Subject: Re: [PATCH] home: services: Add 'home-sway-service-type'.

From: Arnaud Daby-Seesaram <[email-masked]>
Date: Sat, 05 Oct 2024 19:02:11 +0200

Hello Florian,

> I’d welcome if you, Arnaud, sent a patch calling your sway-menu script.
> 
> Also I’d be happy if more careful commiters would push it; I prefer to
> restrict my commits to translation updates.

I will proof-read and re-test the whole patch soon, hoping to avoid
additional careless bugs on my end.

Also: given that you assisted me quite a lot, do you want me to add a
line in the commit message to express that you helped me write the patch
(such as "This patch was co-authored with Florian Pelz.", as in Guix
commit 9371cf2138711ea7305951d82c5cf0b36ac4d6f1)?

I will send a v8 as soon as I have both seen your answer and proof-read
the patch.
NB: I think that the v8 can be the last version of the patch.  Thank you
for your help and for your patience :)!

> Sorry for having proposed compiled-file previously.

No problem.  I actually meant `program-file' instead of `computed-file'
(which was incorrectly used in my previous email).  This way, the
lowered object in the store will be executable, allowing to define the
menu directly like this¹:

--8<---------------cut here---------------start------------->8---
(define %sway-default-variables
  `([...]
    (menu  . ,sway-menu)))
--8<---------------cut here---------------end--------------->8---

¹: In the next version of the patch, I allow any file-like object in
   `string-ish' instead of file-append objects only, so that Sway
   variables can be bound to anything that can be lowered into a file
   (in additions to strings and G-expressions).

> At first I had thought a compiled sway-menu.go would be appropriate,
> created in a computed-file, which invokes `guild compile` on the .scm
> code, but apparently this is not useful.  I do not know enough here
> and gnu/services/shepherd.scm does it in the scm->go procedure.

Thank you for the pointer, `scm->go' is an interesting function.
I experimented and bit and was able to compile the menu to byte-code
using a similar function.  However, I do not know a way to compile to
native code in Guile.  Hence, I will stick to `program-file'.

> Anyway, some feedback:
>
>> (define (directory->files dir)
>>   (define (executable-file? f)
>>     ;; Cf. `(@@ (guix build utils) executable-file?)' for an
>>     ;; explanation of `(zero? ...)'.
>
> This is a comment anyway, but one @ in (@ (guix build utils)
> executable-file?) would be enough, since the executable-file?
> predicate is exported.
Thx, fixed.

>>            (lambda (s)
>
> To reduce clutter in the wmenu suggestions more, I’d prefer
>
> (and=> (and (not (eq? (string-ref f 0) #\.))
>             (stat f))
>        (lambda (s)
Indeed, this is better.

>>              (not (or (zero? (logand (stat:mode s) #o100))
>>                       (eq? (stat:type s) 'directory))))))
>>   (with-directory-excursion dir
>>     (scandir "." executable-file?)))
>> 
>> (let ((path (string-append (getenv "HOME")
>>                            "/.guix-home/profile/bin"))
>>       (wmenu #$(file-append wmenu "/bin/wmenu"))
>>       (swaymsg #$(file-append sway "/bin/swaymsg")))
>>   (receive (from to pid)
>>       ((@@ (ice-9 popen) open-process) OPEN_BOTH wmenu)
>
> Better use @ instead of @@.
Unfortunately, `open-process' is not exported in `(ice-9 popen)', so I
kept @@.

>>     (for-each
>>      (lambda (c) (format to "~a~%" c))
>>      (directory->files path))
>>     (close to)
>>     (let ((choice (read-line from)))
>>       (close from)
>>       (waitpid pid)
>>       (execl swaymsg swaymsg "exec"
>>              (string-append path "/" choice))))))))
>
> Even though I like to get suggestions only for
> ~/.guix-home/profile/bin, if you do not prepend path, [...]
> then it will remain possible to write shell commands in wmenu [...]
> to run apps without installing them.

Yes; I removed the string-append here.  (As ~/.guix-home/profile/bin is
supposed to be in the path, this should work properly).

> Since you told me about wmenu-run, I also locally updated wmenu [1]
> and tested the menu config
>
> (menu  .  ,#~(string-append
>              #$wmenu "/bin/wmenu-run"))
>
> which would also work, but in my opinion the suggestions are better
> when tied to .guix-home/profile.  The wmenu-run does not use exec but
> a protocol called XDG_ACTIVATION_TOKEN.  But I do not see an advantage
> to it.  It behaves like always.

It is nice that this works too.
NB: if you want, you can use `(file-append pkg "stuff")' instead of
    `#~(string-append #$pkg "stuff")'.

I do not know much about the XDG_ACTIVATION stuff; only that it has to
do with focused clients on Wayland IIRC.  In my menu, I use `swaymsg
exec -- [command]', which takes care of a few things as well, as
explained below.

--8<---------------cut here---------------start------------->8---
Note: pass the final command to swaymsg so that the resulting window can
be opened on the original workspace that the command was run on.
--8<---------------cut here---------------end--------------->8---
Source: commit c3353bb27317d294a91a8accec9a554ea392de04 of Sway.  It
explains why the menu is piped to 'swaymg exec --'.  (I have added the
"--" argument in the v8).

> Also one more thing, in the commit message, you meant to write
> flatmap instead of flatten.
Indeed, thx.

Best regards,

-- 
Arnaud