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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2010, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id$
package scala.util.automata
import scala.collection.{Set, Map}
/** A deterministic automaton. States are integers, where
* 0 is always the only initial state. Transitions are represented
* in the delta function. A default transitions is one that
* is taken when no other transition can be taken.
* All states are reachable. Accepting states are those for which
* the partial function 'finals' is defined.
*
* @author Burak Emir
* @version 1.0
*/
abstract class DetWordAutom[T <: AnyRef] {
val nstates: Int
val finals: Array[Int]
val delta: Array[Map[T,Int]]
val default: Array[Int]
def isFinal(q: Int) = finals(q) != 0
def isSink(q: Int) = delta(q).isEmpty && default(q) == q
def next(q: Int, label: T) = {
delta(q).get(label) match {
case Some(p) => p
case _ => default(q)
}
}
override def toString() = {
val sb = new StringBuilder("[DetWordAutom nstates=")
sb.append(nstates)
sb.append(" finals=")
val map = Map(finals.zipWithIndex map (_.swap): _*)
sb.append(map.toString())
sb.append(" delta=\n")
for (i <- 0 until nstates) {
sb append "%d->%s\n".format(i, delta(i))
if (i < default.length)
sb append "_>%s\n".format(default(i))
}
sb.toString
}
}
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