Whitespace fix

1 files changed, 1 insertions, 1 deletions

diff --git a/src/expr.h b/src/expr.h
index 83fe33dd..fc6a76b1 100644
--- a/src/expr.h
+++ b/src/expr.h
@@ -171,7 +171,7 @@ private:
   friend class boost::serialization::access;
 
   template<class Archive>
-  void serialize(Archive & ar, const unsigned int /* version */) {
+  void serialize(Archive& ar, const unsigned int /* version */) {
     ar & ptr;
     ar & context;
     ar & str;