channels: Add 'latest-channel-derivation' convenience procedure.

* guix/channels.scm (latest-channel-derivations): Remove.
(latest-channel-instances*, latest-channel-derivation): New procedures.

1 files changed, 12 insertions, 9 deletions

diff --git a/guix/channels.scm b/guix/channels.scm
index ec3e05eaf5..794383fe22 100644
--- a/guix/channels.scm
+++ b/guix/channels.scm
@@ -48,7 +48,7 @@
 
             latest-channel-instances
             channel-instance-derivations
-            latest-channel-derivations
+            latest-channel-derivation
             channel-instances->manifest))
 
 ;;; Commentary:
@@ -216,14 +216,6 @@ INSTANCES."
                                         (list core))))
           instances)))
 
-(define latest-channel-derivations
-  (let ((latest-channel-instances (store-lift latest-channel-instances)))
-    (lambda (channels)
-      "Return, as a monadic value, the list of derivations for the latest
-instances of CHANNELS."
-      (mlet %store-monad ((instances (latest-channel-instances channels)))
-        (channel-instance-derivations instances)))))
-
 (define (whole-package-for-legacy name modules)
   "Return a full-blown Guix package for MODULES, a derivation that builds Guix
 modules in the old ~/.config/guix/latest style."
@@ -290,3 +282,14 @@ channel instances."
                        (entries     (mapm %store-monad instance->entry
                                           (zip instances derivations))))
     (return (manifest entries))))
+
+(define latest-channel-instances*
+  (store-lift latest-channel-instances))
+
+(define* (latest-channel-derivation #:optional (channels %default-channels))
+  "Return as a monadic value the derivation that builds the profile for the
+latest instances of CHANNELS."
+  (mlet* %store-monad ((instances ((store-lift latest-channel-instances)
+                                   channels))
+                       (manifest  (channel-instances->manifest instances)))
+    (profile-derivation manifest)))