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

[Stefan Monnier <monnier@iro.umontreal.ca>]

> Attached is a reworked patch. Is it better now?

Yes, please install after fixing the details below.

> -- 
> Deniz Dogan

> === 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)

Nitpick: the barf-if-buffer-read-only should be in the interactive form.
You can keep passing nil rather than point-min/max when the region is
not used (see below).

>    (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)

But here you shouldn't assume that start/end won't be nil, since the
function might be called without arguments from Elisp code.


        Stefan