Add a function to test for invisible characters?

Add a function to test for invisible characters?

[Lennart Borgman (gmail)]

I asked some time ago if a function to test if a character is invisible. 
I think nothing has been done to this, or am I mistaken?

I think some code in Emacs currently gets this wrong. Do for example 
reveal get this right?

Below is such a function that I use and that I think follow the 
specifications for this. Should not something like this be in Emacs?

(defun tabkey2-invisible-p (pos)
   "Return non-nil if the character after POS is currently invisible."
   (let ((prop (get-char-property pos 'invisible)))
     (if (eq buffer-invisibility-spec t)
         prop
       (if (listp prop)
           (catch 'invis
             (dolist (p prop)
               (when (or (memq p buffer-invisibility-spec)
                         (assq p buffer-invisibility-spec))
                 (throw 'invis t))))
         (or (memq prop buffer-invisibility-spec)
             (assq prop buffer-invisibility-spec))))))

Re: Add a function to test for invisible characters?

[Stefan Monnier]

> I asked some time ago if a function to test if a character is
> invisible. I think nothing has been done to this, or am I mistaken?

It's called `invisible-p'.



        Stefan

Re: Add a function to test for invisible characters?

[Lennart Borgman (gmail)]

Stefan Monnier wrote:
>> I asked some time ago if a function to test if a character is
>> invisible. I think nothing has been done to this, or am I mistaken?
> 
> It's called `invisible-p'.


Ah, thanks, there it is. Very nice.

Re: Add a function to test for invisible characters?

[Lennart Borgman (gmail)]

Lennart Borgman (gmail) wrote:
> Stefan Monnier wrote:
>>> I asked some time ago if a function to test if a character is
>>> invisible. I think nothing has been done to this, or am I mistaken?
>>
>> It's called `invisible-p'.
> 
> 
> Ah, thanks, there it is. Very nice.

I grepped for "'invisible" to see if there were any places where this 
should/could be used. In some cases I do not understand what should be 
done. For example allout.el has

   (defsubst allout-hidden-p (&optional pos)
     "Non-nil if the character after point is invisible."
     (eq (get-char-property (or pos (point)) 'invisible) 'allout))

However here are a some that I think maybe should use invisible-p or 
perhaps test a little bit more careful:

   isearch.el (isearch-range-invisible)
   nxml-outln.el (nxml-outline-pre-adjust-point,
       nxml-outline-adjust-point, nxml-back-to-section-start)
   org-exp.el (org-find-visible, org-find-invisible)
   org.el (org-cycle, org-cycle-show-empty-lines, org-invisible-p,
       org-invisible-p2)
   outline.el (outline-invisible-p)
   ps-def.el (ps-generate-postscript-with-faces1)
   reveal.el (reveal-open-new-overlays)
   simple.el (newline, forward-visible-line, end-of-visible-line,
        move-end-of-line)
   mac-win.el (mac-ts-update-active-input-area)
   reftex-ref.el (reftex-show-entry)

I have tried to cc the maintainers here.

Re: Add a function to test for invisible characters?

[ken manheimer]

On Mon, Jun 23, 2008 at 3:34 PM, Lennart Borgman (gmail)
<lennart.borgman@gmail.com> wrote:
> Lennart Borgman (gmail) wrote:
>>
>> Stefan Monnier wrote:
>>>>
>>>> I asked some time ago if a function to test if a character is
>>>> invisible. I think nothing has been done to this, or am I mistaken?
>>>
>>> It's called `invisible-p'.
>>
>>
>> Ah, thanks, there it is. Very nice.
>
> I grepped for "'invisible" to see if there were any places where this
> should/could be used. In some cases I do not understand what should be done.
> For example allout.el has
>
>  (defsubst allout-hidden-p (&optional pos)
>    "Non-nil if the character after point is invisible."
>    (eq (get-char-property (or pos (point)) 'invisible) 'allout))
>
> However here are a some that I think maybe should use invisible-p or perhaps
> test a little bit more careful:
> [...]

i think you inferred correctly that i deliberately didn't use
invisible-p.  that's because i needed to detect points that are hidden
specifically by allout, not for some other purpose.  i guess i the
docstring should be clearer about that.

-- 
ken
http://myriadicity.net

Add a function to test for invisible characters?

[T. V. Raman]

I'd definitely find this useful in the emacspeak layer. I've
defined it myself in the emacspeak codebase in the past, and have
gotten it wrong  at times as well

>>>>> "Lennart" == Lennart Borgman (gmail) <lennart.borgman@gmail.com> writes:
    Lennart> I asked some time ago if a function to test if a
    Lennart> character is invisible.  I think nothing has been
    Lennart> done to this, or am I mistaken?
    Lennart> 
    Lennart> I think some code in Emacs currently gets this
    Lennart> wrong. Do for example reveal get this right?
    Lennart> 
    Lennart> Below is such a function that I use and that I think
    Lennart> follow the specifications for this. Should not
    Lennart> something like this be in Emacs?
    Lennart> 
    Lennart> (defun tabkey2-invisible-p (pos) "Return non-nil if
    Lennart> the character after POS is currently invisible."
    Lennart> (let ((prop (get-char-property pos 'invisible))) (if
    Lennart> (eq buffer-invisibility-spec t) prop (if (listp
    Lennart> prop) (catch 'invis (dolist (p prop) (when (or (memq
    Lennart> p buffer-invisibility-spec) (assq p
    Lennart> buffer-invisibility-spec)) (throw 'invis t)))) (or
    Lennart> (memq prop buffer-invisibility-spec) (assq prop
    Lennart> buffer-invisibility-spec))))))
    Lennart> 

-- 
Best Regards,
--raman

      
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