Re: [EXPERIMENTAL PATCH] Extending Isearch-repeat-forward/backward to support a prefix argument following suggesion by Juri Linkov

[Gideon Stupp <gideon.stupp@gmail.com>]

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On 1/31/12, Juri Linkov <juri@jurta.org> wrote:
>> So how about the following behavior (for brevity I will describe only
>> isearch-repeat-forward): (1) if you use isearch-repeat-forward then at
>> the end of the operation you must be in a search-forward state; (2)
>> the numerical value decides how many searches are done and (3) the
>> sign defines the direction.
>
> Thanks.  I agree that these rules are reasonable.
>
Hi Juri,
Please see attached patch. Note that I decided to stop the repeated
search at wraparound and any other case where the search fails (eq
isearch-sucess nil).

Thanks, Gideon.

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diff --git a/lisp/isearch.el b/lisp/isearch.el
index ce75911..04f29ba 100644
--- a/lisp/isearch.el
+++ b/lisp/isearch.el
@@ -1340,15 +1340,60 @@ Use `isearch-exit' to quit without signaling."
   (isearch-push-state)
   (isearch-update))
 
-(defun isearch-repeat-forward ()
+(defun isearch-repeat-forward (&optional arg)
   "Repeat incremental search forwards."
-  (interactive)
-  (isearch-repeat 'forward))
-
-(defun isearch-repeat-backward ()
+  (interactive "P")
+  (if arg
+      (let ((narg (prefix-numeric-value arg)))
+	(if (< narg 0)
+	    ;; Go backward.
+	    (progn
+	      ;; Switch direction if necessary
+	      (if isearch-forward (isearch-repeat 'backward))
+	      ;; Go back narg times
+	      (while (and isearch-success (< narg 0))
+		(isearch-repeat 'backward)
+		(setq narg (1+ narg)))
+	      ;; Switch back to forward search
+	      (isearch-repeat 'forward))
+	  ;; Go forward
+	  (progn
+	    ;; Switch direction if necessary
+	    (or isearch-forward (isearch-repeat 'forward))
+	    ;; Go forward narg times
+	    (while (and isearch-success (> narg 0))
+	      (isearch-repeat 'forward)
+	      (setq narg (1- narg))))))
+    ;; No argument
+    (isearch-repeat 'forward)))
+
+(defun isearch-repeat-backward (&optional arg)
   "Repeat incremental search backwards."
-  (interactive)
-  (isearch-repeat 'backward))
+  (interactive "P")
+  (if arg
+    (let ((narg (prefix-numeric-value arg)))
+     (if (< narg 0)
+	 ;; Go forward.
+	 (progn
+	   ;; Switch direction if necessary
+	   (or isearch-forward (isearch-repeat 'forward))
+	   ;; Go back narg times
+	   (while (and isearch-success(< narg 0))
+	     (isearch-repeat 'forward)
+	     (setq narg (1+ narg)))
+	   ;; Switch back to backward search
+	   (isearch-repeat 'backward))
+       ;; Go backward
+       (progn
+	 ;; Switch direction if necessary
+	 (if isearch-forward (isearch-repeat 'backward))
+	 ;; Go backward narg times
+	 (while (and isearch-success (> narg 0))
+	   (isearch-repeat 'backward)
+	   (setq narg (1- narg))))))
+    ;; No argument
+    (isearch-repeat 'backward)))
+
 
 (defun isearch-toggle-regexp ()
   "Toggle regexp searching on or off."