Re: mark parent element?

[Thorsten Jolitz <tjolitz@gmail.com>]

Matt Price <moptop99@gmail.com> writes:

> Hi,
>
> I'm trying to write a function that will mark the parent of the
> current element.  I think I understand how to do it but for some
> reason I can get the mark to persist after the funciton is called.  I
> think it's really an elisp problem, not an org problem, but am hoping
> someone can ehelp me.  Here's what I have:
>
> (defun er/mark-org-parent-element ()
>   "Marks an org parent element"
>   (interactive)
>   (let ((parent (plist-get (car (cdr (org-element-at-point))) :parent)))
>     (let ((parent-props (car (cdr parent))))
>       ;; (print parent-props)
>       ;; (print (plist-get parent-props :begin))
>       ;; (print (plist-get parent-props :end))
>       (if (plist-get parent-props :begin)
>           (progn
>             (goto-char (plist-get parent-props :begin))
>             (set-mark (point))
>             (goto-char (plist-get parent-props :end))
>             (exchange-point-and-mark)
>             )))
>     )
> )

the set-mark doc give two hints in my eyes:

,-----------------------------------------------------------------------
| set-mark is a compiled Lisp function in `simple.el'.
| 
| (set-mark POS)
| 
| Set this buffer's mark to POS.  Don't use this function!
| That is to say, don't use this function unless you want
| the user to see that the mark has moved, and you want the previous
| mark position to be lost.
| 
| Normally, when a new mark is set, the old one should go on the stack.
| This is why most applications should use `push-mark', not `set-mark'.
| 
| Novice Emacs Lisp programmers often try to use the mark for the wrong
| purposes.  The mark saves a location for the user's convenience.
| Most editing commands should not alter the mark.
| To remember a location for internal use in the Lisp program,
| store it in a Lisp variable.  Example:
| 
|    (let ((beg (point))) (forward-line 1) (delete-region beg (point))).
`-----------------------------------------------------------------------

 1. maybe try push-mark instead of set-mark?  
 
 2. maybe avoid marks completely if you just want make your program act
 on a region


-- 
cheers,
Thorsten