+rule_t* rule_new ()
+{
+ rule_t* rule;
+ rule = g_malloc (sizeof (rule_t));
+ rule->right = NULL;
+ return rule;
+}
+
+void rule_append (rule_t* rule, symbol_t* right)
+{
+ rule->right = g_list_append (rule->right, right);
+}
+
+rule_t* rule_copy (rule_t* rule)
+{
+ rule_t* new_rule;
+ GList* r;
+ new_rule = rule_new ();
+ r = rule->right;
+ while (r != NULL)
+ {
+ rule_append (new_rule, symbol_copy (r->data));
+ r = g_list_next (r);
+ }
+ return new_rule;
+}
+
+symbol_t* rule_pop (rule_t* rule)
+{
+ GList* r;
+ if ((r = g_list_first (rule->right)) == NULL)
+ return NULL;
+ rule->right = g_list_remove_link (r, r);
+ g_free (r->data);
+ g_list_free (r);
+ if (rule->right == NULL)
+ return NULL;
+ return rule->right->data;
+}
+
+void rule_delete (rule_t* rule)
+{
+ GList* l;
+ for (l = g_list_first (rule->right); l != NULL; l = g_list_next (l))
+ {
+ g_free (l->data);
+ }
+ g_list_free (rule->right);
+ g_free (rule);
+}
+
+void rules_delete (GList** list)
+{
+ GList* l;
+ for (l = g_list_first (*list); l != NULL; l = g_list_next (l))
+ {
+ rule_delete (l->data);
+ }
+ g_list_free (*list);
+ g_free (list);
+}
+