old_contents: 'use strict';
  
  var stoke = require('../');
  
  stoke('echo "foo `echo \'bar baz\'`"');
  /* [
   *   {
   *     type: 'unquoted',
   *     body: 'echo'
   *   },
   *   {
   *     type: 'double-quoted',
   *     body: [
   *       {
   *         type: 'unquoted',
   *         body: 'foo '
   *       },
   *       {
   *         type: 'back-quoted',
   *         body: [
   *           {
   *             type: 'unquoted',
   *             body: 'echo'
   *           },
   *           {
   *             type: 'single-quoted',
   *             body: 'bar baz'
   *           }
   *         ]
   *       }
   *     ]
   *   }
   * ]
   */
  
new_contents: 'use strict';
  
  var permute = require('../');
  
  var iter = permute(['foo', 'bar', 'baz']);
  while (iter.hasNext()) {
    iter.next();
    //=> [ 'foo', 'bar', 'baz' ]
    //=> [ 'foo', 'baz', 'bar' ]
    //=> [ 'baz', 'foo', 'bar' ]
    //=> [ 'baz', 'bar', 'foo' ]
    //=> [ 'bar', 'baz', 'foo' ]
    //=> [ 'bar', 'foo', 'baz' ]
  }
  
subject: Add example