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Scala 3/scala/scala.quoted/Quotes/reflectModule/SymbolModule

SymbolModule

scala.quoted.Quotes.reflectModule.SymbolModule

trait SymbolModule

Methods of the module object val Symbol

Attributes

Source: Quotes.scala
Graph
Supertypes: class Object

trait Matchable

class Any
Self type: Symbol.type

Members list

Value members

Abstract methods

The class Symbol of a global class definition

Attributes

Source: Quotes.scala

Generates a pattern bind symbol with the given parent, name and type.

This symbol starts without an accompanying definition. It is the meta-programmer's responsibility to provide exactly one corresponding definition by passing this symbol to the BindDef constructor.

Value parameters

flags: extra flags to with which the symbol should be constructed. Case flag will be added. Can be Case
name: The name of the binding
parent: The owner of the binding
tpe: The type of the binding

Attributes

Note: As a macro can only splice code into the point at which it is expanded, all generated symbols must be direct or indirect children of the reflection context's owner.
Source: Quotes.scala

Generates a new method symbol with the given parent, name and type.

To define a member method of a class, use the newMethod within the decls function of newClass.

Value parameters

name: The name of the method
parent: The owner of the method
tpe: The type of the method (MethodType, PolyType, ByNameType) This symbol starts without an accompanying definition. It is the meta-programmer's responsibility to provide exactly one corresponding definition by passing this symbol to the DefDef constructor.

Attributes

Note: As a macro can only splice code into the point at which it is expanded, all generated symbols must be direct or indirect children of the reflection context's owner.
Source: Quotes.scala

Works as the other newMethod, but with additional parameters.

To define a member method of a class, use the newMethod within the decls function of newClass.

Value parameters

flags: extra flags to with which the symbol should be constructed. Method flag will be added. Can be Private | Protected | Override | Deferred | Final | Method | Implicit | Given | Local | JavaStatic | Synthetic | Artifact
name: The name of the method
parent: The owner of the method
privateWithin: the symbol within which this new method symbol should be private. May be noSymbol.
tpe: The type of the method (MethodType, PolyType, ByNameType)

Attributes

Source: Quotes.scala

Generates a new val/var/lazy val symbol with the given parent, name and type.

This symbol starts without an accompanying definition. It is the meta-programmer's responsibility to provide exactly one corresponding definition by passing this symbol to the ValDef constructor.

Note: Also see ValDef.let

Value parameters

flags: extra flags to with which the symbol should be constructed. Can be Private | Protected | Override | Deferred | Final | Param | Implicit | Lazy | Mutable | Local | ParamAccessor | Module | Package | Case | CaseAccessor | Given | Enum | JavaStatic | Synthetic | Artifact
name: The name of the val/var/lazy val
parent: The owner of the val/var/lazy val
privateWithin: the symbol within which this new method symbol should be private. May be noSymbol.
tpe: The type of the val/var/lazy val

Attributes

Note: As a macro can only splice code into the point at which it is expanded, all generated symbols must be direct or indirect children of the reflection context's owner.
Source: Quotes.scala

Definition not available

Attributes

Source: Quotes.scala

Get class symbol if class is either defined in current compilation run or present on classpath.

Attributes

Source: Quotes.scala

Get method symbol if method is either defined in current compilation run or present on classpath. Throws if the method has an overload.

Attributes

Source: Quotes.scala

Get module symbol if module is either defined in current compilation run or present on classpath.

Attributes

Source: Quotes.scala

Get package symbol if package is either defined in current compilation run or present on classpath.

Attributes

Source: Quotes.scala

Symbol of the definition that encloses the current splicing context.

For example, the following call to spliceOwner would return the symbol x.

val x = ${ ... Symbol.spliceOwner ... }

For a macro splice, it is the symbol of the definition where the macro expansion happens.

Attributes

Source: Quotes.scala

Experimental methods

A fresh name for class or member symbol names.

Fresh names are constructed using the following format prefix + "$macro$" + freshIndex. The freshIndex are unique within the current source file.

