#define _INTERACTION_H__ 1
#include <stdbool.h>
+#include "libpspp/compiler.h"
#include "data/missing-values.h"
+struct ccase;
struct interaction;
-struct variable;
struct string;
+struct variable;
#include <stddef.h>
+
+/* An interaction is a structure containing a "product" of other variables.
+ The variables can be either string or numeric.
+
+ Interaction is commutative. That means, that from a mathematical point of
+ view, the order of the variables is irrelevant. However, for display
+ purposes, and for matching with an interaction's value the order is
+ pertinent. Therefore, when using these functions, make sure the orders of
+ variables and values match when appropriate.
+
+ Some functions for interactions will not work properly for interactions that
+ contain a given variable more than once, so this should be regarded as an
+ invariant. The functions to modify interactions don't check for this
+ invariant. */
struct interaction
-{
- size_t n_vars;
- const struct variable **vars;
-};
+ {
+ const struct variable **vars;
+ size_t n_vars;
+ };
-struct interaction * interaction_create (const struct variable *);
+struct interaction *interaction_create (const struct variable *);
+struct interaction *interaction_clone (const struct interaction *);
void interaction_destroy (struct interaction *);
void interaction_add_variable (struct interaction *, const struct variable *);
void interaction_dump (const struct interaction *);
-void interaction_to_string (const struct interaction *iact, struct string *str);
+void interaction_to_string (const struct interaction *, struct string *str);
+bool interaction_is_proper_subset (const struct interaction *,
+ const struct interaction *);
+bool interaction_is_subset (const struct interaction *,
+ const struct interaction *);
-struct ccase;
-unsigned int interaction_case_hash (const struct interaction *, const struct ccase *);
-bool interaction_case_equal (const struct interaction *, const struct ccase *, const struct ccase *);
-bool interaction_case_is_missing (const struct interaction *, const struct ccase *, enum mv_class);
+unsigned int interaction_case_hash (const struct interaction *,
+ const struct ccase *,
+ unsigned int base) WARN_UNUSED_RESULT;
+bool interaction_case_equal (const struct interaction *, const struct ccase *,
+ const struct ccase *);
+bool interaction_case_is_missing (const struct interaction *,
+ const struct ccase *, enum mv_class);
+int interaction_case_cmp_3way (const struct interaction *,
+ const struct ccase *, const struct ccase *);
#endif