diff -r e9d14d58be3c -r daf561a83ba6 main_templates3/re.scala
--- a/main_templates3/re.scala	Thu Jan 13 12:55:03 2022 +0000
+++ b/main_templates3/re.scala	Mon Apr 11 23:55:27 2022 +0100
@@ -12,28 +12,12 @@
 case class SEQ(r1: Rexp, r2: Rexp) extends Rexp   // sequence
 case class STAR(r: Rexp) extends Rexp             // star
 
-import scala.language.implicitConversions    
-import scala.language.reflectiveCalls 
-
-def charlist2rexp(s: List[Char]): Rexp = s match {
-  case Nil => ONE
-  case c::Nil => CHAR(c)
-  case c::s => SEQ(CHAR(c), charlist2rexp(s))
-}
-implicit def string2rexp(s: String): Rexp = charlist2rexp(s.toList)
-
-
-// "a|b"
-ALT(CHAR('a'), CHAR('b'))
-
-val reg : Rexp = "a" | "b" // CHAR('a')
-
-// some convenience for typing regular expressions
-
 //the usual binary choice can be defined in terms of ALTs
 def ALT(r1: Rexp, r2: Rexp) = ALTs(List(r1, r2))
 
 
+// some convenience for typing regular expressions
+
 import scala.language.implicitConversions    
 import scala.language.reflectiveCalls 
 
@@ -44,9 +28,6 @@
 }
 implicit def string2rexp(s: String): Rexp = charlist2rexp(s.toList)
 
-
-
-
 implicit def RexpOps (r: Rexp) = new {
   def | (s: Rexp) = ALT(r, s)
   def % = STAR(r)
@@ -61,6 +42,11 @@
   def ~ (r: String) = SEQ(s, r)
 }
 
+
+// ALT(CHAR('a'), CHAR('b'))
+// val reg : Rexp = "a" | "b" 
+
+
 // (1) Complete the function nullable according to
 // the definition given in the coursework; this 
 // function checks whether a regular expression