completed

src/main/scala/project2/Compiler.scala

@@ -199,6 +199,8 @@ abstract class X86Compiler extends BugReporter with Codegen {
    * TODO: Fill in transUn with the appropriate code.
    */
   def transUn(op: String)(sp: Loc) = op match {
+    case "-" => emitln(s"neg ${regs(sp)}")
+    case "+" => ()
     case _ => BUG(s"Unary operator $op undefined")
   }
 
@@ -223,6 +225,7 @@ abstract class X86Compiler extends BugReporter with Codegen {
 
   var nLabel = 0
   def freshLabel(pref: String) = { nLabel += 1; s"$pref$nLabel" }
+  
 
   /*
    * Generate code that jumps to the label 'label'
@@ -260,18 +263,48 @@ abstract class X86Compiler extends BugReporter with Codegen {
   def trans(exp: Exp, sp: Loc)(env: LocationEnv): Unit = exp match {
     case Lit(x) =>
       emitln(s"movq $$$x, ${regs(sp)}")
-    case Unary(op, v) => ()
+    case Unary(op, v) => 
-    case Prim(op, lop, rop) => ()
+      trans(v, sp)(env)
-    case Let(x, a, b) => ()
+      transUn(op)(sp)
-    case Ref(x) => ()
+    case Prim(op, lop, rop) => 
-    case Cond(op, l, r) => ()
+      trans(lop, sp)(env)
-    case If(cond, tBranch, eBranch) => ()
+      trans(rop, sp + 1)(env)
-    case VarDec(x, rhs, body) => ()
+      transBin(op)(sp, sp + 1)
-    case VarAssign(x, rhs) => ()
+    case Let(x, a, b) => 
+      trans(a, sp)(env)
+      trans(b, sp + 1)(env.withVal(x, sp))
+      emitln(s"movq ${regs(sp + 1)}, ${regs(sp)}")
+    case Ref(x) => 
+      emitln(s"movq ${regs(env.apply(x))}, ${regs(sp)}")
+    case Cond(op, l, r) => 
+      trans(l, sp)(env)
+      trans(r, sp + 1)(env)
+      emitln(s"cmpq ${regs(sp + 1)}, ${regs(sp)}")
+    case If(cond, tBranch, eBranch) => 
+      trans(cond, sp)(env)
+      val lab = freshLabel("if")
+      transJumpIf(cond.op)(lab)
+      trans(eBranch, sp)(env)
+      emitln(s"jmp ${lab}_skip")
+      emitln(s"${lab}:", 0)
+      trans(tBranch, sp)(env)
+      emitln(s"${lab}_skip:", 0)
+    case VarDec(x, rhs, body) => 
+      trans(rhs, sp)(env)
+      trans(body, sp + 1)(env.withVal(x, sp))
+      emitln(s"movq ${regs(sp + 1)}, ${regs(sp)}")
+    case VarAssign(x, rhs) => 
+      trans(rhs, sp)(env)
+      emitln(s"movq ${regs(sp)}, ${regs(env.apply(x))}")
     case While(cond, lBody, body) =>
       val lab = freshLabel("loop")
       emitln(s"jmp ${lab}_cond")
       emitln(s"${lab}_body:", 0)
-      () // TODO: continue ...
+      trans(lBody, sp)(env)
+      emitln(s"${lab}_cond:", 0)
+      trans(cond, sp)(env)
+      transJumpIf(cond.op)(s"${lab}_body")
+      trans(body, sp)(env)
+      // TODO: continue ... Done
   }
 }

src/main/scala/project2/Interpreter.scala

@@ -190,6 +190,8 @@ class StackInterpreter extends Interpreter with BugReporter {
    * TODO: Implement the appropriate code as defined in the handout.
    */
   def evalUn(op: String)(sp: Loc) = op match {
+    case "+" => memory(sp)
+    case "-" => -memory(sp)
     case _ => BUG(s"Unary operator $op undefined")
   }
 
