素数を出力するプログラム

prime.rb

class Prime 
  def self.calc
    primes = [2]
    puts 2
    i = 3
    loop do
      max = Math.sqrt(i).floor
      primes.each do |p|
        if p > max  then
          yield i
          primes  << i
          break
        end
        if i % p == 0 then
          break
        end
      end
      i += 1
    end
  end
end

if $0 == __FILE__
  Prime.calc { |p|
    puts p
  }
end