updated
authorChristian Urban <urbanc@in.tum.de>
Thu, 07 Dec 2017 12:05:10 +0000
changeset 164 7ada03135b2e
parent 163 84917f2e16cd
child 165 1347bbd86c52
updated
template3/bf.scala
template3/re.scala
templates3/template3/bf.scala
templates3/template3/re.scala
--- a/template3/bf.scala	Thu Dec 07 12:04:31 2017 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,151 +0,0 @@
-// Part 2 about an Interpreter for the Brainf*** language
-//========================================================
-
-object CW8b {
-
-type Mem = Map[Int, Int]
-
-// (2a) Complete the functions for safely reading  
-// and writing brainf*** memory. Safely read should
-// Return the value stored in the Map for a given memory
-// pointer, if it exists; otherwise it Returns 0. The
-// writing function generates a new Map with the
-// same data, except at the given memory pointer the
-// value v is stored.
-
-
-//def sread(mem: Mem, mp: Int) : Int = ...
-
-//def write(mem: Mem, mp: Int, v: Int) : Mem = ...
-
-
-// (2b) Implement the two jumping instructions in the 
-// brainf*** language. In jumpRight, given a program and 
-// a program counter move the counter to the right 
-// until the command after the *matching* ]-command. Similarly, 
-// jumpLeft implements the move to the left to just after
-// the *matching* [-command. The levels are used to find the
-// *matching* bracket.
-
-//def jumpRight(prog: String, pc: Int, level: Int) : Int = ...
-
-//def jumpLeft(prog: String, pc: Int, level: Int) : Int = ...
-
-
-
-// (2c) Complete the run function that interprets (runs) a brainf***
-// program: the arguments are a program, a program counter,
-// a memory counter and a brainf*** memory. It Returns the
-// memory at the stage when the execution of the brainf*** program
-// finishes. The interpretation finishes once the program counter
-// pc is pointing to something outside the program string.
-// If the pc points to a character inside the program, the pc, 
-// memory pointer and memory need to be updated according to 
-// rules of the brainf*** language. Then, recursively, the run 
-// function continues with the command at the new program
-// counter. 
-//
-// Implement the start function that calls run with the program
-// counter and memory counter set to 0.
-
-//def run(prog: String, pc: Int, mp: Int, mem: Mem) : Mem = ...
-
-//def start(prog: String, mem: Mem) = ...
-
-
-
-
-
-
-// some sample bf programs collected from the Internet
-//==================================================
-
-
-/*
-// first some contrived (small) programs
-
-// clears the 0-cell
-start("[-]", Map(0 -> 100)) 
-
-// copies content of the 0-cell to 1-cell
-start("[->+<]", Map(0 -> 10))
-
-// copies content of the 0-cell to 2-cell and 4-cell
-start("[>>+>>+<<<<-]", Map(0 -> 42))
-
-start("+++[>+++++<-]", Map(0 -> 10))
-
-
-// prints out numbers 0 to 9
-start("""+++++[->++++++++++<]>--<+++[->>++++++++++<<]>>++<<----------[+>.>.<+<]""", Map())
-
-
-// some more "useful" programs
-
-// hello world program 1
-start("""++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++
-       ..+++.>>.<-.<.+++.------.--------.>>+.>++.""", Map())
-
