use prefix correctly

diff --git a/extra/tar/tar.factor b/extra/tar/tar.factor
index e83908b00282bc76ba32e93a8ad20263c21f75e5..50d3f2559364e2b117cbf17ff26e73b7f5c7e05a 100755 (executable)
--- a/extra/tar/tar.factor
+++ b/extra/tar/tar.factor
@@ -71,8 +71,9 @@ ERROR: checksum-error ;
     ] if ;
 
 ERROR: unknown-typeflag ch ;
+
 M: unknown-typeflag summary ( obj -- str )
-    ch>> "Unknown typeflag: " prefix ;
+    ch>> [ "Unknown typeflag: " ] dip prefix ;
 
 : read/write-blocks ( tar-header path -- )
     binary [ read-data-blocks ] with-file-writer ;