How do I add an item to the 'org-publish-project-alist' variable?
reddit / emacs

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DeltaBuffalo · 2022-04-21 16:46

Hi all,

Beginner in emacs-lisp I address to you concerning the following
project: [https://github.com/DarkBuffalo/org-easy-
blog](https://github.com/DarkBuffalo/org-easy-blog).

Is it possible to add an item to the 'org-publish-project-alist'
variable instead of redefining it with setq like in the following bad
example? : [https://github.com/DarkBuffalo/org-easy-
blog/blob/4a30b86158d3554ab96de8afd3e8979ba31bcb9c/org-easy-
blog.el#L293](https://github.com/DarkBuffalo/org-easy-
blog/blob/4a30b86158d3554ab96de8afd3e8979ba31bcb9c/org-easy-
blog.el#L293)

thank you

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usaoc · 2022-04-21 17:07

My choice would be to use [the generalized setter `setf`](https://www.
gnu.org/software/emacs/manual/html_node/elisp/Setting-Generalized-
Variables.html) with an [`alist-get` call](https://www.gnu.org/softwar
e/emacs/manual/html_node/elisp/Association-Lists.html) as the place in
a [`with-eval-after-load`
form](https://www.gnu.org/software/emacs/manual/html_node/elisp/Hooks-
for-Loading.html) of [the `ox-publish`
library](https://github.com/emacs-straight/org-
mode/blob/b8656a2cef3d5da7270e391222d8139fc042edd5/lisp/ox-
publish.el#L65).

    (with-eval-after-load 'ox-publish
      (setf (alist-get KEY org-publish-project-alist
                       nil nil #'string=)
            VALUE))

Edit: Ah, [`ox-publish` is already
`require`d](https://github.com/DarkBuffalo/org-easy-
blog/blob/4a30b86158d3554ab96de8afd3e8979ba31bcb9c/org-easy-
blog.el#L32), so `with-eval-after-load` is not needed.

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DeltaBuffalo · 2022-04-21 17:57

Thank you very much, I will test this.

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DeltaBuffalo · 2022-04-21 19:44

thanks for the advice. Here is the result:

https://github.com/DarkBuffalo/org-easy-
blog/blob/0a3931acafa01361308233ae9504ca6e0883b502/org-easy-
blog.el#L293

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deltille · 2022-04-21 20:10

Try the function (add-to-list), its function help should tell you what
you need.

There's a few ways to add something to a list, a lot of them do
involve re-defining with setq, but specifically re-defining it to the
old list + your new entry. Add-to-list will just modify the list in
place though.

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DeltaBuffalo · 2022-04-22 09:46

Thanks,
There are several ways to do the same thing. Emacs-lisp is awesome.