# HG changeset patch
# User Christian Urban <christian dot urban at kcl dot ac dot uk>
# Date 1353892315 0
# Node ID 191daa3ee29e1106f9c20ec660e129056ed36fee
# Parent  fd894e017e125d5453d61f199f2a979b9ff53503
tuned

diff -r fd894e017e12 -r 191daa3ee29e compile.scala
--- a/compile.scala	Sat Nov 24 15:10:43 2012 +0000
+++ b/compile.scala	Mon Nov 26 01:11:55 2012 +0000
@@ -10,7 +10,7 @@
 val NUM = PLUS(DIGIT)
 val KEYWORD = ALTS("skip", "while", "do", "if", "then", "else", "true", "false", "write") 
 val SEMI: Rexp = ";"
-val OP: Rexp = ALTS(":=", "=", "-", "+", "*", "!", "<", ">")
+val OP: Rexp = ALTS(":=", "=", "-", "+", "*", "!=", "<", ">")
 val WHITESPACE = PLUS(RANGE(" \n"))
 val RPAREN: Rexp = ")"
 val LPAREN: Rexp = "("
@@ -65,7 +65,7 @@
 
 case object True extends BExp
 case object False extends BExp
-case class Bop(o: String, a1: AExp, a2: AExp) extends BExp
+case class Relop(o: String, a1: AExp, a2: AExp) extends BExp
 
 // atomic parsers
 case class TokParser(tok: Token) extends Parser[List[Token], Token] {
@@ -107,10 +107,10 @@
   (T_KWD("true") ==> ((_) => True: BExp)) || 
   (T_KWD("false") ==> ((_) => False: BExp)) ||
   (T_LPAREN ~> BExp <~ T_RPAREN) ||
-  (AExp ~ T_OP("=") ~ AExp) ==> { case ((x, y), z) => Bop("=", x, z): BExp } || 
-  (AExp ~ T_OP("!=") ~ AExp) ==> { case ((x, y), z) => Bop("!=", x, z): BExp } || 
-  (AExp ~ T_OP("<") ~ AExp) ==> { case ((x, y), z) => Bop("<", x, z): BExp } || 
-  (AExp ~ T_OP(">") ~ AExp) ==> { case ((x, y), z) => Bop("<", z, x): BExp } 
+  (AExp ~ T_OP("=") ~ AExp) ==> { case ((x, y), z) => Relop("=", x, z): BExp } || 
+  (AExp ~ T_OP("!=") ~ AExp) ==> { case ((x, y), z) => Relop("!=", x, z): BExp } || 
+  (AExp ~ T_OP("<") ~ AExp) ==> { case ((x, y), z) => Relop("<", x, z): BExp } || 
+  (AExp ~ T_OP(">") ~ AExp) ==> { case ((x, y), z) => Relop("<", z, x): BExp } 
 
 lazy val Stmt: Parser[List[Token], Stmt] =
   (T_KWD("skip") ==> ((_) => Skip: Stmt)) ||
@@ -128,9 +128,9 @@
   (T_BEGIN ~> Stmts <~ T_END) || 
   (Stmt ==> ((s) => List(s)))
 
-// interpreter
+// compiler
 val beginning = """
-.class public examples/HelloWorld
+.class public XXX.XXX
 .super java/lang/Object
 
 .method public <init>()V
@@ -172,8 +172,9 @@
 }
 
 type Env = Map[String, String]
+type Instrs = List[String]
 
-def compile_aexp(a: AExp, env : Env) : List[String] = a match {
+def compile_aexp(a: AExp, env : Env) : Instrs = a match {
   case Num(i) => List("ldc " + i.toString + "\n")
   case Var(s) => List("iload " + env(s) + "\n")
   case Aop("+", a1, a2) => compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ List("iadd\n")
@@ -181,19 +182,24 @@
   case Aop("*", a1, a2) => compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ List("imul\n")
 }
 
-def compile_bexp(b: BExp, env : Env, jmp: String) : List[String] = b match {
-  case Bop("=", a1, a2) => 
+def compile_bexp(b: BExp, env : Env, jmp: String) : Instrs = b match {
+  case True => Nil
+  case False => List("goto " + jmp + "\n")
+  case Relop("=", a1, a2) => 
     compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ List("if_icmpne " + jmp + "\n")
-  case Bop("<", a1, a2) => 
+  case Relop("!=", a1, a2) => 
+    compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ List("if_icmpeq " + jmp + "\n")
+  case Relop("<", a1, a2) => 
     compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ List("if_icmpge " + jmp + "\n")
 }
 
 
-def compile_stmt(s: Stmt, env: Env) : (List[String], Env) = s match {
+def compile_stmt(s: Stmt, env: Env) : (Instrs, Env) = s match {
   case Skip => (Nil, env)
   case Assign(x, a) => {
     val index = if (env.isDefinedAt(x)) env(x) else env.keys.size.toString
-    (compile_aexp(a, env) ++ List("istore " + index + "\n"), env + (x -> index))
+    (compile_aexp(a, env) ++ 
+     List("istore " + index + "\n"), env + (x -> index))
   } 
   case If(b, bl1, bl2) => {
     val if_else = Fresh("If_else")
@@ -218,10 +224,10 @@
      List("\n" + loop_end + ":\n\n"), env1)
   }
   case Write(x) => 
-    (List("iload " + env(x) + "\n" + "invokestatic examples/HelloWorld/write(I)V\n"), env)
+    (List("iload " + env(x) + "\n" + "invokestatic XXX/XXX/write(I)V\n"), env)
 }
 
