[PATCH] Filter list-buffers by a regexp (interactively)

[PATCH] Filter list-buffers by a regexp (interactively)

[Bastien]

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The patch below allows to use C-u C-u C-x C-b to interactively enter
a regular expression to only list buffers with a matching name.

The need came up on Org-mode when people have many agenda buffers and
want to only list those.

Any comment and/or improvement appreciated, thanks!


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=== modified file 'lisp/buff-menu.el'
*** lisp/buff-menu.el	2014-07-21 05:38:17 +0000
--- lisp/buff-menu.el	2014-07-28 13:12:57 +0000
***************
*** 127,132 ****
--- 127,133 ----
      (define-key map "b" 'Buffer-menu-bury)
      (define-key map "V" 'Buffer-menu-view)
      (define-key map "T" 'Buffer-menu-toggle-files-only)
+     (define-key map "*" 'Buffer-menu-filter-by-regexp)
      (define-key map (kbd "M-s a C-s")   'Buffer-menu-isearch-buffers)
      (define-key map (kbd "M-s a M-C-s") 'Buffer-menu-isearch-buffers-regexp)
      (define-key map (kbd "M-s a C-o") 'Buffer-menu-multi-occur)
***************
*** 146,151 ****
--- 147,155 ----
        '(menu-item "Show Only File Buffers" Buffer-menu-toggle-files-only
  		  :button (:toggle . Buffer-menu-files-only)
  		  :help "Toggle whether the current buffer-menu displays only file buffers"))
+     (bindings--define-key menu-map [tr]
+       '(menu-item "Filter List by Regexp" Buffer-menu-filter-by-regexp
+ 		  :help "Filter the list of buffers by a regular expression"))
      (bindings--define-key menu-map [s1] menu-bar-separator)
      ;; FIXME: The "Select" entries could use better names...
      (bindings--define-key menu-map [sel]
***************
*** 243,258 ****
  \\[Buffer-menu-toggle-read-only]    Toggle read-only status of buffer on this line.
  \\[revert-buffer]    Update the list of buffers.
  \\[Buffer-menu-toggle-files-only]    Toggle whether the menu displays only file buffers.
  \\[Buffer-menu-bury]    Bury the buffer listed on this line."
    (set (make-local-variable 'buffer-stale-function)
         (lambda (&optional _noconfirm) 'fast))
    (add-hook 'tabulated-list-revert-hook 'list-buffers--refresh nil t))
  
! (defun buffer-menu (&optional arg)
    "Switch to the Buffer Menu.
  By default, the Buffer Menu lists all buffers except those whose
  names start with a space (which are for internal use).  With
! prefix argument ARG, show only buffers that are visiting files.
  
  In the Buffer Menu, the first column (denoted \"C\") shows \".\"
  for the buffer from which you came, \">\" for buffers you mark to
--- 247,267 ----
  \\[Buffer-menu-toggle-read-only]    Toggle read-only status of buffer on this line.
  \\[revert-buffer]    Update the list of buffers.
  \\[Buffer-menu-toggle-files-only]    Toggle whether the menu displays only file buffers.
+ \\[Buffer-menu-filter-by-regexp]     Prompt for a regexp and display matching buffers.
  \\[Buffer-menu-bury]    Bury the buffer listed on this line."
    (set (make-local-variable 'buffer-stale-function)
         (lambda (&optional _noconfirm) 'fast))
    (add-hook 'tabulated-list-revert-hook 'list-buffers--refresh nil t))
  
! (defun buffer-menu (&optional arg regexp)
    "Switch to the Buffer Menu.
  By default, the Buffer Menu lists all buffers except those whose
  names start with a space (which are for internal use).  With
! a prefix argument ARG, show only buffers that are visiting files.
! With two universal prefix argument, prompt for a regular expression
! to only display buffers with a matching name.
! 
! When REGEXP is non-nil, only list buffers matching the regexp.
  
  In the Buffer Menu, the first column (denoted \"C\") shows \".\"
  for the buffer from which you came, \">\" for buffers you mark to
***************
*** 268,300 ****
  See `Buffer-menu-mode' for the keybindings available the Buffer
  Menu."
    (interactive "P")
!   (switch-to-buffer (list-buffers-noselect arg))
!   (message
!    "Commands: d, s, x, u; f, o, 1, 2, m, v; ~, %%; q to quit; ? for help."))
  
