--- a/src/Pure/System/options.ML Sat Sep 04 21:45:43 2021 +0200
+++ b/src/Pure/System/options.ML Sat Sep 04 22:05:35 2021 +0200
@@ -156,8 +156,8 @@
fun encode (Options tab) =
let
val opts =
- (tab, []) |-> Symtab.fold (fn (name, {pos, typ, value}) =>
- cons (Position.properties_of pos, (name, (typ, value))));
+ build (tab |> Symtab.fold (fn (name, {pos, typ, value}) =>
+ cons (Position.properties_of pos, (name, (typ, value)))));
open XML.Encode;
in list (pair properties (pair string (pair string string))) opts end;