* How to use display text property with after-string?
@ 2016-10-21 6:15 Marcin Borkowski
2016-10-21 6:59 ` Joost Kremers
2016-10-21 7:35 ` Eli Zaretskii
0 siblings, 2 replies; 7+ messages in thread
From: Marcin Borkowski @ 2016-10-21 6:15 UTC (permalink / raw)
To: Help Gnu Emacs mailing list
Hi all,
I want to set the "display" text property so that some text is displayed
after the buffer part I'm setting the property to. However, I can't do
it. Consider an Elisp buffer with these contents:
--8<---------------cut here---------------start------------->8---
;; this is a comment
(put-text-property 14 21 'display '(after-string " which is cool!"))
--8<---------------cut here---------------end--------------->8---
After C-x C-e with point at the end, I see this:
--8<---------------cut here---------------start------------->8---
;; this is a comment
(put-text-property 14 21 'display '(after-string " which is cool!"))
--8<---------------cut here---------------end--------------->8---
but I expected this:
--8<---------------cut here---------------start------------->8---
;; this is a commentcomment
(put-text-property 14 21 'display '(after-string " which is cool!"))
--8<---------------cut here---------------end--------------->8---
What am I doing wrong?
TIA,
--
Marcin Borkowski
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: How to use display text property with after-string?
2016-10-21 6:15 How to use display text property with after-string? Marcin Borkowski
@ 2016-10-21 6:59 ` Joost Kremers
2016-10-21 7:35 ` Eli Zaretskii
1 sibling, 0 replies; 7+ messages in thread
From: Joost Kremers @ 2016-10-21 6:59 UTC (permalink / raw)
To: Marcin Borkowski; +Cc: Help Gnu Emacs mailing list
On Fri, Oct 21 2016, Marcin Borkowski wrote:
> Hi all,
>
> I want to set the "display" text property so that some text is
> displayed
> after the buffer part I'm setting the property to. However, I
> can't do
> it. Consider an Elisp buffer with these contents:
>
> --8<---------------cut
> here---------------start------------->8---
> ;; this is a comment
>
> (put-text-property 14 21 'display '(after-string " which is
> cool!"))
> --8<---------------cut
> here---------------end--------------->8---
>
> After C-x C-e with point at the end, I see this:
>
> --8<---------------cut
> here---------------start------------->8---
> ;; this is a comment
>
> (put-text-property 14 21 'display '(after-string " which is
> cool!"))
> --8<---------------cut
> here---------------end--------------->8---
>
> but I expected this:
>
> --8<---------------cut
> here---------------start------------->8---
> ;; this is a commentcomment
>
> (put-text-property 14 21 'display '(after-string " which is
> cool!"))
> --8<---------------cut
> here---------------end--------------->8---
>
I'm getting this (Emacs 25.1.2):
,----
| ;; this is a comment
|
| (put-text-property 14 21 'display '(after-string " which is
cool!"))
`----
But looknig through the Elisp manual, it seems that `after-string'
is an overlay property, not a text property, so what you're after
probably isn't supposed to work.
--
Joost Kremers
Life has its moments
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: How to use display text property with after-string?
2016-10-21 6:15 How to use display text property with after-string? Marcin Borkowski
2016-10-21 6:59 ` Joost Kremers
@ 2016-10-21 7:35 ` Eli Zaretskii
2016-10-21 19:41 ` Marcin Borkowski
1 sibling, 1 reply; 7+ messages in thread
From: Eli Zaretskii @ 2016-10-21 7:35 UTC (permalink / raw)
To: help-gnu-emacs
> From: Marcin Borkowski <mbork@mbork.pl>
> Date: Fri, 21 Oct 2016 08:15:31 +0200
>
> --8<---------------cut here---------------start------------->8---
> ;; this is a comment
>
> (put-text-property 14 21 'display '(after-string " which is cool!"))
> --8<---------------cut here---------------end--------------->8---
>
> After C-x C-e with point at the end, I see this:
>
> --8<---------------cut here---------------start------------->8---
> ;; this is a comment
>
> (put-text-property 14 21 'display '(after-string " which is cool!"))
> --8<---------------cut here---------------end--------------->8---
>
> but I expected this:
>
> --8<---------------cut here---------------start------------->8---
> ;; this is a commentcomment
>
> (put-text-property 14 21 'display '(after-string " which is cool!"))
> --8<---------------cut here---------------end--------------->8---
>
> What am I doing wrong?
The 'display' property doesn't support after-string, only the overlay
properties do.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: How to use display text property with after-string?
2016-10-21 7:35 ` Eli Zaretskii
@ 2016-10-21 19:41 ` Marcin Borkowski
2016-10-21 20:04 ` Eli Zaretskii
2016-10-22 19:49 ` Stefan Monnier
0 siblings, 2 replies; 7+ messages in thread
From: Marcin Borkowski @ 2016-10-21 19:41 UTC (permalink / raw)
To: Eli Zaretskii; +Cc: help-gnu-emacs
On 2016-10-21, at 09:35, Eli Zaretskii <eliz@gnu.org> wrote:
>> From: Marcin Borkowski <mbork@mbork.pl>
>> Date: Fri, 21 Oct 2016 08:15:31 +0200
>>
>> --8<---------------cut here---------------start------------->8---
>> ;; this is a comment
>>
>> (put-text-property 14 21 'display '(after-string " which is cool!"))
>> --8<---------------cut here---------------end--------------->8---
>>
>> After C-x C-e with point at the end, I see this:
>>
>> --8<---------------cut here---------------start------------->8---
>> ;; this is a comment
>>
>> (put-text-property 14 21 'display '(after-string " which is cool!"))
