scala.quoted.Exprs.scala Maven / Gradle / Ivy

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scala3-library-bootstrapped

There is a newer version: 3.6.4-RC1-bin-20241220-0bfa1af-NIGHTLY

package scala.quoted

object Exprs:

  /** Matches literal sequence of literal constant value expressions and return a sequence of values.
   *
   *  Usage:
   *  ```scala
   *  inline def sum(args: Int*): Int = ${ sumExpr('args) }
   *  def sumExpr(argsExpr: Expr[Seq[Int]])(using Quotes): Expr[Int] = argsExpr match
   *    case Varargs(Exprs(args)) => ???
   *      // args: Seq[Int]
   *  ```
   *  To directly get the value of all expressions in a sequence `exprs: Seq[Expr[T]]` consider using `exprs.map(_.value)`/`exprs.map(_.valueOrError)` instead.
   */
  def unapply[T](exprs: Seq[Expr[T]])(using FromExpr[T])(using Quotes): Option[Seq[T]] =
    val builder = Seq.newBuilder[T]
    val iter = exprs.iterator
    while iter.hasNext do
      iter.next().value match
        case Some(value) => builder += value
        case _ => return None
    Some(builder.result())

end Exprs