-// hello world program 2
-start("""++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>+
-      +.<<+++++++++++++++.>.+++.------.--------.>+.>.""", Map())
-
-
-// draws the Sierpinski triangle
-start("""++++++++[>+>++++<<-]>++>>+<[-[>>+<<-]+>>]>+[-<<<[
-      ->[+[-]+>++>>>-<<]<[<]>>++++++[<<+++++>>-]+<<++.[-]<<
-      ]>.>+[>>]>+]""", Map())
-
-//Fibonacci numbers below 100
-start("""+++++++++++
-      >+>>>>++++++++++++++++++++++++++++++++++++++++++++
-      >++++++++++++++++++++++++++++++++<<<<<<[>[>>>>>>+>
-      +<<<<<<<-]>>>>>>>[<<<<<<<+>>>>>>>-]<[>++++++++++[-
-      <-[>>+>+<<<-]>>>[<<<+>>>-]+<[>[-]<[-]]>[<<[>>>+<<<
-      -]>>[-]]<<]>>>[>>+>+<<<-]>>>[<<<+>>>-]+<[>[-]<[-]]
-      >[<<+>>[-]]<<<<<<<]>>>>>[+++++++++++++++++++++++++
-      +++++++++++++++++++++++.[-]]++++++++++<[->-<]>++++
-      ++++++++++++++++++++++++++++++++++++++++++++.[-]<<
-      <<<<<<<<<<[>>>+>+<<<<-]>>>>[<<<<+>>>>-]<-[>>.>.<<<
-      [-]]<<[>>+>+<<<-]>>>[<<<+>>>-]<<[<+>-]>[<+>-]<<<-]""", Map())
-
-
-//outputs the square numbers up to 10000
-start("""++++[>+++++<-]>[<+++++>-]+<+[
-    >[>+>+<<-]++>>[<<+>>-]>>>[-]++>[-]+
-    >>>+[[-]++++++>>>]<<<[[<++++++++<++>>-]+<.<[>----<-]<]
-    <<[>>>>>[>>>[-]+++++++++<[>-<-]+++++++++>[-[<->-]+[<<<]]<[>+<-]>]<<-]<<-]""", Map())
-
-
-//Collatz numbers (need to be typed in)
-start(""">,[[----------[
-      >>>[>>>>]+[[-]+<[->>>>++>>>>+[>>>>]++[->+<<<<<]]<<<]
-      ++++++[>------<-]>--[>>[->>>>]+>+[<<<<]>-],<]>]>>>++>+>>[
-      <<[>>>>[-]+++++++++<[>-<-]+++++++++>[-[<->-]+[<<<<]]<[>+<-]>]
-      >[>[>>>>]+[[-]<[+[->>>>]>+<]>[<+>[<<<<]]+<<<<]>>>[->>>>]+>+[<<<<]]
-      >[[>+>>[<<<<+>>>>-]>]<<<<[-]>[-<<<<]]>>>>>>>
-      ]>>+[[-]++++++>>>>]<<<<[[<++++++++>-]<.[-]<[-]<[-]<]<,]""", Map())
-
-
-// infinite Collatz (never stops)
-start(""">>+>+<[[->>[>>]>>>[>>]+[<<]<<<[<<]>[>[>>]>>+>[>>]<+<[<<]<<<[<
-      <]>-]>[>>]>>[<<<<[<<]>+>[>>]>>-]<<<<[<<]+>>]<<[+++++[>+++++++
-      +<-]>.<++++++[>--------<-]+<<]>>[>>]+[>>>>[<<+>+>-]<-[>+<-]+<
-      [<<->>-[<<+>>[-]]]>>>[<<<+<<+>>>>>-]<<<[>>>+<<<-]<<[[-]>+>>->
-      [<+<[<<+>>-]<[>+<-]<[>+<-]>>>>-]<[>+<-]+<[->[>>]<<[->[<+++>-[
-      <+++>-[<+++>-[<[-]++>>[-]+>+<<-[<+++>-[<+++>-[<[-]+>>>+<<-[<+
-      ++>-[<+++>-]]]]]]]]]<[>+<-]+<<]>>>+<[->[<+>-[<+>-[<+>-[<+>-[<
-      +>-[<+>-[<+>-[<+>-[<+>-[<[-]>>[-]+>+<<-[<+>-]]]]]]]]]]]<[>+<-
-      ]+>>]<<[<<]>]<[->>[->+>]<[-[<+>-[<->>+<-[<+>-[<->>+<-[<+>-[<-
-      >>+<-[<+>-[<->>+<-[<+>-[<->>+<-[<+>-[<->>+<-[<+>-[<->>+<-[<+>
-      -[<->>+<-[<+>-[<->>+<-[<+>-]]]]]]]]]]]]]]]]]]]>[<+>-]<+<[<+++
-      +++++++>-]<]>>[<+>->>]<<[>+>+<<-]>[<+>-]+>[<->[-]]<[-<<-]<<[<
-      <]]++++++[>+++++++<-]>++.------------.[-]>[>>]<<[+++++[>+++++
-      +++<-]>.<++++++[>--------<-]+<<]+<]>[<+>-]<]>>>[>>]<<[>[-]<-<
-      <]++++++++++.[-]<<<[<<]>>>+<[->[<+>-[<+>-[<+>-[<+>-[<+>-[<+>-
-      [<+>-[<+>-[<+>-[<[-]>>[-]+>+<<-]]]]]]]]]]<[>+<-]+>>]<<[<<]>>]""", Map())
-
-
-*/ 
-
-}
--- a/template3/re.scala	Thu Dec 07 12:04:31 2017 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,127 +0,0 @@
-// Part 1 about Regular Expression Matching
-//==========================================
-
-
-object CW8a {
-
-abstract class Rexp
