diff options
Diffstat (limited to 'gnu/packages.scm')
| -rw-r--r-- | gnu/packages.scm | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/gnu/packages.scm b/gnu/packages.scm index 65ab7a7c1e..2ba838fd0a 100644 --- a/gnu/packages.scm +++ b/gnu/packages.scm @@ -66,6 +66,8 @@ specification->location specifications->manifest + package-unique-version-prefix + generate-package-cache)) ;;; Commentary: @@ -559,3 +561,22 @@ output." ;; fiddle with multiple-value returns. (packages->manifest (map (compose list specification->package+output) specs))) + +(define (package-unique-version-prefix name version) + "Search among all the versions of package NAME that are available, and +return the shortest unambiguous version prefix to designate VERSION. If only +one version of the package is available, return the empty string." + (match (map package-version (find-packages-by-name name)) + ((_) + ;; A single version of NAME is available, so do not specify the version + ;; number, even if the available version doesn't match VERSION. + "") + (versions + ;; If VERSION is the latest version, don't specify any version. + ;; Otherwise return the shortest unique version prefix. Note that this + ;; is based on the currently available packages so the result may vary + ;; over time. + (if (every (cut version>? version <>) + (delete version versions)) + "" + (version-unique-prefix version versions))))) |