-def compile_bl(bl: Block, env: Env) : (List[String], Env) = bl match {
+def compile_bl(bl: Block, env: Env) : (Instrs, Env) = bl match {
   case Nil => (Nil, env)
   case s::bl => {
     val (instrs1, env1) = compile_stmt(s, env)
@@ -230,18 +236,88 @@
   }
 }
 
-def compile(name: String) : String = {
-  val tks = Tok.fromFile(name)
+def compile(input: String) : String = {
+  val class_name = input.split('.')(0)
+  val tks = Tok.fromFile(input)
   val ast = Stmts.parse_single(tks)
   val instructions = compile_bl(ast, Map.empty)._1
-  beginning ++ instructions.mkString ++ ending
+  (beginning ++ instructions.mkString ++ ending).replaceAllLiterally("XXX", class_name)
 }
 
 
+def compile_to(input: String, output: String) = {
+  val fw = new java.io.FileWriter(output) 
+  fw.write(compile(input)) 
+  fw.close()
+}
+
+//
+val tks = Tok.fromString("x := x + 1")
+val ast = Stmt.parse_single(tks)
+println(compile_stmt(ast, Map("x" -> "n"))._1.mkString)
+
+
+
 //examples
 
-println(compile("loops.while"))
-//println(compile("fib.while"))
+//compile_to("loops.while", "loops.j")
+//compile_to("fib.while", "fib.j")
+
+
+// testing cases for time measurements
+
+def time_needed[T](i: Int, code: => T) = {
+  val start = System.nanoTime()
+  for (j <- 1 to i) code
+  val end = System.nanoTime()
+  (end - start)/(i * 1.0e9)
+}
+
+// for testing
+import scala.sys.process._
+
+val test_prog = """
+start := XXX;
+x := start;
+y := start;
+z := start;
+while 0 < x do {
+ while 0 < y do {
+  while 0 < z do {
+    z := z - 1
+  };
+  z := start;
+  y := y - 1
+ };     
+ y := start;
+ x := x - 1
+};
+write x;
+write y;
+write z
+"""
+
+
+def compile_test(n: Int) : Unit = {
+  val class_name = "LOOP"
+  val tks = Tok.fromString(test_prog.replaceAllLiterally("XXX", n.toString))
+  val ast = Stmts.parse_single(tks)
+  val instructions = compile_bl(ast, Map.empty)._1
+  val assembly = (beginning ++ instructions.mkString ++ ending).replaceAllLiterally("XXX", class_name)
+  val fw = new java.io.FileWriter(class_name + ".j") 
+  fw.write(assembly) 
+  fw.close()
+  val test = ("java -jar jvm/jasmin-2.4/jasmin.jar " + class_name + ".j").!!
+  println(n + " " + time_needed(2, ("java " + class_name + "/" + class_name).!!))
+}
+
+List(1, 5000, 10000, 50000, 100000, 250000, 500000, 750000, 1000000).map(compile_test(_))
+
+
+
+// javabyte code assmbler
+//
+// java -jar jvm/jasmin-2.4/jasmin.jar loops.j
 
 
 
@@ -249,5 +325,3 @@
 
 
 
