1. A method for scalable, rule-based processing, the method comprising: constructing a plurality of automatons corresponding to a plurality of trigger rules and a plurality of word lists that are employed by the trigger rules; evaluating any of the plurality of trigger rules with respect to an input document by : selecting any of the automatons to evaluate a given one of the plurality of trigger rules, parsing the input document using the selected automatons, determining whether conditions of the given trigger rule are met, and identifying any actions that are associated with the given trigger rule, and displaying in a rule tracing any of the plurality of trigger rules that are evaluated, together with indicia for different portions of the displayed trigger rules indicating an evaluation result of each of the different portions.