struct dictionary;
struct casereader;
struct casewriter;
+struct subcase;
struct ccase *casereader_read (struct casereader *);
bool casereader_destroy (struct casereader *);
bool (*destroy) (void *aux),
void *aux);
+struct casereader *casereader_project (struct casereader *,
+ const struct subcase *);
+struct casereader *casereader_project_1 (struct casereader *, int column);
/* A function which creates a numberic value from an existing case */
typedef double new_value_func (const struct ccase *, casenumber, void *);