alvinalexander.com | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Scala example source code file (Input.scala)

This example Scala source code file (Input.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Scala tags/keywords

a, arrayinput, b, failure, input, input, int, iterator, nothing, nothing, result, result, success, success

The Scala Input.scala source code

// -----------------------------------------------------------------------------
//
//  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
package scalax
package rules

trait Input[+A] extends Iterable[A] { 

  def next : Result[Input[A], A, Nothing]
  def index : Int

  def iterator = 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 = this.iterator.mkString("\"", "", "\"")
}


class IterableInput[A](iterator : Iterator[A], val index : Int) extends Input[A] {
  def this(iterable : Iterable[A]) = this(iterable.iterator, 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 = this.iterator.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
  }
}

Other Scala examples (source code examples)

Here is a short list of links related to this Scala Input.scala source code file:

... this post is sponsored by my books ...

#1 New Release!

FP Best Seller

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.