DeptDirectory
abstract
class DeptDirectory {}
class
Empty extends DeptDirectory {}
class
Cons extends DeptDirectory {
Entry first;
DeptDirectory rest;
Cons(Entry f, DeptDirectory r) {
this.first = f;
this.rest = r;
}
Entry getFirst() { return this.first;
}
DeptDirectory getRest() { return
this.rest; }
}