code: function envar(key)
  {
    var i, value;
  
    // be extra paranoid
    if (typeof key != 'string' || !key) return undefined;
  
    // lookup according to the order
    for (i=0; i<state.order.length; i++)
    {
      if ((value = lookup[state.order[i]](key)) !== undefined)
      {
        return value;
      }
    }
  
    // nothing found
    return undefined;
  }
docs: Looks up requested variable
  
  @param   {string} key - variable name to look for
  @returns {mixed} - found variable or `undefined` if nothing found