emacs: Generalize buffer interface.

Extract the code for defining buffer interface from "guix-base.el",
generalize it and move to "guix-buffer.el".

* emacs.am (ELFILES): Add "emacs/guix-buffer.el".
* emacs/guix-base.el (guix-profile, guix-entries, guix-buffer-type)
  (guix-entry-type, guix-search-type, guix-search-vals, guix-set-vars)
  (guix-get-symbol, guix-show-entries, guix-get-show-entries)
  (guix-set-buffer, guix-history-call, guix-make-history-item)
  (guix-get-params-for-receiving): Remove.
  (guix-switch-to-buffer): Rename to 'guix-buffer-display' and move to
  "guix-buffer.el".
  (guix-get-entries): Rename to 'guix-ui-get-entries' and move to
  "guix-ui.el".
  (guix-buffer-data, guix-buffer-value, guix-buffer-param-title)
  (guix-buffer-name, guix-buffer-history-size)
  (guix-buffer-revert-confirm?, guix-buffer-map, guix-buffer-revert)
  (guix-buffer-after-redisplay-hook, guix-buffer-redisplay)
  (guix-buffer-redisplay-goto-button): Move to...
* emacs/guix-buffer.el: ... here.  New file.
  (guix-buffer-item): New variable.
  (guix-buffer-with-item, guix-buffer-with-current-item)
  (guix-buffer-define-current-item-accessor)
  (guix-buffer-define-current-item-accessors)
  (guix-buffer-define-current-args-accessor)
  (guix-buffer-define-current-args-accessors): New macros.
  (guix-buffer-get-entries, guix-buffer-mode-enable)
  (guix-buffer-mode-initialize, guix-buffer-insert-entries)
  (guix-buffer-show-entries-default, guix-buffer-show-entries)
  (guix-buffer-message, guix-buffer-history-item, guix-buffer-set)
  (guix-buffer-display-entries-current)
  (guix-buffer-get-display-entries-current)
  (guix-buffer-display-entries, guix-buffer-get-display-entries): New
  procedures.
* emacs/guix-info.el: Adjust for the procedures renaming.
  (guix-info-define-interface): Add ':show-entries-function' keyword.
* emacs/guix-list.el: Likewise.
* emacs/guix-ui.el (guix-ui-define-interface): Generate
  'guix-ENTRY-TYPE-BUFFER-TYPE-get-entries' procedure based on
  'guix-ui-get-entries'.
* emacs/guix.el (guix-get-show-packages, guix-get-show-generations):
  Adjust for the procedures renaming.

6 files changed, 779 insertions, 469 deletions

diff --git a/emacs/guix-base.el b/emacs/guix-base.el
index 21be02d26d..4bd88992c4 100644
--- a/emacs/guix-base.el
+++ b/emacs/guix-base.el
@@ -22,9 +22,6 @@
 ;; This file provides some base and common definitions for guix.el
 ;; package.
 
-;; List and info buffers have many common patterns that are defined
-;; using `guix-buffer-define-interface' macro from this file.
-
 ;;; Code:
 
 (require 'cl-lib)
@@ -34,8 +31,6 @@
 (require 'guix-guile)
 (require 'guix-utils)
 (require 'guix-ui)
-(require 'guix-history)
-(require 'guix-messages)
 
 
 ;;; Parameters of the entries
@@ -143,227 +138,6 @@ For the meaning of location, see `guix-find-location'."
    #'string<))
 
 
-;;; Buffers
-
-(defun guix-switch-to-buffer (buffer)
-  "Switch to a 'list' or 'info' BUFFER."
-  (pop-to-buffer buffer
-                 '((display-buffer-reuse-window
-                    display-buffer-same-window))))
-
-
-;;; Common definitions for buffer types
-
-(defvar guix-buffer-data nil
-  "Alist with 'buffer' data.
-This alist is filled by `guix-buffer-define-interface' macro.")
-
-(defun guix-buffer-value (buffer-type entry-type symbol)
-  "Return SYMBOL's value for BUFFER-TYPE/ENTRY-TYPE from `guix-buffer-data'."
-  (symbol-value
-   (guix-assq-value guix-buffer-data buffer-type entry-type symbol)))
-
-(defun guix-buffer-param-title (buffer-type entry-type param)
-  "Return PARAM title for BUFFER-TYPE/ENTRY-TYPE."
-  (or (guix-assq-value (guix-buffer-value buffer-type entry-type 'titles)
-                       param)
-      ;; Fallback to a title defined in 'info' interface.
-      (unless (eq buffer-type 'info)
-        (guix-assq-value (guix-buffer-value 'info entry-type 'titles)
-                         param))
-      (guix-symbol-title param)))
-
-(defun guix-buffer-name (buffer-type entry-type profile)
-  "Return name of BUFFER-TYPE buffer for displaying ENTRY-TYPE entries."
-  (let ((str-or-fun (guix-buffer-value buffer-type entry-type
-                                       'buffer-name)))
-    (if (stringp str-or-fun)
-        str-or-fun
-      (funcall str-or-fun profile))))
-
-(defun guix-buffer-history-size (buffer-type entry-type)
-  "Return history size for BUFFER-TYPE/ENTRY-TYPE."
-  (guix-buffer-value buffer-type entry-type 'history-size))
-
-(defun guix-buffer-revert-confirm? (buffer-type entry-type)
-  "Return 'revert-confirm' value for BUFFER-TYPE/ENTRY-TYPE."
-  (guix-buffer-value buffer-type entry-type 'revert-confirm))
-
-(defvar guix-buffer-map
-  (let ((map (make-sparse-keymap)))
-    (define-key map (kbd "l") 'guix-history-back)
-    (define-key map (kbd "r") 'guix-history-forward)
-    (define-key map (kbd "g") 'revert-buffer)
-    (define-key map (kbd "R") 'guix-buffer-redisplay)
-    map)
-  "Parent keymap for Guix buffer modes.")
-
-(defvar-local guix-profile nil
-  "Profile used for the current buffer.")
-(put 'guix-profile 'permanent-local t)
-
-(defvar-local guix-entries nil
-  "List of the currently displayed entries.
-Each element of the list is alist with entry info of the
-following form:
-
-  ((PARAM . VAL) ...)
-
-PARAM is a name of the entry parameter.
-VAL is a value of this parameter.")
-(put 'guix-entries 'permanent-local t)
-
-(defvar-local guix-buffer-type nil
-  "Type of the current buffer.")
-(put 'guix-buffer-type 'permanent-local t)
-
-(defvar-local guix-entry-type nil
-  "Type of the current entry.")
-(put 'guix-entry-type 'permanent-local t)
-
-(defvar-local guix-search-type nil
-  "Type of the current search.")
-(put 'guix-search-type 'permanent-local t)
-
-(defvar-local guix-search-vals nil
-  "Values of the current search.")
-(put 'guix-search-vals 'permanent-local t)
-
-(defsubst guix-set-vars (profile entries buffer-type entry-type
-                         search-type search-vals)
-  "Set local variables for the current Guix buffer."
-  (setq default-directory profile
-        guix-profile      profile
-        guix-entries      entries
-        guix-buffer-type  buffer-type
-        guix-entry-type   entry-type
-        guix-search-type  search-type
-        guix-search-vals  search-vals))
-
-(defun guix-get-symbol (postfix buffer-type &optional entry-type)
-  (intern (concat "guix-"
-                  (when entry-type
-                    (concat (symbol-name entry-type) "-"))
-                  (symbol-name buffer-type) "-" postfix)))
-
-(defmacro guix-buffer-define-interface (buffer-type entry-type &rest args)
-  "Define BUFFER-TYPE interface for displaying ENTRY-TYPE entries.
-Remaining arguments (ARGS) should have a form [KEYWORD VALUE] ...
-In the following description TYPE means ENTRY-TYPE-BUFFER-TYPE.
-
-The following stuff should be defined outside this macro:
-
-  - `guix-BUFFER-TYPE-mode' - parent mode of the generated mode.
-
-  - `guix-TYPE-mode-initialize' (optional) - function for
-  additional mode settings; it is called without arguments.
-
-Required keywords:
-
-  - `:buffer-name' - default value of the generated
-    `guix-TYPE-buffer-name' variable.
-
-Optional keywords:
-
-  - `:titles' - default value of the generated
-    `guix-TYPE-titles' variable.
-
-  - `:history-size' - default value of the generated
-    `guix-TYPE-history-size' variable.
-
-  - `:revert-confirm?' - default value of the generated
-    `guix-TYPE-revert-confirm' variable.
-
-  - `:reduced?' - if non-nil, generate only group, faces group
-    and titles variable."
-  (declare (indent 2))
-  (let* ((entry-type-str     (symbol-name entry-type))
-         (buffer-type-str    (symbol-name buffer-type))
-         (Entry-type-str     (capitalize entry-type-str))
-         (Buffer-type-str    (capitalize buffer-type-str))
-         (entry-str          (concat entry-type-str " entries"))
-         (prefix             (concat "guix-" entry-type-str "-"
-                                     buffer-type-str))
-         (group              (intern prefix))
-         (faces-group        (intern (concat prefix "-faces")))
-         (mode-map-str       (concat prefix "-mode-map"))
-         (parent-mode        (intern (concat "guix-" buffer-type-str "-mode")))
-         (mode               (intern (concat prefix "-mode")))
-         (mode-init-fun      (intern (concat prefix "-mode-initialize")))
-         (buffer-name-var    (intern (concat prefix "-buffer-name")))
-         (titles-var         (intern (concat prefix "-titles")))
-         (history-size-var   (intern (concat prefix "-history-size")))
-         (revert-confirm-var (intern (concat prefix "-revert-confirm"))))
-    (guix-keyword-args-let args
-        ((buffer-name-val    :buffer-name)
-         (titles-val         :titles)
-         (history-size-val   :history-size 20)
-         (revert-confirm-val :revert-confirm? t)
-         (reduced?           :reduced?))
-      `(progn
-         (defgroup ,group nil
-           ,(format "Display '%s' entries in '%s' buffer."
-                    entry-type-str buffer-type-str)
-           :prefix ,(concat prefix "-")
-           :group ',(intern (concat "guix-" buffer-type-str)))
-
-         (defgroup ,faces-group nil
-           ,(format "Faces for displaying '%s' entries in '%s' buffer."
-                    entry-type-str buffer-type-str)
-           :group ',(intern (concat "guix-" buffer-type-str "-faces")))
-
-         (defcustom ,titles-var ,titles-val
-           ,(format "Alist of titles of '%s' parameters."
-                    entry-type-str)
-           :type '(alist :key-type symbol :value-type string)
-           :group ',group)
-
-         ,(unless reduced?
-            `(progn
-               (defcustom ,buffer-name-var ,buffer-name-val
-                 ,(format "\
-Default name of '%s' buffer for displaying '%s' entries."
-                          buffer-type-str entry-type-str)
-                 :type 'string
-                 :group ',group)
-
-               (defcustom ,history-size-var ,history-size-val
-                 ,(format "\
-Maximum number of items saved in history of `%S' buffer.
-If 0, the history is disabled."
-                          buffer-name-var)
-                 :type 'integer
-                 :group ',group)
-
-               (defcustom ,revert-confirm-var ,revert-confirm-val
-                 ,(format "\
-If non-nil, ask to confirm for reverting `%S' buffer."
-                          buffer-name-var)
-                 :type 'boolean
-                 :group ',group)
-
-               (guix-alist-put!
-                '((buffer-name    . ,buffer-name-var)
-                  (history-size   . ,history-size-var)
-                  (revert-confirm . ,revert-confirm-var))
-                'guix-buffer-data ',buffer-type ',entry-type)
-
-               (define-derived-mode ,mode ,parent-mode
-                 ,(concat "Guix-" Buffer-type-str)
-                 ,(concat "Major mode for displaying information about "
-                          entry-str ".\n\n"
-                          "\\{" mode-map-str "}")
-                 (setq-local revert-buffer-function 'guix-buffer-revert)
-                 (setq-local guix-history-size
-                             (guix-buffer-history-size
-                              ',buffer-type ',entry-type))
-                 (and (fboundp ',mode-init-fun) (,mode-init-fun)))))
-
-         (guix-alist-put!
-          ',titles-var 'guix-buffer-data
-          ',buffer-type ',entry-type 'titles)))))
-
-
 ;;; Getting and displaying info about packages and generations
 
