Scala Reflection Library2.13.15 < Back
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# Packages

-  package root
  Definition Classes
    root
-  package scala
  Definition Classes
    root
-  package reflect
  Definition Classes
    scala
-  package api

  EXPERIMENTAL

  EXPERIMENTAL

  The Scala Reflection API (located in scala-reflect.jar).

  In Scala 2.10.0, the Scala Reflection API and its implementation have an "experimental" status. This means that the API and the docs are not complete and can be changed in binary- and source-incompatible manner in 2.10.1. This also means that the implementation has some known issues.

  The following types are the backbone of the Scala Reflection API, and serve as a good starting point for information about Scala Reflection:

  - scala.reflect.api.Symbols
  - scala.reflect.api.Types
  - scala.reflect.api.Mirrors
  - scala.reflect.api.Universe

  For more information about Scala Reflection, see the Reflection Guide

  Definition Classes
    reflect
-  trait Symbols extends AnyRef

  EXPERIMENTAL

  EXPERIMENTAL

  This trait defines symbols and operations on them.

  Symbols are used to establish bindings between a name and the entity it refers to, such as a class or a method. Anything you define and can give a name to in Scala has an associated symbol.

  Symbols contain all available information about the declaration of an entity (class/object/trait etc.) or a member (vals/vars/defs etc.), and as such are an integral abstraction central to both runtime reflection and macros.

  A symbol can provide a wealth of information ranging from the basic `name` method available on all symbols to other, more involved, concepts such as getting the `baseClasses` from `ClassSymbol`. Other common use cases of symbols include inspecting members' signatures, getting type parameters of a class, getting the parameter type of a method or finding out the type of a field.

  Example usage of runtime reflection; getting a method's type signature:

      scala> import scala.reflect.runtime.universe._
      import scala.reflect.runtime.universe._

      scala> class C[T] { def test[U](x: T)(y: U): Int = ??? }
      defined class C

      scala> val test = typeOf[C[Int]].member(TermName("test")).asMethod
      test: reflect.runtime.universe.MethodSymbol = method test

      scala> test.info
      res0: reflect.runtime.universe.Type = [U](x: T)(y: U)scala.Int

  Symbols are organized in a hierarchy. For example, a symbol that represents a parameter of a method is owned by the corresponding method symbol, a method symbol is owned by its enclosing class, a class is owned by a containing package and so on.

  Certain types of tree nodes, such as Ident (references to identifiers) and Select (references to members) expose method `symbol` to obtain the symbol that represents their declaration. During the typechecking phase, the compiler looks up the symbol based on the name and scope and sets the `symbol` field of tree nodes.

  For more information about `Symbol` usage and attached intricacies, see the Reflection Guide: Symbols

  Definition Classes
    api
- ClassSymbol
- ClassSymbolApi
- MethodSymbol
- MethodSymbolApi
- ModuleSymbol
- ModuleSymbolApi
- Symbol
- SymbolApi
- TermSymbol
- TermSymbolApi
- TypeSymbol
- TypeSymbolApi

a

scala.reflect.api.Symbols

# Symbol

###

#### abstract type Symbol >: Null <: Universe.SymbolApi

The type of symbols representing declarations.

Source
  Symbols.scala

Linear Supertypes
Universe.SymbolApi, AnyRef, Any
Known Subclasses
FreeTermSymbol, FreeTypeSymbol, ClassSymbol, MethodSymbol, ModuleSymbol, TermSymbol, TypeSymbol

Ordering

1. Grouped
2. Alphabetic
3. By Inheritance

Inherited

1. Symbol
2. SymbolApi
3. AnyRef
4. Any

1. Hide All
2. Show All

Visibility

1. Public
2. Protected

### Type Members

1.  abstract type NameType >: Null <: Universe.Name

   The type of the symbol name.

   The type of the symbol name. Can be either `TermName` or `TypeName` depending on whether this is a `TermSymbol` or a `TypeSymbol`.