@@ -218,6 +220,11 @@ class StackInterpreter extends Interpreter with BugReporter {
   def evalCond(op: String)(sp: Loc, sp1: Loc) = {
     flag = op match {
       case "==" => memory(sp) == memory(sp1)
+      case "!=" => memory(sp) != memory(sp1)
+      case ">=" => memory(sp) >= memory(sp1)
+      case "<=" => memory(sp) <= memory(sp1)
+      case ">" => memory(sp) > memory(sp1)
+      case "<" => memory(sp) < memory(sp1)
       case _ => BUG(s"Binary operator $op undefined")
     }
   }
@@ -249,14 +256,32 @@ class StackInterpreter extends Interpreter with BugReporter {
   def eval(exp: Exp, sp: Loc)(env: LocationEnv): Unit = exp match {
     case Lit(x) =>
       memory(sp) = x
-    case Unary(op, v) => ???
+    case Unary(op, v) => 
-    case Prim(op, lop, rop) => ???
+      eval(v, sp)(env)
-    case Let(x, a, b) => ???
+      evalUn(op)(sp)
-    case Ref(x) => ???
+    case Prim(op, lop, rop) => 
-    case Cond(op, l, r) => ???
+      eval(a, sp)(env)
-    case If(cond, tBranch, eBranch) => ???
+      eval(b, sp + 1)(env)
-    case VarDec(x, rhs, body) => ???
+      evalBin(sp, sp + 1)
-    case VarAssign(x, rhs) => ???
+    case Let(x, a, b) => 
+      eval(a, sp)(env)
+      eval(b, sp + 1)(env.withVal(x, sp))
+      memory(sp) = memory(sp + 1)
+    case Ref(x) => 
+      memory(sp) = memory(env.apply(x)) 
+    case Cond(op, l, r) => 
+      eval(l, sp)(env)
+      eval(r, sp + 1)(env)
+      evalCond(op)(sp, sp + 1)
+    case If(cond, tBranch, eBranch) => 
+      eval(cond, sp)(env)
+      eval(if(flag)tBranch else eBranch, sp)
+    case VarDec(x, rhs, body) => 
+      eval(rhs, sp)(env)
+      eval(body, sp + 1)(env.withVal(x, sp))
+    case VarAssign(x, rhs) => 
+      eval(rhs, sp)(env)
+      memory(env.apply(x)) = memory(sp)
     case While(cond, lbody, body) =>
       eval(cond, sp)(env)
       while (flag) {

src/main/scala/project2/Parser.scala

@@ -1,5 +1,7 @@
 package project2
 
+import java.awt.RenderingHints.Key
+
 // Class used to carry position information within the source code
 case class Position(gapLine: Int, gapCol: Int, startLine: Int, startCol: Int, endLine: Int, endCol: Int)
 
@@ -426,7 +428,11 @@ class ArithParser(in: Scanner) extends Parser(in) {
   def parseExpression: Exp = parseExpression(0)
   def parseExpression(min: Int): Exp = {
     var res = parseUAtom
-    // TODO: complete
+    // TODO: complete DONE?
+    if (in.hasNext(isOperator)) {
+      val (op, pos) = getOperator
+      Prim(op, res, parseUAtom).withPos(pos)
+    }
     res
   }
 }
@@ -469,7 +475,7 @@ class LetParser(in: Scanner) extends ArithParser(in) {
     case Ident(x) =>
       val (_, pos) = getName
       Ref(x).withPos(pos)
-      // TODO: remove ??? and add the implementation for this case
+      // TODO: remove ??? and add the implementation for this case DONE
     case _ => abort(s"Illegal start of simple expression")
   }
 
@@ -532,7 +538,20 @@ class BranchParser(in: Scanner) extends LetParser(in) {
   }
 
