diff -r 9c2dd041477b -r 5ec68c1a07d8 src/Pure/ROOT.scala
--- a/src/Pure/ROOT.scala	Mon Jun 28 12:29:00 2021 +0200
+++ b/src/Pure/ROOT.scala	Mon Jun 28 13:13:31 2021 +0200
@@ -21,3 +21,4 @@
   val proper_string = Library.proper_string _
   def proper_list[A](list: List[A]): Option[List[A]] = Library.proper_list(list)
 }
+