Return the value that matches the most restrictive set or just return the default value

super_set.rb

require 'set'

class SuperSet

  def initialize(default)
    @default = default
    @hash = Hash.new
  end

  def ask(terms)
    return @default if terms.nil? || terms.empty?
    
    t = @hash.find_all{|a,b| a.superset?(Set.new(terms)) }
    t.sort!{|a,b| a.first.superset?(b.first) ? 1 : -1 } if t
    (t && !t.empty?) ? t.first.last : @default
  end

  def add(value,terms)
    @hash[Set.new(terms)] = value
  end


end


s = SuperSet.new :clone

s.add(:luke,[:jedi])
s.add(:vader,[:jedi,:father])

puts "luke ?=  #{s.ask([:jedi])}"
puts "vader ?= #{s.ask([:jedi,:father])}"
puts "clone ?= #{s.ask([:wookie])}"
puts "clone ?= #{s.ask([])}"
puts "clone ?= #{s.ask(nil)}"