Buffer Navigation

Buffer Navigation

[Shug Boabby]

Hi everyone,

The CVS GNU Emacs has introduced a neat way to navigate buffers with
(C-x left/right), reproducible with the code at the end of this message
for older Emacs versions.

However, this navigation goes through *all* buffers, not just the ones
I am editing/reading. Does anyone know of a way I could set up a
similar navigation system that only navigates through *scratch* and
files I have opened myself, i.e. not some temporary buffer a function
or mode has created or opened.

One possible solution I have thought of (*very* roundabout, I'm not
proud of it) would be to create a wrapper function for opening/closing
files which adds/removes the name of the file to/from a list (which is
ordered in some way, such as alphabetically or chronological). then i
bind C-x C-f and C-x k to these wrappers. then navigate only the
buffers in that list.

Please let me know if anyone has a better solution!

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(if (< emacs-major-version 22)
    (progn
      (defalias 'switch-to-next-buffer 'bury-buffer)
      (defun switch-to-previous-buffer ()
        "Switches to previous buffer"
        (interactive)
        (switch-to-buffer (nth (- (length (buffer-list)) 1)
(buffer-list))))))

(if (< emacs-major-version 22)          ; Use C-x <left> and C-x
<right>
    (progn                              ; for buffer navigation
      (global-set-key [(control x) (left)] 'switch-to-previous-buffer)
      (global-set-key [(control x) (right)] 'switch-to-next-buffer)))

RE: Buffer Navigation

[Drew Adams]

    The CVS GNU Emacs has introduced a neat way to navigate buffers with
    (C-x left/right)...

    Does anyone know of a way I could set up a
    similar navigation system that only navigates through *scratch* and
    files I have opened myself, i.e. not some temporary buffer a function
    or mode has created or opened.

There are many libraries that let you quickly switch among existing buffers
(ignoring the temporary buffers you want to ignore). Here is a good place to
start: http://www.emacswiki.org/cgi-bin/wiki/SwitchingBuffers.

I (naturally) recommend my own library, Icicles, which does what you want
(IIUC) and more. The library is here:
http://www.emacswiki.org/cgi-bin/emacs/icicles.el. Doc is here:
http://www.emacswiki.org/cgi-bin/wiki/Icicles.

HTH.

Re: Buffer Navigation

[Shug Boabby]

thanks Drew... I skimmed the documentation which seems to focus on the
completion power of icicle more than the buffer management. how would i
use your library as a drop in replacement for my C-x left/right
bindings?

also, i'm not so keen on the C-h remapping... i unset that standard
"helpful" binding as delete sends C-h in a compliant xterm.

RE: Buffer Navigation

[Drew Adams]

    thanks Drew... I skimmed the documentation which seems to focus on the
    completion power of icicle more than the buffer management.

That's because buffer management is but a tiny consequence of Icicles
general behavior. Icicles does the same thing for any object (file, command,
variable...) as it does for buffers.

    how would i use your library as a drop in replacement
    for my C-x left/right bindings?

Better to continue off-list if you have more questions, as the details are
probably not interesting to others.  Anyway, this should get you started:

Just use your standard buffer-switching command - for example,
`switch-to-buffer' (on `C-x b'). Then use the up/down arrows (or
`C-p'/`C-n') to cycle among buffer-names and choose one (RET). This doesn't
let you use `C-x left' and `C-x right' - you use up/down instead (fewer
keystrokes).

Even better: use command `icicle-buffer'.  Make these bindings, for example.

   (define-key ctl-x-map   "b" 'icicle-buffer) ; `C-x b'
   (define-key ctl-x-4-map "b" 'icicle-buffer-other-window) ; `C-x 4 b'

Now do as in #1, or you can use `C-up'/`C-down' to cycle among buffers,
switching to them at the same time (no need to hit `RET'). With `C-x b' the
switched-to buffer replaces the current buffer in its window. With `C-x 4 b'
the switched-to buffer is opened in another window.

    also, i'm not so keen on the C-h remapping... i unset that standard
    "helpful" binding as delete sends C-h in a compliant xterm.

`C-h' is only rebound for the minibuffer - Icicles changes no global
bindings. From what you said, you've apparently already figured out how to
unset the `C-h' bindings (and bind `icicle-help-on-candidate' to another
minibuffer key sequence).

