4. The apparatus of claim 1 , wherein the range-dependent match function is order independent.
1. An apparatus configured to match a list of keywords against a target document, the apparatus comprising: data storage configured to store computer-readable instruction code and data; a processor configured to access the data storage and to execute said computer-readable instruction code; a keyword searcher implemented using the instruction code and configured to receive the list of keywords and a textual string corresponding to the target document file, and search the textual string for instances of the keywords so as to generate a sequence of keyword instances; a keyword object generator implemented using the instruction code and configured to receive the sequence of keyword instances, and generate a keyword object, wherein the keyword object includes a range-dependent match function.