Method swap

src/jvm/clojure/lang/Atom.java:33–45

(IFn f)

}

public Object swap(IFn f) {
	for(; ;)
		{
		Object v = deref();
		Object newv = f.invoke(v);
		validate(newv);
		if(state.compareAndSet(v, newv))
			{
			notifyWatches(v, newv);
			return newv;
			}
		}
}

public Object swap(IFn f, Object arg) {
	for(; ;)