 (defcustom guix-package-list-type 'output
@@ -384,159 +158,6 @@ information)."
                  (const :tag "Display outputs" output))
   :group 'guix)
 
-(defun guix-get-entries (profile entry-type search-type search-vals
-                         &optional params)
-  "Search for entries of ENTRY-TYPE.
-
-Call an appropriate scheme function and return a list of the
-form of `guix-entries'.
-
-ENTRY-TYPE should be one of the following symbols: `package',
-`output' or `generation'.
-
-SEARCH-TYPE may be one of the following symbols:
-
-- If ENTRY-TYPE is `package' or `output': `id', `name', `regexp',
-  `all-available', `newest-available', `installed', `obsolete',
-  `generation'.
-
-- If ENTRY-TYPE is `generation': `id', `last', `all', `time'.
-
-PARAMS is a list of parameters for receiving.  If nil, get
-information with all available parameters."
-  (guix-eval-read (guix-make-guile-expression
-                   'entries
-                   profile params entry-type search-type search-vals)))
-
-(defun guix-get-show-entries (profile buffer-type entry-type search-type
-                              &rest search-vals)
-  "Search for ENTRY-TYPE entries and show results in BUFFER-TYPE buffer.
-See `guix-get-entries' for the meaning of SEARCH-TYPE and SEARCH-VALS."
-  (let ((entries (guix-get-entries profile entry-type search-type search-vals
-                                   (guix-get-params-for-receiving
-                                    buffer-type entry-type))))
-    (guix-set-buffer profile entries buffer-type entry-type
-                     search-type search-vals)))
-
-(defun guix-set-buffer (profile entries buffer-type entry-type search-type
-                        search-vals &optional history-replace no-display)
-  "Set up BUFFER-TYPE buffer for displaying ENTRY-TYPE ENTRIES.
-
-Insert ENTRIES in buffer, set variables and make history item.
-ENTRIES should have a form of `guix-entries'.
-
-See `guix-get-entries' for the meaning of SEARCH-TYPE and SEARCH-VALS.
-
-If HISTORY-REPLACE is non-nil, replace current history item,
-otherwise add the new one.
-
-If NO-DISPLAY is non-nil, do not switch to the buffer."
-  (when entries
-    (let ((buf (if (and (eq major-mode
-                            (guix-get-symbol "mode" buffer-type entry-type))
-                        (equal guix-profile profile))
-                   (current-buffer)
-                 (get-buffer-create
-                  (guix-buffer-name buffer-type entry-type profile)))))
-      (with-current-buffer buf
-        (guix-show-entries entries buffer-type entry-type)
-        (guix-set-vars profile entries buffer-type entry-type
-                       search-type search-vals)
-        (funcall (if history-replace
-                     #'guix-history-replace
-                   #'guix-history-add)
-                 (guix-make-history-item)))
-      (or no-display
-          (guix-switch-to-buffer buf))))
-  (guix-result-message profile entries entry-type
-                       search-type search-vals))
-
-(defun guix-show-entries (entries buffer-type entry-type)
-  "Display ENTRY-TYPE ENTRIES in the current BUFFER-TYPE buffer."
-  (let ((inhibit-read-only t))
-    (erase-buffer)
-    (funcall (symbol-function (guix-get-symbol
-                               "mode" buffer-type entry-type)))
-    (funcall (guix-get-symbol "insert-entries" buffer-type)
-             entries entry-type)
-    (goto-char (point-min))))
-
-(defun guix-history-call (profile entries buffer-type entry-type
-                          search-type search-vals)
-  "Function called for moving by history."
-  (guix-show-entries entries buffer-type entry-type)
-  (guix-set-vars profile entries buffer-type entry-type
-                 search-type search-vals)
-  (guix-result-message profile entries entry-type
-                       search-type search-vals))
-
-(defun guix-make-history-item ()
-  "Make and return a history item for the current buffer."
-  (list #'guix-history-call
-        guix-profile guix-entries guix-buffer-type guix-entry-type
-        guix-search-type guix-search-vals))
-
-(defun guix-get-params-for-receiving (buffer-type entry-type)
-  "Return parameters that should be received for BUFFER-TYPE, ENTRY-TYPE."
-  (let* ((required-var (guix-get-symbol "required-params"
-                                        buffer-type entry-type))
-         (required (symbol-value required-var)))
-    (unless (equal required 'all)
-      (cl-union required
-                (funcall (guix-get-symbol "displayed-params"
-                                          buffer-type)
-                         entry-type)))))
-
-(defun guix-buffer-revert (_ignore-auto noconfirm)
-  "Update information in the current buffer.
-The function is suitable for `revert-buffer-function'.
-See `revert-buffer' for the meaning of NOCONFIRM."
-  (when (or noconfirm
-            (guix-buffer-revert-confirm? guix-buffer-type
-                                         guix-entry-type)
-            (y-or-n-p "Update current information? "))
-    (let* ((params (guix-get-params-for-receiving guix-buffer-type
-                                                  guix-entry-type))
-           (entries (guix-get-entries
-                     guix-profile guix-entry-type
-                     guix-search-type guix-search-vals params)))
-      (guix-set-buffer guix-profile entries guix-buffer-type guix-entry-type
-                       guix-search-type guix-search-vals t t))))
-
-(defvar guix-buffer-after-redisplay-hook nil
-  "Hook run by `guix-buffer-redisplay'.
-This hook is called before seting up a window position.")
-
-(defun guix-buffer-redisplay ()
-  "Redisplay the current Guix buffer.
-Restore the point and window positions after redisplaying.
-
-This function does not update the buffer data, use
-'\\[revert-buffer]' if you want the full update."
-  (interactive)
-  (let* ((old-point (point))
-         ;; For simplicity, ignore an unlikely case when multiple
-         ;; windows display the same buffer.
-         (window (car (get-buffer-window-list (current-buffer) nil t)))
-         (window-start (and window (window-start window))))
-    (guix-set-buffer guix-profile guix-entries guix-buffer-type
-                     guix-entry-type guix-search-type guix-search-vals
-                     t t)
-    (goto-char old-point)
-    (run-hooks 'guix-buffer-after-redisplay-hook)
-    (when window
-      (set-window-point window (point))
-      (set-window-start window window-start))))
-
-(defun guix-buffer-redisplay-goto-button ()
-  "Redisplay the current buffer and go to the next button, if needed."
-  (let ((guix-buffer-after-redisplay-hook
-         (cons (lambda ()
-                 (unless (button-at (point))
-                   (forward-button 1)))
-               guix-buffer-after-redisplay-hook)))
-    (guix-buffer-redisplay)))
-
 
