This package contains classes for implementing rules. Most rules are
taclet rules, represented by {@link
de.uka.ilkd.key.rule.Taclet}. The package includes the
representation of applications of taclets ({@link
de.uka.ilkd.key.rule.TacletApp}) and the builders of taclets ({@link
de.uka.ilkd.key.rule.TacletBuilder}). Besides taclets, there are
built-in rules implemented directly in Java.