-
-
diff -r fd894e017e12 -r 191daa3ee29e compile1.scala
--- a/compile1.scala	Sat Nov 24 15:10:43 2012 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,266 +0,0 @@
-// A parser and evaluator for teh while language
-// 
-//:load matcher.scala
-//:load parser3.scala
-
-// some regular expressions
-val SYM = RANGE("ABCDEFGHIJKLMNOPQRSTUVXYZabcdefghijklmnopqrstuvwxyz_")
-val DIGIT = RANGE("0123456789")
-val ID = SEQ(SYM, STAR(ALT(SYM, DIGIT))) 
-val NUM = PLUS(DIGIT)
-val KEYWORD = ALTS("skip", "while", "do", "if", "then", "else", "true", "false", "write") 
-val SEMI: Rexp = ";"
-val OP: Rexp = ALTS(":=", "=", "-", "+", "*", "!=", "<", ">")
-val WHITESPACE = PLUS(RANGE(" \n"))
-val RPAREN: Rexp = ")"
-val LPAREN: Rexp = "("
-val BEGIN: Rexp = "{"
-val END: Rexp = "}"
-val COMMENT = SEQS("/*", NOT(SEQS(STAR(ALLC), "*/", STAR(ALLC))), "*/")
-
-// tokens for classifying the strings that have been recognised
-abstract class Token
-case object T_WHITESPACE extends Token
-case object T_COMMENT extends Token
-case object T_SEMI extends Token
-case object T_LPAREN extends Token
-case object T_RPAREN extends Token
-case object T_BEGIN extends Token
-case object T_END extends Token
-case class T_ID(s: String) extends Token
-case class T_OP(s: String) extends Token
-case class T_NUM(s: String) extends Token
-case class T_KWD(s: String) extends Token
-
-val lexing_rules: List[Rule[Token]] = 
-  List((KEYWORD, (s) => T_KWD(s.mkString)),
-       (ID, (s) => T_ID(s.mkString)),
-       (OP, (s) => T_OP(s.mkString)),
-       (NUM, (s) => T_NUM(s.mkString)),
-       (SEMI, (s) => T_SEMI),
-       (LPAREN, (s) => T_LPAREN),
-       (RPAREN, (s) => T_RPAREN),
-       (BEGIN, (s) => T_BEGIN),
-       (END, (s) => T_END),
-       (WHITESPACE, (s) => T_WHITESPACE),
-       (COMMENT, (s) => T_COMMENT))
-
-// the tokenizer
-val Tok = Tokenizer(lexing_rules, List(T_WHITESPACE, T_COMMENT))
-
-// the abstract syntax trees
-abstract class Stmt
-abstract class AExp
-abstract class BExp 
-type Block = List[Stmt]
-case object Skip extends Stmt
-case class If(a: BExp, bl1: Block, bl2: Block) extends Stmt
-case class While(b: BExp, bl: Block) extends Stmt
-case class Assign(s: String, a: AExp) extends Stmt
-case class Write(s: String) extends Stmt
-
-case class Var(s: String) extends AExp
-case class Num(i: Int) extends AExp
-case class Aop(o: String, a1: AExp, a2: AExp) extends AExp
-
-case object True extends BExp
-case object False extends BExp
-case class Relop(o: String, a1: AExp, a2: AExp) extends BExp
-
-// atomic parsers
-case class TokParser(tok: Token) extends Parser[List[Token], Token] {
-  def parse(ts: List[Token]) = ts match {
-    case t::ts if (t == tok) => Set((t, ts)) 
-    case _ => Set ()
-  }
-}
-implicit def token2tparser(t: Token) = TokParser(t)
-
-case object NumParser extends Parser[List[Token], Int] {
-  def parse(ts: List[Token]) = ts match {
-    case T_NUM(s)::ts => Set((s.toInt, ts)) 
-    case _ => Set ()
-  }
-}
-
-case object IdParser extends Parser[List[Token], String] {
-  def parse(ts: List[Token]) = ts match {
-    case T_ID(s)::ts => Set((s, ts)) 
-    case _ => Set ()
-  }
-}
-
-
-// arithmetic expressions
-lazy val AExp: Parser[List[Token], AExp] = 
-  (T ~ T_OP("+") ~ AExp) ==> { case ((x, y), z) => Aop("+", x, z): AExp } ||
-  (T ~ T_OP("-") ~ AExp) ==> { case ((x, y), z) => Aop("-", x, z): AExp } || T  
-lazy val T: Parser[List[Token], AExp] = 
-  (F ~ T_OP("*") ~ T) ==> { case ((x, y), z) => Aop("*", x, z): AExp } || F
-lazy val F: Parser[List[Token], AExp] = 
-  (T_LPAREN ~> AExp <~ T_RPAREN) || 
-  IdParser ==> Var || 
-  NumParser ==> Num
-
-// boolean expressions
-lazy val BExp: Parser[List[Token], BExp] = 
-  (T_KWD("true") ==> ((_) => True: BExp)) || 
-  (T_KWD("false") ==> ((_) => False: BExp)) ||
-  (T_LPAREN ~> BExp <~ T_RPAREN) ||
-  (AExp ~ T_OP("=") ~ AExp) ==> { case ((x, y), z) => Relop("=", x, z): BExp } || 
-  (AExp ~ T_OP("!=") ~ AExp) ==> { case ((x, y), z) => Relop("!=", x, z): BExp } || 
-  (AExp ~ T_OP("<") ~ AExp) ==> { case ((x, y), z) => Relop("<", x, z): BExp } || 
-  (AExp ~ T_OP(">") ~ AExp) ==> { case ((x, y), z) => Relop("<", z, x): BExp } 
-
-lazy val Stmt: Parser[List[Token], Stmt] =
-  (T_KWD("skip") ==> ((_) => Skip: Stmt)) ||
-  (IdParser ~ T_OP(":=") ~ AExp) ==> { case ((x, y), z) => Assign(x, z): Stmt } ||
-  (T_KWD("if") ~ BExp ~ T_KWD("then") ~ Block ~ T_KWD("else") ~ Block) ==>
-    { case (((((x,y),z),u),v),w) => If(y, u, w): Stmt } ||
-  (T_KWD("while") ~ BExp ~ T_KWD("do") ~ Block) ==> { case (((x, y), z), w) => While(y, w) } || 
-  (T_KWD("write") ~ IdParser) ==> { case (x, y) => Write(y) } 
-
-lazy val Stmts: Parser[List[Token], Block] =
-  (Stmt ~ T_SEMI ~ Stmts) ==> { case ((x, y), z) => x :: z : Block } ||
-  (Stmt ==> ((s) => List(s) : Block))
-
-lazy val Block: Parser[List[Token], Block] =
-  (T_BEGIN ~> Stmts <~ T_END) || 
-  (Stmt ==> ((s) => List(s)))
-
-// compiler
-val beginning = """
-.class public examples/HelloWorld
-.super java/lang/Object
-
-.method public <init>()V
-   aload_0
-   invokenonvirtual java/lang/Object/<init>()V
-   return
-.end method
-
-.method public static write(I)V 
-    .limit locals 5 
-    .limit stack 5 
-    iload 0 
-    getstatic java/lang/System/out Ljava/io/PrintStream; 
-    swap 
-    invokevirtual java/io/PrintStream/println(I)V 
-    return 
-.end method
-
-
-.method public static main([Ljava/lang/String;)V
-   .limit locals 200
-   .limit stack 200
-
-"""
-
-val ending = """
-
-   return
-
-.end method
-"""
-
-// for generating new labels
-var counter = -1
-
-def Fresh(x: String) = {
-  counter += 1
-  x ++ "_" ++ counter.toString()
-}
-
-type Env = Map[String, String]
-type Instrs = List[String]
-
-def compile_aexp(a: AExp, env : Env) : Instrs = a match {
-  case Num(i) => List("ldc " + i.toString + "\n")
-  case Var(s) => List("iload " + env(s) + "\n")
-  case Aop("+", a1, a2) => compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ List("iadd\n")
-  case Aop("-", a1, a2) => compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ List("isub\n")
-  case Aop("*", a1, a2) => compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ List("imul\n")
-}
-
-def compile_bexp(b: BExp, env : Env, jmp: String) : Instrs = b match {
-  case True => Nil
-  case False => List("goto " + jmp + "\n")
-  case Relop("=", a1, a2) => 
-    compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ List("if_icmpne " + jmp + "\n")
-  case Relop("!=", a1, a2) => 
-    compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ List("if_icmpeq " + jmp + "\n")
-  case Relop("<", a1, a2) => 
-    compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ List("if_icmpge " + jmp + "\n")
-}
-
-
-def compile_stmt(s: Stmt, env: Env) : (Instrs, Env) = s match {
-  case Skip => (Nil, env)
-  case Assign(x, a) => {
-    val index = if (env.isDefinedAt(x)) env(x) else env.keys.size.toString
-    (compile_aexp(a, env) ++ 
-     List("istore " + index + "\n"), env + (x -> index))
-  } 
-  case If(b, bl1, bl2) => {
-    val if_else = Fresh("If_else")
-    val if_end = Fresh("If_end")
-    val (instrs1, env1) = compile_bl(bl1, env)
-    val (instrs2, env2) = compile_bl(bl2, env1)
-    (compile_bexp(b, env, if_else) ++
-     instrs1 ++
-     List("goto " + if_end + "\n") ++
-     List("\n" + if_else + ":\n\n") ++
-     instrs2 ++
-     List("\n" + if_end + ":\n\n"), env2)
-  }
-  case While(b, bl) => {
-    val loop_begin = Fresh("Loop_begin")
-    val loop_end = Fresh("Loop_end")
-    val (instrs1, env1) = compile_bl(bl, env)
-    (List("\n" + loop_begin + ":\n\n") ++
-     compile_bexp(b, env, loop_end) ++
-     instrs1 ++
-     List("goto " + loop_begin + "\n") ++
-     List("\n" + loop_end + ":\n\n"), env1)
-  }
-  case Write(x) => 
-    (List("iload " + env(x) + "\n" + "invokestatic examples/HelloWorld/write(I)V\n"), env)
-}
-
-def compile_bl(bl: Block, env: Env) : (Instrs, Env) = bl match {
-  case Nil => (Nil, env)
-  case s::bl => {
-    val (instrs1, env1) = compile_stmt(s, env)
-    val (instrs2, env2) = compile_bl(bl, env1)
-    (instrs1 ++ instrs2, env2)
-  }
-}
-
-def compile(input: String) : String = {
-  val tks = Tok.fromFile(input)
-  val ast = Stmts.parse_single(tks)
-  val instructions = compile_bl(ast, Map.empty)._1
-  beginning ++ instructions.mkString ++ ending
-}
-
-
-def compile_to(input: String, output: String) = {
-  val fw = new java.io.FileWriter(output) 
-  fw.write(compile(input)) 
-  fw.close()
-}
-
-
-//examples
-
-compile_to("loops.while", "loops.j")
-compile_to("fib.while", "fib.j")
-
-
-
-
-
-
-
-
-
diff -r fd894e017e12 -r 191daa3ee29e fib.while
--- a/fib.while	Sat Nov 24 15:10:43 2012 +0000
+++ b/fib.while	Mon Nov 26 01:11:55 2012 +0000
@@ -1,17 +1,12 @@
-/*
-  
-  Fibonacci Program
-
-  input: n
-  output: fib_res
-
-*/
+/* Fibonacci Program
+   input: n
+   output: fib_res */
 
