diff -r 04346d82fe01 -r 0b63c0edfb09 progs/cw1.scala
--- a/progs/cw1.scala	Wed Nov 13 20:07:26 2013 +0000
+++ b/progs/cw1.scala	Thu Nov 14 20:08:39 2013 +0000
@@ -57,16 +57,20 @@
       case r => NTIMES(r, n)
     }
 }
-case class NMTIMES(r: Rexp, n: Int, m: Int) extends Rexp {
-  if(m < n) throw new IllegalArgumentException("the number m cannot be smaller than n.")
-
+case class NUPTOM(r: Rexp, n: Int, m: Int) extends Rexp {
   override def simp = if (m == 0) EMPTY else 
     r.simp match {
       case NULL => NULL
       case EMPTY => EMPTY
-      case r => NMTIMES(r, n, m)
+      case r => NUPTOM(r, n, m)
     }
 }
+def NMTIMES(r: Rexp, n: Int, m: Int) = {
+  if(m < n) throw new IllegalArgumentException("the number m cannot be smaller than n.")
+  else NUPTOM(r, n, m - n)
+}
+
+
 case class NOT(r: Rexp) extends Rexp {
   override def simp = NOT(r.simp)
 }
@@ -85,7 +89,7 @@
   case STAR(_) => true
   case PLUS(r) => nullable(r)
   case NTIMES(r, i) => if (i == 0) true else nullable(r)
-  case NMTIMES(r, i, j) => if (i == 0) true else nullable(r)
+  case NUPTOM(r, i, j) => if (i == 0) true else nullable(r)
   case RANGE(_) => false
   case NOT(r) => !(nullable(r))
   case OPT(_) => true
@@ -101,13 +105,13 @@
     if (nullable(r1)) ALT(SEQ(der(c, r1), r2), der(c, r2))
     else SEQ(der(c, r1), r2)
   case STAR(r) => SEQ(der(c, r), STAR(r))
-  case PLUS(r) => der(c, SEQ(r, STAR(r)))
+  case PLUS(r) => SEQ(der(c, r), STAR(r))
   case NTIMES(r, i) => 
     if (i == 0) NULL else der(c, SEQ(r, NTIMES(r, i - 1)))
-  case NMTIMES(r, i, j) => 
-    if (j == 0) NULL 
-    if (i == 0) der(c, NTIMES(r, j))
-    else der(c, SEQ(r, NMTIMES(r, i - 1, j - 1)))
+  case NUPTOM(r, i, j) =>
+    if (i == 0 && j == 0) NULL else 
+    if (i == 0) ALT(der(c, NTIMES(r, j)), der(c, NUPTOM(r, 0, j - 1)))
+    else der(c, SEQ(r, NUPTOM(r, i - 1, j)))
   case RANGE(cs) => if (cs contains c) EMPTY else NULL
   case NOT(r) => NOT(der (c, r))
   case OPT(r) => der(c, r)
@@ -188,3 +192,22 @@
 println(matcher(EVIL2, "aaa" * 40))
 println(matcher(EVIL2, "aaa" * 43 + "aa"))
 println(matcher(EVIL2, "aaa" * 45 + "a"))
+
+println("TEST")
+val test = NMTIMES(RANGE(LOWERCASE + "."), 2, 6)
+  
+println(matcher(test,"ab"))
+println(matcher(test,"abcdef"))
+println(matcher(test,"abc"))
+println(matcher(test,"...."))
+println(matcher(test,"asdfg"))
+println(matcher(test,"abcdefg"))
+
+println(test)
+println(ders_simp("a".toList, test))
+println(ders_simp("aa".toList, test))
+println(ders_simp("aaa".toList, test))
+println(ders_simp("aaaa".toList, test))
+println(ders_simp("aaaaa".toList, test))
+println(ders_simp("aaaaaa".toList, test))
+println(ders_simp("aaaaaaa".toList, test))