title: nested associative arrays in bash
body: <p>Can one construct an associative array whose elements contain arrays in bash? For instance, suppose one has the following arrays:</p>
  
  <pre><code>a=(a aa)
  b=(b bb bbb)
  c=(c cc ccc cccc)
  </code></pre>
  
  <p>Can one create an associate array to access these variables? For instance,</p>
  
  <pre><code>declare -A letters
  letters[a]=$a
  letters[b]=$b
  letters[c]=$c
  </code></pre>
  
  <p>and then access individual elements by a command such as</p>
  
  <pre><code>letter=${letters[a]}
  echo ${letter[1]}
  </code></pre>
  
  <p>This mock syntax for creating and accessing elements of the associate array does not work. Do valid expressions accomplishing the same goals exist?</p>