add the middle class: `Container` to help resolve circular issues

1 files changed, 1 insertions, 1 deletions

diff --git a/types.h b/types.h
index a364e55..93dac66 100644
--- a/types.h
+++ b/types.h
@@ -44,7 +44,7 @@ class PairReprCons;
  * more, a syntax tree
  * (car . cdr) in Scheme
  */
-class Pair : public EvalObj {/*{{{*/
+class Pair : public Container {/*{{{*/
     public:
         EvalObj *car;                   /**< car (as in Scheme) */
         EvalObj *cdr;                      /**< cdr (as in Scheme) */