add eval

1 files changed, 1 insertions, 0 deletions

diff --git a/src/sexp.h b/src/sexp.h
index 92ff11b..22b2c8a 100644
--- a/src/sexp.h
+++ b/src/sexp.h
@@ -56,6 +56,7 @@ typedef enum {
     kEnvSExp,
     kBindingSExp,
     kMacroSExp,
+    kErrSExp,
 } SExpType;
 
 struct sexp {