// 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)

}