06/11: ui: Add 'current-message-language'.

[guix-commits]

civodul pushed a commit to branch master
in repository guix.

commit a725504a3a2f855c6a618e9b4cd222df91901113
Author: Ludovic Courtès <address@hidden>
Date:   Sun Sep 15 17:54:05 2019 +0200

    ui: Add 'current-message-language'.
    
    * guix/ui.scm (%default-message-language): New variable.
    (current-message-language): New procedure.
---
 guix/ui.scm | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/guix/ui.scm b/guix/ui.scm
index 4be31db..069d542 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -121,6 +121,10 @@
             roll-back*
             switch-to-generation*
             delete-generation*
+
+            %default-message-language
+            current-message-language
+
             run-guix-command
             run-guix
             guix-main))
@@ -428,6 +432,20 @@ exiting.  ARGS is the list of arguments received by the 
'throw' handler."
 report them in a user-friendly way."
   (call-with-unbound-variable-handling (lambda () exp ...)))
 
+(define %default-message-language
+  ;; Default language to use for messages.
+  (make-parameter "en"))
+
+(define (current-message-language)
+  "Return the language used for messages according to the current locale.
+Return %DEFAULT-MESSAGE-LANGUAGE if that information could not be obtained.  
The
+result is an ISO-639-2 language code such as \"ar\", without the territory
+part."
+  (let ((locale (setlocale LC_MESSAGES)))
+    (match (string-index locale #\_)
+      (#f    locale)
+      (index (string-take locale index)))))
+
 (define (install-locale)
   "Install the current locale settings."
   (catch 'system-error