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Re: Using button-label in pcase
From: |
Stephen Berman |
Subject: |
Re: Using button-label in pcase |
Date: |
Mon, 24 Jul 2023 22:07:11 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) |
On Mon, 24 Jul 2023 19:14:27 +0000 uzibalqa <uzibalqa@proton.me> wrote:
> Want to print some text as a result of clicking a button. With the code below
> I end up with
>
> (wrong-type-argument integer-or-marker-p nil)
> buffer-substring-no-properties(nil nil)
> button-label(#<overlay in no buffer>)
> (let* ((val (button-label button))) (if (equal val '"[FA]") (let nil
> (insert qrh-c))))
> (closure ((button . #<overlay in no buffer>)) nil (let* ((val (button-label
> button))) (if (equal val '"[FA]") (let nil (insert qrh-c)))))()
> help--window-setup("*Help*" (closure ((button . #<overlay in no buffer>))
> nil (let* ((val (button-label button))) (if (equal val '"[FA]") (let nil
> (insert qrh-c))))))
> qrh-b(#<overlay in no buffer>)
> button-activate(#<overlay in no buffer> t)
> push-button(3 t)
>
> What is going on. Is there a fix?
>
> (defconst qrh-c "[FA] Some Text")
>
> (defun qrh-b (button)
> "Prints information about how to install emacs."
> (with-help-window (help-buffer)
> (pcase (button-label button)
> ("[FA]" (insert qrh-c))) ))
>
> (defun qrh-a ()
> "Prints information about how to install emacs."
> (interactive)
> (with-help-window (help-buffer)
> (insert-button "[FC]"
> 'action 'qrh-b 'follow-link t) ))
The error is raised because qrh-b calls with-help-window with the *Help*
buffer current, but with-help-window erases the buffer, so when
`(button-label button)' is evaluated, there is no button and this
signals the error.
If you want to use the existing *Help* buffer, just remove the call to
with-help-window in qrh-b. However, *Help* buffers are read-only, so
trying to insert text will raise another error. To avoid this, you can
let-bind buffer-read-only in qrh-b. However, since qrh-a inserts "[FC]"
but qrh-b tries to match "[FA]", the match will fail, so the insertion
in qrh-b will not happen.
Steve Berman
- Using button-label in pcase, uzibalqa, 2023/07/24
- Re: Using button-label in pcase,
Stephen Berman <=
- Re: Using button-label in pcase, uzibalqa, 2023/07/24
- Re: Using button-label in pcase, Stephen Berman, 2023/07/24
- Re: Using button-label in pcase, uzibalqa, 2023/07/24
- Re: Using button-label in pcase, Stephen Berman, 2023/07/24
- Re: Using button-label in pcase, uzibalqa, 2023/07/24
- Re: Using button-label in pcase, Stephen Berman, 2023/07/24
- Re: Using button-label in pcase, uzibalqa, 2023/07/24