 ;;; Generations
 
@@ -640,13 +261,14 @@ Create the buffer if needed."
 
 (defun guix-profile-generation-manifest-file (generation)
   "Return the file name of a GENERATION's manifest.
-GENERATION is a generation number of `guix-profile' profile."
-  (guix-manifest-file guix-profile generation))
+GENERATION is a generation number of the current profile."
+  (guix-manifest-file (guix-ui-current-profile) generation))
 
 (defun guix-profile-generation-packages-buffer (generation)
   "Insert GENERATION's package outputs in a buffer and return it.
-GENERATION is a generation number of `guix-profile' profile."
-  (guix-generation-packages-buffer guix-profile generation))
+GENERATION is a generation number of the current profile."
+  (guix-generation-packages-buffer (guix-ui-current-profile)
+                                   generation))
 
 
 ;;; Actions on packages and generations
@@ -757,7 +379,7 @@ Ask a user if needed (see `guix-operation-confirm').
 INSTALL, UPGRADE, REMOVE are 'package action specifications'.
 See `guix-process-package-actions' for details."
   (or (null guix-operation-confirm)
-      (let* ((entries (guix-get-entries
+      (let* ((entries (guix-ui-get-entries
                        profile 'package 'id
                        (append (mapcar #'car install)
                                (mapcar #'car upgrade)
@@ -930,12 +552,12 @@ See Info node `(guix) Invoking guix package' for details.
 Interactively, use the current profile and prompt for manifest
 FILE.  With a prefix argument, also prompt for PROFILE."
   (interactive
-   (let* ((default-profile (or guix-profile guix-current-profile))
+   (let* ((current-profile (guix-ui-current-profile))
           (profile (if current-prefix-arg
                        (guix-profile-prompt)
-                     default-profile))
+                     (or current-profile guix-current-profile)))
           (file (read-file-name "File with manifest: "))
-          (buffer (and guix-profile (current-buffer))))
+          (buffer (and current-profile (current-buffer))))
      (list profile file buffer)))
   (when (or (not guix-operation-confirm)
             (y-or-n-p (format "Apply manifest from '%s' to profile '%s'? "
diff --git a/emacs/guix-buffer.el b/emacs/guix-buffer.el
new file mode 100644
index 0000000000..5687a250aa
--- /dev/null
+++ b/emacs/guix-buffer.el
@@ -0,0 +1,566 @@
+;;; guix-buffer.el --- Buffer interface for displaying data  -*- lexical-binding: t -*-
+
+;; Copyright © 2014, 2015 Alex Kost <alezost@gmail.com>
+
+;; This file is part of GNU Guix.
+
+;; GNU Guix is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Guix is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; This file provides a general 'buffer' interface for displaying an
+;; arbitrary data.
+
+;;; Code:
+
+(require 'cl-lib)
+(require 'guix-history)
+(require 'guix-utils)
+
+(defvar guix-buffer-map
+  (let ((map (make-sparse-keymap)))
+    (define-key map (kbd "l") 'guix-history-back)
+    (define-key map (kbd "r") 'guix-history-forward)
+    (define-key map (kbd "g") 'revert-buffer)
+    (define-key map (kbd "R") 'guix-buffer-redisplay)
+    map)
+  "Parent keymap for Guix buffer modes.")
+
+
+;;; Buffer item
+
+(cl-defstruct (guix-buffer-item
+               (:constructor nil)
+               (:constructor guix-buffer-make-item
+                             (entries buffer-type entry-type args))
+               (:copier      nil))
+  entries buffer-type entry-type args)
+
+(defvar-local guix-buffer-item nil
+  "Data (structure) for the current Guix buffer.
+The structure consists of the following elements:
+
+- `entries': list of the currently displayed entries.
+
+  Each element of the list is an alist with an entry data of the
+  following form:
+
+    ((PARAM . VAL) ...)
+
+  PARAM is a name of the entry parameter.
+  VAL is a value of this parameter.
+
+- `entry-type': type of the currently displayed entries.
+
+- `buffer-type': type of the current buffer.
+
+- `args': search arguments used to get the current entries.")
+(put 'guix-buffer-item 'permanent-local t)
+
+(defmacro guix-buffer-with-item (item &rest body)
+  "Evaluate BODY using buffer ITEM.
+The following local variables are available inside BODY:
+`%entries', `%buffer-type', `%entry-type', `%args'.
+See `guix-buffer-item' for details."
+  (declare (indent 1) (debug t))
+  (let ((item-var (make-symbol "item")))
+    `(let ((,item-var ,item))
+       (let ((%entries     (guix-buffer-item-entries     ,item-var))
+             (%buffer-type (guix-buffer-item-buffer-type ,item-var))
+             (%entry-type  (guix-buffer-item-entry-type  ,item-var))
+             (%args        (guix-buffer-item-args        ,item-var)))
+         ,@body))))
+
+(defmacro guix-buffer-with-current-item (&rest body)
+  "Evaluate BODY using `guix-buffer-item'.
+See `guix-buffer-with-item' for details."
+  (declare (indent 0) (debug t))
+  `(guix-buffer-with-item guix-buffer-item
+     ,@body))
+
+(defmacro guix-buffer-define-current-item-accessor (name)
+  "Define `guix-buffer-current-NAME' function to access NAME
+element of `guix-buffer-item' structure.
+NAME should be a symbol."
+  (let* ((name-str (symbol-name name))
+         (accessor (intern (concat "guix-buffer-item-" name-str)))
+         (fun-name (intern (concat "guix-buffer-current-" name-str)))
+         (doc      (format "\
+Return '%s' of the current Guix buffer.
+See `guix-buffer-item' for details."
+                           name-str)))
+    `(defun ,fun-name ()
+       ,doc
+       (and guix-buffer-item
+            (,accessor guix-buffer-item)))))
+
+(defmacro guix-buffer-define-current-item-accessors (&rest names)
+  "Define `guix-buffer-current-NAME' functions for NAMES.
+See `guix-buffer-define-current-item-accessor' for details."
+  `(progn
+     ,@(mapcar (lambda (name)
+                 `(guix-buffer-define-current-item-accessor ,name))
+               names)))
+
+(guix-buffer-define-current-item-accessors
+ entries entry-type buffer-type args)
+
+(defmacro guix-buffer-define-current-args-accessor (n prefix name)
+  "Define `PREFIX-NAME' function to access Nth element of 'args'
+field of `guix-buffer-item' structure.
+PREFIX and NAME should be strings."
+  (let ((fun-name (intern (concat prefix "-" name)))
+        (doc      (format "\
+Return '%s' of the current Guix buffer.
+'%s' is the element number %d in 'args' of `guix-buffer-item'."
+                          name name n)))
+    `(defun ,fun-name ()
+       ,doc
+       (nth ,n (guix-buffer-current-args)))))
+
+(defmacro guix-buffer-define-current-args-accessors (prefix &rest names)
+  "Define `PREFIX-NAME' functions for NAMES.
+See `guix-buffer-define-current-args-accessor' for details."
+  `(progn
+     ,@(cl-loop for name in names
+                for i from 0
+                collect `(guix-buffer-define-current-args-accessor
+                          ,i ,prefix ,name))))
+
+
+;;; Wrappers for defined variables
+
+(defvar guix-buffer-data nil
+  "Alist with 'buffer' data.
+This alist is filled by `guix-buffer-define-interface' macro.")
+
+(defun guix-buffer-value (buffer-type entry-type symbol)
+  "Return SYMBOL's value for BUFFER-TYPE/ENTRY-TYPE from `guix-buffer-data'."
+  (symbol-value
+   (guix-assq-value guix-buffer-data buffer-type entry-type symbol)))
+
+(defun guix-buffer-get-entries (buffer-type entry-type args)
+  "Return ENTRY-TYPE entries.
+Call an appropriate 'get-entries' function from `guix-buffer'
+using ARGS as its arguments."
+  (apply (guix-buffer-value buffer-type entry-type 'get-entries)
+         args))
+
+(defun guix-buffer-mode-enable (buffer-type entry-type)
+  "Turn on major mode to display ENTRY-TYPE ENTRIES in BUFFER-TYPE buffer."
+  (funcall (guix-buffer-value buffer-type entry-type 'mode)))
+
+(defun guix-buffer-mode-initialize (buffer-type entry-type)
+  "Set up the current BUFFER-TYPE buffer to display ENTRY-TYPE entries."
+  (let ((fun (guix-buffer-value buffer-type entry-type 'mode-init)))
+    (when fun
+      (funcall fun))))
+
+(defun guix-buffer-insert-entries (entries buffer-type entry-type)
+  "Show ENTRY-TYPE ENTRIES in the current BUFFER-TYPE buffer."
+  (funcall (guix-buffer-value buffer-type entry-type 'insert-entries)
+           entries))
+
+(defun guix-buffer-show-entries-default (entries buffer-type entry-type)
