The speed difference looks too extreme too me:


  caps = []
  File.open('caps_u8.dic').each {|line| caps << line.split(';')[0]}

=> 1.8 seconds



  require 'rio'
  caps = rio('caps_u8.dic').csv(";").columns(0)[].flatten
  p caps

=> 50.9 seconds

  
What exactly is so slow here? It's not the /flatten/. 
Am I using Rio in a particularly dumb way?
-- 
Bug:  An elusive creature living in a program that makes it incorrect.
      The activity of "debugging," or removing bugs from a program, ends
      when people get tired of doing it, not when the bugs are removed.