-case object ZERO extends Rexp
-case object ONE extends Rexp
-case class CHAR(c: Char) extends Rexp
-case class ALT(r1: Rexp, r2: Rexp) extends Rexp   // alternative 
-case class SEQ(r1: Rexp, r2: Rexp) extends Rexp   // sequence
-case class STAR(r: Rexp) extends Rexp             // star
-
-
-// some convenience for typing in regular expressions
-
-import scala.language.implicitConversions    
-import scala.language.reflectiveCalls 
-
-def charlist2rexp(s: List[Char]): Rexp = s match {
-  case Nil => ONE
-  case c::Nil => CHAR(c)
-  case c::s => SEQ(CHAR(c), charlist2rexp(s))
-}
-implicit def string2rexp(s: String): Rexp = charlist2rexp(s.toList)
-
-implicit def RexpOps (r: Rexp) = new {
-  def | (s: Rexp) = ALT(r, s)
-  def % = STAR(r)
-  def ~ (s: Rexp) = SEQ(r, s)
-}
-
-implicit def stringOps (s: String) = new {
-  def | (r: Rexp) = ALT(s, r)
-  def | (r: String) = ALT(s, r)
-  def % = STAR(s)
-  def ~ (r: Rexp) = SEQ(s, r)
-  def ~ (r: String) = SEQ(s, r)
-}
-
-// (1a) Complete the function nullable according to
-// the definition given in the coursework; this 
-// function checks whether a regular expression
-// can match the empty string and Returns a boolean
-// accordingly.
-
-//def nullable (r: Rexp) : Boolean = ...
-
-
-// (1b) Complete the function der according to
-// the definition given in the coursework; this
-// function calculates the derivative of a 
-// regular expression w.r.t. a character.
-
-//def der (c: Char, r: Rexp) : Rexp = ...
-
-
-// (1c) Complete the simp function according to
-// the specification given in the coursework; this
-// function simplifies a regular expression from
-// the inside out, like you would simplify arithmetic 
-// expressions; however it does not simplify inside 
-// STAR-regular expressions.
-
-//def simp(r: Rexp) : Rexp = ... 
-
-
-// (1d) Complete the two functions below; the first 
-// calculates the derivative w.r.t. a string; the second
-// is the regular expression matcher taking a regular
-// expression and a string and checks whether the
-// string matches the regular expression
-
-//def ders (s: List[Char], r: Rexp) : Rexp = ... 
-
-//def matcher(r: Rexp, s: String): Boolean = ...
-
-
-// (1e) Complete the size function for regular
-// expressions according to the specification 
-// given in the coursework.
-
-//def size(r: Rexp): Int = ...
-
-
-// some testing data
-
-/*
-matcher(("a" ~ "b") ~ "c", "abc")  // => true
-matcher(("a" ~ "b") ~ "c", "ab")   // => false
-
-// the supposedly 'evil' regular expression (a*)* b
-val EVIL = SEQ(STAR(STAR(CHAR('a'))), CHAR('b'))
-
-matcher(EVIL, "a" * 1000 ++ "b")   // => true
-matcher(EVIL, "a" * 1000)          // => false
-
-// size without simplifications
-size(der('a', der('a', EVIL)))             // => 28
-size(der('a', der('a', der('a', EVIL))))   // => 58
-
-// size with simplification
-size(simp(der('a', der('a', EVIL))))           // => 8
-size(simp(der('a', der('a', der('a', EVIL))))) // => 8
-
-// Java needs around 30 seconds for matching 28 a's with EVIL. 
-//
-// Lets see how long it takes to match strings with 
-// 0.5 Million a's...it should be in the range of some
-// seconds.