+  "Show ENTRY-TYPE ENTRIES in the current BUFFER-TYPE buffer."
+  (let ((inhibit-read-only t))
+    (erase-buffer)
+    (guix-buffer-mode-enable buffer-type entry-type)
+    (guix-buffer-insert-entries entries buffer-type entry-type)
+    (goto-char (point-min))))
+
+(defun guix-buffer-show-entries (entries buffer-type entry-type)
+  "Show ENTRY-TYPE ENTRIES in the current BUFFER-TYPE buffer."
+  (funcall (guix-buffer-value buffer-type entry-type 'show-entries)
+           entries))
+
+(defun guix-buffer-message (entries buffer-type entry-type args)
+  "Display a message for BUFFER-ITEM after showing entries."
+  (let ((fun (guix-buffer-value buffer-type entry-type 'message)))
+    (when fun
+      (apply fun entries args))))
+
+(defun guix-buffer-name (buffer-type entry-type args)
+  "Return name of BUFFER-TYPE buffer for displaying ENTRY-TYPE entries."
+  (let ((str-or-fun (guix-buffer-value buffer-type entry-type
+                                       'buffer-name)))
+    (if (stringp str-or-fun)
+        str-or-fun
+      (apply str-or-fun args))))
+
+(defun guix-buffer-param-title (buffer-type entry-type param)
+  "Return PARAM title for BUFFER-TYPE/ENTRY-TYPE."
+  (or (guix-assq-value (guix-buffer-value buffer-type entry-type 'titles)
+                       param)
+      ;; Fallback to a title defined in 'info' interface.
+      (unless (eq buffer-type 'info)
+        (guix-assq-value (guix-buffer-value 'info entry-type 'titles)
+                         param))
+      (guix-symbol-title param)))
+
+(defun guix-buffer-history-size (buffer-type entry-type)
+  "Return history size for BUFFER-TYPE/ENTRY-TYPE."
+  (guix-buffer-value buffer-type entry-type 'history-size))
+
+(defun guix-buffer-revert-confirm? (buffer-type entry-type)
+  "Return 'revert-confirm' value for BUFFER-TYPE/ENTRY-TYPE."
+  (guix-buffer-value buffer-type entry-type 'revert-confirm))
+
+
+;;; Displaying entries
+
+(defun guix-buffer-display (buffer)
+  "Switch to a Guix BUFFER."
+  (pop-to-buffer buffer
+                 '((display-buffer-reuse-window
+                    display-buffer-same-window))))
+
+(defun guix-buffer-history-item (buffer-item)
+  "Make and return a history item for displaying BUFFER-ITEM."
+  (list #'guix-buffer-set buffer-item))
+
+(defun guix-buffer-set (buffer-item &optional history)
+  "Set up the current buffer for displaying BUFFER-ITEM.
+HISTORY should be one of the following:
+
+  `nil' - do not save BUFFER-ITEM in history,
+
+  `add' - add it to history,
+
+  `replace' - replace the current history item."
+  (guix-buffer-with-item buffer-item
+    (when %entries
+      (guix-buffer-show-entries %entries %buffer-type %entry-type)
+      (setq guix-buffer-item buffer-item)
+      (when history
+        (funcall (cl-ecase history
+                   (add     #'guix-history-add)
+                   (replace #'guix-history-replace))
+                 (guix-buffer-history-item buffer-item))))
+    (guix-buffer-message %entries %buffer-type %entry-type %args)))
+
+(defun guix-buffer-display-entries-current
+    (entries buffer-type entry-type args &optional history)
+  "Show ENTRIES in the current Guix buffer.
+See `guix-buffer-item' for the meaning of BUFFER-TYPE, ENTRY-TYPE
+and ARGS, and `guix-buffer-set' for the meaning of HISTORY."
+  (let ((item (guix-buffer-make-item entries buffer-type
+                                     entry-type args)))
+    (guix-buffer-set item history)))
+
+(defun guix-buffer-get-display-entries-current
+    (buffer-type entry-type args &optional history)
+  "Search for entries and show them in the current Guix buffer.
+See `guix-buffer-display-entries-current' for details."
+  (guix-buffer-display-entries-current
+   (guix-buffer-get-entries buffer-type entry-type args)
+   buffer-type entry-type args history))
+
+(defun guix-buffer-display-entries
+    (entries buffer-type entry-type args &optional history)
+  "Show ENTRIES in a BUFFER-TYPE buffer.
+See `guix-buffer-display-entries-current' for details."
+  (let ((buffer (get-buffer-create
+                 (guix-buffer-name buffer-type entry-type args))))
+    (with-current-buffer buffer
+      (guix-buffer-display-entries-current
+       entries buffer-type entry-type args history))
+    (when entries
+      (guix-buffer-display buffer))))
+
+(defun guix-buffer-get-display-entries
+    (buffer-type entry-type args &optional history)
+  "Search for entries and show them in a BUFFER-TYPE buffer.
+See `guix-buffer-display-entries-current' for details."
+  (guix-buffer-display-entries
+   (guix-buffer-get-entries buffer-type entry-type args)
+   buffer-type entry-type args history))
+
+(defun guix-buffer-revert (_ignore-auto noconfirm)
+  "Update the data in the current Guix buffer.
+This function is suitable for `revert-buffer-function'.
+See `revert-buffer' for the meaning of NOCONFIRM."
+  (guix-buffer-with-current-item
+    (when (or noconfirm
+              (not (guix-buffer-revert-confirm? %buffer-type %entry-type))
+              (y-or-n-p "Update the current buffer? "))
+      (guix-buffer-get-display-entries-current
+       %buffer-type %entry-type %args 'replace))))
+
+(defvar guix-buffer-after-redisplay-hook nil
+  "Hook run by `guix-buffer-redisplay'.
+This hook is called before seting up a window position.")
+
+(defun guix-buffer-redisplay ()
+  "Redisplay the current Guix buffer.
+Restore the point and window positions after redisplaying.
+
+This function does not update the buffer data, use
+'\\[revert-buffer]' if you want the full update."
+  (interactive)
+  (let* ((old-point (point))
+         ;; For simplicity, ignore an unlikely case when multiple
+         ;; windows display the same buffer.
+         (window (car (get-buffer-window-list (current-buffer) nil t)))
+         (window-start (and window (window-start window))))
+    (guix-buffer-set guix-buffer-item)
+    (goto-char old-point)
+    (run-hooks 'guix-buffer-after-redisplay-hook)
+    (when window
+      (set-window-point window (point))
+      (set-window-start window window-start))))
+
+(defun guix-buffer-redisplay-goto-button ()
+  "Redisplay the current buffer and go to the next button, if needed."
+  (let ((guix-buffer-after-redisplay-hook
+         (cons (lambda ()
+                 (unless (button-at (point))
+                   (forward-button 1)))
+               guix-buffer-after-redisplay-hook)))
+    (guix-buffer-redisplay)))
+
+
+;;; Interface definer
+
+(defmacro guix-buffer-define-interface (buffer-type entry-type &rest args)
+  "Define BUFFER-TYPE interface for displaying ENTRY-TYPE entries.
+Remaining arguments (ARGS) should have a form [KEYWORD VALUE] ...
+In the following description TYPE means ENTRY-TYPE-BUFFER-TYPE.
+
+Required keywords:
+
+  - `:buffer-name' - default value of the generated
+    `guix-TYPE-buffer-name' variable.
+
+  - `:get-entries-function' - default value of the generated
+    `guix-TYPE-get-function' variable.
+
+  - `:show-entries-function' - default value of the generated
+    `guix-TYPE-show-function' variable.
+
+  Alternatively, if `:show-entries-function' is not specified, a
+  default `guix-TYPE-show-entries' will be generated, and the
+  following keyword should be specified instead:
+
+  - `:insert-entries-function' - default value of the generated
+    `guix-TYPE-insert-function' variable.
+
+Optional keywords:
+
+  - `:message-function' - default value of the generated
+    `guix-TYPE-message-function' variable.
+
+  - `:titles' - default value of the generated
+    `guix-TYPE-titles' variable.
+
+  - `:history-size' - default value of the generated
+    `guix-TYPE-history-size' variable.
+
+  - `:revert-confirm?' - default value of the generated
+    `guix-TYPE-revert-confirm' variable.
+
+  - `:mode-name' - name (a string appeared in the mode-line) of
+     the generated `guix-TYPE-mode'.
+
+  - `:mode-init-function' - default value of the generated
+    `guix-TYPE-mode-initialize-function' variable.
+
+  - `:reduced?' - if non-nil, generate only group, faces group
+    and titles variable (if specified); all keywords become
+    optional."
+  (declare (indent 2))
+  (let* ((entry-type-str     (symbol-name entry-type))
+         (buffer-type-str    (symbol-name buffer-type))
+         (prefix             (concat "guix-" entry-type-str "-"
