--- a/solutions/cw2/lexer.sc	Sun Sep 17 19:12:57 2023 +0100
+++ b/solutions/cw2/lexer.sc	Tue Sep 19 09:54:41 2023 +0100
@@ -1,5 +1,7 @@
-import scala.language.implicitConversions    
-import scala.language.reflectiveCalls
+// CW 2
+//======
+
+
 
 // Rexp
 abstract class Rexp
@@ -27,7 +29,7 @@
 case class Rec(x: String, v: Val) extends Val
 
 
-// Convenience typing
+// Convenience for typing
 def charlist2rexp(s : List[Char]): Rexp = s match {
   case Nil => ONE
   case c::Nil => CHAR(c)
@@ -207,17 +209,18 @@
 // Language specific code
 val KEYWORD : Rexp = "while" | "if" | "then" | "else" | "do" | "for" | "to" | "true" | "false" | "read" | "write" | "skip" 
 val OP : Rexp = "+" | "-" | "*" | "%" | "/" | "==" | "!=" | ">" | "<" | ">=" | "<=" | ":=" | "&&" | "||"
-val LET: Rexp = RANGE(('A' to 'Z').toSet ++ ('a' to 'z'))
-val SYM : Rexp = LET | RANGE(Set('.', '_', '>', '<', '=', ';', ',', ':', ')', '('))
+val LET: Rexp = RANGE(('A' to 'Z').toSet ++ ('a' to 'z').toSet)
+val SYM : Rexp = RANGE(Set('.', '_', '>', '<', '=', ';', ',', ':'))
 val PARENS : Rexp = "(" | "{" | ")" | "}"
 val SEMI : Rexp = ";"
 val WHITESPACE : Rexp = PLUS(" ") | "\n" | "\t" | "\r"
 val DIGIT : Rexp = RANGE(('0' to '9').toSet)
 val DIGIT1 : Rexp = RANGE(('1' to '9').toSet)
-val STRING : Rexp = "\"" ~ (SYM | " " | "\\n" | DIGIT).% ~ "\""
+val STRING : Rexp = "\"" ~ (LET | DIGIT | SYM | PARENS | " " | "\\n").% ~ "\""
 val ID : Rexp = LET ~ (LET | "_" | DIGIT).%
 val NUM : Rexp = "0" | (DIGIT1 ~ DIGIT.%)
-val COMMENT : Rexp = "//" ~ (SYM | " " | DIGIT).% ~ ("\n" | "\r\n") 
+val EOL : Rexp = "\n" | "\r\n"
+val COMMENT : Rexp = "//" ~ (LET | DIGIT | SYM | " ").% ~ EOL 
 
 val WHILE_REGS = (("k" $ KEYWORD) | 
                   ("o" $ OP) | 
@@ -227,7 +230,7 @@
                   ("w" $ WHITESPACE) | 
                   ("i" $ ID) | 
                   ("n" $ NUM) |
-		              ("c" $ COMMENT)).%
+		  ("c" $ COMMENT)).%
 
 def esc(raw: String): String = {
   import scala.reflect.runtime.universe._
@@ -263,6 +266,7 @@
 
 
 // Q2 Tests
+
 lex_simp(NTIMES("a", 3), "aaa".toList)
 lex_simp(NTIMES(("a" | ONE), 3), "aa".toList)
 
@@ -312,7 +316,7 @@
 println(tokenise(prog3))
 
 
-println("MY TESTS")
+// More tests
 
 println(lex_simp("x" $ OPTIONAL("a"), "a".toList))
 println(lex_simp("x" $ OPTIONAL("a"), "".toList))