diff --git a/src/LexBNF.x b/src/LexBNF.x
index 927e15d..aea3386 100644
--- a/src/LexBNF.x
+++ b/src/LexBNF.x
@@ -11,2 +11,3 @@ import qualified Data.Bits
 import Data.Word (Word8)
+import Data.Char (ord)
 }