translate.scala

package week6

import scala.io.Source

object mnemonics {
  val in = Source.fromURL("https://raw.github.com/jpalmour/progfun/master/forcomp/src/main/resources/forcomp/linuxwords.txt")
  
  val words = in.getLines.toList filter (word => word forall (chr => chr.isLetter))
                                                
  val mnem = Map(
  	'2' -> "ABC", '3' -> "DEF", '4' -> "GHI", '5' -> "JKL",
  	'6' -> "MNO", '7' -> "PQRS", '8' -> "TUV", '9' -> "WXYZ")
  	
  val charCode: Map[Char, Char] =
  	for ((digit, str) <- mnem; ltr <- str) yield ltr -> digit
  
  def wordCode(word: String): String =
  	word.toUpperCase map charCode
  	
  val wordsForNum: Map[String, Seq[String]] =
    words groupBy wordCode withDefaultValue Seq()
                                                  
  def encode(number: String): Set[List[String]] =
    if (number.isEmpty) Set(List())
    else {
    	for {
    		split <- 1 to number.length
    		word <- wordsForNum(number take split)
    		rest <- encode(number drop split)
    	} yield word :: rest
   	}.toSet                                   
   	
  encode("847825")                            
}