 n := 90;
 minus1 := 0;
 minus2 := 1;
 temp := 0;
-while n > 0 do  {
+while n > 0 do {
        temp := minus2;
        minus2 := minus1 + minus2;
        minus1 := temp;
diff -r fd894e017e12 -r 191daa3ee29e slides09.pdf
Binary file slides09.pdf has changed
diff -r fd894e017e12 -r 191daa3ee29e slides09.tex
--- a/slides09.tex	Sat Nov 24 15:10:43 2012 +0000
+++ b/slides09.tex	Mon Nov 26 01:11:55 2012 +0000
@@ -105,17 +105,27 @@
 
 % The data files, written on the first run.
 \begin{filecontents}{compiled.data}
-1 0.0207
-5000 0.0217
-10000 0.0297
-50000 0.1034
-100000 0.3873
-500000 1.27949
-1000000 5. 35424
+%1 0.234146
+%5000 0.227539
+%10000 0.280748
+50000 1.087897
+100000 3.713165
+250000 21.6624545
+500000 85.872613
+750000 203.6408015
+1000000 345.736574
 \end{filecontents}
 
 \begin{filecontents}{interpreted.data}
-
+%1 0.00503
+200 1.005863
+400 7.8296765
+500 15.43106
+600 27.2321885
+800 65.249271
+1000 135.4493445
+1200 232.134097
+1400 382.527227
 \end{filecontents}
 
 
@@ -146,6 +156,26 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \mode<presentation>{
 \begin{frame}[c]
+
+Imagine the following situation: You talk to somebody
+and you find out that she/he has implemented a compiler.\smallskip
+
+What is your reaction? Check all that apply.\bigskip\pause
+
+ \begin{itemize}
+ \item[$\Box$] You think she/he is God
+ \item[$\Box$] \"Uberhacker
+ \item[$\Box$] superhuman
+ \item[$\Box$] wizard
+ \item[$\Box$] supremo
+ \end{itemize}
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[c]
 \frametitle{\begin{tabular}{c}While-Language\end{tabular}}
 
