daemianmack/iflipb

iflipb.el - interactively flip between recently visited buffers

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. 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.)

Operation

iflipb provides two commands: iflipb-next-buffer and iflipb-previous-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 regarded as 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.

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 names start 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 the variables iflipb-ignore-buffers and iflipb-always-ignore-buffers for how to change this.

Installation

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

(require 'iflipb)

in your .emacs file or equivalent.

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, put something like this in your .emacs:

(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)

Configuration

There are four variables that 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 may be either 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 (a return value of nil from the function means include and non-nil means exclude). If the value is a list, the filter matches if any of the elements in the value match.

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

  This variable determines which buffers to always ignore. The value may be either 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 (a return value of nil from the function means include and non-nil means exclude). If the value is a list, the filter matches if any of the elements in the value 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.

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