1 files changed, 4 insertions, 0 deletions
diff --git a/dataType.ml b/dataType.ml
index 3937465..2fcbd0d 100755
--- a/dataType.ml
+++ b/dataType.ml
@@ -109,6 +109,10 @@ module Num = struct
     | NAN -> NAN
     | N n1 -> N (Num.abs_num n1)
 
+  let neg = function
+    | NAN -> NAN
+    | N n1 -> N (Num.minus_num n1)
+
 end
 
 module Bool = struct