+size_t categoricals_n_total (const struct categoricals *cat);
+
+/* Return the total degrees of freedom */
+size_t categoricals_df_total (const struct categoricals *cat);
+
+
+/*
+ Return the total number of variables which participated in these categoricals.
+ Due to the possibility of missing values, this is NOT necessarily
+ equal to the number of variables passed in when the object was
+ created.
+*/
+size_t categoricals_get_n_variables (const struct categoricals *cat);
+
+
+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);
+
+
+/*
+ The *_by_subscript functions use the short map.
+ Their intended use is by covariance matrix routines, where normally 1 less than
+ the total number of distinct values of each categorical variable should
+ be considered.
+ */
+double categoricals_get_weight_by_subscript (const struct categoricals *cat, int subscript);
+const struct interaction *categoricals_get_interaction_by_subscript (const struct categoricals *cat, int subscript);
+
+double categoricals_get_sum_by_subscript (const struct categoricals *cat, int subscript);
+
+double categoricals_get_code_for_case (const struct categoricals *cat, int subscript, const struct ccase *c);
+
+
+/* These use the long map. Useful for descriptive statistics. */
+
+/* Return the value corresponding to the N'th category */
+const union value * categoricals_get_value_by_category (const struct categoricals *cat, int n);
+
+const struct ccase *
+categoricals_get_case_by_category_real (const struct categoricals *cat, int iact, int n);
+
+void *
+categoricals_get_user_data_by_category_real (const struct categoricals *cat, int iact, int n);
+
+
+void * categoricals_get_user_data_by_category (const struct categoricals *cat, int category);
+
+const struct ccase * categoricals_get_case_by_category (const struct categoricals *cat, int subscript);
+
+
+struct payload
+{
+ void* (*create) (const void *aux1, void *aux2);
+ void (*update) (const void *aux1, void *aux2, void *user_data, const struct ccase *, double weight);
+ void (*destroy) (const void *aux1, void *aux2, void *user_data);
+};
+
+
+void categoricals_set_payload (struct categoricals *cats, const struct payload *p, const void *aux1, void *aux2);