code: function coordSystem() {
    var args = mlutil.asArray.apply(null, arguments);
    switch(args.length) {
    case 0:
      throw new Error('missing identifier for coordinate system');
    case 1:
      return new CoordSystemDef(args[0]);
    default:
      throw new Error('too many arguments for coordinate system identifier: '+args.length);
    }
  }
docs: Identifies the coordinate system used by a geospatial path index.
  @method
  @since 1.0
  @memberof queryBuilder#
  @param {string} coord - the name of the coordinate system
  @returns {queryBuilder.CoordSystem} a coordinate system identifier