Scala 3/scala.quoted/Quotes

Quotes

trait Quotes

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.

Source:
Quotes.scala
class Object
trait Matchable
class Any

Type members

Classlikes

trait reflectModule

Low-level Typed AST metaprogramming API.

Low-level Typed AST metaprogramming API.

Provides all functionality related to AST-based metaprogramming.

Each type XYZ in the API is defined as an abstract type type XYZ. Methods on XYZ are provided by a given XYZMethods which implements extension methods on XYZ in the trait XYZMethods. The XYZ module is defined by a val XYZ: XYZModule which contains the methods defined in XYZModule. Type tests (TypeTest) are also given to perform subtype checks on these types.

Type hierarchy


+- Tree -+- PackageClause
         |
         +- Statement -+- Import
         |             +- Export
         |             +- Definition --+- ClassDef
         |             |               +- TypeDef
         |             |               +- DefDef
         |             |               +- ValDef
         |             |
         |             +- Term --------+- Ref -+- Ident
         |                             |       +- Select
         |                             |
         |                             +- Literal
         |                             +- This
         |                             +- New
         |                             +- NamedArg
         |                             +- Apply
         |                             +- TypeApply
         |                             +- Super
         |                             +- Typed
         |                             +- Assign
         |                             +- Block
         |                             +- Closure
         |                             +- If
         |                             +- Match
         |                             +- SummonFrom
         |                             +- Try
         |                             +- Return
         |                             +- Repeated
         |                             +- Inlined
         |                             +- SelectOuter
         |                             +- While
         |
         |
         +- TypeTree ----+- Inferred
         |               +- TypeIdent
         |               +- TypeSelect
         |               +- TypeProjection
         |               +- Singleton
         |               +- Refined
         |               +- Applied
         |               +- Annotated
         |               +- MatchTypeTree
         |               +- ByName
         |               +- LambdaTypeTree
         |               +- TypeBind
         |               +- TypeBlock
         |
         +- TypeBoundsTree
         +- WildcardTypeTree
         |
         +- CaseDef
         |
         +- TypeCaseDef
         +- Bind
         +- Unapply
         +- Alternatives

+- ParamClause -+- TypeParamClause
                +- TermParamClause

+- TypeRepr -+- NamedType -+- TermRef
             |             +- TypeRef
             +- ConstantType
             +- SuperType
             +- Refinement
             +- AppliedType
             +- AnnotatedType
             +- AndOrType -+- AndType
             |             +- OrType
             +- MatchType
             +- ByNameType
             +- ParamRef
             +- ThisType
             +- RecursiveThis
             +- RecursiveType
             +- LambdaType -+- MethodOrPoly -+- MethodType
             |              |                +- PolyType
             |              +- TypeLambda
             +- MatchCase
             +- TypeBounds
             +- NoPrefix

+- Selector -+- SimpleSelector
             +- RenameSelector
             +- OmitSelector
             +- GivenSelector

+- Signature

+- Position

+- SourceFile

+- Constant -+- BooleanConstant
             +- ByteConstant
             +- ShortConstant
             +- IntConstant
             +- LongConstant
             +- FloatConstant
             +- DoubleConstant
             +- CharConstant
             +- StringConstant
             +- UnitConstant
             +- NullConstant
             +- ClassOfConstant
+- Symbol

+- Flags
Source:
Quotes.scala

Types

type Nested = Quotes

Type of a Quotes provided by a splice within a quote that took this context.

Type of a Quotes provided by a splice within a quote that took this context.

Source:
Quotes.scala

Value members

Abstract fields

val reflect: reflectModule

Low-level Typed AST metaprogramming API.

Low-level Typed AST metaprogramming API.

Provides all functionality related to AST-based metaprogramming.

Usage:

import scala.quoted._
def f(expr: Expr[Int])(using Quotes) =
  import quotes.reflect._
  val ast: Term = expr.asTerm
  ...

See reflectModule for full API.

Source:
Quotes.scala

Extensions

Extensions

extension [T](self: Expr[T])
def matches(that: Expr[Any]): Boolean

Pattern matches this against that. Effectively performing a deep equality check. It does the equivalent of

Pattern matches this against that. Effectively performing a deep equality check. It does the equivalent of

this match
  case '{...} => true // where the contents of the pattern are the contents of `that`
  case _ => false
Source:
Quotes.scala
def show: String

Show a source code like representation of this expression

Show a source code like representation of this expression

Source:
Quotes.scala
def value(using FromExpr[T]): Option[T]

Return the value of this expression.

Return the value of this expression.

Returns None if the expression does not represent a value or possibly contains side effects. Otherwise returns the Some of the value.

Source:
Quotes.scala
def valueOrAbort(using FromExpr[T]): T

Return the value of this expression.

Return the value of this expression.

Emits an error and aborts if the expression does not represent a value or possibly contains side effects. Otherwise returns the value.

Source:
Quotes.scala
def valueOrError(using FromExpr[T]): T

Return the value of this expression.

Return the value of this expression.

Emits an error and throws if the expression does not represent a value or possibly contains side effects. Otherwise returns the value.

Source:
Quotes.scala
extension (self: Expr[Any])
def asExprOf[X](using Type[X]): Expr[X]

Convert this to an quoted.Expr[X] if this expression is a valid expression of type X or throws

Convert this to an quoted.Expr[X] if this expression is a valid expression of type X or throws

Source:
Quotes.scala
def isExprOf[X](using Type[X]): Boolean

Checks is the quoted.Expr[?] is valid expression of type X

Checks is the quoted.Expr[?] is valid expression of type X

Source:
Quotes.scala