Tuple

scala> :paste
// Entering paste mode (ctrl-D to finish)

    val t1 = (1, 2)
    val t2 = 1 -> 2
    val t3 = 1 → 2
    val t4 = Tuple2(1,2)
    val t5 = Pair(1, 2)
    val t6 = Triple(1, 2, 3)

// Exiting paste mode, now interpreting.

<pastie>:15: warning: object Pair in object Predef is deprecated (since 2.11.0): use built-in tuple syntax or
Tuple2 instead
    val t5 = Pair(1, 2)
             ^
<pastie>:16: warning: object Triple in object Predef is deprecated (since 2.11.0): use built-in tuple syntax o
r Tuple3 instead
    val t6 = Triple(1, 2, 3)
             ^
t1: (Int, Int) = (1,2)
t2: (Int, Int) = (1,2)
t3: (Int, Int) = (1,2)
t4: (Int, Int) = (1,2)
t5: (Int, Int) = (1,2)
t6: (Int, Int, Int) = (1,2,3)

PairとTripleは2.11.0から非推奨だって
Play Framework2.8ではScala 2.11のサポートが終了するのでもうこいつらは忘れていい、さようなら

t1

(1, 2)は(1 -> 2)の糖衣構文

t2, t3

  /** @group implicit-classes-any */
  implicit final class ArrowAssoc[A](private val self: A) extends AnyVal {
    @inline def -> [B](y: B): Tuple2[A, B] = Tuple2(self, y)
    def →[B](y: B): Tuple2[A, B] = ->(y)
  }

t5, t6

Predef

  type Pair[+A, +B] = Tuple2[A, B]
  type Triple[+A, +B, +C] = Tuple3[A, B, C]

t4

ただのTuple2オブジェクト
Scala Standard Library 2.13.1 - scala.Tuple2
最大22まで標準搭載
Scala Standard Library 2.13.1 - scala.Tuple22

23は要素多いすぎエラー
タプルってことは認識されてるようだ

scala> val t = (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23)
<console>:1: error: too many elements for tuple: 23, allowed: 22
       val t = (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23)
               ^

Tuple1

Scala Standard Library 2.13.1 - scala.Tuple1
型指定すればつかえる、どこで使うのかはしらん

scala> :paste
// Entering paste mode (ctrl-D to finish)

val t = (1)
val t1 = Tuple1(1)

// Exiting paste mode, now interpreting.

t: Int = 1
t1: (Int,) = (1,)