Idempotently add id to tag index

1 files changed, 4 insertions, 1 deletions

diff --git a/z.scm b/z.scm
index 46e6fcf..6cec0dd 100644
--- a/z.scm
+++ b/z.scm
@@ -161,7 +161,10 @@
               (dict.update
                *tags*
                tag
-               (/. ids (cons id ids))))))))
+               (/. ids
+                   (if (contains? ids id)
+                       ids
+                       (cons id ids)))))))))
 
 (define (reindex)
   (set! *titles* (dict.empty))