Varargs

scala.quoted.Varargs

object Varargs

Expression representation of literal sequence of expressions.

Varargs can be used to create the an expression args that will be used as varargs '{ f($args: _*) } or it can be used to extract all the arguments of the a varargs.

Attributes

Source: Varargs.scala
Graph
Supertypes: class Object

trait Matchable

class Any
Self type: Varargs.type

Members list

Value members

Concrete methods

Lifts this sequence of expressions into an expression of a sequence

Transforms a sequence of expression Seq(e1, e2, ...) where ei: Expr[T] to an expression equivalent to '{ Seq($e1, $e2, ...) } typed as an Expr[Seq[T]]

Usage:

def f(using Quotes) = {
  import quotes.reflect.*
  '{ List(${Varargs(List('{1}, '{2}, '{3}))}: _*) } // equivalent to '{ List(1, 2, 3) }
}

Type parameters

T: the element type of the expressions in the sequence

Value parameters

xs: the sequence of individual expressions to lift into a single expression

Attributes

Returns: an expression representing the sequence Seq(xs(0), xs(1), ...) as an Expr[Seq[T]]
Source: Varargs.scala

Matches a literal sequence of expressions and returns a sequence of expressions.

Usage:

inline def sum(args: Int*): Int = ${ sumExpr('args) }
def sumExpr(argsExpr: Expr[Seq[Int]])(using Quotes): Expr[Int] = argsExpr match
  case Varargs(argVarargs) => Expr(argVarargs.size)
    // argVarargs: Seq[Expr[Int]]

Type parameters

T: the element type of the varargs sequence

Value parameters

expr: the expression of a sequence to destructure into individual expressions

Attributes

Returns: Some containing the individual element expressions, or None if the expression is not a literal sequence
Source: Varargs.scala

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