mark parent element?

mark parent element?

[Matt Price]

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)
            )))
    )
)

Re: mark parent element?

[Thorsten Jolitz]

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

Re: mark parent element?

[Oleh]

Hi Matt,

> 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 probelm here is that `(org-element-at-point)` doesn't always have
a parent. I'm using plain outline functions for this purpose.
See `worf-mark-left' at https://github.com/abo-abo/worf/blob/master/worf.el.

regards,
Oleh

Re: mark parent element?

[Nicolas Goaziou]

Hello,

Matt Price <moptop99@gmail.com> writes:

> 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)))

It is better to use (org-element-property :parent (org-element-at-point))

>     (let ((parent-props (car (cdr parent))))

You shouldn't extract properties this way. See below.

>       ;; (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))

It is better to use (org-element-property :begin parent)

>             (set-mark (point))
>             (goto-char (plist-get parent-props :end))

It is better to use (org-element-property :end parent)

Anyway, I suggest to use `org-up-element' and `org-mark-element'
instead.


Regards,

-- 
Nicolas Goaziou

Re: mark parent element?

[Matt Price]

On Fri, Mar 14, 2014 at 2:11 PM, Nicolas Goaziou <n.goaziou@gmail.com> wrote:
> Hello,
>
> Matt Price <moptop99@gmail.com> writes:
>
>> 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)))
>
> It is better to use (org-element-property :parent (org-element-at-point))
>
>>     (let ((parent-props (car (cdr parent))))
>
> You shouldn't extract properties this way. See below.
>
>>       ;; (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))
>
> It is better to use (org-element-property :begin parent)
>
>>             (set-mark (point))
>>             (goto-char (plist-get parent-props :end))
>
> It is better to use (org-element-property :end parent)
>
> Anyway, I suggest to use `org-up-element' and `org-mark-element'

I am a little stunned by how awesome this is. it was worth not
noticing org-up-element in the docs to learn the proper way to address
org-element properties.  Thank you Nicolas!  And everyone else too of
course.

Matt



> instead.
>
>
> Regards,
>
> --
> Nicolas Goaziou