! (defun buffer-menu-other-window (&optional arg)
    "Display the Buffer Menu in another window.
  See `buffer-menu' for a description of the Buffer Menu.
  
  By default, all buffers are listed except those whose names start
! with a space (which are for internal use).  With prefix argument
! ARG, show only buffers that are visiting files."
    (interactive "P")
!   (switch-to-buffer-other-window (list-buffers-noselect arg))
!   (message
!    "Commands: d, s, x, u; f, o, 1, 2, m, v; ~, %%; q to quit; ? for help."))
  
  ;;;###autoload
! (defun list-buffers (&optional arg)
    "Display a list of existing buffers.
  The list is displayed in a buffer named \"*Buffer List*\".
  See `buffer-menu' for a description of the Buffer Menu.
  
  By default, all buffers are listed except those whose names start
  with a space (which are for internal use).  With prefix argument
! ARG, show only buffers that are visiting files."
    (interactive "P")
!   (display-buffer (list-buffers-noselect arg)))
  
  (defun Buffer-menu-toggle-files-only (arg)
    "Toggle whether the current buffer-menu displays only file buffers.
--- 277,353 ----
  See `Buffer-menu-mode' for the keybindings available the Buffer
  Menu."
    (interactive "P")
!   (let ((re-filter
! 	 (or regexp
! 	     (and (equal arg '(16))
! 		  (read-from-minibuffer "Regexp filter: ")))))
!     (switch-to-buffer
!      (list-buffers-noselect
!       arg
!       (if re-filter
! 	  (delq
! 	   nil
! 	   (mapcar (lambda (b)
! 		     (if (string-match re-filter (buffer-name b)) b))
! 		   (buffer-list)))))
!      (message
!       "Commands: d, s, x, u; f, o, 1, 2, m, v; ~, %%; q to quit; ? for help."))))
  
! (defun buffer-menu-other-window (&optional arg regexp)
    "Display the Buffer Menu in another window.
  See `buffer-menu' for a description of the Buffer Menu.
  
  By default, all buffers are listed except those whose names start
! with a space (which are for internal use).  With a single prefix
! argument ARG, show only buffers that are visiting files.  With two
! universal prefix argument, prompt for a regular expression to only
! display buffers with a matching name.
! 
! When REGEXP is non-nil, only list buffers matching the regexp."
    (interactive "P")
!   (let ((re-filter
! 	 (or regexp
! 	     (and (equal arg '(16))
! 		  (read-from-minibuffer "Regexp filter: ")))))
!     (switch-to-buffer-other-window
!      (list-buffers-noselect
!       arg
!       (if re-filter
! 	  (delq
! 	   nil
! 	   (mapcar (lambda (b)
! 		     (if (string-match re-filter (buffer-name b)) b))
! 		   (buffer-list))))))
!     (message
!      "Commands: d, s, x, u; f, o, 1, 2, m, v; ~, %%; q to quit; ? for help.")))
  
  ;;;###autoload
! (defun list-buffers (&optional arg regexp)
    "Display a list of existing buffers.
  The list is displayed in a buffer named \"*Buffer List*\".
  See `buffer-menu' for a description of the Buffer Menu.
  
  By default, all buffers are listed except those whose names start
  with a space (which are for internal use).  With prefix argument
! ARG, show only buffers that are visiting files.  With two universal
! prefix argument, prompt for a regular expression to only display
! buffers with a matching name.
! 
! When REGEXP is non-nil, only list buffers matching the regexp."
    (interactive "P")
!   (let ((re-filter
! 	 (or regexp
! 	     (and (equal arg '(16))
! 		  (read-from-minibuffer "Regexp filter: ")))))
!     (display-buffer
!      (list-buffers-noselect
!       arg
!       (if re-filter
! 	  (delq
! 	   nil
! 	   (mapcar (lambda (b)
! 		     (if (string-match re-filter (buffer-name b)) b))
! 		   (buffer-list))))))))
  
  (defun Buffer-menu-toggle-files-only (arg)
    "Toggle whether the current buffer-menu displays only file buffers.
***************
*** 309,314 ****
--- 362,373 ----
  	     "Showing all non-internal buffers."))
    (revert-buffer))
  
+ (defun Buffer-menu-filter-by-regexp ()
+   "Limit the buffer list to buffers which name matches a regexp."
+   (interactive)
+   (list-buffers '(16))
+   (message "Hit `g' to remove the filter"))
+ 
  (defalias 'Buffer-menu-sort 'tabulated-list-sort)
  \f
  