>> --8<---------------cut here---------------end--------------->8---
>>
>> but I expected this:
>>
>> --8<---------------cut here---------------start------------->8---
>> ;; this is a commentcomment
>>
>> (put-text-property 14 21 'display '(after-string " which is cool!"))
>> --8<---------------cut here---------------end--------------->8---
>>
>> What am I doing wrong?
>
> The 'display' property doesn't support after-string, only the overlay
> properties do.
I see. I was a bit afraid that is the case.
Is there any other way to put some nonexistent text in the buffer?
Overlays are not very good that, since I hear many overlays in a buffer
may slow things down. My use case is as follows: I want to write
a function which will find all the dates in the US format (M/D/Y) in the
buffer and put a date in a sane format (maybe together with something
like "3 days ago" or "tomorrow") next to them. (That would be very
useful for me, since I sometimes get emails from Americans, and dealing
with dates in M/D/Y format is a huge cognitive load for me;-).)
TIA,
--
Marcin Borkowski
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: How to use display text property with after-string?
2016-10-21 19:41 ` Marcin Borkowski
@ 2016-10-21 20:04 ` Eli Zaretskii
2016-10-22 3:57 ` Marcin Borkowski
2016-10-22 19:49 ` Stefan Monnier
1 sibling, 1 reply; 7+ messages in thread
From: Eli Zaretskii @ 2016-10-21 20:04 UTC (permalink / raw)
To: help-gnu-emacs
> From: Marcin Borkowski <mbork@mbork.pl>
> Cc: help-gnu-emacs@gnu.org
> Date: Fri, 21 Oct 2016 21:41:21 +0200
>
> > The 'display' property doesn't support after-string, only the overlay
> > properties do.
>
> I see. I was a bit afraid that is the case.
>
> Is there any other way to put some nonexistent text in the buffer?
What's wrong with 'display' text property? Just make its value be a
string, not '(after-string "something").
> Overlays are not very good that, since I hear many overlays in a buffer
> may slow things down. My use case is as follows: I want to write
> a function which will find all the dates in the US format (M/D/Y) in the
> buffer and put a date in a sane format (maybe together with something
> like "3 days ago" or "tomorrow") next to them. (That would be very
> useful for me, since I sometimes get emails from Americans, and dealing
> with dates in M/D/Y format is a huge cognitive load for me;-).)
The 'display' text property whose value is a string causes that string
be displayed _instead_ of the text covered by the text property.
Which sounds exactly what you want. One caveat: you cannot move
cursor through the display string (the same is true for
after-strings).
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: How to use display text property with after-string?
2016-10-21 20:04 ` Eli Zaretskii
@ 2016-10-22 3:57 ` Marcin Borkowski
0 siblings, 0 replies; 7+ messages in thread
From: Marcin Borkowski @ 2016-10-22 3:57 UTC (permalink / raw)
To: Eli Zaretskii; +Cc: help-gnu-emacs
On 2016-10-21, at 22:04, Eli Zaretskii <eliz@gnu.org> wrote:
>> From: Marcin Borkowski <mbork@mbork.pl>
>> Cc: help-gnu-emacs@gnu.org
>> Date: Fri, 21 Oct 2016 21:41:21 +0200
>>
>> > The 'display' property doesn't support after-string, only the overlay
>> > properties do.
>>
>> I see. I was a bit afraid that is the case.
>>
>> Is there any other way to put some nonexistent text in the buffer?
>
> What's wrong with 'display' text property? Just make its value be a
> string, not '(after-string "something").
OK.
>> Overlays are not very good that, since I hear many overlays in a buffer
>> may slow things down. My use case is as follows: I want to write
>> a function which will find all the dates in the US format (M/D/Y) in the
>> buffer and put a date in a sane format (maybe together with something
>> like "3 days ago" or "tomorrow") next to them. (That would be very
>> useful for me, since I sometimes get emails from Americans, and dealing
>> with dates in M/D/Y format is a huge cognitive load for me;-).)
>
> The 'display' text property whose value is a string causes that string
> be displayed _instead_ of the text covered by the text property.
> Which sounds exactly what you want. One caveat: you cannot move
> cursor through the display string (the same is true for
> after-strings).
Thanks. It was not exactly what I wanted: I wanted a fragment of buffer
containing e.g.
10/25/16
to display as
10/25/16 [2016-10-25, 3 days from today]
Of course, I can include the original text in the `display' property,
but as you have pointed out, this is not the same (though I'm not even
shure whether it's not actually _better_).
Thanks a lot,
--
Marcin Borkowski
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: How to use display text property with after-string?
2016-10-21 19:41 ` Marcin Borkowski
2016-10-21 20:04 ` Eli Zaretskii
@ 2016-10-22 19:49 ` Stefan Monnier
1 sibling, 0 replies; 7+ messages in thread
From: Stefan Monnier @ 2016-10-22 19:49 UTC (permalink / raw)
To: help-gnu-emacs
> Overlays are not very good that, since I hear many overlays in a buffer
> may slow things down.
They have some performance issues, but it's not so terrible that it
should stop you from using them.
Stefan
^ permalink raw reply [flat|nested] 7+ messages in thread
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2016-10-21 6:15 How to use display text property with after-string? Marcin Borkowski
2016-10-21 6:59 ` Joost Kremers
2016-10-21 7:35 ` Eli Zaretskii
2016-10-21 19:41 ` Marcin Borkowski
2016-10-21 20:04 ` Eli Zaretskii
2016-10-22 3:57 ` Marcin Borkowski
2016-10-22 19:49 ` Stefan Monnier
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