 
@@ -177,7 +207,7 @@
 \mbox{}\\[-18mm]\mbox{}
 
 {\lstset{language=While}\fontsize{10}{12}\selectfont
-\texttt{\lstinputlisting{app9.while}}}
+\texttt{\lstinputlisting{fib.while}}}
 
 \end{frame}}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
@@ -187,11 +217,468 @@
 \begin{frame}[c]
 \frametitle{\begin{tabular}{c}Interpreter\end{tabular}}
 
+\begin{center}
+\bl{\begin{tabular}{@{}lcl@{}}
+$\text{eval}(n, E)$ & $\dn$ & $n$\\
+$\text{eval}(x, E)$ & $\dn$ & $E(x)$ \;\;\;\textcolor{black}{lookup \bl{$x$} in \bl{$E$}}\\
+$\text{eval}(a_1 + a_2, E)$ & $\dn$ & $\text{eval}(a_1, E) + \text{eval}(a_2, E)$\\
+$\text{eval}(a_1 - a_2, E)$ & $\dn$ & $\text{eval}(a_1, E) - \text{eval}(a_2, E)$\\
+$\text{eval}(a_1 * a_2, E)$ & $\dn$ & $\text{eval}(a_1, E) * \text{eval}(a_2, E)$\bigskip\\
+$\text{eval}(a_1 = a_2, E)$ & $\dn$ & $\text{eval}(a_1, E) = \text{eval}(a_2, E)$\\
+$\text{eval}(a_1\,!\!= a_2, E)$ & $\dn$ & $\neg(\text{eval}(a_1, E) = \text{eval}(a_2, E))$\\
+$\text{eval}(a_1 < a_2, E)$ & $\dn$ & $\text{eval}(a_1, E) < \text{eval}(a_2, E)$\
+\end{tabular}}
+\end{center}
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[c]
+\frametitle{\begin{tabular}{c}Interpreter (2)\end{tabular}}
+
+\begin{center}
+\bl{\begin{tabular}{@{}lcl@{}}
+$\text{eval}(\text{skip}, E)$ & $\dn$ & $E$\\
+$\text{eval}(x:=a, E)$ & $\dn$ & \bl{$E(x \mapsto \text{eval}(a, E))$}\\
+\multicolumn{3}{@{}l@{}}{$\text{eval}(\text{if}\;b\;\text{then}\;cs_1\;\text{else}\;cs_2 , E) \dn$}\\
+\multicolumn{3}{@{}l@{}}{\hspace{2cm}$\text{if}\;\text{eval}(b,E)\;\text{then}\;
+\text{eval}(cs_1,E)$}\\
+\multicolumn{3}{@{}l@{}}{\hspace{2cm}$\phantom{\text{if}\;\text{eval}(b,E)\;}\text{else}\;\text{eval}(cs_2,E)$}\\
+\multicolumn{3}{@{}l@{}}{$\text{eval}(\text{while}\;b\;\text{do}\;cs, E) \dn$}\\
+\multicolumn{3}{@{}l@{}}{\hspace{2cm}$\text{if}\;\text{eval}(b,E)$}\\
+\multicolumn{3}{@{}l@{}}{\hspace{2cm}$\text{then}\;
+\text{eval}(\text{while}\;b\;\text{do}\;cs, \text{eval}(cs,E))$}\\
+\multicolumn{3}{@{}l@{}}{\hspace{2cm}$\text{else}\; E$}\\
+$\text{eval}(\text{print}\; x, E)$ & $\dn$ & $\{\;\text{println}(E(x))\; ;\;E\;\}$\\
+\end{tabular}}
+\end{center}
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[c]
+\frametitle{\begin{tabular}{c}Test Program\end{tabular}}
+
+\mbox{}\\[-18mm]\mbox{}
+
+{\lstset{language=While}\fontsize{10}{12}\selectfont
+\texttt{\lstinputlisting{loops.while}}}
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[t]
+\frametitle{\begin{tabular}{c}Interpreted Code\end{tabular}}
+
+\begin{center}
+\begin{tikzpicture}
+\begin{axis}[axis x line=bottom, axis y line=left, xlabel=n, ylabel=secs]
+\addplot+[smooth] file {interpreted.data};
+\end{axis}
+\end{tikzpicture}
+\end{center}
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[c]
+\frametitle{\begin{tabular}{c}Java Virtual Machine\end{tabular}}
+
+\begin{itemize}
+\item introduced in 1995
+\item is a stack-based VM (like Postscript, CLR of .Net)
+\item contains a JIT compiler
+\item many languages take advantage of the infrastructure (JRE)
+\item languages compiled to the JVM: Scala, Clojure\ldots
+\item garbage collected
+\end{itemize}
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[t]
+\frametitle{\begin{tabular}{c}Compiling AExps\end{tabular}}
+
+{\Large\bl{1 + 2}}
+
+\begin{center}
+\bl{\begin{tabular}{l}
+ldc 1\\
+ldc 2\\
+iadd\\
+\end{tabular}}
+\end{center}\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[t]
+\frametitle{\begin{tabular}{c}Compiling AExps\end{tabular}}
+
+{\Large\bl{1 + 2 + 3}}
+
+\begin{center}
+\bl{\begin{tabular}{l}
+ldc 1\\
+ldc 2\\
+iadd\\
+ldc 3\\
+iadd\\
+\end{tabular}}
+\end{center}
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[t]
+\frametitle{\begin{tabular}{c}Compiling AExps\end{tabular}}
+
+{\Large\bl{1 + (2 + 3)}}
+
+\begin{center}
+\bl{\begin{tabular}{l}
+ldc 1\\
+ldc 2\\
+ldc 3\\
+iadd\\
+iadd\\
+\end{tabular}}
+\end{center}\bigskip\pause
+\vfill
+
+\bl{dadd, fadd, ladd, \ldots}
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[t]
+\frametitle{\begin{tabular}{c}Compiling AExps\end{tabular}}
+
+\begin{center}
+\bl{\begin{tabular}{@{}lcl@{}}
+$\text{compile}(n)$ & $\dn$ & $\text{ldc}\;n$\\
+$\text{compile}(a_1 + a_2)$ & $\dn$\\ 
+\multicolumn{3}{l}{$\qquad\text{compile}(a_1) \;@\;\text{compile}(a_2)\;@\; \text{iadd}$}\smallskip\\
