diff -r a80d8ec6c998 -r 3dda49e08b9d src/Tools/Code/code_haskell.ML
--- a/src/Tools/Code/code_haskell.ML	Fri Jan 04 21:49:06 2019 +0100
+++ b/src/Tools/Code/code_haskell.ML	Fri Jan 04 23:22:53 2019 +0100
@@ -516,7 +516,7 @@
   #> fold (fold (Code_Target.add_reserved target) o snd) prelude_import_unqualified_constr);
 
 val _ =
-  Outer_Syntax.command @{command_keyword code_monad} "define code syntax for monads"
+  Outer_Syntax.command \<^command_keyword>\<open>code_monad\<close> "define code syntax for monads"
     (Parse.term -- Parse.name >> (fn (raw_bind, target) =>
       Toplevel.theory (add_monad target raw_bind)));