
    )

Person = Struct.new(:age)
nope = (18..22).map(&Person.method(:new))
bad_news = (19..24).map(&Person.method(:new))
okay = (25..35).map(&Person.method(:new))
fine = (30..45).map(&Person.method(:new))

Bar = Struct.new(:people, :open)
trappeze = Bar.new(okay, true)
nineties = Bar.new(nope, true)
eighties = Bar.new(nope, false)
some_pig = Bar.new(fine, false)

bars = [trappeze, nineties, eighties, some_pig]

WhichBar.new(bars).records.first
=> trappeze