case with predicates

gistfile1.rb

threeven = -> n { n % 3 == 0 }
fourven = -> n { n % 4 == 0 }
fiven = -> n { n % 5 == 0 }

rs = (0..10000).to_a.sample(30)

rs.each do |r|

  case r

  when -> n { n.zero? }
    puts "#{r} is zero"

  when fiven
    puts "#{r} is fiven"

  when fourven
    puts "#{r} is fourven"

  when threeven
    puts "#{r} is threeven"

  when -> n { n.even? }
    puts "#{r} is even"

  when -> n { n.odd? }
    puts "#{r} is odd"

  else raise "unpossible"
  end

end