* elmo-pipe.el (elmo-folder-get-primitive-list): Likewise.
* elmo-filter.el (elmo-folder-get-primitive-list): Fixed.
+2003-11-23  Hiroya Murata  <lapis-lazuli@pop06.odn.ne.jp>
+
+       * elmo-multi.el (elmo-folder-newsgroups): Simplify.
+
+       * elmo-pipe.el (elmo-folder-get-primitive-list): Likewise.
+
+       * elmo-filter.el (elmo-folder-get-primitive-list): Fixed.
+
 2003-11-22  Hiroya Murata  <lapis-lazuli@pop06.odn.ne.jp>
 
        * elmo-version.el (elmo-version): Up to 2.11.22.
 
 
 (luna-define-method elmo-folder-get-primitive-list ((folder
                                                     elmo-filter-folder))
-  (list (elmo-filter-folder-target-internal folder)))
+  (elmo-folder-get-primitive-list (elmo-filter-folder-target-internal folder)))
 
 (luna-define-method elmo-folder-contains-type ((folder elmo-filter-folder)
                                               type)
 
                                      elmo-msgdb-directory)))
 
 (luna-define-method elmo-folder-newsgroups ((folder elmo-multi-folder))
-  (delq nil
-       (elmo-flatten
-        (mapcar
-         'elmo-folder-newsgroups
-         (elmo-flatten
-          (mapcar
-           'elmo-folder-get-primitive-list
-           (elmo-multi-folder-children-internal folder)))))))
+  (apply  #'nconc
+         (mapcar
+          'elmo-folder-newsgroups
+          (elmo-multi-folder-children-internal folder))))
 
 (luna-define-method elmo-folder-get-primitive-list ((folder elmo-multi-folder))
   (elmo-flatten
 
   folder)
 
 (luna-define-method elmo-folder-get-primitive-list ((folder elmo-pipe-folder))
-  (elmo-flatten
-   (mapcar
-    'elmo-folder-get-primitive-list
-    (list (elmo-pipe-folder-src-internal folder)
-         (elmo-pipe-folder-dst-internal folder)))))
+  (nconc
+   (elmo-folder-get-primitive-list (elmo-pipe-folder-src-internal folder))
+   (elmo-folder-get-primitive-list (elmo-pipe-folder-dst-internal folder))))
 
 (luna-define-method elmo-folder-contains-type ((folder elmo-pipe-folder)
                                               type)