Re: Buffer Navigation

[Shug Boabby]

from that wiki entry i found the bs calls... silly me for trying to
re-implement their simple next/previous stuff. bs-show is nice too.

however, none of these numerous adons do what i want... which is to
only navigate through files which i, myself, not some mode or function
call, have opened. i don't want to go writing out regexs for the types
of files i usually edit... i just want emacs to be smart enough to know
what i have opened by hand. is that kind of information stored anyway?
or is writing a wrapper for open/close the only solution...

RE: Buffer Navigation

[Drew Adams]

    from that wiki entry i found the bs calls... silly me for trying to
    re-implement their simple next/previous stuff. bs-show is nice too.

    however, none of these numerous adons do what i want... which is to
    only navigate through files which i, myself, not some mode or function
    call, have opened. i don't want to go writing out regexs for the types
    of files i usually edit... i just want emacs to be smart enough to know
    what i have opened by hand. is that kind of information stored anyway?
    or is writing a wrapper for open/close the only solution...

Buffer and file commands normally filter out uninteresting buffers (those
whose names start with a space) and files (those whose names match
`completion-ignored-extensions', for example), but that isn't exactly what
you're asking for.

You can certainly write something yourself - just keep track of the buffers
and files you open yourself. If you put their names on a list, you can use
Icicles cycling and completion to access them. But this requires a little
Emacs Lisp.

If a list of recently used files is sufficient for you (they might not still
be open, so this is not exactly what you asked for), then there are
libraries that do that too.

Icicles, for instance, has commands `icicle-recent-file' and
`icicle-recent-file-other-window', which let you open a recently visited
file (filename completion and cycling available, as usual). This uses
library `recentf.el', which persistently records your visited files.

You can also cycle through the files you opened during the current session
only, by using Icicles command `icicle-history' (bound to `M-h' in the
minibuffer). You can use this on any minibuffer input, including filename
input. During file-name completion, it lets you complete to, or cycle
through, your recently visited files of the current session. For instance,
`C-x f', then `M-h', then use up/down arrows to cycle through recent files
and choose one (RET).

(If you use library `savehistory.el', then `icicle-history' uses the
persistent minibuffer histories saved by that library.)

HTH.

Re: Buffer Navigation

[Thien-Thi Nguyen]

"Shug Boabby" <Shug.Boabby@gmail.com> writes:

> is writing a wrapper for open/close the only solution...

write a function that sets a buffer-local variable (for example, you
could name it `shug-boabby-interesting-buffer-p') to a recognizable
value.  arrange for `find-file-hook' to call this function, but only if
`this-command' is `find-file'.  use your buffer-selection/management
package of choice to test for this value during its filtering pass.

when you kill the buffer, the buffer-local variable will be deleted
along w/ the buffer, so that side of things is worry free.

of course, you can write a wrapper anyway for the exercise.  there's
nothing wrong w/ finding and following many paths.

thi

Re: Buffer Navigation

[Shug Boabby]

actually the bs- commands seem to be doing what i want. with one small
issue to sort out: i currently have:

  (setq bs-default-sort-name "by name")
  (setq bs-must-always-show-regexp "\\*scratch\\*\\|\\*Python\\*")
  (setq bs-dont-show-regexp "*_region_\\.tex*")

but the buffer (and file) named "_region_.tex" keeps appearing in my
buffer list! grr... how do i get it out of my buffer menu and cycle
list? i can't seem to get the dont-show list working for anything... am
i setting it's value correctly? is it perhaps broken in the CVS Emacs
at the moment?

Re: Buffer Navigation

[Kevin Rodgers]

Shug Boabby wrote:
> actually the bs- commands seem to be doing what i want. with one small
> issue to sort out: i currently have:
> 
>   (setq bs-default-sort-name "by name")
>   (setq bs-must-always-show-regexp "\\*scratch\\*\\|\\*Python\\*")
>   (setq bs-dont-show-regexp "*_region_\\.tex*")
> 
> but the buffer (and file) named "_region_.tex" keeps appearing in my
> buffer list! grr... how do i get it out of my buffer menu and cycle
> list? i can't seem to get the dont-show list working for anything... am
> i setting it's value correctly? is it perhaps broken in the CVS Emacs
> at the moment?

The asterisk at the beginning of the regexp is interpreted literally.

I think you want just

(setq bs-dont-show-regexp "_region_\\.tex")

-- 
Kevin Rodgers

Re: Buffer Navigation

[Shug Boabby]

cheers kevin, but apparently in newer versions of emacs (and i suppose
incorrectly documented for older versions of bs-*), this is not a user
editable variable... talk about killing the power of the mode.