99 Bottles of Beer/Scala

From Rosetta Code
99 Bottles of Beer/Scala is part of 99 Bottles of Beer. You may find other members of 99 Bottles of Beer at Category:99 Bottles of Beer.
Library: Scala

The trivial solution[edit]

The trivial solution to it would be this:

99 to 1 by -1 foreach { n =>
println(
f"$n%d bottles of beer on the wall\n" +
f"$n%d bottles of beer\n" +
f"Take one down, pass it around\n" +
f"${n - 1}%d bottles of beer on the wall\n")
}

Running in parallel[edit]

The above n parallel using a ParRange, fast but shuffles the output.

(99 to 1 by -1).par foreach { n =>
println(
f"$n%d bottles of beer on the wall\n" +
f"$n%d bottles of beer\n" +
f"Take one down, pass it around\n" +
f"${n - 1}%d bottles of beer on the wall\n")
}

Regex solution[edit]

object NinetyNineBottlesOfBeer {
val verse = """|99 bottles of beer on the wall
|99 bottles of beer
|Take one down, pass it around
|98 bottles of beer on the wall"
"".stripMargin
 
val song = new scala.collection.mutable.Queue() ++= verse.lines += ""
val Bottles = "(\\d+) bottles of beer.*".r
 
def changeLine(line: String) = line match {
case Bottles("0") => song clear ()
case Bottles(n) => song enqueue line.replace(n, n.toInt - 1 toString)
case _ => song enqueue line
}
 
def sing = while(!song.isEmpty) {
val line = song dequeue ()
println(line)
changeLine(line)
}
}

A preferred ☺ sollution[edit]

object Song {
import scala.actors._
import scala.actors.Actor._
 
abstract class Beverage { def name = this.toString.toLowerCase }
case object Beer extends Beverage
 
object Wall {
private var contents: List[Beverage] = Nil
 
def count(what: Beverage) = contents count (_ == what)
def isEmpty = contents isEmpty
def stock(n: Int, what: Beverage) = contents :::= List.fill(n)(what)
def get(what: Beverage) {
def takeOneFrom(contents: List[Beverage]): List[Beverage] = contents match {
case `what` :: rest => rest
case other :: rest => other :: takeOneFrom(rest)
case Nil => println("Sorry, we are out of "+what.toString.toLowerCase); Nil
}
contents = takeOneFrom(contents)
}
}
 
sealed abstract class Messages
case class SingSong(what: Beverage) extends Messages
case class HowManyMore(what: Beverage) extends Messages
case class HowManyNow(what: Beverage) extends Messages
case class ThereAreStill(n: Int, what: Beverage) extends Messages
case class ThereAreNow(n: Int, what: Beverage) extends Messages
case class Gimme(what: Beverage) extends Messages
case class HereIs(what: Beverage) extends Messages
case object ClosingTime extends Messages
 
def plural(count: Int, noun: String, nouns: String) = if (count == 1) noun else nouns
def countIt(n: Int, what: Beverage) = "%d %s of %s" format (n, plural(n, "bottle", "bottles"), what.name)
 
object Waitress extends Actor {
def tellThem(what: String) = println("%s on the wall" format what)
 
def act = loop {
react {
case HowManyMore(it) =>
val total = Wall count it
tellThem(countIt(total, it))
reply (ThereAreStill(total, it))
case Gimme(it) =>
print("Take one down, ")
Wall get it
reply (HereIs(it))
case HowManyNow(it) =>
val total = Wall count it
tellThem(countIt(total, it))
if (Wall isEmpty) {
reply (ClosingTime) // You don't have to go home, but you can't stay here
exit
} else
reply (ThereAreNow(total, it))
case _ =>
println("You wish, honey!")
}
}
}
 
object Patrons extends Actor {
def act = loop {
react {
case SingSong(what: Beverage) =>
Waitress ! HowManyMore(what)
case ThereAreStill(n, it) =>
println(countIt(n, it))
Waitress ! Gimme(it)
case HereIs(it) =>
println("pass it around")
Waitress ! HowManyNow(it)
case ThereAreNow(n, it) =>
println()
Waitress ! HowManyMore(it)
case ClosingTime =>
exit
case _ =>
println("Say what???")
}
}
}
 
def Sing99Beers = {
Wall stock (99, Beer)
Waitress.start
Patrons.start
 
Patrons ! SingSong(Beer)
}
}