2 files changed, 22 insertions, 5 deletions
diff --git a/src/cuirass/base.scm b/src/cuirass/base.scm
index c7c23e2..63e1b7a 100644
--- a/src/cuirass/base.scm
+++ b/src/cuirass/base.scm
@@ -1,6 +1,7 @@
 ;;;; base.scm - Cuirass base module
 ;;;
 ;;; Copyright © 2012, 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2016 Mathieu Lirzin <mthl@gnu.org>
 ;;;
 ;;; This file is part of Cuirass.
 ;;;
@@ -20,9 +21,23 @@
 (define-module (cuirass base)
   #:use-module (ice-9 format)
   #:use-module (srfi srfi-19)
-  #:export (guix-variable
-            with-directory-excursion
-            call-with-time-display))
+  #:export (;; Procedures.
+            guix-variable
+            call-with-time-display
+            ;; Parameters.
+            %program-name
+            ;; Macros.
+            with-directory-excursion))
+
+(define %program-name
+  ;; Similar in spirit to Gnulib 'progname' module.
+  (make-parameter ""
+    (λ (val)
+      (cond ((not (string? val))
+             (scm-error 'wrong-type-arg
+                        "%program-name" "Not a string: ~S" (list #f) #f))
+            ((string-rindex val #\/) => (λ (idx) (substring val (1+ idx))))
+            (else val)))))
 
 (define (guix-variable module name)
   "Dynamically link variable NAME under Guix module MODULE and return it.
diff --git a/src/cuirass/ui.scm b/src/cuirass/ui.scm
index d953f8a..d351e4e 100644
--- a/src/cuirass/ui.scm
+++ b/src/cuirass/ui.scm
@@ -18,13 +18,15 @@
 ;;; along with Cuirass.  If not, see <http://www.gnu.org/licenses/>.
 
 (define-module (cuirass ui)
+  #:use-module (cuirass base)
   #:use-module (cuirass config)
   #:export (show-version
             show-package-information))
 
-(define (show-version prog)
+(define (show-version)
   "Display version information for COMMAND."
-  (simple-format #t "~a (~a) ~a~%" prog %package-name %package-version)
+  (simple-format #t "~a (~a) ~a~%"
+                 (%program-name) %package-name %package-version)
   (display "Copyright (C) 2016 the Cuirass authors
 License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
 This is free software: you are free to change and redistribute it.