--- a/src/Pure/General/path.scala Tue Nov 10 12:48:56 2020 +0100
+++ b/src/Pure/General/path.scala Wed Nov 11 20:55:25 2020 +0100
@@ -156,6 +156,7 @@
def is_absolute: Boolean = elems.nonEmpty && elems.last.isInstanceOf[Path.Root]
def is_root: Boolean = elems match { case List(Path.Root(_)) => true case _ => false }
def is_basic: Boolean = elems match { case List(Path.Basic(_)) => true case _ => false }
+ def starts_basic: Boolean = elems.nonEmpty && elems.last.isInstanceOf[Path.Basic]
def +(other: Path): Path = new Path((other.elems :\ elems)(Path.apply_elem))