+bool categoricals_is_complete (const struct categoricals *cat);
+
+
+/*
+ Must be called (once) before any call to the *_by_subscript or *_by_category
+ functions, but AFTER any calls to categoricals_update.
+ If this function returns false, then no calls to _by_subscript or *_by_category
+ are allowed.
+*/
+bool categoricals_done (const struct categoricals *cat);