Examples: See scala.annotation.MacroAnnotation

Value parameters

prefix: Prefix of the fresh name

Attributes

Experimental: true
Source: Quotes.scala

Generate a new type symbol for a type bounds with the given parent, name and type

This symbol starts without an accompanying definition. It is the meta-programmer's responsibility to provide exactly one corresponding definition by passing this symbol to the TypeDef constructor.

Value parameters

flags: extra flags to with which symbol can be constructed. Deferred flag will be added. Can be Private | Protected | Override | Deferred | Final | Infix | Local
name: The name of the type
parent: The owner of the type
privateWithin: the symbol within which this new type symbol should be private. May be noSymbol.
tpe: The bounds of the type

Attributes

Note: As a macro can only splice code into the point at which it is expanded, all generated symbols must be direct or indirect children of the reflection context's owner.
Experimental: true
Source: Quotes.scala

Generates a new class symbol for a class with a public parameterless constructor. For more settings, look to the other newClass methods.

Example usage:

val name: String = "myClass"
val parents = List(TypeTree.of[Object], TypeTree.of[Foo])
def decls(cls: Symbol): List[Symbol] =
  List(Symbol.newMethod(cls, "foo", MethodType(Nil)(_ => Nil, _ => TypeRepr.of[Unit])))

val cls = Symbol.newClass(Symbol.spliceOwner, name, parents = parents.map(_.tpe), decls, selfType = None)
val fooSym = cls.declaredMethod("foo").head

val fooDef = DefDef(fooSym, argss => Some('{println(s"Calling foo")}.asTerm))
val clsDef = ClassDef(cls, parents, body = List(fooDef))
val newCls = Typed(Apply(Select(New(TypeIdent(cls)), cls.primaryConstructor), Nil), TypeTree.of[Foo])

Block(List(clsDef), newCls).asExprOf[Foo]

constructs the equivalent to

'{
  class myClass() extends Object with Foo {
    def foo(): Unit = println("Calling foo")
  }
  new myClass(): Foo
}

Value parameters

decls: The member declarations of the class provided the symbol of this class
name: The name of the class
owner: The owner of the class
parents: The parent classes of the class. The first parent must not be a trait.
selfType: The self type of the class if it has one This symbol starts without an accompanying definition. It is the meta-programmer's responsibility to provide exactly one corresponding definition by passing this symbol to the ClassDef constructor.

Attributes

Note: As a macro can only splice code into the point at which it is expanded, all generated symbols must be direct or indirect children of the reflection context's owner.
Experimental: true
Source: Quotes.scala

Generates a new class symbol for a class with a public single term clause constructor.

Example usage:

val name = "myClass"
def decls(cls: Symbol): List[Symbol] =
  List(Symbol.newMethod(cls, "foo", MethodType(Nil)(_ => Nil, _ => TypeRepr.of[Unit])))
val parents = List(TypeTree.of[Object])
val cls = Symbol.newClass(
  Symbol.spliceOwner,
  name,
  parents = _ => parents.map(_.tpe),
  decls,
  selfType = None,
  clsFlags = Flags.EmptyFlags,
  Symbol.noSymbol,
  List(("idx", TypeRepr.of[Int]), ("str", TypeRepr.of[String]))
)

val fooSym = cls.declaredMethod("foo").head
val idxSym = cls.fieldMember("idx")
val strSym = cls.fieldMember("str")
val fooDef = DefDef(fooSym, argss =>
  Some('{println(s"Foo method call with (${${Ref(idxSym).asExpr}}, ${${Ref(strSym).asExpr}})")}.asTerm)
)
val clsDef = ClassDef(cls, parents, body = List(fooDef))
val newCls = Apply(Select(New(TypeIdent(cls)), cls.primaryConstructor), List('{0}.asTerm, '{string}.asTerm))

