diff -r 877834bfe53b -r 82a99eec5b73 exps/Spiral.scala
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/exps/Spiral.scala	Mon Feb 04 13:10:26 2019 +0000
@@ -0,0 +1,169 @@
+import Element.elem
+import RexpRelated._
+import RexpRelated.Rexp._
+object Spiral{
+
+  val space = elem(" ")
+  val corner = elem("+")
+
+  def spiral(nEdges: Int, direction: Int): Element = {
+    if(nEdges == 1)
+      elem("+")
+    else {
+      val sp = spiral(nEdges - 1, (direction + 3) % 4)
+      def verticalBar = elem('|', 1, sp.height)
+      def horizontalBar = elem('-', sp.width, 1)
+      if(direction == 0)
+        (corner beside horizontalBar) above sp//(sp beside space)
+      else if (direction == 1)
+        sp beside (corner above verticalBar)
+      else if (direction == 2)
+        (space beside sp) above (horizontalBar beside corner)
+      else
+        (verticalBar above corner) beside (space above sp)
+    }
+  }
+  val alphabet = ("""abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.:"=()\;-+*!<>\/%{} """+"\n\t").toSet//Set('a','b','c')
+  def regx_tree(r: ARexp): Element = {
+    r match {
+      case APRED(bs, f) => {
+        val Some(d) = alphabet.find(f)
+        d match {
+          case '\n' => elem("\\n")
+          case '\t' => elem("\\t")
+          case ' ' => elem("space")
+          case d => elem(d.toString)
+        }   
+      }
+      case AONE(bs) => {
+        elem("ONE")
+      }
+      case AZERO => {
+        elem("ZERO")
+      }
+      case ASEQ(bs, r1, r2) => {
+        binary_print("SEQ", r1, r2)
+      }
+      case AALTS(bs, rs) => {
+        //elem("Awaiting completion")
+        list_print("ALT", rs)
+      }
+      case ASTAR(bs, r) => {
+        list_print("STA", List(r))
+      }
+    }
+  }
+  val port = elem(" └-")
+  def list_print(name: String, rs: List[ARexp]): Element = {
+    rs match {
+      case r::Nil => {
+        val pref = regx_tree(r)
+        val head = elem(name)
+        (head left_align (port up_align pref) ) 
+      }
+      case r2::r1::Nil => {
+        binary_print(name, r2, r1)
+      }
+      case r::rs1 => {
+        val pref = regx_tree(r)
+        val head = elem(name)
+        if (pref.height > 1){
+          val link = elem('|', 1, pref.height - 1)
+          (head left_align ((port above link) beside pref)) left_align tail_print(rs1)    
+        }
+        else{
+          (head left_align (port beside pref) ) left_align tail_print(rs1)
+        }
+      }
+    }
+  }
+  def tail_print(rs: List[ARexp]): Element = {
+
+    rs match {
+      case r2::r1::Nil => {
+        val pref = regx_tree(r2)
+        val suff = regx_tree(r1)
+        if (pref.height > 1){
+          val link = elem('|', 1, pref.height - 1)
+          ((port above link) beside pref) left_align (port up_align suff)
+        }
+        else{
+          (port beside pref) left_align (port up_align suff)
+        } 
+      }
+      case r2::rs1 => {
+        val pref = regx_tree(r2)
+        
+        if (pref.height > 1){
+          val link = elem('|', 1, pref.height - 1)
+          ((port above link) beside pref) left_align tail_print(rs1)//(port up_align tail_print(rs1) )
+        }
+        else{
+          (port beside pref) left_align tail_print(rs1)//(port up_align tail_print(rs1))
+        } 
+        //pref left_align tail_print(rs1)
+      }
+    }
+  }
+
+  def binary_print(name: String, r1: ARexp, r2: ARexp): Element = {
+    val pref = regx_tree(r1)
+    val suff = regx_tree(r2)
+    val head = elem(name)
+    if (pref.height > 1){
+      val link = elem('|', 1, pref.height - 1)
+      (head left_align ((port above link) beside pref) ) left_align (port up_align suff)
+    }
+    else{
+      (head left_align (port beside pref) ) left_align (port up_align suff)
+    }
+  }
+  def illustration(r: Rexp, s: String){
+    var i_like_imperative_style = internalise(r)
+    val all_chars = s.toList
+    for (i <- 0 to s.length - 1){
+      val der_res =  bder(all_chars(i), i_like_imperative_style)
+      val simp_res = bsimp(der_res)
+      println("The three regxes are the original regex, the regex after derivative w.r.t " + all_chars(i) + " and the simplification of the derivative.")
+      //println(regx_tree(i_like_imperative_style) up_align regx_tree(der_res) up_align regx_tree(simp_res))
+      println(asize(i_like_imperative_style), asize(der_res), asize(simp_res))
+      i_like_imperative_style = simp_res
+    }
+  }
+  val ran = scala.util.Random
+  var alphabet_size = 3
+  def balanced_seq_star_gen(depth: Int, star: Boolean): Rexp = {
+    if(depth == 1){
+      ((ran.nextInt(6) + 97).toChar).toString
+    }
+    else if(star){
+      STAR(balanced_seq_star_gen(depth - 1, false))
+    }
+    else{
+      SEQ(balanced_seq_star_gen(depth - 1, true), balanced_seq_star_gen(depth - 1, true))
+    }
+  }
+  def random_struct_gen(depth:Int): Rexp = {
+    val dice = ran.nextInt(3)
+    (dice, depth) match {
+      case (_, 0) => ((ran.nextInt(alphabet_size) + 97).toChar).toString
+      case (0, i) => STAR(random_struct_gen(i - 1))
+      case (1, i) => SEQ(random_struct_gen(i - 1), random_struct_gen(i - 1))
+      case (2, i) => ALTS( List(random_struct_gen(i - 1), random_struct_gen(i - 1)) )
+    }
+  }
+  def rd_string_gen(alp_size: Int, len: Int): String = {
+    ((ran.nextInt(alp_size) + 97).toChar).toString + rd_string_gen(alp_size, len - 1)
+  }
+  //def stay_same_hpth(r: Rexp, )
+  def main(args: Array[String]) {
+    val depth = args(0).toInt
+    alphabet_size = args(1).toInt
+    //illustration(random_struct_gen(depth), rd_string_gen(alphabet_size, 20))//"abcabadaaadcabdbabcdaadbabbcbbdabdabbcbdbabdbcdb")
+    for( i <- 50 to 400 by 20){
+      println(i+" iterations of prog2:")
+      blexing_simp(AWHILE_REGS, prog2 * i)
+    }
+      
+  } 
+}
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