filter_mapping - return a selective sub-mapping

mapping filter_mapping(mapping map, string fun, object ob, mixed extra, ...);

mapping filter_array(mapping map, function f, mixed extra, ...);

filter_mapping() is really the same as the filter() efun.

See also:
 filter

 Tim Hollebeek  Beek@ZorkMUD, Lima Bean, IdeaExchange, and elsewhere
