[PATCH 1/3] gwl/ui: Check for log-events configuration

[Olivier Dion <olivier.dion@polymtl.ca>]

Some GWL sub-commands might not accept the log-events switch.
This results in returning `#f' from `(%config 'log-events)'

Fix this by checking that 'log-events was configured.  Also memoize the result.
---
 gwl/ui.scm | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/gwl/ui.scm b/gwl/ui.scm
index 35bd127..bfe20a9 100644
--- a/gwl/ui.scm
+++ b/gwl/ui.scm
@@ -17,6 +17,8 @@
   #:use-module (gwl config)
   #:use-module (gwl errors)
   #:use-module (guix colors)
+  #:use-module ((guix memoization)
+                #:select (mlambdaq))
   #:use-module (srfi srfi-26)
   #:use-module (ice-9 format)
   #:export (G_
@@ -63,11 +65,16 @@
       (format (current-error-port) "~a"
               (prefix-color prefix))))
 
+(define print?
+  (mlambdaq (type)
+    (let ((log-events (%config 'log-events)))
+      (and log-events
+           (or (member 'all log-events)
+               (member type log-events))
+           #t))))
+
 (define (log-event type . message)
-  (define print?
-    (or (member 'all (%config 'log-events))
-        (member type (%config 'log-events))))
-  (when print?
+  (when (print? type)
     (case type
       ((error)
        (print-diagnostic-prefix (G_ "error: ") #:colors %error-color))
-- 
2.36.1