diff -r 3020f8c76baa -r 9e7897f25e13 testing4/re_test2.scala
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/testing4/re_test2.scala	Thu Nov 29 17:15:11 2018 +0000
@@ -0,0 +1,6 @@
+
+
+assert(der('a', ZERO | ONE) == (ZERO | ZERO))
+assert(der('a', (CHAR('a') | ONE) ~ CHAR('a')) == ALT((ONE | ZERO) ~ CHAR('a'), ONE))
+assert(der('a', STAR(CHAR('a'))) == (ONE ~ STAR(CHAR('a'))))
+assert(der('b', STAR(CHAR('a'))) == (ZERO ~ STAR(CHAR('a'))))