+                                     buffer-type-str))
+         (group              (intern prefix))
+         (faces-group        (intern (concat prefix "-faces")))
+         (get-entries-var    (intern (concat prefix "-get-function")))
+         (show-entries-var   (intern (concat prefix "-show-function")))
+         (show-entries-fun   (intern (concat prefix "-show-entries")))
+         (message-var        (intern (concat prefix "-message-function")))
+         (buffer-name-var    (intern (concat prefix "-buffer-name")))
+         (titles-var         (intern (concat prefix "-titles")))
+         (history-size-var   (intern (concat prefix "-history-size")))
+         (revert-confirm-var (intern (concat prefix "-revert-confirm"))))
+    (guix-keyword-args-let args
+        ((get-entries-val    :get-entries-function)
+         (show-entries-val   :show-entries-function)
+         (insert-entries-val :insert-entries-function)
+         (mode-name          :mode-name (capitalize prefix))
+         (mode-init-val      :mode-init-function)
+         (message-val        :message-function)
+         (buffer-name-val    :buffer-name)
+         (titles-val         :titles)
+         (history-size-val   :history-size 20)
+         (revert-confirm-val :revert-confirm? t)
+         (reduced?           :reduced?))
+      `(progn
+         (defgroup ,group nil
+           ,(format "Display '%s' entries in '%s' buffer."
+                    entry-type-str buffer-type-str)
+           :prefix ,(concat prefix "-")
+           :group ',(intern (concat "guix-" buffer-type-str)))
+
+         (defgroup ,faces-group nil
+           ,(format "Faces for displaying '%s' entries in '%s' buffer."
+                    entry-type-str buffer-type-str)
+           :group ',(intern (concat "guix-" buffer-type-str "-faces")))
+
+         (defcustom ,titles-var ,titles-val
+           ,(format "Alist of titles of '%s' parameters."
+                    entry-type-str)
+           :type '(alist :key-type symbol :value-type string)
+           :group ',group)
+
+         ,(unless reduced?
+            `(progn
+               (defvar ,get-entries-var ,get-entries-val
+                 ,(format "\
+Function used to receive '%s' entries for '%s' buffer."
+                          entry-type-str buffer-type-str))
+
+               (defvar ,show-entries-var
+                 ,(or show-entries-val `',show-entries-fun)
+                 ,(format "\
+Function used to show '%s' entries in '%s' buffer."
+                          entry-type-str buffer-type-str))
+
+               (defvar ,message-var ,message-val
+                 ,(format "\
+Function used to display a message after showing '%s' entries.
+If nil, do not display messages."
+                          entry-type-str))
+
+               (defcustom ,buffer-name-var ,buffer-name-val
+                 ,(format "\
+Default name of '%s' buffer for displaying '%s' entries.
+May be a string or a function returning a string.  The function
+is called with the same arguments as `%S'."
+                          buffer-type-str entry-type-str get-entries-var)
+                 :type '(choice string function)
+                 :group ',group)
+
+               (defcustom ,history-size-var ,history-size-val
+                 ,(format "\
+Maximum number of items saved in history of `%S' buffer.
+If 0, the history is disabled."
+                          buffer-name-var)
+                 :type 'integer
+                 :group ',group)
+
+               (defcustom ,revert-confirm-var ,revert-confirm-val
+                 ,(format "\
+If non-nil, ask to confirm for reverting `%S' buffer."
+                          buffer-name-var)
+                 :type 'boolean
+                 :group ',group)
+
+               (guix-alist-put!
+                '((get-entries    . ,get-entries-var)
+                  (show-entries   . ,show-entries-var)
+                  (message        . ,message-var)
+                  (buffer-name    . ,buffer-name-var)
+                  (history-size   . ,history-size-var)
+                  (revert-confirm . ,revert-confirm-var))
+                'guix-buffer-data ',buffer-type ',entry-type)
+
+               ,(unless show-entries-val
+                  `(defun ,show-entries-fun (entries)
+                     ,(format "\
+Show '%s' ENTRIES in the current '%s' buffer."
+                              entry-type-str buffer-type-str)
+                     (guix-buffer-show-entries-default
+                      entries ',buffer-type ',entry-type)))
+
+               ,(when (or insert-entries-val
+                          (null show-entries-val))
+                  (let ((insert-entries-var
+                         (intern (concat prefix "-insert-function"))))
+                    `(progn
+                       (defvar ,insert-entries-var ,insert-entries-val
+                         ,(format "\
+Function used to print '%s' entries in '%s' buffer."
+                                  entry-type-str buffer-type-str))
+
+                       (guix-alist-put!
+                        ',insert-entries-var 'guix-buffer-data
+                        ',buffer-type ',entry-type
+                        'insert-entries))))
+
+               ,(when (or mode-name
+                          mode-init-val
+                          (null show-entries-val))
+                  (let* ((mode-str      (concat prefix "-mode"))
+                         (mode-map-str  (concat mode-str "-map"))
+                         (mode          (intern mode-str))
+                         (parent-mode   (intern
+                                         (concat "guix-" buffer-type-str
+                                                 "-mode")))
+                         (mode-var      (intern
+                                         (concat mode-str "-function")))
+                         (mode-init-var (intern
+                                         (concat mode-str
+                                                 "-initialize-function"))))
+                    `(progn
+                       (defvar ,mode-var ',mode
+                         ,(format "\
+Major mode for displaying '%s' entries in '%s' buffer."
+                                  entry-type-str buffer-type-str))
+
+                       (defvar ,mode-init-var ,mode-init-val
+                         ,(format "\
+Function used to set up '%s' buffer for displaying '%s' entries."
+                                  buffer-type-str entry-type-str))
+
+                       (define-derived-mode ,mode ,parent-mode ,mode-name
+                         ,(format "\
+Major mode for displaying '%s' entries in '%s' buffer.
+
+\\{%s}"
+                                  entry-type-str buffer-type-str mode-map-str)
+                         (setq-local revert-buffer-function
+                                     'guix-buffer-revert)
+                         (setq-local guix-history-size
+                                     (guix-buffer-history-size
+                                      ',buffer-type ',entry-type))
+                         (guix-buffer-mode-initialize
+                          ',buffer-type ',entry-type))
+
+                       (guix-alist-put!
+                        ',mode-var 'guix-buffer-data
+                        ',buffer-type ',entry-type 'mode)
+                       (guix-alist-put!
+                        ',mode-init-var 'guix-buffer-data
+                        ',buffer-type ',entry-type
+                        'mode-init))))))
+
+         (guix-alist-put!
+          ',titles-var 'guix-buffer-data
+          ',buffer-type ',entry-type 'titles)))))
+
+
+(defvar guix-buffer-font-lock-keywords
+  (eval-when-compile
+    `((,(rx "(" (group (or "guix-buffer-with-item"
+                           "guix-buffer-with-current-item"
+                           "guix-buffer-define-interface"))
+            symbol-end)
+       . 1))))
+
+(font-lock-add-keywords 'emacs-lisp-mode guix-buffer-font-lock-keywords)
+
+(provide 'guix-buffer)
+
+;;; guix-buffer.el ends here
diff --git a/emacs/guix-info.el b/emacs/guix-info.el
index 871c4b085f..9c63892d06 100644
--- a/emacs/guix-info.el
+++ b/emacs/guix-info.el
@@ -202,8 +202,7 @@ LEVEL is 1 by default."
   (insert (guix-info-get-indent level)))
 
