code: function makeSelector(sql, markup) {
  	return {
  		sql: (sql instanceof Translatable ? sql.translate.bind(sql) : sql),
  		markup: markup
  	};
  }
docs: Create and return an object for the select list element.
  
  @private
  @param {(string|module:x2node-dbos~Translatable|function)} sql The
  value, which can be a SQL expression, a value expression object or a SQL
  translation function.
  @param {string} markup Markup for the result set parser.
  @returns {Object} The select list element descriptor.