--- a/src/Pure/Syntax/syntax.ML Sun Aug 25 16:00:59 2024 +0200
+++ b/src/Pure/Syntax/syntax.ML Sun Aug 25 20:54:20 2024 +0200
@@ -442,7 +442,9 @@
| NONE => Printer.get_binder prtabs c)
|> Option.map Prefix);
-fun is_const (Syntax ({consts, ...}, _)) = Graph.defined consts;
+fun is_const (Syntax ({consts, ...}, _)) c =
+ Graph.defined consts c andalso not (Lexicon.is_marked c);
+
fun is_keyword (Syntax ({lexicon, ...}, _)) = Scan.is_literal lexicon o Symbol.explode;
fun tokenize (Syntax ({lexicon, ...}, _)) = Lexicon.tokenize lexicon;
fun parse (Syntax ({gram, ...}, _)) = Parser.parse (cache_eval gram);