 (defun guix-info-insert-entries (entries entry-type)
-  "Display ENTRIES of ENTRY-TYPE in the current info buffer.
-ENTRIES should have a form of `guix-entries'."
+  "Display ENTRY-TYPE ENTRIES in the current info buffer."
   (guix-mapinsert (lambda (entry)
                     (guix-info-insert-entry entry entry-type))
                   entries
@@ -371,8 +370,11 @@ BUTTON-OR-FACE is a button type)."
   'face 'guix-package-info-name-button
   'help-echo "Describe this package"
   'action (lambda (btn)
-            (guix-get-show-entries guix-profile 'info guix-package-info-type
-                                   'name (button-label btn))))
+            (guix-buffer-get-display-entries-current
+             'info guix-package-info-type
+             (list (guix-ui-current-profile)
+                   'name (button-label btn))
+             'add)))
 
 (defun guix-info-button-copy-label (&optional pos)
   "Copy a label of the button at POS into kill ring.
@@ -407,7 +409,8 @@ See `insert-text-button' for the meaning of PROPERTIES."
   "Keymap for `guix-info-mode' buffers.")
 
 (define-derived-mode guix-info-mode special-mode "Guix-Info"
-  "Parent mode for displaying information in info buffers.")
+  "Parent mode for displaying data in 'info' form."
+  (setq-local revert-buffer-function 'guix-buffer-revert))
 
 (defun guix-info-mode-initialize ()
   "Set up the current 'info' buffer."
@@ -435,7 +438,8 @@ The rest keyword arguments are passed to
          (group              (intern prefix))
          (format-var         (intern (concat prefix "-format"))))
     (guix-keyword-args-let args
-        ((format-val         :format))
+        ((show-entries-val   :show-entries-function)
+         (format-val         :format))
       `(progn
          (defcustom ,format-var ,format-val
            ,(format "\
@@ -473,9 +477,23 @@ After calling each METHOD, a new line is inserted."
           '((format . ,format-var))
           'guix-info-data ',entry-type)
 
-         (guix-buffer-define-interface info ,entry-type
-           :mode-init-function 'guix-info-mode-initialize
-           ,@%foreign-args)))))
+         ,(if show-entries-val
+              `(guix-buffer-define-interface info ,entry-type
+                 :show-entries-function ,show-entries-val
+                 ,@%foreign-args)
+
+            (let ((insert-fun (intern (concat prefix "-insert-entries"))))
+              `(progn
+                 (defun ,insert-fun (entries)
+                   ,(format "\
+Print '%s' ENTRIES in the current 'info' buffer."
+                            entry-type-str)
+                   (guix-info-insert-entries entries ',entry-type))
+
+                 (guix-buffer-define-interface info ,entry-type
+                   :insert-entries-function ',insert-fun
+                   :mode-init-function 'guix-info-mode-initialize
+                   ,@%foreign-args))))))))
 
 
 ;;; Displaying packages
@@ -675,7 +693,7 @@ ENTRY is an alist with package info."
      type-str
      (lambda (btn)
        (guix-process-package-actions
-        guix-profile
+        (guix-ui-current-profile)
         `((,(button-get btn 'action-type) (,(button-get btn 'id)
                                            ,(button-get btn 'output))))
         (current-buffer)))
@@ -726,15 +744,16 @@ prompt depending on `guix-operation-confirm' variable)."
 Find the file if needed (see `guix-package-info-auto-find-source').
 ENTRY-ID is an ID of the current entry (package or output).
 PACKAGE-ID is an ID of the package which source to show."
-  (let* ((entries guix-entries)
-         (entry   (guix-entry-by-id entry-id guix-entries))
+  (let* ((entries (guix-buffer-current-entries))
+         (entry   (guix-entry-by-id entry-id entries))
          (file    (guix-package-source-path package-id)))
     (or file
         (error "Couldn't define file name of the package source"))
     (let* ((new-entry (cons (cons 'source-file file)
                             entry))
            (new-entries (guix-replace-entry entry-id new-entry entries)))
-      (setq guix-entries new-entries)
+      (setf (guix-buffer-item-entries guix-buffer-item)
+            new-entries)
       (guix-buffer-redisplay-goto-button)
       (if (file-exists-p file)
           (if guix-package-info-auto-find-source
@@ -872,15 +891,19 @@ This function is used to hide a \"Download\" button if needed."
   (guix-info-insert-action-button
    "Packages"
    (lambda (btn)
-     (guix-get-show-entries guix-profile 'list guix-package-list-type
-                            'generation (button-get btn 'number)))
+     (guix-buffer-get-display-entries
+      'list guix-package-list-type
+      (list (guix-ui-current-profile)
+            'generation (button-get btn 'number))
+      'add))
    "Show installed packages for this generation"
    'number number)
   (guix-info-insert-indent)
   (guix-info-insert-action-button
    "Delete"
    (lambda (btn)
-     (guix-delete-generations guix-profile (list (button-get btn 'number))
+     (guix-delete-generations (guix-ui-current-profile)
+                              (list (button-get btn 'number))
                               (current-buffer)))
    "Delete this generation"
    'number number))
@@ -894,7 +917,8 @@ This function is used to hide a \"Download\" button if needed."
     (guix-info-insert-action-button
      "Switch"
      (lambda (btn)
-       (guix-switch-to-generation guix-profile (button-get btn 'number)
+       (guix-switch-to-generation (guix-ui-current-profile)
+                                  (button-get btn 'number)
                                   (current-buffer)))
      "Switch to this generation (make it the current one)"
      'number (guix-entry-value entry 'number))))
diff --git a/emacs/guix-list.el b/emacs/guix-list.el
index 42bc0c87f5..f5c50389ed 100644
--- a/emacs/guix-list.el
+++ b/emacs/guix-list.el
@@ -61,7 +61,7 @@ With prefix argument, describe entries marked with any mark."
   (let* ((ids        (or (apply #'guix-list-get-marked-id-list mark-names)
                          (list (guix-list-current-id))))
          (count      (length ids))
-         (entry-type guix-entry-type))
+         (entry-type (guix-buffer-current-entry-type)))
     (when (or (<= count (guix-list-describe-warning-count entry-type))
               (y-or-n-p (format "Do you really want to describe %d entries? "
                                 count)))
@@ -168,8 +168,7 @@ Return a vector made of values of FUN calls."
            rest-spec))))
 
