def time
  start = Time.now
  yield
  Time.now - start
end

t1 = 0
t2 = 0

10.times do
  a = ""
  t1 += time do
    100000.times do |i|
      a << i.to_s
    end
  end

  a = ""
  t2 += time do
    100000.times do |i|
      a << eval("#{i}").to_s
    end
  end

end


p "El proceso demoro #{t2/t1} veces mas usando eval."
# en mi maquina devuelve "El proceso demoro 21.491598468697706 veces mas usando eval."