diff --git a/eval.scm b/eval.scm
index 1d9ce649..2297d523 100644
--- a/eval.scm
+++ b/eval.scm
@@ -26,6 +26,7 @@
   (cond ((number? exp) #t)
         ((boolean? exp) #t)
         ((string? exp) #t)
+        ((vector? exp) #t)
         ((char? exp) #t)
         ((eof-object? exp) #t)
         (else #f)))