Ludovic Courtès (2016-01-25 18:06 +0300) wrote: > Alex Kost <alez...@gmail.com> skribis: > >> From f3d21e3ec8a100a966153d03264639ebe48e8872 Mon Sep 17 00:00:00 2001 >> From: Alex Kost <alez...@gmail.com> >> Date: Mon, 25 Jan 2016 11:18:00 +0300 >> Subject: [PATCH] service: Improve 'service-list'. >> >> * modules/shepherd/service.scm (service-list): Use >> 'lookup-canonical-service' on each name instead of removing duplicates >> from the final list. > > [...] > >> diff --git a/modules/shepherd/service.scm b/modules/shepherd/service.scm >> index f84d1dd..94f2aae 100644 >> --- a/modules/shepherd/service.scm >> +++ b/modules/shepherd/service.scm >> @@ -871,12 +871,13 @@ Return #f if service is not found." >> >> (define (service-list) >> "Return the list of services currently defined." >> - (delete-duplicates >> - (hash-fold (lambda (key services result) >> - (append services result)) >> - '() >> - %services) >> - eq?)) >> + (hash-fold (lambda (name services result) >> + (let ((service (lookup-canonical-service name services))) >> + (if service >> + (cons service result) >> + result))) >> + '() >> + %services)) > > OK, except that we know that SERVICE is necessarily true, because the > canonical service for NAME is necessarily among SERVICES. > > So I would remove the ‘if’ and add a comment explaining the above. > > OK with this change?
No, the service is not necessarily true. When a service has several names (e.g., "root" and "shepherd"), then %services table will contain 2 entries (with 'root' and 'shepherd' keys and the same (#<<service> …>) value). So for one of the hash-table entries: (lookup-canonical-service 'root (list root-service)) returns #t, and for the other: (lookup-canonical-service 'shepherd (list root-service)) it returns #f. -- Alex
