progs/app03.scala
author Christian Urban <christian.urban@kcl.ac.uk>
Wed, 21 Oct 2020 14:55:20 +0100
changeset 786 da2488db453e
parent 400 e4afe3f46c29
permissions -rw-r--r--
updated

abstract class Rexp
case object ZERO extends Rexp
case object ONE 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