diff --git a/src/language/PEGGrammar.hpp b/src/language/PEGGrammar.hpp
index 723d9a710f277aff551508ef849632c24e727575..5f8b21d3aca42e79fc00354488a98e247f2bf8bc 100644
--- a/src/language/PEGGrammar.hpp
+++ b/src/language/PEGGrammar.hpp
@@ -46,7 +46,7 @@ struct real
                      >,
                 opt< exponent >
                 >,
-           seq< plus< digit, exponent > >
+           seq< plus< digit > , exponent >
          >{};
 
 struct escaped_c : one< '\'', '"', '?', '\\', 'a', 'b', 'f', 'n', 'r', 't', 'v' > {};