diff -r 1bbd4db36151 -r bb69fdebf05a marking3/re1a_test.scala
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/marking3/re1a_test.scala	Tue Jan 16 10:47:29 2018 +0000
@@ -0,0 +1,11 @@
+import CW8a._
+
+assert(nullable(ZERO) == false)
+assert(nullable(ONE) == true)
+assert(nullable(CHAR('a')) == false)
+assert(nullable(ZERO | ONE) == true)
+assert(nullable(ZERO | CHAR('a')) == false)
+assert(nullable(ONE ~  ONE) == true)
+assert(nullable(ONE ~ CHAR('a')) == false)
+assert(nullable(STAR(ZERO)) == true)
+