title: Concatenating an array of arrays in Coffeescript
body: <p>I'm trying to find an elegant way in Coffeescript to merge an array of arrays, so that [[1,2,3],[4,5,6],[7,8,9]] ==> [1,2,3,4,5,6,7,8,9].</p>
  
  <p>As you might imagine, I need this because I'm generating arrays from a function in a "for in" construct and need to concatenate the resulting nested array:</p>
  
  <blockquote>
    <p>result = (generate_array(x) for x in arr) </p>
  </blockquote>
  
  <p>Is there an elegant way to handle this? Thanks for any pointers!</p>