diff -r f5d2453c5640 -r 5070392a1bd7 progs/lexer/lexer.sc
--- a/progs/lexer/lexer.sc	Wed Oct 25 13:54:11 2023 +0100
+++ b/progs/lexer/lexer.sc	Thu Oct 26 14:30:20 2023 +0100
@@ -59,9 +59,6 @@
 
 
 
-val r : Rexp = ("a" | "b").% 
-println(r) 
-
 def nullable(r: Rexp) : Boolean = r match {
   case ZERO => false
   case ONE => true
@@ -84,8 +81,6 @@
   case RECD(_, r1) => der(c, r1)
 }
 
-println(der('a', ALT(STAR("a"), "b")))
-
 // extracts a string from a value
 def flatten(v: Val) : String = v match {
   case Empty => ""
@@ -338,7 +333,8 @@
 //
 // which has been removed in Scala 3.
 //
-// for escaping strings in Scala 3
+// for escaping strings in Scala 3 use this equivalent code
+
 import scala.quoted._
 
 def escapeImpl(raw: Expr[String])(using Quotes): Expr[String] = {