Sorry, I forgot (modify-services) function again.

Trying first config was unsuccessful, but using examples from here https://wiki.archlinux.org/index.php/Libinput I've got my touchpad reacts on tap and double-clicks.

I think the driver option is important for me Driver \"libinput\"

Here's my workable config for touchpad in GuixSD:

(services (cons*
                    ;;(service postgresql-service-type)
                    (xfce-desktop-service)
                    (modify-services
                      ;;(remove (lambda (service)
                      ;; (eq? (service-kind service)
                      ;;    wpa-supplicant-service-type))
                      ;; (remove (lambda (service)
                      ;;    (eq? (service-kind service)
                      ;;      static-networking-service-type))
                          (remove (lambda (service)
                            (eq? (service-kind service)
                              ntp-service-type))
                            (remove (lambda (service)
                              (eq? (service-kind service)
                                avahi-service-type))
                              (modify-services %desktop-services

                                (slim-service-type config =>
                                              (slim-configuration
                                               (inherit config)
                                               (startx
                                                (xorg-start-command
                                                 #:configuration-file
                                                 (xorg-configuration-file
                                                  #:extra-config
                                                  '(
"Section \"InputClass\"
        Identifier \"touchpad\"
        Driver \"libinput\"
        MatchIsTouchpad \"on\"
        Option \"Tapping\" \"on\"
EndSection"
                                 ))))))
)

                            ) ;end of remove avahi
                          ) ;end of remove2 ntp
                        ;;) ;end of remove3 networking
                      ;) ;end of remove4 wpa-supplicant
                      (elogind-service-type
                        c => (elogind-configuration (handle-lid-switch 'ignore)))
                    );;end of modify desktop-services
));;end of services

See attachment with full config.scm

Thanks, Pierr Neidhardt for that link here https://lists.gnu.org/archive/html/help-guix/2018-10/msg00140.html !

Feb 10, 2019, 11:36 AM by znavko@tutanota.com:

Hello! I am not able to determine what is the problem while I'm trying to reconfigure system.

I only add code for touchpad tap from 63 to 78 lines in config.scm (see attachment).

# guix system reconfigure /etc/config.scm

/etc/config.scm:47:20: error: config: unbound variable

hint: Did you forget a `use-modules' form?

Please, what I need to use in use-modules section?

=========part f config.scm=========

(use-modules (gnu) (gnu system nss)

(gnu system locale) ;;for locale-definition

(gnu services desktop)

;;(gnu services dns) ;;for dnsmasq

(srfi srfi-1) ;;for remove function

(gnu services networking) ;;for remove ntp

(gnu services avahi) ;;for remove avahi

(gnu services xorg)

;;(gnu services databases);;for postgres

(gnu packages admin) ;;for wpa_supplicant

)

(use-service-modules desktop)

(use-package-modules certs gnome)

(services (cons*

;;(service postgresql-service-type)

(xfce-desktop-service)

(modify-services

;;(remove (lambda (service)

;; (eq? (service-kind service)

;; wpa-supplicant-service-type))

;; (remove (lambda (service)

;; (eq? (service-kind service)

;; static-networking-service-type))

(remove (lambda (service)

(eq? (service-kind service)

ntp-service-type))

(remove (lambda (service)

(eq? (service-kind service)

avahi-service-type))

%desktop-services

(slim-service-type config =>

(slim-configuration

(inherit config)

(startx

(xorg-start-command

#:configuration-file

(xorg-configuration-file

#:extra-config

"Section \"InputClass\"

Identifier \"touchpad-all\"

MatchIsTouchpad \"on\"

Option \"Tapping\" \"on\"

EndSection"

))))))

) ;end of remove avahi

) ;end of remove2 ntp

;;) ;end of remove3 networking

;) ;end of remove4 wpa-supplicant

(elogind-service-type

c => (elogind-configuration (handle-lid-switch 'ignore)))

);;end of modify desktop-services

));;end of services

====================