progs/app03.scala
author Christian Urban <christian dot urban at kcl dot ac dot uk>
Fri, 02 Oct 2015 07:48:56 +0100
changeset 341 ac1187b2e5c9
parent 288 39aeca14af8c
child 400 e4afe3f46c29
permissions -rw-r--r--
updated program

abstract class Rexp
case object NULL extends Rexp
case object EMPTY extends Rexp
case class CHAR(c: Char) extends Rexp
case class ALT(r1: Rexp, r2: Rexp) extends Rexp 
case class SEQ(r1: Rexp, r2: Rexp) extends Rexp 
case class STAR(r: Rexp) extends Rexp 
case class REC(x: String, r: Rexp) extends Rexp