Re: master 262a7c9ea0: New minor mode elide-head-mode

[Po Lu <luangruo@yahoo.com>]

Stefan Kangas <stefankangas@gmail.com> writes:

>  (defun elide-head (&optional arg)
>    "Hide header material in buffer according to `elide-head-headers-to-hide'.
> @@ -88,43 +151,17 @@ The header is made invisible with an overlay.  With a prefix arg, show
>  an elided material again.
>  
>  This is suitable as an entry on `find-file-hook' or appropriate mode hooks."
> +  (declare (obsolete elide-head-mode "29.1"))
>    (interactive "P")
>    (if arg
> -      (elide-head-show)
> -    (save-excursion
> -      (save-restriction
> -	(let ((rest elide-head-headers-to-hide)
> -	      beg end)
> -	  (widen)
> -	  (goto-char (point-min))
> -	  (while rest
> -	    (save-excursion
> -	      (when (re-search-forward (caar rest) nil t)
> -		(setq beg (point))
> -		(when (re-search-forward (cdar rest) nil t)
> -		  (setq end (point-marker)
> -			rest nil))))
> -	    (if rest (setq rest (cdr rest))))
> -	  (if (not (and beg end))
> -	      (if (called-interactively-p 'interactive)
> -		  (message "No header found"))
> -	    (goto-char beg)
> -	    (end-of-line)
> -	    (if (overlayp elide-head-overlay)
> -		(move-overlay elide-head-overlay (point-marker) end)
> -	      (setq elide-head-overlay (make-overlay (point-marker) end)))
> -	    (overlay-put elide-head-overlay 'invisible t)
> -	    (overlay-put elide-head-overlay 'evaporate t)
> -	    (overlay-put elide-head-overlay 'after-string "...")))))))
> +      (elide-head--show)
> +    (elide-head--hide)))
>  
>  (defun elide-head-show ()
>    "Show a header in the current buffer elided by \\[elide-head]."
> +  (declare (obsolete elide-head-mode "29.1"))
>    (interactive)
> -  (if (and (overlayp elide-head-overlay)
> -	   (overlay-buffer elide-head-overlay))
> -      (delete-overlay elide-head-overlay)
> -    (if (called-interactively-p 'interactive)
> -	(message "No header hidden"))))
> +  (elide-head--show))

Hmm... couldn't those two obsolete commands be made wrappers around
`elide-head-mode'?

For example:

   (defun elide-head-show ()
     "Show a header in the current buffer elided by \\[elide-head]."
     (interactive)
     (elide-head-mode 0))

And if those commands are made such simple wrappers, they could be
un-obsoleted as well, since it would be useful to explictly disable or
enable elide-head-mode inside `find-file-hook' and other similar places.

Thanks.