PLEAC: File Access (Scala)

gistfile1.scala

/* File Access
 * see http://pleac.sourceforge.net/pleac_perl/fileaccess.html
 * Scala 2.9.1
 */

import scripting.file._
import scripting.file.Implicits._

/* Introduction */

// scala/java regex do not match substrings, as do languages like perl and ruby

io.Source.fromFile("/usr/local/widgets/data").getLines.foreach { line =>
  if (".*(blue).*".r.pattern.matcher(line).matches)
    println(line)
}

val Blue = ".*(blue).*".r
io.Source.fromFile("/usr/local/widgets/data").getLines.foreach { line =>
  line match {
    case Blue(blue) => println(line)
    case _ =>
  }
}

// getLine() on Source is deprecated; if you need to explicitly open a file
// and read lines you can drop into Java-land...

import java.io.{File, DataInputStream, FileInputStream}

val file = new File("/usr/local/widgets/data")
val dis = new DataInputStream(new FileInputStream(file))
while (dis.available > 0) {
  val = dis.readLine
  line match {
    case Blue(blue) => println(line)
    case _ =>
  }
}

val Digit = ".*(\\d).*".r
Source.stdin.getLines.foreach { line =>                         // reads from STDIN
  line match {
    case Digit(digit) => Console.out.println("Read: " + line)   // writes to STDOUT
    case _ => Console.err.println("No digit found")             // writes to STDERR
  }
}

import java.io.FileOutputStream

val logfile = "log.txt".f
val fos = new FileOutputStream(logfile)
Console.withOut(fos) {                             // switch to logfile for output
  println("Countdown initiated ...")
}                                                  // return to original output
println("You have 30 seconds to reach minimum safety distance.")