--- a/progs/app5.scala	Sat Sep 26 23:45:40 2020 +0100
+++ b/progs/app5.scala	Sun Sep 27 09:15:32 2020 +0100
@@ -23,5 +23,5 @@
   case c::s => ders(s, der(c, r))
 }
 
-def matches(r: Rexp, s: String) : Boolean = 
+def matcher(r: Rexp, s: String) : Boolean = 
   nullable(ders(s.toList, r))