Scala example source code file (InteractiveReader.scala)

This example Scala source code file (InteractiveReader.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

boolean, compiler, history, int, interactivereader, interrupted, ioexception, nsc, r, simplereader, string, unit

The InteractiveReader.scala Scala example source code

/* NSC -- new Scala compiler
 * Copyright 2005-2013 LAMP/EPFL
 * @author Stepan Koltsov
 */

package scala.tools.nsc
package interpreter

import java.io.IOException
import session.History
import InteractiveReader._
import Properties.isMac

/** Reads lines from an input stream */
trait InteractiveReader {
  val interactive: Boolean

  def reset(): Unit
  def history: History
  def completion: Completion
  def redrawLine(): Unit

  def readYesOrNo(prompt: String, alt: => Boolean): Boolean = readOneKey(prompt) match {
    case 'y'  => true
    case 'n'  => false
    case _    => alt
  }

  protected def readOneLine(prompt: String): String
  protected def readOneKey(prompt: String): Int

  def readLine(prompt: String): String =
    // hack necessary for OSX jvm suspension because read calls are not restarted after SIGTSTP
    if (isMac) restartSysCalls(readOneLine(prompt), reset())
    else readOneLine(prompt)
}

object InteractiveReader {
  val msgEINTR = "Interrupted system call"
  def restartSysCalls[R](body: => R, reset: => Unit): R =
    try body catch {
      case e: IOException if e.getMessage == msgEINTR => reset ; body
    }

  def apply(): InteractiveReader = SimpleReader()
  @deprecated("Use `apply` instead.", "2.9.0")
  def createDefault(): InteractiveReader = apply() // used by sbt
}