quill-tuples.scala

// WARNING: mysql versions before 5.7.3 do not properly use index lookups for this construction.

trait TupleQuery { self: io.getquill.context.Context[_, _] =>

  /**
    * Allows `where (x, y) in ((c1, c2))` queries via `liftTuples(tuples).contains((p.name, p.age))`
    * See https://github.com/getquill/quill/issues/651
    */
  def liftTuples[T1: Encoder, T2: Encoder](
      tuples: Seq[(T1, T2)]
  ): Quoted[Query[(T1, T2)]] =
    liftTuplesRec(2, tuples, (t: (T1, T2)) => infix"(${lift(t._1)}, ${lift(t._2)})")

  def liftTuples[T1: Encoder, T2: Encoder, T3: Encoder](
      tuples: Seq[(T1, T2, T3)]
  ): Quoted[Query[(T1, T2, T3)]] =
    liftTuplesRec(
      3,
      tuples,
      (t: (T1, T2, T3)) => infix"(${lift(t._1)}, ${lift(t._2)}, ${lift(t._3)})")

  def liftTuples[T1: Encoder, T2: Encoder, T3: Encoder, T4: Encoder](
      tuples: Seq[(T1, T2, T3, T4)]
  ): Quoted[Query[(T1, T2, T3, T4)]] =
    liftTuplesRec(
      4,
      tuples,
      (t: (T1, T2, T3, T4)) => infix"(${lift(t._1)}, ${lift(t._2)}, ${lift(t._3)}, ${lift(t._4)})")

  private def liftTuplesRec[T, U](arity: Int, l: Seq[T], f: T => Quoted[Any]): Quoted[Query[U]] = {
    l match {
      case Seq() if arity == 2 =>
        infix"SELECT NULL, NULL FROM DUAL WHERE FALSE".as[Query[U]]
      case Seq() if arity == 3 =>
        infix"SELECT NULL, NULL, NULL FROM DUAL WHERE FALSE".as[Query[U]]
      case Seq() if arity == 4 =>
        infix"SELECT NULL, NULL, NULL, NULL FROM DUAL WHERE FALSE".as[Query[U]]

      case Seq(head) => infix"${f(head)}".as[Query[U]]

      case head +: tail =>
        infix"${f(head)}, ${liftTuplesRec(arity, tail, f)}".as[Query[U]]
    }
  }
}