first version that runs

src/main/scala/project2/Interpreter.scala

@@ -260,8 +260,8 @@ class StackInterpreter extends Interpreter with BugReporter {
       eval(v, sp)(env)
       evalUn(op)(sp)
     case Prim(op, lop, rop) => 
-      eval(a, sp)(env)
-      eval(b, sp + 1)(env)
+      eval(lop, sp)(env)
+      eval(rop, sp + 1)(env)
       evalBin(sp, sp + 1)
     case Let(x, a, b) => 
       eval(a, sp)(env)
@@ -275,7 +275,7 @@ class StackInterpreter extends Interpreter with BugReporter {
       evalCond(op)(sp, sp + 1)
     case If(cond, tBranch, eBranch) => 
       eval(cond, sp)(env)
-      eval(if(flag)tBranch else eBranch, sp)
+      eval(if(flag)tBranch else eBranch, sp)(env)
     case VarDec(x, rhs, body) => 
       eval(rhs, sp)(env)
       eval(body, sp + 1)(env.withVal(x, sp))

src/main/scala/project2/Parser.scala

@@ -129,8 +129,8 @@ class Scanner(in: Reader[Char]) extends Reader[Tokens.Token] with Reporter {
    */
   def getNum() = {
     val buf = new java.lang.StringBuilder
-    while (in.hasNext(isNum)) {
-      buf += in.next
+    while (in.hasNext(isDigit)) {
+      buf += in.next()
     }
     Number(buf.toString().toInt)
   }
@@ -589,7 +589,7 @@ class VariableParser(in: Scanner) extends BranchParser(in) {
       val rhs = parseSimpleExpression
       accept(';')
       val body = parseExpression
-      Var(name, rhs, body).withPos(pos)
+      VarDec(name, rhs, body).withPos(pos)
     case _ => parseSimpleExpression
   }
 

src/main/scala/project2/SemanticAnalyzer.scala

@@ -137,9 +137,9 @@ class SemanticAnalyzer(parser: Parser) extends Reporter {
     case Cond(op, l, r) =>
       if (!isBOperator(op))
         error(s"$op is not a boolean operator")
-      analyze(op)
-      analyze(l)
-      analyze(r)
+      analyze(op)(env)
+      analyze(l)(env)
+      analyze(r)(env)
       // Done
     case If(cond, tBranch, eBranch) =>
       analyze(cond)(env)
@@ -154,12 +154,12 @@ class SemanticAnalyzer(parser: Parser) extends Reporter {
     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"}")
-      analyze(rhs)
+      analyze(rhs)(env)
       // TODO
     case While(cond, lBody, body) =>
-      analyze(cond)
-      analyze(lBody)
-      analyze(body)
+      analyze(cond)(env)
+      analyze(lBody)(env)
+      analyze(body)(env)
       // TODO
     case _ => abort(s"unknown AST node $exp")
   }