scala.quoted

Quoted expression of type T.

Expr has extension methods that are defined in scala.quoted.Quotes.

Constructors for expressions

A type class for types that can convert a quoted.Expr[T] to a T.

• Converts expression containing literal values to their values:
  • '{1} -> 1, '{2} -> 2, ...
  • For all primitive types and String
• Converts an expression that constructs a copy of its value.
  • This expression must be some kind of data structure (Some, List, Either, ...)
  • Calls to new X or X.apply can be lifted into its value
  • Arguments of constructors can be recursively unlifted

Default given instances of FromExpr

Quotation context provided by a macro expansion or in the scope of scala.quoted.staging.run. Used to perform all operations on quoted Expr or Type.

It contains the low-level Typed AST API metaprogramming API. This API does not have the static type guarantees that Expr and Type provide. Quotes are generated from an enclosing ${ ... } or scala.staging.run. For example:

import scala.quoted._
inline def myMacro: Expr[T] =
  ${ /* (quotes: Quotes) ?=> */ myExpr }
def myExpr(using Quotes): Expr[T] =
  '{ f(${ /* (quotes: Quotes) ?=> */ myOtherExpr }) }
}
def myOtherExpr(using Quotes): Expr[U] = '{ ... }

A type class for types that can convert a value of T into quoted.Expr[T] an expression that will create a copy of the value.

Default given instances of ToExpr

Type (or type constructor) T needed contextually when using T in a quoted expression '{... T ...}

Methods to interact with the current Type[T] in scope

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.

Current Quotes in scope

Usage:

import scala.quoted._
def myExpr[T](using Quotes): Expr[T] = {
   import quotes.reflect._
   ???
}