From 9008debc54aaa4d65444d5cef85df83455d48d7b Mon Sep 17 00:00:00 2001
From: Chris Marusich <cmmarusich@gmail.com>
Date: Tue, 1 Nov 2016 22:48:11 -0700
Subject: [PATCH] profiles: Extract a procedure for getting relative generation
numbers.
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* 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>
---
guix/profiles.scm | 19 +++++++++++++++++++
guix/scripts/package.scm | 8 ++------
2 files changed, 21 insertions(+), 6 deletions(-)
diff --git a/guix/profiles.scm b/guix/profiles.scm
index 96f8b65c3e7..33a5f50a531 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 @@ (define-module (guix profiles)
generation-number
generation-numbers
profile-generations
+ relative-generation-spec->number
relative-generation
previous-generation-number
generation-time
@@ -1039,6 +1041,23 @@ (define (profile-generations profile)
'()
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.
diff --git a/guix/scripts/package.scm b/guix/scripts/package.scm
index 70ed0a7ea65..96a22f6fabe 100644
--- a/guix/scripts/package.scm
+++ b/guix/scripts/package.scm
@@ -5,6 +5,7 @@
;;; Copyright © 2014, 2016 Alex Kost <alezost@gmail.com>
;;; Copyright © 2016 Roel Janssen <roel@gnu.org>
;;; Copyright © 2016 Benz Schenk <benz.schenk@uzh.ch>
+;;; Copyright © 2016 Chris Marusich <cmmarusich@gmail.com>
;;;
;;; This file is part of GNU Guix.
;;;
@@ -782,12 +783,7 @@ (define* (switch-generation-action store profile spec opts
#:key dry-run?)
"Switch PROFILE to the generation specified by SPEC."
(unless dry-run?
- (let* ((number (string->number spec))
- (number (and number
- (case (string-ref spec 0)
- ((#\+ #\-)
- (relative-generation profile number))
- (else number)))))
+ (let ((number (relative-generation-spec->number profile spec)))
(if number
(switch-to-generation* profile number)
(leave (_ "cannot switch to generation '~a'~%") spec)))))
--
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