-
-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 (i <- 0 to 5000000 by 500000) {
-  println(i + " " + "%.5f".format(time_needed(2, matcher(EVIL, "a" * i))))
-}
-
-*/
-
-
-}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/templates3/template3/bf.scala	Thu Dec 07 12:05:10 2017 +0000
@@ -0,0 +1,151 @@
+// Part 2 about an Interpreter for the Brainf*** language
+//========================================================
+
+object CW8b {
+
+type Mem = Map[Int, Int]
+
+// (2a) Complete the functions for safely reading  
+// and writing brainf*** memory. Safely read should
+// Return the value stored in the Map for a given memory
+// pointer, if it exists; otherwise it Returns 0. The
+// writing function generates a new Map with the
+// same data, except at the given memory pointer the
+// value v is stored.
+
+
+//def sread(mem: Mem, mp: Int) : Int = ...
+
+//def write(mem: Mem, mp: Int, v: Int) : Mem = ...
+
+
+// (2b) Implement the two jumping instructions in the 
+// brainf*** language. In jumpRight, given a program and 
+// a program counter move the counter to the right 
+// until the command after the *matching* ]-command. Similarly, 
+// jumpLeft implements the move to the left to just after
+// the *matching* [-command. The levels are used to find the
+// *matching* bracket.
+
+//def jumpRight(prog: String, pc: Int, level: Int) : Int = ...
+
+//def jumpLeft(prog: String, pc: Int, level: Int) : Int = ...
+
+
+
+// (2c) Complete the run function that interprets (runs) a brainf***
+// program: the arguments are a program, a program counter,
+// a memory counter and a brainf*** memory. It Returns the
+// memory at the stage when the execution of the brainf*** program
+// finishes. The interpretation finishes once the program counter
+// pc is pointing to something outside the program string.
+// If the pc points to a character inside the program, the pc, 
+// memory pointer and memory need to be updated according to 
+// rules of the brainf*** language. Then, recursively, the run 
+// function continues with the command at the new program
+// counter. 
+//
+// Implement the start function that calls run with the program
+// counter and memory counter set to 0.
+
+//def run(prog: String, pc: Int, mp: Int, mem: Mem) : Mem = ...
+
+//def start(prog: String, mem: Mem) = ...
+
+
+
+
+
+
+// some sample bf programs collected from the Internet
+//==================================================
+
+
+/*
+// first some contrived (small) programs
+
+// clears the 0-cell
+start("[-]", Map(0 -> 100)) 
+
+// copies content of the 0-cell to 1-cell
+start("[->+<]", Map(0 -> 10))
+
+// copies content of the 0-cell to 2-cell and 4-cell
+start("[>>+>>+<<<<-]", Map(0 -> 42))
+
+start("+++[>+++++<-]", Map(0 -> 10))
+
+
+// prints out numbers 0 to 9
+start("""+++++[->++++++++++<]>--<+++[->>++++++++++<<]>>++<<----------[+>.>.<+<]""", Map())
+
+
+// some more "useful" programs
+
+// hello world program 1
+start("""++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++
+       ..+++.>>.<-.<.+++.------.--------.>>+.>++.""", Map())
+
+// hello world program 2
+start("""++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>+
