S99 Problem 8

s99p8.scala

scala> //Eliminate consecutive duplicates of list elements.

scala> val l = List('a, 'a, 'a, 'a, 'b, 'c, 'c, 'a, 'a, 'd, 'e, 'e, 'e, 'e)
l: List[Symbol] = List('a, 'a, 'a, 'a, 'b, 'c, 'c, 'a, 'a, 'd, 'e, 'e, 'e, 'e)

scala> l.foldLeft(List[Symbol]()){
     |   case (acc,s) if acc.isEmpty   => s :: acc
     |   case (acc,s) if s == acc.head => acc
     |   case (acc,s)                  => s :: acc
     | }.reverse

res10: List[Symbol] = List('a, 'b, 'c, 'a, 'd, 'e)