progs/app03.scala
author Christian Urban <christian dot urban at kcl dot ac dot uk>
Wed, 25 Nov 2015 15:59:32 +0000
changeset 385 7f8516ff408d
parent 288 39aeca14af8c
child 400 e4afe3f46c29
permissions -rw-r--r--
updated

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