diff -r 18d19d039ac9 -r f476c98cad28 progs/scala/re-ext.scala
--- a/progs/scala/re-ext.scala	Sat Mar 11 12:50:01 2017 +0000
+++ b/progs/scala/re-ext.scala	Sat Mar 11 19:33:38 2017 +0000
@@ -2,6 +2,7 @@
 import scala.language.reflectiveCalls
 import scala.annotation.tailrec   
 import scala.io.Source
+import scala.util._
 
 abstract class Rexp 
 case object ZERO extends Rexp
@@ -157,7 +158,8 @@
   case c::cs => inj(r, c, lex(der(c, r), cs))
 }
 
-import scala.util._
+
+
 def lexing(r: Rexp, s: String) : Try[Val] = Try(lex(r, s.toList))
 
 
@@ -218,7 +220,7 @@
   }
 }
 
-def lexing_simp(r: Rexp, s: String) : Val = lex_simp(r, s.toList)
+def lexing_simp(r: Rexp, s: String) : Try[Val] = Try(lex_simp(r, s.toList))
 
 
 // Some Tests
@@ -249,10 +251,11 @@
 val ALL = CHARS((c) => true)
 val reg = ALL.% ~ "a" ~ NTIMES(ALL, 3) ~ "bc"
 
-println(lexing(reg, "axaybzbc"))     // true
-println(lexing(reg, "aaaaxaybzbc"))  // true
-println(nullable(ders("axaybzbd".toList, reg)))     // false
-println(lexing(reg, "axaybzbd"))     // false
+println(lexing(reg, "axaybzbc"))                     // true
+println(lexing(reg, "aaaaxaybzbc"))                  // true
+
+println(nullable(ders("axaybzbd".toList, reg)))      // false
+println(lexing(reg, "axaybzbd"))                     // false
 
 
 
@@ -302,12 +305,12 @@
 println("prog0 test")
 
 val prog0 = """read n"""
-println(env(lexing_simp(WHILE_REGS, prog0)))
+println(env(lexing_simp(WHILE_REGS, prog0).get))
 
 println("prog1 test")
 
 val prog1 = """read  n; write (n)"""
-println(env(lexing_simp(WHILE_REGS, prog1)))
+println(env(lexing_simp(WHILE_REGS, prog1).get))
 
 
 // Bigger Test
@@ -327,7 +330,15 @@
 }"""
 
 println("prog2 test - tokens")
-println(env(lexing_simp(WHILE_REGS, prog2)))
+println(env(lexing_simp(WHILE_REGS, prog2).get))
+
+
+// replicate prog2
+
+println("prog2 replicated test")
+for (i <- 1 to 88 by 5) {
+  println(i + ": " + "%.5f".format(time_needed(2, lexing_simp(WHILE_REGS, prog2 * i))))
+}
 
 
 val prog3 = """
@@ -346,13 +357,9 @@
 """
 
 println("prog3 test - tokens")
-println(env(lexing_simp(WHILE_REGS, prog3)))
-
-println("prog2 replicated test")
+println(env(lexing_simp(WHILE_REGS, prog3).get))
 
-for (i <- 1 to 88) {
-  println(i + ": " + "%.5f".format(time_needed(2, lexing_simp(WHILE_REGS, prog2 * i))))
-}
+
 
 
 // Sulzmann's tests
@@ -377,7 +384,7 @@
 val reWord = CHARS("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" contains _)
 
 val reWordStar = STAR(reWord)
-val reWordPlus = reWord ~ reWordStar
+val reWordPlus = PLUS(reWord)
 val optionSet1 = "-" | "+" | "."
 val optionSet2 = "-" | "."
 val atTheRate = "@"