text: 'use strict';
  
  module.exports = extractList;
  
  // copied from https://github.com/pegjs/pegjs/blob/2005345/examples/css.pegjs#L27-L37
  function extractList (list, index) {
    var result = [], i;
  
    for (i = 0; i < list.length; i++) {
      if (list[i][index] !== null) {
        result.push(list[i][index]);
      }
    }
  
    return result;
  }
  