Rules that return more than a single value must return an object containing all the values. Besides the properties defined in RuleLabelScope.predefinedRulePropertiesScope there may be user-defined return values. This class simply defines the minimum properties that are always defined and methods to access the others that might be available depending on output option such as template and tree. Note text is not an actual property of the return value, it is computed from start and stop using the input stream's toString() method. I could add a ctor to this so that we can pass in and store the input stream, but I'm not sure we want to do that. It would seem to be undefined to get the .text property anyway if the rule matches tokens from multiple input streams. I do not use getters for fields of objects that are used simply to group values such as this aggregate. The getters/setters are there to satisfy the superclass interface.