+      +.<<+++++++++++++++.>.+++.------.--------.>+.>.""", Map())
+
+
+// draws the Sierpinski triangle
+start("""++++++++[>+>++++<<-]>++>>+<[-[>>+<<-]+>>]>+[-<<<[
+      ->[+[-]+>++>>>-<<]<[<]>>++++++[<<+++++>>-]+<<++.[-]<<
+      ]>.>+[>>]>+]""", Map())
+
+//Fibonacci numbers below 100
+start("""+++++++++++
+      >+>>>>++++++++++++++++++++++++++++++++++++++++++++
+      >++++++++++++++++++++++++++++++++<<<<<<[>[>>>>>>+>
+      +<<<<<<<-]>>>>>>>[<<<<<<<+>>>>>>>-]<[>++++++++++[-
+      <-[>>+>+<<<-]>>>[<<<+>>>-]+<[>[-]<[-]]>[<<[>>>+<<<
+      -]>>[-]]<<]>>>[>>+>+<<<-]>>>[<<<+>>>-]+<[>[-]<[-]]
+      >[<<+>>[-]]<<<<<<<]>>>>>[+++++++++++++++++++++++++
+      +++++++++++++++++++++++.[-]]++++++++++<[->-<]>++++
+      ++++++++++++++++++++++++++++++++++++++++++++.[-]<<
+      <<<<<<<<<<[>>>+>+<<<<-]>>>>[<<<<+>>>>-]<-[>>.>.<<<
+      [-]]<<[>>+>+<<<-]>>>[<<<+>>>-]<<[<+>-]>[<+>-]<<<-]""", Map())
+
+
+//outputs the square numbers up to 10000
+start("""++++[>+++++<-]>[<+++++>-]+<+[
+    >[>+>+<<-]++>>[<<+>>-]>>>[-]++>[-]+
+    >>>+[[-]++++++>>>]<<<[[<++++++++<++>>-]+<.<[>----<-]<]
+    <<[>>>>>[>>>[-]+++++++++<[>-<-]+++++++++>[-[<->-]+[<<<]]<[>+<-]>]<<-]<<-]""", Map())
+
+
+//Collatz numbers (need to be typed in)
+start(""">,[[----------[
+      >>>[>>>>]+[[-]+<[->>>>++>>>>+[>>>>]++[->+<<<<<]]<<<]
+      ++++++[>------<-]>--[>>[->>>>]+>+[<<<<]>-],<]>]>>>++>+>>[
+      <<[>>>>[-]+++++++++<[>-<-]+++++++++>[-[<->-]+[<<<<]]<[>+<-]>]
+      >[>[>>>>]+[[-]<[+[->>>>]>+<]>[<+>[<<<<]]+<<<<]>>>[->>>>]+>+[<<<<]]
+      >[[>+>>[<<<<+>>>>-]>]<<<<[-]>[-<<<<]]>>>>>>>
+      ]>>+[[-]++++++>>>>]<<<<[[<++++++++>-]<.[-]<[-]<[-]<]<,]""", Map())
+
+
+// infinite Collatz (never stops)
+start(""">>+>+<[[->>[>>]>>>[>>]+[<<]<<<[<<]>[>[>>]>>+>[>>]<+<[<<]<<<[<
+      <]>-]>[>>]>>[<<<<[<<]>+>[>>]>>-]<<<<[<<]+>>]<<[+++++[>+++++++
+      +<-]>.<++++++[>--------<-]+<<]>>[>>]+[>>>>[<<+>+>-]<-[>+<-]+<
+      [<<->>-[<<+>>[-]]]>>>[<<<+<<+>>>>>-]<<<[>>>+<<<-]<<[[-]>+>>->
+      [<+<[<<+>>-]<[>+<-]<[>+<-]>>>>-]<[>+<-]+<[->[>>]<<[->[<+++>-[
+      <+++>-[<+++>-[<[-]++>>[-]+>+<<-[<+++>-[<+++>-[<[-]+>>>+<<-[<+
+      ++>-[<+++>-]]]]]]]]]<[>+<-]+<<]>>>+<[->[<+>-[<+>-[<+>-[<+>-[<
+      +>-[<+>-[<+>-[<+>-[<+>-[<[-]>>[-]+>+<<-[<+>-]]]]]]]]]]]<[>+<-
+      ]+>>]<<[<<]>]<[->>[->+>]<[-[<+>-[<->>+<-[<+>-[<->>+<-[<+>-[<-
+      >>+<-[<+>-[<->>+<-[<+>-[<->>+<-[<+>-[<->>+<-[<+>-[<->>+<-[<+>
+      -[<->>+<-[<+>-[<->>+<-[<+>-]]]]]]]]]]]]]]]]]]]>[<+>-]<+<[<+++
+      +++++++>-]<]>>[<+>->>]<<[>+>+<<-]>[<+>-]+>[<->[-]]<[-<<-]<<[<
+      <]]++++++[>+++++++<-]>++.------------.[-]>[>>]<<[+++++[>+++++
+      +++<-]>.<++++++[>--------<-]+<<]+<]>[<+>-]<]>>>[>>]<<[>[-]<-<
+      <]++++++++++.[-]<<<[<<]>>>+<[->[<+>-[<+>-[<+>-[<+>-[<+>-[<+>-
+      [<+>-[<+>-[<+>-[<[-]>>[-]+>+<<-]]]]]]]]]]<[>+<-]+>>]<<[<<]>>]""", Map())
+
+
+*/ 
+
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/templates3/template3/re.scala	Thu Dec 07 12:05:10 2017 +0000
@@ -0,0 +1,127 @@
+// Part 1 about Regular Expression Matching
+//==========================================
+
+
+object CW8a {
+
+abstract class Rexp
+case object ZERO extends Rexp
+case object ONE extends Rexp
+case class CHAR(c: Char) extends Rexp
+case class ALT(r1: Rexp, r2: Rexp) extends Rexp   // alternative 
