+ bool has_symmetry() const {return type != none || !children.empty(); }
+ /** Check whether this node involves anything non symmetric. */
+ bool has_nonsymmetric() const;
+ /** Check whether this node involves a cyclic symmetry. */
+ bool has_cyclic() const;
+
+ /** Save (a.k.a. serialize) object into archive. */
+ void archive(archive_node& n) const;
+ /** Read (a.k.a. deserialize) object from archive. */
+ void read_archive(const archive_node& n, lst& syms);
+protected:
+ void do_print(const print_context & c, unsigned level) const;
+ void do_print_tree(const print_tree & c, unsigned level) const;
+ unsigned calchash() const;