# File lib/ferret/index.rb, line 412
412:     def doc(*arg)
413:       @dir.synchronize do
414:         id = arg[0]
415:         if id.kind_of?(String) or id.kind_of?(Symbol)
416:           ensure_reader_open()
417:           term_doc_enum = @reader.term_docs_for(@id_field, id.to_s)
418:           return term_doc_enum.next? ? @reader[term_doc_enum.doc] : nil
419:         else
420:           ensure_reader_open(false)
421:           return @reader[*arg]
422:         end
423:       end
424:     end