1 files changed, 2 insertions, 0 deletions
diff --git a/dataType.mli b/dataType.mli
index 09b0082..901346c 100755
--- a/dataType.mli
+++ b/dataType.mli
@@ -17,6 +17,8 @@ module Num: sig
 
   val to_num: t -> Num.num
 
+  val neg: t -> t
+
   val eq: t -> t -> bool
   val neq: t -> t -> bool
   val lt: t -> t -> bool