***************
*** 588,594 ****
      (with-current-buffer buffer
        (Buffer-menu-mode)
        (setq Buffer-menu-files-only
! 	    (and files-only (>= (prefix-numeric-value files-only) 0)))
        (list-buffers--refresh buffer-list old-buffer)
        (tabulated-list-print))
      buffer))
--- 647,654 ----
      (with-current-buffer buffer
        (Buffer-menu-mode)
        (setq Buffer-menu-files-only
! 	    (and (equal '(4) files-only)
! 		 (>= (prefix-numeric-value files-only) 0)))
        (list-buffers--refresh buffer-list old-buffer)
        (tabulated-list-print))
      buffer))


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-- 
 Bastien

Re: [PATCH] Filter list-buffers by a regexp (interactively)

[Bastien]

Bastien <bzg@gnu.org> writes:

> The patch below allows to use C-u C-u C-x C-b to interactively enter
> a regular expression to only list buffers with a matching name.
>
> The need came up on Org-mode when people have many agenda buffers and
> want to only list those.
>
> Any comment and/or improvement appreciated, thanks!

I plan to commit this to trunk by the end of the month if there are
no comments/questions.

Thanks,

-- 
 Bastien

Re: [PATCH] Filter list-buffers by a regexp (interactively)

[Stefan Monnier]

> The patch below allows to use C-u C-u C-x C-b to interactively enter
> a regular expression to only list buffers with a matching name.

We generally try to avoid using things like C-u C-u.
IOW we should try to find some other way to provide this functionality.


        Stefan

Re: [PATCH] Filter list-buffers by a regexp (interactively)

[Bastien]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> The patch below allows to use C-u C-u C-x C-b to interactively enter
>> a regular expression to only list buffers with a matching name.
>
> We generally try to avoid using things like C-u C-u.

Good to know.  (I don't dare looking at changes we need in Org to
follow this recommendation.  But I will.)

> IOW we should try to find some other way to provide this
> functionality.

Maybe adding a new command and bind it to C-x C-B?  Or perhaps
this is also not recommended?

Thanks for the feedback,

-- 
 Bastien

Re: [PATCH] Filter list-buffers by a regexp (interactively)

[Stefan Monnier]

>>> The patch below allows to use C-u C-u C-x C-b to interactively enter
>>> a regular expression to only list buffers with a matching name.
>> We generally try to avoid using things like C-u C-u.
> Good to know.  (I don't dare looking at changes we need in Org to
> follow this recommendation.  But I will.)

Org being its own program, it's not too terrible if it has its own set
of conventions.  But C-x C-b is a "core" command.

> Maybe adding a new command and bind it to C-x C-B?  Or perhaps
> this is also not recommended?

C-B is pretty hard to get to in some cases (e.g. ttys), so indeed, we
prefer not to do that.

But maybe we can change the meaning of C-u C-x C-b, or something like that.


        Stefan

RE: [PATCH] Filter list-buffers by a regexp (interactively)

[Herring, Davis]

> But maybe we can change the meaning of C-u C-x C-b, or something like that.

Since C-x C-b is fast to execute, and typing the regexp is already several keystrokes, what about providing a filter command within the buffer list?

Davis

Re: [PATCH] Filter list-buffers by a regexp (interactively)

[Juri Linkov]

> Since C-x C-b is fast to execute, and typing the regexp is already several keystrokes,
> what about providing a filter command within the buffer list?

Like in Ibuffer: '% n' - Mark buffers by their name, using a regexp.

Re: [PATCH] Filter list-buffers by a regexp (interactively)

[Bastien]

Juri Linkov <juri@jurta.org> writes:

>> Since C-x C-b is fast to execute, and typing the regexp is already several keystrokes,
>> what about providing a filter command within the buffer list?

Yes, that's already what '*' does in the original patch.

> Like in Ibuffer: '% n' - Mark buffers by their name, using a regexp.

Yes, why not too.

What about C-u C-x C-b prompting the user if she wants to filter by
[f]iles only or by a [r]egexp?

-- 
 Bastien

Re: [PATCH] Filter list-buffers by a regexp (interactively)

[Stefan Monnier]

> What about C-u C-x C-b prompting the user if she wants to filter by
> [f]iles only or by a [r]egexp?

An empty regexp could mean "only show file buffers".
It's an "incompatible change" and some users may not like it, but maybe
more users will benefit than will suffer.  What do people think?


        Stefan