diff -r dc31a099dc98 -r 6bb67c2dcfd3 progs/lexer/lex.sc
--- a/progs/lexer/lex.sc	Sun Oct 29 00:06:30 2023 +0100
+++ b/progs/lexer/lex.sc	Sun Oct 29 13:05:09 2023 +0000
@@ -46,13 +46,10 @@
   def ~ (s: Rexp) = SEQ(r, s)
 }
 
+// to use & for records, instead of $ which had
+// its precedence be changed in Scala 3
 extension (s: String) {
-  def | (r: Rexp) = ALT(s, r)
-  def | (r: String) = ALT(s, r)
-  def % = STAR(s)
-  def ~ (r: Rexp) = SEQ(s, r)
-  def ~ (r: String) = SEQ(s, r)
-  def $ (r: Rexp) = RECD(s, r)
+  def & (r: Rexp) = RECD(s, r)
 }
 
 val TEST = ("ab" | "ba").%
@@ -166,20 +163,20 @@
 val STRING: Rexp = "\"" ~ SYM.% ~ "\""
 
 
-val WHILE_REGS = (("k" $ KEYWORD) | 
-                  ("i" $ ID) | 
-                  ("o" $ OP) | 
-                  ("n" $ NUM) | 
-                  ("s" $ SEMI) | 
-                  ("str" $ STRING) |
-                  ("p" $ (LPAREN | RPAREN)) | 
-                  ("w" $ WHITESPACE)).%
+val WHILE_REGS = (("k" & KEYWORD) | 
+                  ("i" & ID) | 
+                  ("o" & OP) | 
+                  ("n" & NUM) | 
+                  ("s" & SEMI) | 
+                  ("str" & STRING) |
+                  ("p" & (LPAREN | RPAREN)) | 
+                  ("w" & WHITESPACE)).%
 
 val KY : Rexp = "if" | "read" | "write"
 val WH : Rexp = " " | "\n"
 
-val TRIV_REGS = (("k" $ KY) | 
-                  ("w" $ WHITESPACE)).%
+val TRIV_REGS = (("k" & KY) | 
+                  ("w" & WHITESPACE)).%
 
 // Two Simple While Tests
 //========================
@@ -201,8 +198,3 @@
   println(lexing(WHILE_REGS, prog2))
 }
 
-
-
-
-
-// runs with amm2 and amm3