宋文武 <iyzs...@envs.net> writes:
> ```
> (define (exclude-some-packages lst)
> (filter (lambda (pkg)
> (not (memq pkg (list
> gnome-terminal
> gnome-user-docs
> gnome-maps))))
> lst))
>
>
> (service gnome-desktop-service-type
> (let ((cfg (gnome-desktop-configuration)))
> (gnome-desktop-configuration
> (core-services
> (exclude-some-packages (gnome-desktop-configuration-core-services cfg)))
> (shell
> (exclude-some-packages (gnome-desktop-configuration-shell cfg)))
> (utilities
> (exclude-some-packages (gnome-desktop-configuration-utilities cfg)))
> (extra-packages
> (exclude-some-packages (gnome-desktop-configuration-utilities cfg))))))
> ```
Thank you this has been very helpful, in the end I adapted your code
like so:
```scheme
(define (gnome-exclude-packages cfg . exclude)
(let ((exclude-packages (λ (pkgs)
(remove (λ (pkg)
(memq pkg exclude))
pkgs))))
(gnome-desktop-configuration
(core-services
(exclude-packages (gnome-desktop-configuration-core-services cfg)))
(shell
(exclude-packages (gnome-desktop-configuration-shell cfg)))
(utilities
(exclude-packages (gnome-desktop-configuration-utilities cfg)))
(extra-packages
(exclude-packages (gnome-desktop-configuration-extra-packages cfg))))))
; ...
(service gnome-desktop-service-type
(gnome-exclude-packages
(gnome-desktop-configuration)
gnome-music epiphany cheese))
```
I wonder if this is the best or most elegant way of achieving this. I'm
interested to see what others think.
> Hope it helps.
Very much, it was a good opportunity to play around in the REPL and see
the data structures for myself which I must admit I was apprehensive
about. Many thanks.
