Re: Simple isearch concerns

[Gregory Heytings <gregory@heytings.org>]

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>>> 1) Are there any option to move the cursor to the start of the 
>>> candidate after the search? I see that there is an isearch-other-end. 
>>> But it is not a custom but an internal variable. Now I am using a hook 
>>> but it seems a bit hacky.
>> 
>> As you see from the discussion, adding a defcustom makes little sense, 
>> because this feature might be needed only occasionally, so better to be 
>> bound to a special key, e.g. C-RET to exit and move to other-end, S-RET 
>> to exit and mark the found string as a region.
>
> Note that neither C-RET nor S-RET are available in a terminal.
>
> What I consider to be the most useful feature of CTRLF, namely the 
> possibility to scroll among the matches, has not much been discussed so 
> far, alas.  I attach a short patch which implements that feature in 
> isearch.  I've been using it for a day, and I'm convinced it's a 
> must-have, it makes navigating among the search matches much faster. 
> WDYT?
>

Sorry, there was a typo in the previous patch, I attach a corrected one.

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From a1dd7f1f93f0a2b74c7f9e43d97f5b5f09e16b69 Mon Sep 17 00:00:00 2001
From: Gregory Heytings <gregory@heytings.org>
Date: Tue, 6 Apr 2021 00:17:39 +0000
Subject: [PATCH] New user option to scroll isearch matches

* lisp/isearch.el (isearch-allow-match-scroll): New user option.
(isearch-scroll-up, isearch-scroll-down): New commands to scroll
the current search match, that complement the existing
isearch-beginning-of-buffer and isearch-end-of-buffer commands.
(isearch-pre-command-hook): Handle the new option and commands.

* etc/NEWS: Mention the new user option.

* doc/emacs/search.texi: Document the new user option.
---
 doc/emacs/search.texi |  8 ++++++++
 etc/NEWS              |  8 ++++++++
 lisp/isearch.el       | 47 ++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/doc/emacs/search.texi b/doc/emacs/search.texi
index f3c42bcea7..6c161d4c58 100644
--- a/doc/emacs/search.texi
+++ b/doc/emacs/search.texi
@@ -587,6 +587,14 @@ Not Exiting Isearch
 an incremental search.  This feature is disabled if
 @code{isearch-allow-scroll} is @code{nil} (which it is by default).
 
+@vindex isearch-allow-match-scroll
+  Likewise, if you change the variable @code{isearch-allow-match-scroll}
+to a non-@code{nil} value, this enables the use of the keyboard scrolling
+commands @kbd{M-<}, @kbd{M->}, @kbd{C-v} and @kbd{M-v}, to move
+respectively to the first first occurrence of the current search
+string in the buffer, the last one, the first one after the current
+window, and the last one before the current window.
+
 @item Motion Commands
 @cindex motion commands, during incremental search
 When @code{isearch-yank-on-move} is customized to @code{shift},
diff --git a/etc/NEWS b/etc/NEWS
index c8400ba8c2..411ea72e7c 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -367,6 +367,14 @@ trying to be non-destructive.
 This command opens a new buffer called "*Memory Report*" and gives a
 summary of where Emacs is using memory currently.
 
++++
+** New user option 'isearch-allow-match-scroll'.
+When this option is set, the commands 'beginning-of-buffer',
+'end-of-buffer', 'scroll-up-command' and 'scroll-down-command' move
+respectively to the first first occurrence of the current search
+string in the buffer, the last one, the first one after the current
+window, and the last one before the current window.
+
 ** Outline
 
 +++
diff --git a/lisp/isearch.el b/lisp/isearch.el
index 943e24aa56..bdb2f147ab 100644
--- a/lisp/isearch.el
+++ b/lisp/isearch.el
@@ -1942,6 +1942,23 @@ isearch-end-of-buffer
     (goto-char (point-max))
     (isearch-repeat 'backward arg)))
 
+(defun isearch-scroll-up ()
+  "Go to the first occurrence of the current search string after window.
+Move point to the end of the window, and search forward."
+  (interactive)
+  (setq isearch-just-started t)
+  (goto-char (window-end))
+  (isearch-repeat 'forward))
+
+(defun isearch-scroll-down ()
+  "Go to the first occurrence of the current search string before window.
+Move point to the beginning of the window, recenter it, and search backward."
+  (interactive)
+  (setq isearch-just-started t)
+  (goto-char (window-start))
+  (recenter nil t)
+  (isearch-repeat 'backward))
+
 \f
 ;;; Toggles for `isearch-regexp-function' and `search-default-mode'.
 (defmacro isearch-define-mode-toggle (mode key function &optional docstring &rest body)
@@ -2840,12 +2857,35 @@ isearch-allow-scroll
 However, you cannot scroll far enough that the current match is
 no longer visible (is off screen).  But if the value is `unlimited'
 that limitation is removed and you can scroll any distance off screen.
-If nil, scrolling commands exit Isearch mode."
+If nil, scrolling commands exit Isearch mode.
+See also the related option `isearch-allow-match-scroll'."
   :type '(choice (const :tag "Scrolling exits Isearch" nil)
                  (const :tag "Scrolling with current match on screen" t)
                  (const :tag "Scrolling with current match off screen" unlimited))
   :group 'isearch)
 
+(put 'beginning-of-buffer 'isearch-match-scroll t)
+(put 'end-of-buffer 'isearch-match-scroll t)
+(put 'scroll-up-command 'isearch-match-scroll t)
+(put 'scroll-down-command 'isearch-match-scroll t)
+
+(put 'beginning-of-buffer 'isearch-match-scroll-command 'isearch-beginning-of-buffer)
+(put 'end-of-buffer 'isearch-match-scroll-command 'isearch-end-of-buffer)
+(put 'scroll-up-command 'isearch-match-scroll-command 'isearch-scroll-up)
+(put 'scroll-down-command 'isearch-match-scroll-command 'isearch-scroll-down)
+
+(defcustom isearch-allow-match-scroll nil
+  "Whether scrolling to another match is allowed during incremental search.
+If non-nil, the four scrolling commands `beginning-of-buffer',
+`end-of-buffer', `scroll-up-command' and `scroll-down-command' move
+respectively to the first first occurrence of the current search string in
+the buffer, the last one, the first one after the current window, and the
+last one before the current window.
+See also the related option `isearch-allow-scroll'."
+  :type '(choice (const :tag "Off" nil)
+                 (const tag "On" t))
+  :group 'isearch)
+
 (defcustom isearch-allow-prefix t
   "Whether prefix arguments are allowed during incremental search.
 If non-nil, entering a prefix argument will not terminate the
@@ -2947,6 +2987,11 @@ isearch-pre-command-hook
      ;; Optionally edit the search string instead of exiting.
      ((eq search-exit-option 'edit)
       (setq this-command 'isearch-edit-string))
+     ;; Handle match scrolling functions
+     ((and isearch-allow-match-scroll
+           (symbolp this-command)
+           (eq (get this-command 'isearch-match-scroll) t))
+      (setq this-command (get this-command 'isearch-match-scroll-command)))
      ;; Handle a scrolling function or prefix argument.
      ((or (and isearch-allow-prefix
                (memq this-command '(universal-argument universal-argument-more
-- 
2.30.2