+ gboolean retval = TRUE;
+
+ struct casereader *reader;
+ size_t value_cnt;
+ casenumber case_cnt;
+ unsigned long int lazy_serial;
+
+ /* When the user executes a number of snippets of syntax in a
+ row, none of which read from the active file, the GUI becomes
+ progressively less responsive. The reason is that each syntax
+ execution encapsulates the active file data in another
+ datasheet layer. The cumulative effect of having a number of
+ layers of datasheets wastes time and space.
+
+ To solve the problem, we use a "lazy casereader", a wrapper
+ around the casereader obtained from the data store, that
+ only actually instantiates that casereader when it is
+ needed. If the data store casereader is never needed, then
+ it is reused the next time syntax is run, without wrapping
+ it in another layer. */
+ value_cnt = psppire_data_store_get_value_count (the_data_store);
+ case_cnt = psppire_data_store_get_case_count (the_data_store);
+ reader = lazy_casereader_create (value_cnt, case_cnt,
+ create_casereader_from_data_store,
+ the_data_store, &lazy_serial);