+case class SEQ(r1: Rexp, r2: Rexp) extends Rexp   // sequence
+case class STAR(r: Rexp) extends Rexp             // star
+
+
+// some convenience for typing in regular expressions
+
+import scala.language.implicitConversions    
+import scala.language.reflectiveCalls 
+
+def charlist2rexp(s: List[Char]): Rexp = s match {
+  case Nil => ONE
+  case c::Nil => CHAR(c)
+  case c::s => SEQ(CHAR(c), charlist2rexp(s))
+}
+implicit def string2rexp(s: String): Rexp = charlist2rexp(s.toList)
+
+implicit def RexpOps (r: Rexp) = new {
+  def | (s: Rexp) = ALT(r, s)
+  def % = STAR(r)
+  def ~ (s: Rexp) = SEQ(r, s)
+}
+
+implicit def stringOps (s: String) = new {
+  def | (r: Rexp) = ALT(s, r)
+  def | (r: String) = ALT(s, r)
+  def % = STAR(s)
+  def ~ (r: Rexp) = SEQ(s, r)
+  def ~ (r: String) = SEQ(s, r)
+}
+
+// (1a) Complete the function nullable according to
+// the definition given in the coursework; this 
+// function checks whether a regular expression
+// can match the empty string and Returns a boolean
+// accordingly.
+
+//def nullable (r: Rexp) : Boolean = ...
+
+
+// (1b) Complete the function der according to
+// the definition given in the coursework; this
+// function calculates the derivative of a 
+// regular expression w.r.t. a character.
+
+//def der (c: Char, r: Rexp) : Rexp = ...
+
+
+// (1c) Complete the simp function according to
+// the specification given in the coursework; this
+// function simplifies a regular expression from
+// the inside out, like you would simplify arithmetic 
+// expressions; however it does not simplify inside 
+// STAR-regular expressions.
+
+//def simp(r: Rexp) : Rexp = ... 
+
+
+// (1d) Complete the two functions below; the first 
+// calculates the derivative w.r.t. a string; the second
+// is the regular expression matcher taking a regular
+// expression and a string and checks whether the
+// string matches the regular expression
+
+//def ders (s: List[Char], r: Rexp) : Rexp = ... 
+
+//def matcher(r: Rexp, s: String): Boolean = ...
+
+
+// (1e) Complete the size function for regular
+// expressions according to the specification 
+// given in the coursework.
+
+//def size(r: Rexp): Int = ...
+
+
+// some testing data
+
+/*
+matcher(("a" ~ "b") ~ "c", "abc")  // => true
+matcher(("a" ~ "b") ~ "c", "ab")   // => false
+
+// the supposedly 'evil' regular expression (a*)* b
+val EVIL = SEQ(STAR(STAR(CHAR('a'))), CHAR('b'))
+
+matcher(EVIL, "a" * 1000 ++ "b")   // => true
+matcher(EVIL, "a" * 1000)          // => false
+
+// size without simplifications
+size(der('a', der('a', EVIL)))             // => 28
+size(der('a', der('a', der('a', EVIL))))   // => 58
+
+// size with simplification
+size(simp(der('a', der('a', EVIL))))           // => 8
+size(simp(der('a', der('a', der('a', EVIL))))) // => 8
+
+// Java needs around 30 seconds for matching 28 a's with EVIL. 
+//
+// Lets see how long it takes to match strings with 
+// 0.5 Million a's...it should be in the range of some
+// seconds.
+
+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 (i <- 0 to 5000000 by 500000) {
+  println(i + " " + "%.5f".format(time_needed(2, matcher(EVIL, "a" * i))))
+}
+
+*/
+
+
+}