// f is a function or an instance of Cache (the dependee)
sclass DependentCache<A> extends Cache<A> {
  O depF, lastDep;
  
  *() {}
  *(O *maker, O *depF) {}
  
  A get() {
    if (hasLock(lock)) ret value; // Must be called from within maker
    {
      lock lock;
      O dep;
      if (depF instanceof Cache) dep = depF/Cache.changeCount;
      else {
        dep = callF(depF);
        if (dep instanceof Cache) dep = dep/Cache.changeCount;
      }
      if (neq(dep, lastDep)) {
        clear();
        lastDep = dep;
      }
    }
    ret super.get();
  }
}