// for testing tokenisation

import scala.util.{Try, Success, Failure}
import $file.cw024_add
import cw024_add._

def listcmp[A](xs: List[A], ys: List[A]): List[A] = (xs, ys) match {
  case (Nil, Nil) => Nil
  case (x::xs, y::ys) => if (x == y) listcmp(xs, ys) else (x::xs)
  case _ => xs
} 


// some students eliminated "..." therefore a specific comparison function
def lsteq(xs: List[Token], ys: List[Token]): Boolean = (xs, ys) match {
  case (Nil, Nil) => true
  case (T_STRING(s1)::xs, T_STRING(s2)::ys) => 
    (s1 == s2 || s2.drop(1).dropRight(1) == s1) && lsteq(xs, ys)
  case (x::xs, y::ys) => x == y && lsteq(xs, ys)
  case _ => false
} 

// some students kept string T_Num
import scala.language.implicitConversions
given Conversion[Int, String] = (n => n.toString)
given Conversion[String,Char] = (s => s.head)

// programs to test (and number of toplevel definitions)
//val uregs = List((RECD("x", PLUS(CHAR('a'))), "aaa")) 

val tks = 
  List(T_ID("bnd"), 
       T_OP(":="), 
       T_NUM(1), 
       T_SEMI, 
       T_KEYWORD("while"), 
       T_ID("bnd"), 
       T_OP("<"), 
       T_NUM(101), 
       T_KEYWORD("do"), 
       T_PAREN("{"), 
       T_KEYWORD("write"), 
       T_ID("bnd"), 
       T_SEMI, 
       T_KEYWORD("write"), 
       T_STRING("\": \""), 
       T_SEMI, 
       T_ID("n"), 
       T_OP(":="), 
       T_ID("bnd"), 
       T_SEMI, 
       T_ID("cnt"), 
       T_OP(":="), 
       T_NUM(0), 
       T_SEMI, 
       T_KEYWORD("while"), 
       T_ID("n"), 
       T_OP(">"), 
       T_NUM(1), 
       T_KEYWORD("do"), 
       T_PAREN("{"), 
       T_KEYWORD("write"), 
       T_ID("n"), 
       T_SEMI, 
       T_KEYWORD("write"), 
       T_STRING("\",\""), 
       T_SEMI, 
       T_KEYWORD("if"), 
       T_ID("n"), 
       T_OP("%"), 
       T_NUM(2), 
       T_OP("=="), 
       T_NUM(0), 
       T_KEYWORD("then"), 
       T_ID("n"), 
       T_OP(":="), 
       T_ID("n"), 
       T_OP("/"), 
       T_NUM(2), 
       T_KEYWORD("else"), 
       T_ID("n"), 
       T_OP(":="), 
       T_NUM(3), 
       T_OP("*"), 
       T_ID("n"), 
       T_OP("+"), 
       T_NUM(1), 
       T_SEMI, 
       T_ID("cnt"), 
       T_OP(":="), 
       T_ID("cnt"), 
       T_OP("+"), 
       T_NUM(1), 
       T_PAREN("}"), 
       T_SEMI, 
       T_KEYWORD("write"), 
       T_STRING("\" => \""), 
       T_SEMI, 
       T_KEYWORD("write"), 
       T_ID("cnt"), 
       T_SEMI, 
       T_KEYWORD("write"), 
       T_STRING("\"\\n\""), 
       T_SEMI, 
       T_ID("bnd"), 
       T_OP(":="), 
       T_ID("bnd"), 
       T_OP("+"), 
       T_NUM(1), 
       T_PAREN("}"))



  //print(s"  Testing lexing of ${file.padTo(16, ' ')} ")
val str = os.read(os.pwd / "collatz2.while")
  
Try(test_string(str)) match {
  case Success(v) if lsteq(v, tks) 
                  => println(s"   Generated the correct token sequence.")
  case Success(v) => println(s"   Generated $v\n instead of\n $tks\n\n${listcmp(v, tks)}).") ; throw new Exception("Different")
  case Failure(e) => println(s"   Exception raised.") ; throw(e)
}