scala.util.regexp.WordExp.scala Maven / Gradle / Ivy

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**     ________ ___   / /  ___     Scala API                            **
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package scala.util.regexp

/** 
 *    The class WordExp provides regular word expressions.
 *    Users have to instantiate type member _regexpT <: RegExp
 *    (from class Base) and a type member
 *    _labelT <: Label. Here is a short example:
 *  
 *  import scala.util.regexp._
 *  import scala.util.automata._
 *  object MyLang extends WordExp {
 *    type _regexpT = RegExp
 *    type _labelT = MyChar
 *
 *    case class MyChar(c:Char) extends Label
 *  }
 *  import MyLang._
 *  // (a* | b)*
 *  val rex = Star(Alt(Star(Letter(MyChar('a'))),Letter(MyChar('b'))))
 *  object MyBerriSethi extends WordBerrySethi {
 *    override val lang = MyLang
 *  }
 *  val nfa = MyBerriSethi.automatonFrom(Sequ(rex), 1)
 *  
 *
 *  @author  Burak Emir
 *  @version 1.0
 */
abstract class WordExp extends Base {

  abstract class Label

  type _regexpT <: RegExp
  type _labelT <: Label

  case class Letter(a: _labelT) extends RegExp {
    final lazy val isNullable = false
    var pos = -1
  }

  case class Wildcard() extends RegExp {
    final lazy val isNullable = false
    var pos = -1
  }
}