[bug#62101] home: services: Add xmodmap.

---
 gnu/home/services/desktop.scm | 109 ++++++++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)

Hello,

This looks like a useful addition!

Some comments below; maybe Andrew will bring a different perspective.

conses <contact@conses.eu> skribis:

> ---
>  gnu/home/services/desktop.scm | 109 ++++++++++++++++++++++++++++++++++

It’d be great if you could provide a ChangeLog-style commit log (you can
check the manual and ‘git log’ to see what it’s like); if you can’t, we
can help with that.

More importantly, could you add documentation to guix.texi, similar to
what is done for the other Home services?  That is: a few introductory
lines, an example, and the reference (data types, variables,
procedures).

> +   (alist '())
> +   "Association list of key and value pairs for the
> + @code{xmodmap} configuration file.  Its syntax can take something like
> +the following:
> +
> +@example
> +'((#(add mod4) . Print)
> +    (clear lock)
> +    (clear control)
> +    (#(keycode 66) . Control_L)
> +    (#(add control) . #(Control_L Control_R)))
> +@end example"))

I don’t quite get the syntax.

Use of vectors is unusual in this context, I’d recommend against it.

Regarding pairs: in some cases, the cdr is a symbol/vector, in other
cases it’s a one-element list (as in ‘(clear lock)’).  That also makes
it a bit confusing to me.

Perhaps we should try to make it look more consistent?  WDYT?

> +(define (home-xmodmap-shepherd-service config)
> +  (list
> +   (shepherd-service
> +    (provision '(xmodmap))
> +    (start #~(make-system-constructor
> +              (string-join
> +               (list #$(file-append
> +                        (home-xmodmap-configuration-xmodmap config)
> +                        "/bin/xmodmap")
> +                     #$(home-xmodmap-file config)))))
> +    (one-shot? #t))))

Perhaps it’d be useful to have a ‘stop’ procedure that undoes that
changes?  In which case it wouldn’t be one-shot anymore.

> +  (define serialize-field
> +    (match-lambda
> +      ((? list? e)
> +       (string-join
> +        (map
> +         (lambda (x)
> +           (serialize-term x))
> +         e)
> +        " "))

Just: (string-join (map serialize-term e)).

> +(define home-xmodmap-service-type
> +  (service-type
> +   (name 'home-xmodmap)
> +   (extensions
> +    (list
> +     (service-extension
> +      home-profile-service-type
> +      home-xmodmap-profile-service)
> +     (service-extension
> +      home-xdg-configuration-files-service-type
> +      home-xmodmap-files-service)
> +     (service-extension
> +      home-shepherd-service-type
> +      home-xmodmap-shepherd-service)))
> +   (description "Configure @code{xmodmap} bindings and rules.")

Please expand the description a bit.

TIA!

Ludo’.

Ludovic Courtès <ludo@gnu.org> writes:

> It’d be great if you could provide a ChangeLog-style commit log (you can
> check the manual and ‘git log’ to see what it’s like); if you can’t, we
> can help with that.
>

Apologies for missing this, I added it in v2.

> More importantly, could you add documentation to guix.texi, similar to
> what is done for the other Home services?  That is: a few introductory
> lines, an example, and the reference (data types, variables,
> procedures).
>

Likewise.

>> +   (alist '())
>> +   "Association list of key and value pairs for the
>> + @code{xmodmap} configuration file.  Its syntax can take something like
>> +the following:
>> +
>> +@example
>> +'((#(add mod4) . Print)
>> +    (clear lock)
>> +    (clear control)
>> +    (#(keycode 66) . Control_L)
>> +    (#(add control) . #(Control_L Control_R)))
>> +@end example"))
>
> I don’t quite get the syntax.
>
> Use of vectors is unusual in this context, I’d recommend against it.
>
> Regarding pairs: in some cases, the cdr is a symbol/vector, in other
> cases it’s a one-element list (as in ‘(clear lock)’).  That also makes
> it a bit confusing to me.
>
> Perhaps we should try to make it look more consistent?  WDYT?

I've amended the type of config to be of list instead.  As I've hinted
in the manual, the motivation for including vectors and lists is to
provide a more Lisp-like configuration syntax for those that want it, it
can simply take strings too.  IMO there's no point in making it
consistent since the original syntax isn't consistent in the first
place, you can check out some examples here
<https://wiki.archlinux.org/title/xmodmap>.

>
>> +(define (home-xmodmap-shepherd-service config)
>> +  (list
>> +   (shepherd-service
>> +    (provision '(xmodmap))
>> +    (start #~(make-system-constructor
>> +              (string-join
>> +               (list #$(file-append
>> +                        (home-xmodmap-configuration-xmodmap config)
>> +                        "/bin/xmodmap")
>> +                     #$(home-xmodmap-file config)))))
>> +    (one-shot? #t))))
>
> Perhaps it’d be useful to have a ‘stop’ procedure that undoes that
> changes?  In which case it wouldn’t be one-shot anymore.
>

I found here <https://askubuntu.com/a/1155211> that xmodmap settings can
be simply reversed by calling setxkbmap, so I've added a stop procedure
for this.

>> +(define home-xmodmap-service-type
>> +  (service-type
>> +   (name 'home-xmodmap)
>> +   (extensions
>> +    (list
>> +     (service-extension
>> +      home-profile-service-type
>> +      home-xmodmap-profile-service)
>> +     (service-extension
>> +      home-xdg-configuration-files-service-type
>> +      home-xmodmap-files-service)
>> +     (service-extension
>> +      home-shepherd-service-type
>> +      home-xmodmap-shepherd-service)))
>> +   (description "Configure @code{xmodmap} bindings and rules.")
>
> Please expand the description a bit.
>

Done.