bug#25577: 26.0.50; Show Ibuffer and jump to line listing current buffer

[Tino Calancha]

Severity: wishlist

Suppose current buffer is *foo*, then `list-buffers'
list the buffers with point set at the line listing *foo*.

In the case of `ibuffer', if *Ibuffer* already exists,
the effect of this command is pretty much like
(switch-to-buffer "*Ibuffer*")
i.e., the point is preserved.  This is useful, but quite often
i wish the other behaviour:
To show *Ibuffer* and set point at the line listing *foo*.

This is handy when you have customized `ibuffer-saved-filter-groups',
and you have many lived buffers.

We might get this behaviour in several ways:

1) Via prefix argument: we already use a raw prefix to decide if we
   display *Ibuffer* in a new window or in the current one.
   It might be possible to define prefix "C-u C-u" to mean
   show *Ibuffer* with point at the line showing *foo*.
   This would work but not the easiest to type solution, though.

2) Add a new function:
  (defun ibuffer-jump (&optional other-window-p)
    "Call Ibuffer and set point at the line listing the current buffer."
    (interactive "P")
    (let ((name (buffer-name)))
      (ibuffer other-window-p)
      (ignore-errors (ibuffer-jump-to-buffer name))))

3) Add a new option, something like
  `ibuffer-point-at-current-buffer'.
  When this option is not nil, then `ibuffer' set
  point at *foo*.

I prefer 2) over 3) because i can get both behaviours with easy
in the interactive session.

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>From 5630bf7425ed0114cd1bae55f9761f351b951f5f Mon Sep 17 00:00:00 2001
From: Tino Calancha <tino.calancha@gmail.com>
Date: Mon, 30 Jan 2017 20:21:14 +0900
Subject: [PATCH] Show Ibuffer and jump to line listing current buffer

* lisp/ibuffer.el (ibuffer-jump): New command (Bug#25577).
* etc/NEWS: Add entry for the new command.
---
 etc/NEWS        | 2 ++
 lisp/ibuffer.el | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/etc/NEWS b/etc/NEWS
index 12ff21f39a..b61bbe3b36 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -361,6 +361,8 @@ added: `C-c C-s C-m C-m'.
 ** Ibuffer
 
 ---
+*** New command `ibuffer-jump'.
+---
 *** New filter commands `ibuffer-filter-by-basename',
 `ibuffer-filter-by-file-extension', `ibuffer-filter-by-directory',
 `ibuffer-filter-by-starred-name', `ibuffer-filter-by-modified'
diff --git a/lisp/ibuffer.el b/lisp/ibuffer.el
index c6e5e471a3..8a6040c1aa 100644
--- a/lisp/ibuffer.el
+++ b/lisp/ibuffer.el
@@ -2490,6 +2490,15 @@ ibuffer
        (unless ibuffer-expert
          (message "Commands: m, u, t, RET, g, k, S, D, Q; q to quit; h for 
help"))))))
 
+;;;###autoload
+(defun ibuffer-jump (&optional other-window)
+  "Call Ibuffer and set point at the line listing the current buffer.
+If optional arg OTHER-WINDOW is non-nil, then use another window."
+  (interactive "P")
+  (let ((name (buffer-name)))
+    (ibuffer other-window-p)
+    (ignore-errors (ibuffer-jump-to-buffer name))))
+
 (put 'ibuffer-mode 'mode-class 'special)
 (define-derived-mode ibuffer-mode special-mode "IBuffer"
   "A major mode for viewing a list of buffers.
-- 
2.11.0

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In GNU Emacs 26.0.50.1 (x86_64-pc-linux-gnu, GTK+ Version 3.22.6)
 of 2017-01-29
Repository revision: 8ba236e772b64d0bb021aa691bd7eacf4b7f3ae4