26   public symbol_set(symbol_set other) throws internal_error  in symbol_set()  argument
28       not_null(other);  in symbol_set()
29       _all = (Hashtable)other._all.clone();  in symbol_set()
72   public boolean is_subset_of(symbol_set other) throws internal_error  in is_subset_of()  argument
74       not_null(other);  in is_subset_of()
78     if (!other.contains((symbol)e.nextElement()))  in is_subset_of()
90   public boolean is_superset_of(symbol_set other) throws internal_error  in is_superset_of()  argument
92       not_null(other);  in is_superset_of()
93       return other.is_subset_of(this);  in is_superset_of()
132   public boolean add(symbol_set other) throws internal_error  in add()  argument
136       not_null(other);  in add()
139       for (Enumeration e = other.all(); e.hasMoreElements(); )  in add()
150   public void remove(symbol_set other) throws internal_error  in remove()  argument
152       not_null(other);  in remove()
155       for (Enumeration e = other.all(); e.hasMoreElements(); )  in remove()
162   public boolean equals(symbol_set other)   in equals()  argument
164       if (other == null || other.size() != size()) return false;  in equals()
168         return is_subset_of(other);  in equals()
179   public boolean equals(Object other)  in equals()  argument
181       if (!(other instanceof symbol_set))  in equals()
184     return equals((symbol_set)other);  in equals()