1 files changed, 14 insertions, 0 deletions
diff --git a/guix/ui.scm b/guix/ui.scm
index f8826cd488..7a37ad2cee 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -29,6 +29,7 @@
   #:use-module (srfi srfi-11)
   #:use-module (srfi srfi-26)
   #:use-module (srfi srfi-34)
+  #:use-module (srfi srfi-37)
   #:use-module (ice-9 match)
   #:use-module (ice-9 format)
   #:export (_
@@ -46,6 +47,7 @@
             fill-paragraph
             string->recutils
             package->recutils
+            args-fold*
             run-guix-command
             program-name
             guix-warning-port
@@ -370,6 +372,18 @@ WIDTH columns."
           (and=> (package-description p) description->recutils))
   (newline port))
 
+(define (args-fold* options unrecognized-option-proc operand-proc . seeds)
+  "A wrapper on top of `args-fold' that does proper user-facing error
+reporting."
+  (catch 'misc-error
+    (lambda ()
+      (apply args-fold options unrecognized-option-proc
+             operand-proc seeds))
+    (lambda (key proc msg args . rest)
+      ;; XXX: MSG is not i18n'd.
+      (leave (_ "invalid argument: ~a~%")
+             (apply format #f msg args)))))
+
 (define (show-guix-usage)
   ;; TODO: Dynamically generate a summary of available commands.
   (format (current-error-port)