+ * Revision 1.49 1996-06-04 10:18:11 adam
+ * Search/scan uses character mapping module.
+ *
+ * Revision 1.48 1996/05/28 15:15:01 adam
+ * Bug fix: Didn't handle unknown database correctly.
+ *
+ * Revision 1.47 1996/05/15 18:36:28 adam
+ * Function trans_term transforms unsearchable characters to blanks.
+ *
+ * Revision 1.46 1996/05/15 11:57:56 adam
+ * Fixed bug introduced by set/field mapping in search operations.
+ *
+ * Revision 1.45 1996/05/14 11:34:00 adam
+ * Scan support in multiple registers/databases.
+ *
+ * Revision 1.44 1996/05/14 06:16:44 adam
+ * Compact use/set bytes used in search service.
+ *
+ * Revision 1.43 1996/05/09 09:54:43 adam
+ * Server supports maps from one logical attributes to a list of physical
+ * attributes.
+ * The extraction process doesn't make space consuming 'any' keys.
+ *
+ * Revision 1.42 1996/05/09 07:28:56 quinn
+ * Work towards phrases and multiple registers
+ *
+ * Revision 1.41 1996/03/20 09:36:43 adam
+ * Function dict_lookup_grep got extra parameter, init_pos, which marks
+ * from which position in pattern approximate pattern matching should occur.
+ * Approximate pattern matching is used in relevance=re-2.
+ *
+ * Revision 1.40 1996/02/02 13:44:44 adam
+ * The public dictionary functions simply use char instead of Dict_char
+ * to represent search strings. Dict_char is used internally only.
+ *
+ * Revision 1.39 1996/01/03 16:22:13 quinn
+ * operator->roperator
+ *
+ * Revision 1.38 1995/12/11 09:12:55 adam
+ * The rec_get function returns NULL if record doesn't exist - will
+ * happen in the server if the result set records have been deleted since
+ * the creation of the set (i.e. the search).
+ * The server saves a result temporarily if it is 'volatile', i.e. the
+ * set is register dependent.
+ *
+ * Revision 1.37 1995/12/06 15:05:28 adam
+ * More verbose in count_set.
+ *
+ * Revision 1.36 1995/12/06 12:41:27 adam
+ * New command 'stat' for the index program.
+ * Filenames can be read from stdin by specifying '-'.
+ * Bug fix/enhancement of the transformation from terms to regular
+ * expressons in the search engine.
+ *
+ * Revision 1.35 1995/11/27 09:29:00 adam
+ * Bug fixes regarding conversion to regular expressions.
+ *
+ * Revision 1.34 1995/11/16 17:00:56 adam
+ * Better logging of rpn query.
+ *
+ * Revision 1.33 1995/11/01 13:58:28 quinn
+ * Moving data1 to yaz/retrieval
+ *
+ * Revision 1.32 1995/10/27 14:00:11 adam
+ * Implemented detection of database availability.
+ *
+ * Revision 1.31 1995/10/17 18:02:10 adam
+ * New feature: databases. Implemented as prefix to words in dictionary.
+ *
+ * Revision 1.30 1995/10/16 09:32:38 adam
+ * More work on relational op.
+ *
+ * Revision 1.29 1995/10/13 16:01:49 adam
+ * Work on relations.
+ *
+ * Revision 1.28 1995/10/13 12:26:43 adam
+ * Optimization of truncation.
+ *
+ * Revision 1.27 1995/10/12 17:07:22 adam
+ * Truncation works.
+ *
+ * Revision 1.26 1995/10/12 12:40:54 adam