diff options
| author | Chris Marusich <cmmarusich@gmail.com> | 2016-11-01 22:48:11 -0700 |
|---|---|---|
| committer | Ludovic Courtès <ludo@gnu.org> | 2016-11-06 18:08:53 +0100 |
| commit | 9008debc54aaa4d65444d5cef85df83455d48d7b (patch) | |
| tree | 47c3aa03ea611111a9df541d2b824b0ed0767c2f /guix/profiles.scm | |
| parent | 3382bfe9ea199086134d90e45e3d759aefed3dcf (diff) | |
| download | gnu-guix-9008debc54aaa4d65444d5cef85df83455d48d7b.tar gnu-guix-9008debc54aaa4d65444d5cef85df83455d48d7b.tar.gz | |
profiles: Extract a procedure for getting relative generation numbers.
* guix/profiles.scm (relative-generation-spec->number): New procedure.
* guix/scripts/package.scm (switch-generation-action): Use it.
Signed-off-by: Ludovic Courtès <ludo@gnu.org>
Diffstat (limited to 'guix/profiles.scm')
| -rw-r--r-- | guix/profiles.scm | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/guix/profiles.scm b/guix/profiles.scm index 96f8b65c3e..33a5f50a53 100644 --- a/guix/profiles.scm +++ b/guix/profiles.scm @@ -5,6 +5,7 @@ ;;; Copyright © 2015 Mark H Weaver <mhw@netris.org> ;;; Copyright © 2015 Sou Bunnbu <iyzsong@gmail.com> ;;; Copyright © 2016 Ricardo Wurmus <rekado@elephly.net> +;;; Copyright © 2016 Chris Marusich <cmmarusich@gmail.com> ;;; ;;; This file is part of GNU Guix. ;;; @@ -97,6 +98,7 @@ generation-number generation-numbers profile-generations + relative-generation-spec->number relative-generation previous-generation-number generation-time @@ -1039,6 +1041,23 @@ former profiles were found." '() generations))) +(define (relative-generation-spec->number profile spec) + "Return PROFILE's generation specified by SPEC, which is a string. The SPEC +may be a N, -N, or +N, where N is a number. If the spec is N, then the number +returned is N. If it is -N, then the number returned is the profile's current +generation number minus N. If it is +N, then the number returned is the +profile's current generation number plus N. Return #f if there is no such +generation." + (let ((number (string->number spec))) + (and number + (case (string-ref spec 0) + ((#\+ #\-) + (relative-generation profile number)) + (else (if (memv number (profile-generations profile)) + number + #f)))))) + + (define* (relative-generation profile shift #:optional (current (generation-number profile))) "Return PROFILE's generation shifted from the CURRENT generation by SHIFT. |