+$\text{compile}(a_1 - a_2)$ & $\dn$\\ 
+\multicolumn{3}{l}{$\qquad\text{compile}(a_1) \;@\; \text{compile}(a_2)\;@\; \text{isub}$}\smallskip\\
+$\text{compile}(a_1 * a_2)$ & $\dn$\\ 
+\multicolumn{3}{l}{$\qquad\text{compile}(a_1) \;@\; \text{compile}(a_2)\;@\; \text{imul}$}\smallskip\\
+\end{tabular}}
+\end{center}\pause
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[t]
+\frametitle{\begin{tabular}{c}Compiling AExps\end{tabular}}
+
+{\Large\bl{1 + 2 * 3 + (4 - 3)}}
+
+\begin{center}
+\bl{\begin{tabular}{l}
+ldc 1\\
+ldc 2\\
+ldc 3\\
+imul\\
+ldc 4\\
+ldc 3\\
+isub\\
+iadd\\
+iadd\\
+\end{tabular}}
+\end{center}
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[t]
+\frametitle{\begin{tabular}{c}Variables\end{tabular}}
+
+{\Large\bl{$x := 5 + y * 2$}}\bigskip\pause   
+
+\begin{itemize}
+\item lookup: \bl{$\text{iload}\; number$}
+\item store: \bl{$\text{istore}\; number$}
+\end{itemize}\bigskip\pause
+
+during compilation we have to maintain a map between our identifiers and the
+java bytecode numbers
+
+\begin{center}
+\bl{$\text{compile}(a, E)$}
+\end{center}
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[t]
+\frametitle{\begin{tabular}{c}Compiling AExps\end{tabular}}
+
+\begin{center}
+\bl{\begin{tabular}{@{}lcl@{}}
+$\text{compile}(n, E)$ & $\dn$ & $\text{ldc}\;n$\\
+$\text{compile}(a_1 + a_2, E)$ & $\dn$\\ 
+\multicolumn{3}{l}{$\qquad\text{compile}(a_1, E) \;@\;\text{compile}(a_2. E)\;@\; \text{iadd}$}\smallskip\\
+$\text{compile}(a_1 - a_2, E)$ & $\dn$\\ 
+\multicolumn{3}{l}{$\qquad\text{compile}(a_1, E) \;@\; \text{compile}(a_2, E)\;@\; \text{isub}$}\smallskip\\
+$\text{compile}(a_1 * a_2, E)$ & $\dn$\\ 
+\multicolumn{3}{l}{$\qquad\text{compile}(a_1, E) \;@\; \text{compile}(a_2, E)\;@\; \text{imul}$}\bigskip\\
+$\text{compile}(x, E)$ & $\dn$ & $\text{iload}\;E(x)$\\
+\end{tabular}}
+\end{center}\pause
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[t]
+\frametitle{\begin{tabular}{c}Compiling Statements\end{tabular}}
+
+We return a list of instructions and an environment for the variables
+
+\begin{center}
+\bl{\begin{tabular}{@{}l@{\hspace{1mm}}c@{\hspace{1mm}}l@{}}
+$\text{compile}(\text{skip}, E)$ & $\dn$ & $(Nil, E)$\bigskip\\
+$\text{compile}(x := a, E)$ & $\dn$\\
+\multicolumn{3}{l}{$(\text{compile}(a, E) \;@\;\text{istore}\;index, E(x\mapsto index))$}\\
+\end{tabular}}
+\end{center}\medskip
+
+where \bl{$index$} is \bl{$E(x)$} if it is already defined, or if it is not then the largest index not yet seen
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[t]
+\frametitle{\begin{tabular}{c}Compiling AExps\end{tabular}}
+
+{\Large\bl{$x := x + 1$}}
+
+\begin{center}
+\bl{\begin{tabular}{l}
+iload $n_x$\\
+ldc 1\\
+iadd\\
+istore $n_x$\\
+\end{tabular}}
+\end{center}
+
+where \bl{$n_x$} is the number corresponding to the variable \bl{$x$}
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[t]
+\frametitle{\begin{tabular}{c}Compiling Ifs\end{tabular}}
+
+{\Large\bl{$\text{if}\;b\;\text{else}\;cs_1\;\text{then}\;cs_2$}}\bigskip\bigskip
+
+\onslide<2->{Case }\only<2>{True:}\only<3>{False:}
+
+\begin{center}
+\begin{tikzpicture}[node distance=2mm and 4mm,
+ block/.style={rectangle, minimum size=1cm, draw=black, line width=1mm},
+ point/.style={rectangle, inner sep=0mm, minimum size=0mm, fill=red},
+ skip loop/.style={red, line width=1mm, to path={-- ++(0,-10mm) -| (\tikztotarget)}}]
+\node (A1) [point] {};
+\node (b) [block, right=of A1] {code of \bl{$b$}};
+\node (A2) [point, right=of b] {};
+\node (cs1) [block, right=of A2] {code of \bl{$cs_1$}};
+\node (A3) [point, right=of cs1] {};
+\node (cs2) [block, right=of A3] {code of \bl{$cs_2$}};
+\node (A4) [point, right=of cs2] {};
+
+\only<2>{
+\draw (A1) edge [->, red, line width=1mm] (b);
+\draw (b) edge [->, red, line width=1mm] (cs1);
+\draw (cs1) edge [->, red, line width=1mm] (A3);
+\draw (A3) edge [->,skip loop] (A4);
+\node [below=of cs2] {\raisebox{-5mm}{\small{}jump}};}
+\only<3>{
+\draw (A1) edge [->, red, line width=1mm] (b);
+\draw (b) edge [->, red, line width=1mm] (A2);
+\draw (A2) edge [skip loop] (A3);
+\draw (A3) edge [->, red, line width=1mm] (cs2);
+\draw (cs2) edge [->,red, line width=1mm] (A4);
+\node [below=of cs1] {\raisebox{-5mm}{\small{}conditional jump}};}
+\end{tikzpicture}
+\end{center}
 
