diff -r 553b4d4e3719 -r c6c79d21f8a8 progs/comb1a.scala
--- a/progs/comb1a.scala	Wed Nov 06 21:52:42 2019 +0000
+++ b/progs/comb1a.scala	Wed Nov 06 23:17:05 2019 +0000
@@ -16,7 +16,7 @@
 
   def parse_all(ts: I) : Set[T] =
     for ((head, tail) <- parse(ts); 
-        if (tail.isEmpty)) yield head
+        if tail.isEmpty) yield head
 }