diff --git a/src/compiler/GF/Compile/PGFtoProlog.hs b/src/compiler/GF/Compile/PGFtoProlog.hs
index d24aa34c7..03a29871b 100644
--- a/src/compiler/GF/Compile/PGFtoProlog.hs
+++ b/src/compiler/GF/Compile/PGFtoProlog.hs
@@ -24,7 +24,7 @@ import Data.List (isPrefixOf, mapAccumL)
 grammar2prolog :: PGF -> String
 grammar2prolog pgf
     = ("%% This file was automatically generated by GF" +++++
-       ":- style_check(-singleton)" +++++
+       ":- style_check(-singleton)." +++++
        plFacts wildCId "abstract" 1 "(?AbstractName)"
                    [[plp name]] ++++
        plFacts wildCId "concrete" 2 "(?AbstractName, ?ConcreteName)"