Re: [PATCH] delete-trailing-whitespace on active region

[Deniz Dogan <deniz.a.m.dogan@gmail.com>]

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2011/2/10 Stefan Monnier <monnier@iro.umontreal.ca>:
>> +  (interactive "*r")
>
> Using "r" and then checking region-active-p sounds clever, but is wrong:
> - "r" will fail if the mark has never been set in the current buffer.
> - checking region-active-p is wrong in non-interactive use.
> I.e. the `interactive' spec should do the region-active-p check.
> Oh, and it should use use-region-p instead of region-active-p.
>

Thanks for the review

Attached is a reworked patch. Is it better now?

-- 
Deniz Dogan

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=== modified file 'lisp/simple.el'
--- lisp/simple.el	2011-02-01 21:22:21 +0000
+++ lisp/simple.el	2011-02-10 15:30:53 +0000
@@ -614,22 +614,26 @@
     (if (looking-at "^[ \t]*\n\\'")
 	(delete-region (point) (point-max)))))
 
-(defun delete-trailing-whitespace ()
+(defun delete-trailing-whitespace (&optional start end)
   "Delete all the trailing whitespace across the current buffer.
 All whitespace after the last non-whitespace character in a line is deleted.
 This respects narrowing, created by \\[narrow-to-region] and friends.
-A formfeed is not considered whitespace by this function."
-  (interactive "*")
+A formfeed is not considered whitespace by this function.
+If the region is active, only delete whitespace within the region."
+  (interactive (if (use-region-p)
+                   (list (region-beginning) (region-end))
+                 (list (point-min) (point-max))))
+  (barf-if-buffer-read-only)
   (save-match-data
     (save-excursion
-      (goto-char (point-min))
-      (while (re-search-forward "\\s-$" nil t)
-	(skip-syntax-backward "-" (save-excursion (forward-line 0) (point)))
-	;; Don't delete formfeeds, even if they are considered whitespace.
-	(save-match-data
-	  (if (looking-at ".*\f")
-	      (goto-char (match-end 0))))
-	(delete-region (point) (match-end 0))))))
+      (goto-char start)
+      (while (re-search-forward "\\s-$" end t)
+        (skip-syntax-backward "-" (save-excursion (forward-line 0) (point)))
+        ;; Don't delete formfeeds, even if they are considered whitespace.
+        (save-match-data
+          (if (looking-at ".*\f")
+              (goto-char (match-end 0))))
+        (delete-region (point) (match-end 0))))))
 
 (defun newline-and-indent ()
   "Insert a newline, then indent according to major mode.