code: function Attribute(name, actionDict, builtInDefault) {
    this.name = name;
    this.formals = [];
    this.actionDict = actionDict;
    this.builtInDefault = builtInDefault;
  }
docs: Attributes are Operations whose results are memoized. This means that, for any given semantics, the semantic action for a CST node will be invoked no more than once.