 
 \end{frame}}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
 
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[c]
+\frametitle{\begin{tabular}{c}Conditional Jumps\end{tabular}}
+
+\begin{minipage}{1.1\textwidth}
+\begin{itemize}
+\item \bl{if\_icmpeq $label$} if two ints are equal, then jump\medskip
+\item \bl{if\_icmpne $label$} if two ints aren't equal, then jump\medskip
+\item \bl{if\_icmpge $label$} if one int is greater or equal then another, then jump
+\item[]\ldots
+\end{itemize}
+\end{minipage}\pause
+
+
+\begin{center}
+\bl{\begin{tabular}{l}
+$L_1$:\\
+\hspace{5mm}if\_icmpeq\;$L_2$\\
+\hspace{5mm}iload 1\\
+\hspace{5mm}ldc 1\\
+\hspace{5mm}iadd\\
+\hspace{5mm}if\_icmpeq\;$L_1$\\
+$L_1$:
+\end{tabular}}
+\end{center}
+
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[t]
+\frametitle{\begin{tabular}{c}Compiling BExps\end{tabular}}
+
+{\Large\bl{$a_1 = a_2$}}
+
+\begin{center}
+\bl{\begin{tabular}{l}
+iload $n_x$\\
+ldc 1\\
+iadd\\
+istore $n_x$\\
+\end{tabular}}
+\end{center}
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[t]
+\frametitle{\begin{tabular}{c}Compiling Ifs\end{tabular}}
+
+{\Large\bl{if $b$ then $cs_1$ else $cs_2$}}
+
+\begin{center}
+\bl{\begin{tabular}{l}
+iload $n_x$\\
+ldc 1\\
+iadd\\
+istore $n_x$\\
+\end{tabular}}
+\end{center}
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[t]
+\frametitle{\begin{tabular}{c}Compiling Whiles\end{tabular}}
+
+{\Large\bl{$\text{while}\;b\;\text{do}\;cs$}}\bigskip\bigskip
+
+\onslide<2->{Case }\only<2>{True:}\only<3>{False:}
+
+\begin{center}
+\begin{tikzpicture}[node distance=2mm and 4mm,
+ block/.style={rectangle, minimum size=1cm, draw=black, line width=1mm},
+ point/.style={rectangle, inner sep=0mm, minimum size=0mm, fill=red},
+ skip loop/.style={red, line width=1mm, to path={-- ++(0,-10mm) -| (\tikztotarget)}}]
+\node (A0) [point, left=of A1] {};
+\node (A1) [point] {};
+\node (b) [block, right=of A1] {code of \bl{$b$}};
+\node (A2) [point, right=of b] {};
+\node (cs1) [block, right=of A2] {code of \bl{$cs$}};
+\node (A3) [point, right=of cs1] {};
+\node (A4) [point, right=of A3] {};
+
+\only<2>{
+\draw (A0) edge [->, red, line width=1mm] (b);
+\draw (b) edge [->, red, line width=1mm] (cs1);
+\draw (cs1) edge [->, red, line width=1mm] (A3);
+\draw (A3) edge [->,skip loop] (A1);}
+\only<3>{
+\draw (A0) edge [->, red, line width=1mm] (b);
+\draw (b) edge [->, red, line width=1mm] (A2);
+\draw (A2) edge [skip loop] (A3);
+\draw (A3) edge [->, red, line width=1mm] (A4);}
+\end{tikzpicture}
+\end{center}
+
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[t]
+\frametitle{\begin{tabular}{c}Compiling Whiles\end{tabular}}
+
+{\Large\bl{while $b$ do $cs$}}
+
+\begin{center}
+\bl{\begin{tabular}{l}
+iload $n_x$\\
+ldc 1\\
+iadd\\
+istore $n_x$\\
+\end{tabular}}
+\end{center}
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\mode<presentation>{
+\begin{frame}[t]
+\frametitle{\begin{tabular}{c}Compiling Writes\end{tabular}}
+
+{\Large\bl{write $x$}}
+
+\begin{center}
+\bl{\begin{tabular}{l}
+iload $n_x$\\
+ldc 1\\
+iadd\\
+istore $n_x$\\
+\end{tabular}}
+\end{center}
+
+\end{frame}}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \mode<presentation>{
@@ -200,9 +687,10 @@
 
 \begin{center}
 \begin{tikzpicture}
-\begin{axis}[axis x line=bottom, axis y line=left, xlabel=n, ylabel=mins]
-\addplot file {compiled.data};
-\end{axis}
+\begin{loglogaxis}[axis x line=bottom, axis y line=left, xlabel=n, ylabel=secs]
+\addplot+[smooth] file {interpreted.data};
+\addplot+[smooth] file {compiled.data};
+\end{loglogaxis}
 \end{tikzpicture}
 \end{center}
 