Block(List(clsDef), Apply(Select(newCls, cls.methodMember("foo")(0)), Nil)).asExprOf[Unit]

construct the equivalent to

'{
  class myClass(idx: Int, str: String) extends Object {
    def foo() =
      println(s"Foo method call with $idx, $str")
  }
  new myClass(0, "string").foo()
}

Value parameters

clsFlags: extra flags with which the class symbol should be constructed.
clsPrivateWithin: the symbol within which this new class symbol should be private. May be noSymbol.
conParams: constructor parameter pairs of names and types. Parameters assigned by the constructor can be obtained via classSymbol.memberField. This symbol starts without an accompanying definition. It is the meta-programmer's responsibility to provide exactly one corresponding definition by passing this symbol to the ClassDef constructor.
name: The name of the class
owner: The owner of the class
parents: Function returning the parent classes of the class. The first parent must not be a trait. Takes the constructed class symbol as an argument. Calling cls.typeRef.asType as part of this function will lead to cyclic reference errors.

Attributes

Note: As a macro can only splice code into the point at which it is expanded, all generated symbols must be direct or indirect children of the reflection context's owner.
Experimental: true
Source: Quotes.scala

Generates a new class symbol with a constructor of the shape signified by a passed PolyOrMethod parameter.

Example usage:

val name = "myClass"
def decls(cls: Symbol): List[Symbol] =
  List(Symbol.newMethod(cls, "getParam", MethodType(Nil)(_ => Nil, _ => cls.typeMember("T").typeRef)))
val conMethodType =
  (classType: TypeRepr) => PolyType(List("T"))(_ => List(TypeBounds.empty), polyType =>
    MethodType(List("param"))((_: MethodType) => List(polyType.param(0)), (_: MethodType) =>
      AppliedType(classType, List(polyType.param(0)))
    )
  )
val cls = Symbol.newClass(
  Symbol.spliceOwner,
  name,
  parents = _ => List(TypeRepr.of[Object]),
  decls,
  selfType = None,
  clsFlags = Flags.EmptyFlags,
  clsPrivateWithin = Symbol.noSymbol,
  clsAnnotations = Nil,
  conMethodType,
  conFlags = Flags.EmptyFlags,
  conPrivateWithin = Symbol.noSymbol,
  conParamFlags = List(List(Flags.EmptyFlags), List(Flags.EmptyFlags)),
  conParamPrivateWithins = List(List(Symbol.noSymbol), List(Symbol.noSymbol))
)

val getParamSym = cls.declaredMethod("getParam").head
def getParamRhs(): Option[Term] =
  val paramValue = This(cls).select(cls.fieldMember("param")).asExpr
  Some('{ println("Calling getParam"); $paramValue }.asTerm)
val getParamDef = DefDef(getParamSym, _ => getParamRhs())

val clsDef = ClassDef(cls, List(TypeTree.of[Object]), body = List(getParamDef))
val newCls =
  Apply(
    Select(
      Apply(
        TypeApply(Select(New(TypeIdent(cls)), cls.primaryConstructor), List(TypeTree.of[String])),
        List(Expr("test").asTerm)
      ),
      cls.methodMember("getParam").head
    ),
    Nil
  )

Block(List(clsDef), newCls).asExpr

constructs the equivalent to

'{
  class myClass[T](val param: T) extends Object {
    def getParam: T =
      println("Calling getParam")
      param
  }
  new myClass[String]("test").getParam()
}

