関数合成 ref: http://qiita.com/songfei1983/items/c9df0bc8d5e199fba583

file0.scala

val add1: Int => Int = x => x + 1

val sq = (x: Int) => x * x

val add100 = (x: Int) => x + 100

foo map (add100 compose sq compose add1)
//res9: List[Int] = List(104, 109, 116, 125, 136)
//functionをリストにしたら、自由度高いじゃと思って！下記の方法を見つかった！
// https://bcomposes.wordpress.com/2011/08/20/fun-with-function-composition-in-scala/

val fncs = List(add1, sq, add100)
// fncs: List[Int => Int] = List(<function1>, <function1>, <function1>)

val foo: List[Int] = List(1, 2, 3, 4, 5)

foo map (fncs.reverse reduce( _ compose _ ))
//res10: List[Int] = List(104, 109, 116, 125, 136)
//とりあえずこれか！うん！