@@ -210,44 +698,16 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
 
 
-
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \mode<presentation>{
 \begin{frame}[t]
-\frametitle{\begin{tabular}{c}Compiled vs.~Interpreted Code\end{tabular}}
-
-\mbox{}\\[-25mm]\mbox{}
+\frametitle{\begin{tabular}{c}Compiled Code\end{tabular}}
 
 \begin{center}
-\begin{tikzpicture}[y=.4cm, x=.00000009cm]
- 	%axis
-	\draw (0,0) -- coordinate (x axis mid) (5,0);
-    	\draw (0,0) -- coordinate (y axis mid) (0,5);
-    	%ticks
-    	\foreach \x in {0, 1000,...,10000}
-     		\draw (\x,1pt) -- (\x,-3pt)
-			node[anchor=north] {\small \x{}00};
-    	\foreach \y in {0,0.5,1, ..., 5.5}
-     		\draw (1pt,\y) -- (-3pt,\y) 
-     			node[anchor=east] {\small\y}; 
-	%labels      
-	\node[below=0.6cm] at (x axis mid) {\bl{1}s};
-	\node[rotate=90, left=1.2cm] at (y axis mid) {secs};
-
-	%plots
-	%\draw[color=blue] plot[mark=*, mark options={fill=white}] 
-	%	file {compiled.data};
-         %\only<2->{\draw[color=red] plot[mark=triangle*, mark options={fill=white} ] 
-          %        file {interpreted.data};}
-	%legend
-	%\begin{scope}[shift={(400,20)}] 
-	%\draw[color=blue] (0,0) -- 
-	%	plot[mark=*, mark options={fill=white}] (0.25,0) -- (0.5,0) 
-	%	node[right]{\small unambiguous};
-	%\only<2->{\draw[yshift=\baselineskip, color=red] (0,0) -- 
-          %      plot[mark=triangle*, mark options={fill=white}] (0.25,0) -- (0.5,0)
-          %      node[right]{\small ambiguous};}  
-	%\end{scope}
+\begin{tikzpicture}
+\begin{axis}[axis x line=bottom, axis y line=left, xlabel=n, ylabel=secs]
+\addplot+[smooth] file {compiled.data};
+\end{axis}
 \end{tikzpicture}
 \end{center}
 
@@ -255,9 +715,6 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
 
 
-
-
-
 \end{document}
 
 %%% Local Variables:  
diff -r fd894e017e12 -r 191daa3ee29e while1.scala
--- a/while1.scala	Sat Nov 24 15:10:43 2012 +0000
+++ b/while1.scala	Mon Nov 26 01:11:55 2012 +0000
@@ -10,7 +10,7 @@
 val NUM = PLUS(DIGIT)
 val KEYWORD = ALTS("skip", "while", "do", "if", "then", "else", "true", "false", "write") 
 val SEMI: Rexp = ";"
-val OP: Rexp = ALTS(":=", "=", "-", "+", "*", "!", "<", ">")
+val OP: Rexp = ALTS(":=", "=", "-", "+", "*", "!=", "<", ">")
 val WHITESPACE = PLUS(RANGE(" \n"))
 val RPAREN: Rexp = ")"
 val LPAREN: Rexp = "("
@@ -137,8 +137,6 @@
   case Bop("=", a1, a2) => eval_aexp(a1, env) == eval_aexp(a2, env)
   case Bop("!=", a1, a2) => !(eval_aexp(a1, env) == eval_aexp(a2, env))
   case Bop("<", a1, a2) => eval_aexp(a1, env) < eval_aexp(a2, env)
-  case Bop("&&", a1, a2) => eval_aexp(a1, env) > eval_aexp(a2, env)
-  case Bop("||", a1, a2) => eval_aexp(a1, env) < eval_aexp(a2, env)
 }
 
 def eval_aexp(a: AExp, env : Env) : Int = a match {
@@ -173,14 +171,49 @@
 
 //examples
 
-eval_prog("loops.while")
+//eval_prog("loops.while")
 //eval_prog("fib.while")
 
 
+def time_needed[T](i: Int, code: => T) = {
+  val start = System.nanoTime()
+  for (j <- 1 to i) code
+  val end = System.nanoTime()
+  (end - start)/(i * 1.0e9)
+}
+
+
+val test_prog = """
+start := XXX;
+x := start;
+y := start;
+z := start;
+while 0 < x do {
+ while 0 < y do {
+  while 0 < z do {
+    z := z - 1
+  };
+  z := start;
+  y := y - 1
+ };     
+ y := start;
+ x := x - 1
+}
+"""
+
+
+
+def eval_test(n: Int) : Unit = {
+  val tks = Tok.fromString(test_prog.replaceAllLiterally("XXX", n.toString))
+  val ast = Stmts.parse_single(tks)
+  println(n + " " + time_needed(2, eval_bl(ast, Map.empty)))
+}
+
+List(1, 200, 400, 600, 800, 1000, 1200, 1400, 1600).map(eval_test(_))
+
+
 
 
 
 
 
-
-