Value parameters

clsAnnotations: annotations of the class
clsFlags: extra flags with which the class symbol should be constructed. Can be Private | Protected | PrivateLocal | Local | Final | Trait | Abstract | Open
clsPrivateWithin: the symbol within which this new class symbol should be private. May be noSymbol
conFlags: extra flags with which the constructor symbol should be constructed. Can be Synthetic | Method | Private | Protected | PrivateLocal | Local
conMethodType: Function returning MethodOrPoly type representing the type of the constructor. Takes the result type as parameter which must be returned from the innermost MethodOrPoly and have type parameters applied if those are used. PolyType may only represent the first clause of the constructor.
conParamFlags: extra flags with which the constructor parameter symbols should be constructed. Must match the shape of conMethodType. For type parameters those can be Param | Deferred | Private | PrivateLocal | Local. For term parameters those can be ParamAccessor | Private | Protected | PrivateLocal | Local
conParamPrivateWithins: the symbols within which the constructor parameters should be private. Must match the shape of conMethodType. Can consist of noSymbol. Term and type parameters assigned by the constructor can be obtained via classSymbol.memberField/classSymbol.memberType. This symbol starts without an accompanying definition. It is the meta-programmer's responsibility to provide exactly one corresponding definition by passing this symbol to the ClassDef constructor.
conPrivateWithin: the symbol within which the constructor for this new class symbol should be private. May be noSymbol.
decls: The member declarations of the class provided the symbol of this class
name: The name of the class
owner: The owner of the class
parents: Function returning the parent classes of the class. The first parent must not be a trait Takes the constructed class symbol as an argument. Calling cls.typeRef.asType as part of this function will lead to cyclic reference errors.
selfType: The self type of the class if it has one

Attributes

Note: As a macro can only splice code into the point at which it is expanded, all generated symbols must be direct or indirect children of the reflection context's owner.
Experimental: true
Source: Quotes.scala

Generates a new module symbol with an associated module class symbol, this is equivalent to an object declaration in source code. This method returns the module symbol. The module class can be accessed calling moduleClass on this symbol.

Example usage:

given Quotes = ???
import quotes.reflect.*
val moduleName: String = Symbol.freshName("MyModule")
val parents = List(TypeTree.of[Object])
def decls(cls: Symbol): List[Symbol] =
  List(Symbol.newMethod(cls, "run", MethodType(Nil)(_ => Nil, _ => TypeRepr.of[Unit]), Flags.EmptyFlags, Symbol.noSymbol))

val mod = Symbol.newModule(Symbol.spliceOwner, moduleName, Flags.EmptyFlags, Flags.EmptyFlags, _ => parents.map(_.tpe), decls, Symbol.noSymbol)
val cls = mod.moduleClass
val runSym = cls.declaredMethod("run").head

val runDef = DefDef(runSym, _ => Some('{ println("run") }.asTerm))
val modDef = ClassDef.module(mod, parents, body = List(runDef))

val callRun = Apply(Select(Ref(mod), runSym), Nil)

Block(modDef.toList, callRun)

constructs the equivalent to

given Quotes = ???
import quotes.reflect.*
'{
  object MyModule$macro$1 extends Object:
    def run(): Unit = println("run")
  MyModule$macro$1.run()
}

Value parameters

clsFlags: extra flags with which the module class symbol should be constructed
decls: A function that takes the symbol of the module class as input and return the symbols of its declared members
modFlags: extra flags with which the module symbol should be constructed
name: The name of the class
parent: The owner of the class
parents: A function that takes the symbol of the module class as input and returns the parent classes of the class. The first parent must not be a trait.
privateWithin: the symbol within which this new method symbol should be private. May be noSymbol. This symbol starts without an accompanying definition. It is the meta-programmer's responsibility to provide exactly one corresponding definition by passing this symbol to ClassDef.module.

Attributes

Note: As a macro can only splice code into the point at which it is expanded, all generated symbols must be direct or indirect children of the reflection context's owner.
Experimental: true
Source: Quotes.scala

Generate a new type symbol for a type alias with the given parent, name and type

This symbol starts without an accompanying definition. It is the meta-programmer's responsibility to provide exactly one corresponding definition by passing this symbol to the TypeDef constructor.

Value parameters

flags: extra flags to with which symbol can be constructed. Can be Private | Protected | Override | Final | Infix | Local
name: The name of the type
parent: The owner of the type
privateWithin: the symbol within which this new type symbol should be private. May be noSymbol.
tpe: The rhs the type alias

Attributes

Note: As a macro can only splice code into the point at which it is expanded, all generated symbols must be direct or indirect children of the reflection context's owner.
Experimental: true
Source: Quotes.scala

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