 (defun guix-list-insert-entries (entries entry-type)
-  "Display ENTRIES of ENTRY-TYPE in the current list buffer.
-ENTRIES should have a form of `guix-entries'."
+  "Print ENTRY-TYPE ENTRIES in the current buffer."
   (setq tabulated-list-entries
         (guix-list-tabulated-entries entries entry-type))
   (tabulated-list-print))
@@ -212,14 +211,18 @@ VAL may be nil."
         'follow-link t
         'help-echo "Find file"))
 
+
+;;; 'List' lines
+
 (defun guix-list-current-id ()
-  "Return ID of the current entry."
+  "Return ID of the entry at point."
   (or (tabulated-list-get-id)
       (user-error "No entry here")))
 
 (defun guix-list-current-entry ()
-  "Return alist of the current entry info."
-  (guix-entry-by-id (guix-list-current-id) guix-entries))
+  "Return entry at point."
+  (guix-entry-by-id (guix-list-current-id)
+                    (guix-buffer-current-entries)))
 
 (defun guix-list-for-each-line (fun &rest args)
   "Call FUN with ARGS for each entry line."
@@ -429,8 +432,6 @@ The rest keyword arguments are passed to
   (let* ((entry-type-str     (symbol-name entry-type))
          (prefix             (concat "guix-" entry-type-str "-list"))
          (group              (intern prefix))
-         (mode-str           (concat prefix "-mode"))
-         (init-fun           (intern (concat prefix "-mode-initialize")))
          (describe-var       (intern (concat prefix "-describe-function")))
          (describe-count-var (intern (concat prefix
                                              "-describe-warning-count")))
@@ -438,7 +439,8 @@ The rest keyword arguments are passed to
          (sort-key-var       (intern (concat prefix "-sort-key")))
          (marks-var          (intern (concat prefix "-marks"))))
     (guix-keyword-args-let args
-        ((describe-val       :describe-function)
+        ((show-entries-val   :show-entries-function)
+         (describe-val       :describe-function)
          (describe-count-val :describe-count 10)
          (format-val         :format)
          (sort-key-val       :sort-key)
@@ -498,10 +500,6 @@ See also `guix-list-describe'."
            ,(format "Function used to describe '%s' entries."
                     entry-type-str))
 
-         (defun ,init-fun ()
-           ,(concat "Initial settings for `" mode-str "'.")
-           (guix-list-mode-initialize ',entry-type))
-
          (guix-alist-put!
           '((describe       . ,describe-var)
             (describe-count . ,describe-count-var)
@@ -510,8 +508,30 @@ See also `guix-list-describe'."
             (marks          . ,marks-var))
           'guix-list-data ',entry-type)
 
-         (guix-buffer-define-interface list ,entry-type
-           ,@%foreign-args)))))
+         ,(if show-entries-val
+              `(guix-buffer-define-interface list ,entry-type
+                 :show-entries-function ,show-entries-val
+                 ,@%foreign-args)
+
+            (let ((insert-fun    (intern (concat prefix "-insert-entries")))
+                  (mode-init-fun (intern (concat prefix "-mode-initialize"))))
+              `(progn
+                 (defun ,insert-fun (entries)
+                   ,(format "\
+Print '%s' ENTRIES in the current 'list' buffer."
+                            entry-type-str)
+                   (guix-list-insert-entries entries ',entry-type))
+
+                 (defun ,mode-init-fun ()
+                   ,(format "\
+Set up the current 'list' buffer for displaying '%s' entries."
+                            entry-type-str)
+                   (guix-list-mode-initialize ',entry-type))
+
+                 (guix-buffer-define-interface list ,entry-type
+                   :insert-entries-function ',insert-fun
+                   :mode-init-function ',mode-init-fun
+                   ,@%foreign-args))))))))
 
 
 ;;; Displaying packages
@@ -584,7 +604,7 @@ Colorize it with `guix-package-list-installed' or
   (when (and (not guix-package-list-generation-marking-enabled)
              (or (derived-mode-p 'guix-package-list-mode)
                  (derived-mode-p 'guix-output-list-mode))
-             (eq guix-search-type 'generation))
+             (eq (guix-ui-current-search-type) 'generation))
     (error "Action marks are disabled for lists of 'generation packages'")))
 
 (defun guix-package-list-mark-outputs (mark default
@@ -655,7 +675,7 @@ accept an entry as argument."
   (let ((obsolete (cl-remove-if-not
                    (lambda (entry)
                      (guix-entry-value entry 'obsolete))
-                   guix-entries)))
+                   (guix-buffer-current-entries))))
     (guix-list-for-each-line
      (lambda ()
        (let* ((id (guix-list-current-id))
@@ -682,8 +702,8 @@ FUN should accept action-type as argument."
   (let ((actions (delq nil
                        (mapcar fun '(install delete upgrade)))))
     (if actions
-        (guix-process-package-actions
-         guix-profile actions (current-buffer))
+        (guix-process-package-actions (guix-ui-current-profile)
+                                      actions (current-buffer))
       (user-error "No operations specified"))))
 
 (defun guix-package-list-execute ()
@@ -714,7 +734,7 @@ The specification is suitable for `guix-process-package-actions'."
             (output nil 9 t)
             (installed nil 12 t)
             (synopsis guix-list-get-one-line 30 nil))
-  :required '(package-id)
+  :required '(id package-id)
   :sort-key '(name)
   :marks '((install . ?I)
            (upgrade . ?U)
@@ -784,15 +804,19 @@ The specification is suitable for `guix-process-output-actions'."
   "Describe outputs with IDS (list of output identifiers).
 See `guix-package-info-type'."
   (if (eq guix-package-info-type 'output)
-      (apply #'guix-get-show-entries
-             guix-profile 'info 'output 'id ids)
+      (guix-buffer-get-display-entries
+       'info 'output
+       (cl-list* (guix-ui-current-profile) 'id ids)
+       'add)
     (let ((pids (mapcar (lambda (oid)
                           (car (guix-package-id-and-output-by-output-id
                                 oid)))
                         ids)))
-      (apply #'guix-get-show-entries
-             guix-profile 'info 'package 'id
-             (cl-remove-duplicates pids)))))
+      (guix-buffer-get-display-entries
+       'info 'package
+       (cl-list* (guix-ui-current-profile)
+                 'id (cl-remove-duplicates pids))
+       'add))))
 
 (defun guix-output-list-edit ()
   "Go to the location of the current package."
@@ -837,13 +861,15 @@ VAL is a boolean value."
          (number  (guix-entry-value entry 'number)))
     (if current
         (user-error "This generation is already the current one")
-      (guix-switch-to-generation guix-profile number (current-buffer)))))
+      (guix-switch-to-generation (guix-ui-current-profile)
+                                 number (current-buffer)))))
 
 (defun guix-generation-list-show-packages ()
   "List installed packages for the generation at point."
   (interactive)
-  (guix-get-show-entries guix-profile 'list guix-package-list-type
-                         'generation (guix-list-current-id)))
+  (guix-get-show-packages
+   (guix-ui-current-profile)
+   'generation (guix-list-current-id)))
 
 (defun guix-generation-list-generations-to-compare ()
   "Return a sorted list of 2 marked generations for comparing."
@@ -858,9 +884,12 @@ If 2 generations are marked with \\[guix-list-mark], display
 outputs installed in the latest marked generation that were not
 installed in the other one."
   (interactive)
-  (apply #'guix-get-show-entries
-         guix-profile 'list 'output 'generation-diff
-         (reverse (guix-generation-list-generations-to-compare))))
+  (guix-buffer-get-display-entries
+   'list 'output
+   (cl-list* (guix-ui-current-profile)
+             'generation-diff
+             (reverse (guix-generation-list-generations-to-compare)))
+   'add))
 
 (defun guix-generation-list-show-removed-packages ()
   "List package outputs removed from the latest marked generation.
@@ -868,9 +897,12 @@ If 2 generations are marked with \\[guix-list-mark], display
 outputs not installed in the latest marked generation that were
 installed in the other one."
   (interactive)
-  (apply #'guix-get-show-entries
-         guix-profile 'list 'output 'generation-diff
-         (guix-generation-list-generations-to-compare)))
+  (guix-buffer-get-display-entries
+   'list 'output
+   (cl-list* (guix-ui-current-profile)
+             'generation-diff
+             (guix-generation-list-generations-to-compare))
+   'add))
 
 (defun guix-generation-list-compare (diff-fun gen-fun)
   "Run GEN-FUN on the 2 marked generations and run DIFF-FUN on the results."
@@ -938,7 +970,8 @@ With ARG, mark all generations for deletion."
   (let ((marked (guix-list-get-marked-id-list 'delete)))
     (or marked
         (user-error "No generations marked for deletion"))
-    (guix-delete-generations guix-profile marked (current-buffer))))
+    (guix-delete-generations (guix-ui-current-profile)
+                             marked (current-buffer))))
 
 
 (defvar guix-list-font-lock-keywords
diff --git a/emacs/guix-ui.el b/emacs/guix-ui.el
index a92439baf1..55c3f1b55c 100644
--- a/emacs/guix-ui.el
+++ b/emacs/guix-ui.el
@@ -26,7 +26,10 @@
 
 (require 'cl-lib)
 (require 'guix-backend)
+(require 'guix-buffer)
+(require 'guix-guile)
 (require 'guix-utils)
+(require 'guix-messages)
 
 (defgroup guix-ui nil
   "Settings for Guix package management.
@@ -41,10 +44,38 @@ generations in 'list' and 'info' buffers."
     map)
   "Parent keymap for Guix package/generation buffers.")
 
