diff options
Diffstat (limited to 'gnu/services/shepherd.scm')
| -rw-r--r-- | gnu/services/shepherd.scm | 30 |
1 files changed, 20 insertions, 10 deletions
diff --git a/gnu/services/shepherd.scm b/gnu/services/shepherd.scm index a14f51592a..3cfca8574e 100644 --- a/gnu/services/shepherd.scm +++ b/gnu/services/shepherd.scm @@ -52,6 +52,7 @@ shepherd-service-file + shepherd-service-lookup-procedure shepherd-service-back-edges)) ;;; Commentary: @@ -249,20 +250,29 @@ stored." (gexp->file "shepherd.conf" config))) +(define* (shepherd-service-lookup-procedure services + #:optional + (provision + shepherd-service-provision)) + "Return a procedure that, when passed a symbol, return the item among +SERVICES that provides this symbol. PROVISION must be a one-argument +procedure that takes a service and returns the list of symbols it provides." + (let ((services (fold (lambda (service result) + (fold (cut vhash-consq <> service <>) + result + (provision service))) + vlist-null + services))) + (lambda (name) + (match (vhash-assq name services) + ((_ . service) service) + (#f #f))))) + (define (shepherd-service-back-edges services) "Return a procedure that, when given a <shepherd-service> from SERVICES, returns the list of <shepherd-service> that depend on it." (define provision->service - (let ((services (fold (lambda (service result) - (fold (cut vhash-consq <> service <>) - result - (shepherd-service-provision service))) - vlist-null - services))) - (lambda (name) - (match (vhash-assq name services) - ((_ . service) service) - (#f #f))))) + (shepherd-service-lookup-procedure services)) (define edges (fold (lambda (service edges) |