pass all tests

src/main/scala/project2/Main.scala

@@ -42,6 +42,9 @@ OPTION: compX86, intStack, intValue (default)""")
       args(0)
     }
 
+    // val source = Source.fromFile("examples/unexpected_character.scala")
+    // val src = try source.getLines mkString "\n" finally source.close()
+
     println("============ SRC CODE ============")
     println(src)
     println("==================================\n")
@@ -51,7 +54,7 @@ OPTION: compX86, intStack, intValue (default)""")
 
     // Parser to test!
     // TODO: Change this as you finish parsers
-    val parser = new ArithParser(scanner)
+    val parser = new LoopParser(scanner)
     val ast = parser.parseCode
 
     println("============= AST ================")

src/main/scala/project2/Parser.scala

@@ -88,11 +88,11 @@ class Scanner(in: Reader[Char]) extends Reader[Tokens.Token] with Reporter {
 
   // List of delimiters
   // TODO: Update this as delimiters are added to our language
-  val isDelim      = Set('(',')')
+  val isDelim      = Set('(', ')', ';', '{', '}')
 
   // List of keywords
   // TODO: Update this as keywords are added to our language
-  val isKeyword    = Set[String]("val", "var")
+  val isKeyword    = Set[String]("val", "var", "if", "else", "while")
 
   /*
    * Extract a name from the stream
@@ -429,9 +429,12 @@ class ArithParser(in: Scanner) extends Parser(in) {
   def parseExpression(min: Int): Exp = {
     var res = parseUAtom
     // TODO: complete DONE?
-    if (in.hasNext(isOperator)) {
+    while (
+      in.hasNext(isOperator) && 
+      isInfixOp(min)(in.peek)
+    ) {
       val (op, pos) = getOperator
-      Prim(op, res, parseUAtom).withPos(pos)
+      res = Prim(op, res, parseExpression(prec(op))).withPos(pos)
     }
     res
   }
@@ -538,7 +541,9 @@ class BranchParser(in: Scanner) extends LetParser(in) {
   }
 
   // TODO: remove ??? and complete the implementation.
-  override def parseSimpleExpression: Exp = in.peek match {
+  override def parseSimpleExpression: Exp = {
+    print(in.peek)
+    in.peek match {
     case Keyword("if") => 
       val pos = in.next().pos
       accept('(')
@@ -546,6 +551,7 @@ class BranchParser(in: Scanner) extends LetParser(in) {
       accept(')')
       val if_stmt = parseSimpleExpression
       if (in.hasNext(_ == Keyword("else"))) {
+        in.next()
         val else_stmt = parseSimpleExpression
         If(cond, if_stmt, else_stmt).withPos(pos)
       }
@@ -553,6 +559,7 @@ class BranchParser(in: Scanner) extends LetParser(in) {
     case _ => super.parseSimpleExpression
   }
 }
+}
 
 /*
  * We can now introduce mutable variables using the 'var' keyword.
@@ -596,9 +603,10 @@ class VariableParser(in: Scanner) extends BranchParser(in) {
   // TODO: remove ??? and complete the implementation.
   override def parseSimpleExpression = (in.peek, in.peek1) match {
     case (Ident(x), Delim('=')) => 
-      val pos:Position = in.peek.pos 
+      val pos:Position = in.next().pos
+      accept('=') 
       VarAssign(x, parseSimpleExpression).withPos(pos)
-    case _ => super.parseExpression
+    case _ => super.parseSimpleExpression
   }
 }
 
@@ -635,6 +643,7 @@ class LoopParser(in: Scanner) extends VariableParser(in) {
       val cond = parseCondition
       accept(')')
       val simp = parseSimpleExpression
+      accept(';')
       val body = parseExpression
       While(cond, simp, body).withPos(pos)
     case _ => 

src/main/scala/project2/SemanticAnalyzer.scala

@@ -121,22 +121,22 @@ class SemanticAnalyzer(parser: Parser) extends Reporter {
       analyze(v)(env)
     case Prim(op, lop, rop) => // Done
       if(!(isOperator(op) || isBOperator(op))) 
-        error("undefined primitive operator")
+        error("undefined primitive operator", exp.pos)
       analyze(lop)(env)
       analyze(rop)(env)
     case Let(x, a, b) => // val x = a; b
       // Done: check variable reuse
-      if(!env.vars.contains(x))
-        error(s"cannot assign variable $x")
+      if(env.vars.contains(x))
+        error(s"cannot assign variable $x", exp.pos)
       analyze(a)(env)
       analyze(b)(env.withVal(x))
     case Ref(x) =>
       if (!env.vars.contains(x)) 
-        error(s"symbol $x not defined")
+        error(s"symbol $x not defined", exp.pos)
       // Done
     case Cond(op, l, r) =>
       if (!isBOperator(op))
-        error(s"$op is not a boolean operator")
+        error(s"$op is not a boolean operator", exp.pos)
       analyze(l)(env)
       analyze(r)(env)
       // Done
@@ -146,13 +146,13 @@ class SemanticAnalyzer(parser: Parser) extends Reporter {
       analyze(eBranch)(env)
     case VarDec(x, rhs, body) => // var x = rhs; body
       if (env.vars.contains(x)) 
-        error(s"symbol $x already defined")
+        error(s"symbol $x already defined", exp.pos)
       analyze(rhs)(env)
-      analyze(body)(env)
+      analyze(body)(env.withVar(x))
       // TODO
     case VarAssign(x, rhs) => // x = rhs
       if (!(env.vars.contains(x) && env.vars(x))) 
-        error(s"cannot assign $x: ${if(env.vars.contains(x))"immutable"else"undefined"}")
+        error(s"cannot assign $x: ${if(env.vars.contains(x))"immutable"else"undefined"}", exp.pos)
       analyze(rhs)(env)
       // TODO
     case While(cond, lBody, body) =>