+(guix-buffer-define-current-args-accessors
+ "guix-ui-current" "profile" "search-type" "search-values")
+
+(defun guix-ui-get-entries (profile entry-type search-type search-values
+                                    &optional params)
+  "Receive ENTRY-TYPE entries for PROFILE.
+Call an appropriate scheme procedure and return a list of entries.
+
+ENTRY-TYPE should be one of the following symbols: `package',
+`output' or `generation'.
+
+SEARCH-TYPE may be one of the following symbols:
+
+- If ENTRY-TYPE is `package' or `output': `id', `name', `regexp',
+  `all-available', `newest-available', `installed', `obsolete',
+  `generation'.
+
+- If ENTRY-TYPE is `generation': `id', `last', `all', `time'.
+
+PARAMS is a list of parameters for receiving.  If nil, get data
+with all available parameters."
+  (guix-eval-read
+   (guix-make-guile-expression
+    'entries
+    profile params entry-type search-type search-values)))
+
 (defun guix-ui-list-describe (ids)
   "Describe 'ui' entries with IDS (list of identifiers)."
-  (apply #'guix-get-show-entries
-         guix-profile 'info guix-entry-type 'id ids))
+  (guix-buffer-get-display-entries
+   'info (guix-buffer-current-entry-type)
+   (cl-list* (guix-ui-current-profile) 'id ids)
+   'add))
 
 
 ;;; Buffers and auto updating
@@ -161,7 +192,16 @@ Optional keywords:
     `guix-TYPE-required-params' variable.
 
 The rest keyword arguments are passed to
-`guix-BUFFER-TYPE-define-interface' macro."
+`guix-BUFFER-TYPE-define-interface' macro.
+
+Along with the mentioned definitions, this macro also defines:
+
+  - `guix-TYPE-mode-map' - keymap based on `guix-ui-map' and
+    `guix-BUFFER-TYPE-mode-map'.
+
+  - `guix-TYPE-get-entries' - a wrapper around `guix-ui-get-entries'.
+
+  - `guix-TYPE-message' - a wrapper around `guix-result-message'."
   (declare (indent 2))
   (let* ((entry-type-str  (symbol-name entry-type))
          (buffer-type-str (symbol-name buffer-type))
@@ -173,6 +213,10 @@ The rest keyword arguments are passed to
                                           buffer-type-str)))
          (required-var    (intern (concat prefix "-required-params")))
          (buffer-name-fun (intern (concat prefix "-buffer-name")))
+         (get-fun         (intern (concat prefix "-get-entries")))
+         (message-fun     (intern (concat prefix "-message")))
+         (displayed-fun   (intern (format "guix-%s-displayed-params"
+                                          buffer-type-str)))
          (definer         (intern (format "guix-%s-define-interface"
                                           buffer-type-str))))
     (guix-keyword-args-let args
@@ -188,9 +232,13 @@ The rest keyword arguments are passed to
 
          (defvar ,required-var ,required-val
            ,(format "\
-List of the required '%s' parameters for '%s' buffer.
-These parameters are received along with the displayed parameters."
-                    entry-type-str buffer-type-str))
+List of the required '%s' parameters.
+These parameters are received by `%S'
+along with the displayed parameters.
+
+Do not remove `id' from this list as it is required for
+identifying an entry."
+                    entry-type-str get-fun))
 
          (defun ,buffer-name-fun (profile &rest _)
            ,(format "\
@@ -199,7 +247,27 @@ See `guix-ui-buffer-name' for details."
                     buffer-type-str entry-type-str)
            (guix-ui-buffer-name ,buffer-name-val profile))
 
+         (defun ,get-fun (profile search-type &rest search-values)
+           ,(format "\
+Receive '%s' entries for displaying them in '%s' buffer.
+See `guix-ui-get-entries' for details."
+                    entry-type-str buffer-type-str)
+           (guix-ui-get-entries
+            profile ',entry-type search-type search-values
+            (cl-union ,required-var
+                      (,displayed-fun ',entry-type))))
+
+         (defun ,message-fun (entries profile search-type
+                                      &rest search-values)
+           ,(format "\
+Display a message after showing '%s' entries."
+                    entry-type-str)
+           (guix-result-message
+            profile entries ',entry-type search-type search-values))
+
          (,definer ,entry-type
+           :get-entries-function ',get-fun
+           :message-function ',message-fun
            :buffer-name ',buffer-name-fun
            ,@%foreign-args)))))
 
diff --git a/emacs/guix.el b/emacs/guix.el
index ac6efbb475..12dd4a2553 100644
--- a/emacs/guix.el
+++ b/emacs/guix.el
@@ -56,42 +56,39 @@ If nil, show a single package in the info buffer."
 (defvar guix-search-history nil
   "A history of minibuffer prompts.")
 
-(defun guix-get-show-packages (profile search-type &rest search-vals)
+(defun guix-get-show-packages (profile search-type &rest search-values)
   "Search for packages and show results.
 
 If PROFILE is nil, use `guix-current-profile'.
 
-See `guix-get-entries' for the meaning of SEARCH-TYPE and
-SEARCH-VALS.
+See `guix-ui-get-entries' for the meaning of SEARCH-TYPE and
+SEARCH-VALUES.
 
 Results are displayed in the list buffer, unless a single package
 is found and `guix-list-single-package' is nil."
-  (or profile (setq profile guix-current-profile))
-  (let ((packages (guix-get-entries profile guix-package-list-type
-                                    search-type search-vals
-                                    (guix-get-params-for-receiving
-                                     'list guix-package-list-type))))
+  (let* ((args    (cl-list* (or profile guix-current-profile)
+                            search-type search-values))
+         (entries (guix-buffer-get-entries
+                   'list guix-package-list-type args)))
     (if (or guix-list-single-package
-            (cdr packages))
-        (guix-set-buffer profile packages 'list guix-package-list-type
-                         search-type search-vals)
-      (let ((packages (guix-get-entries profile guix-package-info-type
-                                        search-type search-vals
-                                        (guix-get-params-for-receiving
-                                         'info guix-package-info-type))))
-        (guix-set-buffer profile packages 'info guix-package-info-type
-                         search-type search-vals)))))
-
-(defun guix-get-show-generations (profile search-type &rest search-vals)
+            (null entries)
+            (cdr entries))
+        (guix-buffer-display-entries
+         entries 'list guix-package-list-type args 'add)
+      (guix-buffer-get-display-entries
+       'info guix-package-info-type args 'add))))
+
+(defun guix-get-show-generations (profile search-type &rest search-values)
   "Search for generations and show results.
 
 If PROFILE is nil, use `guix-current-profile'.
 
-See `guix-get-entries' for the meaning of SEARCH-TYPE and
-SEARCH-VALS."
-  (apply #'guix-get-show-entries
-         (or profile guix-current-profile)
-         'list 'generation search-type search-vals))
+See `guix-ui-get-entries' for the meaning of SEARCH-TYPE and
+SEARCH-VALUES."
+  (let ((args (cl-list* (or profile guix-current-profile)
+                        search-type search-values)))
+    (guix-buffer-get-display-entries
+     'list 'generation args 'add)))
 
 ;;;###autoload
 (defun guix-search-by-name (name &optional profile)