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// -----------------------------------------------------------------------------
//
// Scalax - The Scala Community Library
// Copyright (c) 2005-8 The Scalax Project. All rights reserved.
//
// The primary distribution site is http://scalax.scalaforge.org/
//
// This software is released under the terms of the Revised BSD License.
// There is NO WARRANTY. See the file LICENSE for the full text.
//
// -----------------------------------------------------------------------------
package scala.tools.scalap.scalax.rules
trait Input[+A] extends Iterable[A] {
def next : Result[Input[A], A, Nothing]
def index : Int
def elements = new Iterator[A] {
private var input : Input[A] = Input.this
private var result = input.next
def hasNext = result != Failure
def next = {
val Success(input, value) = result
this.input = input
this.result = input.next
value
}
}
}
class ArrayInput[A](val array : Array[A], val index : Int) extends Input[A] {
def this(array : Array[A]) = this(array, 0)
lazy val next : Result[ArrayInput[A], A, Nothing] = if (index >= array.length) Failure
else Success(new ArrayInput[A](array, index + 1), array(index))
override lazy val toString = elements.mkString("\"", "", "\"")
}
class IterableInput[A](iterator : Iterator[A], val index : Int) extends Input[A] {
def this(iterable : Iterable[A]) = this(iterable.elements, 0)
lazy val next : Result[IterableInput[A], A, Nothing] = if (!iterator.hasNext) Failure
else Success(new IterableInput(iterator, index + 1), iterator.next)
override lazy val toString = elements.mkString("\"", "", "\"")
}
/** View one type of input as another based on a transformation rule */
class View[A, B](
transform : Input[A] => Result[Input[A], B, Nothing],
val input : Input[A],
val index : Int)
extends Input[B] {
def next : Result[Input[B], B, Nothing] = transform(input) match {
case Success(context, b) => Success(new View(transform, context, index + 1), b)
case _ => Failure
}
}
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