iflipb

iflipb lets you flip between recently visited buffers in a way that resembles what Alt-(Shift-)TAB does in Microsoft Windows and other graphical window managers.

Operation

iflipb provides three commands: iflipb-next-buffer, iflipb-previous-buffer and iflipb-kill-buffer.

iflipb-next-buffer behaves like Alt-TAB: it switches to the previously used buffer, just like C-x b RET (or C-M-l in XEmacs). However, another consecutive call to iflipb-next-buffer switches to the next buffer in the buffer list, and so on. When such a consecutive call is made, the skipped-over buffer is not considered visited.

While flipping, the names of the most recent buffers are displayed in the minibuffer, and the currently visited buffer is surrounded by square brackets and marked with a bold face.

A key thing to notice here is that iflipb displays the buffer contents after each step forward/backwards (in addition to displaying the buffer names), unlike for instance the buffer switching model of ido-mode where only the buffer names are displayed.

iflipb-previous-buffer behaves like Alt-Shift-TAB: it walks backwards in the buffer list.

iflipb treats the buffer list as a stack, and (by design) it doesn't wrap around. This means that when you have flipped to the last buffer and continue, you don't get to the first buffer again. This is a good thing. (If you disagree and want wrap-around, set iflipb-wrap-around to non-nil.)

Here is an illustration of what happens in a couple of different scenarios:

                   Minibuffer    Actual
                   display       buffer list
--------------------------------------------
Original:                        A B C D E
Forward flip:      A [B] C D E   B A C D E
Forward flip:      A B [C] D E   C A B D E
Forward flip:      A B C [D] E   D A B C E

Original:                        A B C D E
Forward flip:      A [B] C D E   B A C D E
Forward flip:      A B [C] D E   C A B D E
Backward flip:     A [B] C D E   B A C D E

Original:                        A B C D E
Forward flip:      A [B] C D E   B A C D E
Forward flip:      A B [C] D E   C A B D E
[Edit buffer C]:                 C A B D E
Forward flip:      C [A] B D E   A C B D E

iflipb by default ignores buffers whose name starts with an asterisk or space. You can give a prefix argument to iflipb-next-buffer to make it flip between more buffers. See the documentation of iflipb-ignore-buffers and iflipb-always-ignore-buffers for how to change this.

iflipb-kill-buffer is designed to be bound to C-x k. It behaves like kill-buffer but keeps iflipb's buffer list state so that it's possible to kill a buffer and then advance to the next buffer without starting all over again.

Installation

To load iflipb, store iflipb.el in your Emacs load path and put

(require 'iflipb)

in your Emacs configuration file.

iflipb does not install any key bindings for the two commands. I personally use M-h and M-H (i.e., M-S-h) since I don't use the standard binding of M-h (mark-paragraph) and M-h is quick and easy to press. To install iflipb with M-h and M-H as keyboard bindings:

(global-set-key (kbd "M-h") 'iflipb-next-buffer)
(global-set-key (kbd "M-H") 'iflipb-previous-buffer)

Another alternative is to use C-tab and C-S-tab:

(global-set-key (kbd "<C-tab>") 'iflipb-next-buffer)
(global-set-key
 (if (featurep 'xemacs) (kbd "<C-iso-left-tab>") (kbd "<C-S-iso-lefttab>"))
 'iflipb-previous-buffer)

Or perhaps use functions keys like F9 and F10:

(global-set-key (kbd "<f10>") 'iflipb-next-buffer)
(global-set-key (kbd "<f9>")  'iflipb-previous-buffer)

Optionally bind iflip-kill-buffer:

(global-set-key (kbd "C-x k") 'iflipb-kill-buffer)

Configuration

These variables affect iflipb's behavior:

• iflipb-ignore-buffers (default: "^[*]")

  This variable determines which buffers to ignore when a prefix argument has not been given to iflipb-next-buffer. The value should be a regexp string, a function or a list. If the value is a regexp string, it describes buffer names to exclude from the buffer list. If the value is a function, the function will get a buffer name as an argument and should return nil if the buffer should be excluded, otherwise non-nil. If the value is a list, the filter matches if any of the list elements match.

• iflipb-always-ignore-buffers (default: "^ ")

  This variable determines which buffers to always ignore. The value should be a regexp string, a function or a list. If the value is a regexp string, it describes buffer names to exclude from the buffer list. If the value is a function, the function will get a buffer name as an argument and should return nil if the buffer should be excluded, otherwise non-nil. If the value is a list, the filter matches if any of the list elements match.

• iflipb-wrap-around (default: nil)

  This variable determines whether buffer cycling should wrap around when an edge is reached in the buffer list.

• iflipb-permissive-flip-back (default: nil)

  This variable determines whether iflipb-previous-buffer should use the previous buffer list when it's the first iflipb-*-buffer command in a row. In other words: Running iflipb-previous-buffer after editing a buffer will act as if the current buffer was not visited; it will stay in its original place in the buffer list.

• iflipb-other-buffer-template (default "%s")

  This template string says how to display a non-current buffer name. %s expands to the buffer name.

• iflipb-current-buffer-template (default "[%s]")

  This template string says how to display the current buffer name. %s expands to the buffer name.

• iflipb-buffer-list-function (default #'iflipb-buffer-list)

  This function is used to retrieve the buffer list. The current options are 'iflipb-buffer-list and 'iflipb-ido-buffer-list.

• iflipb-format-buffers-function (default #'iflipb-format-buffers-horizontally)

  This function is used to format buffer names. The function will get the current buffer and a buffer list as arguments. A return value is a string to be displayed. Predefined functions are iflipb-format-buffers-horizontally for a horizontal list and iflipb-format-buffers-vertically for a vertical list. See also iflipb-format-buffers-height.

• iflipb-format-buffers-height (default 5)

  This variable determines the minibuffer height to use when displaying buffer names with iflipb-format-buffers-vertically. The actual height will not exceed the height indicated by max-mini-window-height.

About

iflipb was inspired by cycle-buffer.el. cycle-buffer.el has some more features, but doesn't quite behave like I want, so I wrote my own simple replacement.

Have fun!

/Joel Rosdahl joel@rosdahl.net