Provides a tool, that can parse the key word form the text. Each key word take effecting by a IPattern interface, lexicon will try to find it by the order. The find is described by Lexicon.Match. You also can set the two kinds of relation ship: Repellency and Dependency. Repellency, make a pattern not take effecting, when a pattern has been matched. Dependency, make a pattern not take effecting, until a pattern has been matched.