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Language Scala
(Scala with a vengeance)
| Date: | 09/16/09 |
| Author: | Eduardo Costa |
| URL: | http://extremejava.tpk.com.br |
| Comments: | 0 |
| Info: | http://www.scala-lang.org/ |
| Score: |  (3.00 in 18 votes) |
/**
* Scala implementation of "99 beers on the wall" with a vengeance. Contains
* examples of Scala features, like tail recursion.
*
* @author Eduardo Costa http://extremejava.tpk.com.br
*/
object Beers extends Application {
def bottles(qty : Int, f : => String) = // higher-order functions
qty match {
case 0 => "no more bottles of beer" + f
case 1 => "1 bottle of beer" + f
case x => x + " bottles of beer" + f
}
def beers(qty : Int) = bottles(qty, " on the wall.")
def sing(qty : Int)(implicit song : String) : String = {
def takeOne =
qty match {
case 0 => "Go to the store and buy some more."
case x => "Take one down and pass it around."
}
def nextQty = // nested functions
if (qty == 0) 99
else qty - 1
def refrain = {
beers(qty).capitalize + " " + bottles(qty, "") + ".\n" +
takeOne + " " + beers(nextQty) + "\n\n"
}
if (qty == -1) song
else sing(qty - 1)(song + refrain) // tail recursion
}
implicit val headOfSong : String = ""
println(sing(99)) // implicit parameter
}
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Alternative Versions
| Version | Author | Date | Comments | Rate |
|---|---|---|---|---|
| Animated version | D Mackenzie | 10/02/09 | 0 | |
| Fun semi-DSL readable version | Calum Leslie | 01/31/08 | 0 | |
| GrabbaBeer & CaseOfBeers | D Mackenzie | 05/30/09 | 0 | |
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