src/Tools/try.ML

--- a/src/Tools/try.ML	Wed Dec 06 19:34:59 2017 +0100
+++ b/src/Tools/try.ML	Wed Dec 06 20:43:09 2017 +0100
@@ -73,7 +73,7 @@
     |> tap (fn NONE => writeln "Tried in vain" | _ => ());
 
 val _ =
-  Outer_Syntax.command @{command_keyword try}
+  Outer_Syntax.command \<^command_keyword>\<open>try\<close>
     "try a combination of automatic proving and disproving tools"
     (Scan.succeed (Toplevel.keep_proof (ignore o try_tools o Toplevel.proof_of)));