# HG changeset patch
# User Christian Urban <christian dot urban at kcl dot ac dot uk>
# Date 1476783806 -3600
# Node ID 36e5752fa191c035ebc32fa1b3f294a05ac94443
# Parent  b93f4d2aeee1bcde50dfb329ace128c995e13fac
updated

diff -r b93f4d2aeee1 -r 36e5752fa191 progs/app05.scala
--- a/progs/app05.scala	Mon Oct 17 13:18:34 2016 +0100
+++ b/progs/app05.scala	Tue Oct 18 10:43:26 2016 +0100
@@ -3,8 +3,8 @@
     val (r1s, f1s) = simp(r1)
     val (r2s, f2s) = simp(r2)
     (r1s, r2s) match {
-      case (NULL, _) => (r2s, F_RIGHT(f2s))
-      case (_, NULL) => (r1s, F_LEFT(f1s))
+      case (ZERO, _) => (r2s, F_RIGHT(f2s))
+      case (_, ZERO) => (r1s, F_LEFT(f1s))
       case _ => 
          if (r1s == r2s) (r1s, F_LEFT(f1s))
          else (ALT (r1s, r2s), F_ALT(f1s, f2s)) 
diff -r b93f4d2aeee1 -r 36e5752fa191 progs/app06.scala
--- a/progs/app06.scala	Mon Oct 17 13:18:34 2016 +0100
+++ b/progs/app06.scala	Tue Oct 18 10:43:26 2016 +0100
@@ -3,10 +3,10 @@
     val (r1s, f1s) = simp(r1)
     val (r2s, f2s) = simp(r2)
     (r1s, r2s) match {
-      case (NULL, _) => (NULL, F_ERROR)
-      case (_, NULL) => (NULL, F_ERROR)
-      case (EMPTY, _) => (r2s, F_SEQ_Void1(f1s, f2s))
-      case (_, EMPTY) => (r1s, F_SEQ_Void2(f1s, f2s))
+      case (ZERO, _) => (ZERO, F_ERROR)
+      case (_, ZERO) => (ZERO, F_ERROR)
+      case (ONE, _) => (r2s, F_SEQ_Void1(f1s, f2s))
+      case (_, ONE) => (r1s, F_SEQ_Void2(f1s, f2s))
       case _ => (SEQ(r1s,r2s), F_SEQ(f1s, f2s))
     }
   }
diff -r b93f4d2aeee1 -r 36e5752fa191 progs/re1.scala
--- a/progs/re1.scala	Mon Oct 17 13:18:34 2016 +0100
+++ b/progs/re1.scala	Tue Oct 18 10:43:26 2016 +0100
@@ -5,6 +5,12 @@
 case class ALT(r1: Rexp, r2: Rexp) extends Rexp 
 case class SEQ(r1: Rexp, r2: Rexp) extends Rexp 
 case class STAR(r: Rexp) extends Rexp 
+case class RANGE(cs: List[Char]) extends Rexp
+case class PLUS(r: Rexp) extends Rexp
+case class OPT(r: Rexp) extends Rexp
+case class NTIMES(r: Rexp, n : Int) extends Rexp
+case class NMTIMES(r: Rexp, n : Int, m : Int) extends Rexp
+
 
 // nullable function: tests whether the regular 
 // expression can recognise the empty string
@@ -15,6 +21,7 @@
   case ALT(r1, r2) => nullable(r1) || nullable(r2)
   case SEQ(r1, r2) => nullable(r1) && nullable(r2)
   case STAR(_) => true
+
 }
 
 // derivative of a regular expression w.r.t. a character
diff -r b93f4d2aeee1 -r 36e5752fa191 progs/re2.scala
--- a/progs/re2.scala	Mon Oct 17 13:18:34 2016 +0100
+++ b/progs/re2.scala	Tue Oct 18 10:43:26 2016 +0100
@@ -29,7 +29,7 @@
     else SEQ(der(c, r1), r2)
   case STAR(r1) => SEQ(der(c, r1), STAR(r1))
   case NTIMES(r1, i) => 
-    if (i == 0) ZERO else SEQ(der(c, r1), NTIMES(r1, i - 1))
+    if (i == 0) ZERO else der(c, SEQ(r1, NTIMES(r1, i - 1)))
 }
 
 def ders (s: List[Char], r: Rexp) : Rexp = s match {
diff -r b93f4d2aeee1 -r 36e5752fa191 progs/re3.scala
--- a/progs/re3.scala	Mon Oct 17 13:18:34 2016 +0100
+++ b/progs/re3.scala	Tue Oct 18 10:43:26 2016 +0100
@@ -31,7 +31,7 @@
     else SEQ(der(c, r1), r2)
   case STAR(r1) => SEQ(der(c, r1), STAR(r1))
   case NTIMES(r, i) => 
-    if (i == 0) ZERO else SEQ(der(c, r), NTIMES(r, i - 1))
+    if (i == 0) ZERO else der(c, SEQ(r, NTIMES(r, i - 1)))
 }
 
 def simp(r: Rexp) : Rexp = r match {
diff -r b93f4d2aeee1 -r 36e5752fa191 slides/slides03.pdf
Binary file slides/slides03.pdf has changed
diff -r b93f4d2aeee1 -r 36e5752fa191 slides/slides04.pdf
Binary file slides/slides04.pdf has changed
diff -r b93f4d2aeee1 -r 36e5752fa191 slides/slides05.pdf
Binary file slides/slides05.pdf has changed