progs/app03.scala
author Christian Urban <christian dot urban at kcl dot ac dot uk>
Thu, 08 Oct 2015 14:06:18 +0100
changeset 347 22b5294daa2a
parent 288 39aeca14af8c
child 400 e4afe3f46c29
permissions -rw-r--r--
updated hws

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