   // TODO: remove ??? and complete the implementation.
-  override def parseSimpleExpression = ???
+  override def parseSimpleExpression: Exp = in.peek match {
+    case Keyword("if") => 
+      val pos = in.next().pos
+      accept('(')
+      val cond = parseCondition
+      accept(')')
+      val if_stmt = parseSimpleExpression
+      if (in.hasNext(_ == Keyword("else"))) {
+        val else_stmt = parseSimpleExpression
+        If(cond, if_stmt, else_stmt).withPos(pos)
+      }
+      else expected("missing else statement")
+    case _ => super.parseSimpleExpression
+  }
 }
 
 /*
@@ -562,12 +581,24 @@ class VariableParser(in: Scanner) extends BranchParser(in) {
 
   // TODO: remove ??? and complete the implementation.
   override def parseExpression = in.peek match {
-    case _ => ???
+    case Keyword("val") => super.parseExpression
+    case Keyword("var") => 
+      in.next()
+      val (name, pos) = getName
+      accept('=')
+      val rhs = parseSimpleExpression
+      accept(';')
+      val body = parseExpression
+      Var(name, rhs, body).withPos(pos)
+    case _ => parseSimpleExpression
   }
 
   // TODO: remove ??? and complete the implementation.
   override def parseSimpleExpression = (in.peek, in.peek1) match {
-    case _ => ???
+    case (Ident(x), Delim('=')) => 
+      val pos = in.pos 
+      VarAssign(x, parseSimpleExpression).withPos(pos)
+    case _ => super.parseExpression
   }
 }
 
@@ -597,5 +628,16 @@ class LoopParser(in: Scanner) extends VariableParser(in) {
   import Tokens._
 
   // TODO: remove ??? and complete the implementation.
-  override def parseExpression = ???
+  override def parseExpression = in.peek match {
+    case Keyword("while") => 
+      val pos = in.next().pos
+      accept('(')
+      val cond = parseCondition
+      accept(')')
+      val simp = parseSimpleExpression
+      val body = parseExpression
+      While(cond, simp, body).withPos(pos)
+    case _ => 
+      super.parseExpression
+  }
 }

src/main/scala/project2/SemanticAnalyzer.scala

@@ -124,33 +124,43 @@ class SemanticAnalyzer(parser: Parser) extends Reporter {
         error("undefined primitive operator")
       analyze(lop)
       analyze(rop)
-    case Let(x, a, b) =>
+    case Let(x, a, b) => // val x = a; b
       // Done: check variable reuse
-      if(!(env.vars.contains(x) && env.vars[x]))
+      if(!env.vars.contains(x))
         error(s"cannot assign variable $x")
       analyze(a)(env)
       analyze(b)(env.withVal(x))
     case Ref(x) =>
       if (!env.vars.contains(x)) 
-        error(s"symbol $x not found")
+        error(s"symbol $x not defined")
-      ()// Done
+      // Done
     case Cond(op, l, r) =>
-      // if (!isBOperator(op))
+      if (!isBOperator(op))
-      //   error(s"$op is not a boolean operator")
+        error(s"$op is not a boolean operator")
       analyze(op)
       analyze(l)
       analyze(r)
-      () // Done
+      // Done
     case If(cond, tBranch, eBranch) =>
       analyze(cond)(env)
       analyze(tBranch)(env)
       analyze(eBranch)(env)
-    case VarDec(x, rhs, body) =>
+    case VarDec(x, rhs, body) => // var x = rhs; body
-      () // TODO
+      if (env.vars.contains(x)) 
-    case VarAssign(x, rhs) => //diff w/ LET??
+        error(s"symbol $x already defined")
-      () // TODO
+      analyze(rhs)(env)
+      analyze(body)(env)
+      // 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"}")
+      analyze(rhs)
+      // TODO
     case While(cond, lBody, body) =>
-      () // TODO
+      analyze(cond)
+      analyze(lBody)
+      analyze(body)
+      // TODO
     case _ => abort(s"unknown AST node $exp")
   }