diff --git a/module/riverguile.scm b/module/riverguile.scm
index 796ec40..de65daa 100644
--- a/module/riverguile.scm
+++ b/module/riverguile.scm
@@ -49,7 +49,8 @@
 (define (stringify x)
   (cond ((string? x) x)
         ((number? x) (number->string x))
-        ((symbol? x) (symbol->string x))))
+        ((symbol? x) (symbol->string x))
+        ((list? x)   (string-join (append '("(") (map stringify x) '(")")) " "))))
 
 (define-syntax R
   (syntax-rules ()