I want to delete a service from %desktop-services, so I write --8<---------------cut here---------------start------------->8--- … (services (remove (lambda (service) (eq? (service-kind service) that-annoying-service-type)) %desktop-services)) … --8<---------------cut here---------------end--------------->8--- Then I run “guix system build config.scm” and Guix tells me that it doesn’t know what “remove” is: --8<---------------cut here---------------start------------->8--- config.scm:56:18: error: remove: unbound variable hint: Did you forget `(use-modules (rnrs lists))'? --8<---------------cut here---------------end--------------->8--- I add the suggested module import to my file and it no longer complains, but that-annoying-service-type has not actually been removed. Oh no! Of course, the Guix manual says this: --8<---------------cut here---------------start------------->8--- Again, ‘%desktop-services’ is just a list of service objects. If you want to remove services from there, you can do so using the procedures for list filtering (*note (guile)SRFI-1 Filtering and Partitioning::). For instance, the following expression returns a list that contains all the services in ‘%desktop-services’ minus the Avahi service: (remove (lambda (service) (eq? (service-kind service) avahi-service-type)) %desktop-services) --8<---------------cut here---------------end--------------->8--- But maybe I don’t know what SRFI-1 is and I trust that the hint Guix provides will be the right thing to do. But now I’m curious and I look at the documentation for “remove” from (rnrs lists): --8<---------------cut here---------------start------------->8--- -- Scheme Procedure: remp proc list -- Scheme Procedure: remove obj list -- Scheme Procedure: remv obj list -- Scheme Procedure: remq obj list ‘remove’, ‘remv’, and ‘remq’ are identical to the ‘delete’, ‘delv’, and ‘delq’ procedures provided by Guile’s core library, (*note List Modification::). ‘remp’ is identical to the alternate ‘remove’ procedure provided by SRFI-1; *Note SRFI-1 Deleting::. --8<---------------cut here---------------end--------------->8--- Oh. So here are my questions: * can we prefer (srfi srfi-1) over (rnrs lists) in the suggestions for “remove”? * can we avoid this by extending modify-services to support “delete” much like modify-phases, and suggesting to use that instead of “remove”? -- Ricardo