|      4 def F_ALT(f1: Val => Val, f2: Val => Val) = (v:Val) => v match { |      4 def F_ALT(f1: Val => Val, f2: Val => Val) = (v:Val) => v match { | 
|      5   case Right(v) => Right(f2(v)) |      5   case Right(v) => Right(f2(v)) | 
|      6   case Left(v) => Left(f1(v)) |      6   case Left(v) => Left(f1(v)) | 
|      7 } |      7 } | 
|      8 def F_SEQ(f1: Val => Val, f2: Val => Val) = (v:Val) => v match { |      8 def F_SEQ(f1: Val => Val, f2: Val => Val) = (v:Val) => v match { | 
|      9   case Seq(v1, v2) => Seq(f1(v1), f2(v2)) |      9   case Sequ(v1, v2) => Sequ(f1(v1), f2(v2)) | 
|     10 } |     10 } | 
|     11 def F_SEQ_Empty1(f1: Val => Val, f2: Val => Val) =  |     11 def F_SEQ_Empty1(f1: Val => Val, f2: Val => Val) =  | 
|     12   (v:Val) => Seq(f1(Empty), f2(v)) |     12   (v:Val) => Sequ(f1(Empty), f2(v)) | 
|     13 def F_SEQ_Empty2(f1: Val => Val, f2: Val => Val) =  |     13 def F_SEQ_Empty2(f1: Val => Val, f2: Val => Val) =  | 
|     14   (v:Val) => Seq(f1(v), f2(Empty)) |     14   (v:Val) => Sequ(f1(v), f2(Empty)) | 
|     15 def F_ERROR(v: Val): Val = throw new Exception("error") |     15 def F_ERROR(v: Val): Val = throw new Exception("error") | 
|     16  |     16  | 
|     17 // simplification of regular expressions returning also a |     17 // simplification of regular expressions returning also a | 
|     18 // rectification function; no simplification under STAR  |     18 // rectification function; no simplification under STAR  | 
|     19 def simp(r: Rexp): (Rexp, Val => Val) = r match { |     19 def simp(r: Rexp): (Rexp, Val => Val) = r match { |