   Type name namespaces do not intersect with term name namespaces. This fact is reflected in different types for names of `TermSymbol` and `TypeSymbol`.

   Definition Classes
     SymbolApi

### Abstract Value Members

1.  abstract def alternatives: List[Universe.Symbol]

   The overloaded alternatives of this symbol.

   The overloaded alternatives of this symbol.

   Definition Classes
     SymbolApi
2.  abstract def annotations: List[Universe.Annotation]

   A list of annotations attached to this Symbol.

   A list of annotations attached to this Symbol.

   Definition Classes
     SymbolApi
3.  abstract def companion: Universe.Symbol

   For a class: its companion object if exists.

   For a class: its companion object if exists. For a module or a module class: companion class of the module if exists. For a package or a package class: NoSymbol. For all others: NoSymbol.

   Definition Classes
     SymbolApi
4.  abstract def filter(cond: (Universe.Symbol) => Boolean): Universe.Symbol

   Filters the underlying alternatives (or a single-element list composed of the symbol itself if the symbol is not overloaded).

   Filters the underlying alternatives (or a single-element list composed of the symbol itself if the symbol is not overloaded). Returns an overloaded symbol is there are multiple matches. Returns a NoSymbol if there are no matches.

   Definition Classes
     SymbolApi
5.  abstract def fullName: String

   The encoded full path name of this symbol, where outer names and inner names are separated by periods.

   The encoded full path name of this symbol, where outer names and inner names are separated by periods.

   Definition Classes
     SymbolApi
6.  abstract def info: Universe.Type

   The type signature of this symbol.

   The type signature of this symbol.

   This method always returns signatures in the most generic way possible, even if the underlying symbol is obtained from an instantiation of a generic type. For example, signature of the method `def map[B](f: (A) => B): List[B]`, which refers to the type parameter `A` of the declaring class `List[A]`, will always feature `A`, regardless of whether `map` is loaded from the `List[_]` or from `List[Int]`. To get a signature with type parameters appropriately instantiated, one should use `infoIn`.

   Definition Classes
     SymbolApi
7.  abstract def infoIn(site: Universe.Type): Universe.Type

   The type signature of this symbol seen as a member of given type `site`.

   The type signature of this symbol seen as a member of given type `site`.

   Definition Classes
     SymbolApi
8.  abstract def isAbstract: Boolean

   Is this symbol abstract (i.e.

   Is this symbol abstract (i.e. an abstract class, an abstract method, value or type member)?

   Definition Classes
     SymbolApi
9.  abstract def isAbstractOverride: Boolean

   Is this symbol labelled as "abstract override"?

   Is this symbol labelled as "abstract override"?

   Definition Classes
     SymbolApi
10.  abstract def isConstructor: Boolean

    Does this method represent a constructor?

    Does this method represent a constructor?

    If `owner` is a class, then this is a vanilla JVM constructor. If `owner` is a trait, then this is a mixin constructor.

    Definition Classes
      SymbolApi
11.  abstract def isFinal: Boolean

    Is this symbol final?

    Is this symbol final?

    Definition Classes
      SymbolApi
12.  abstract def isImplementationArtifact: Boolean

    Does this symbol represent an implementation artifact that isn't meant for public use? Examples of such artifacts are erasure bridges and outer fields.

    Does this symbol represent an implementation artifact that isn't meant for public use? Examples of such artifacts are erasure bridges and outer fields.

    Definition Classes
      SymbolApi
13.  abstract def isImplicit: Boolean

    Does this symbol represent an implicit value, definition, class or parameter?

    Does this symbol represent an implicit value, definition, class or parameter?

    Definition Classes
      SymbolApi
14.  abstract def isJava: Boolean

    Is this symbol defined by Java?

    Is this symbol defined by Java?

    Definition Classes
      SymbolApi
15.  abstract def isJavaAnnotation: Boolean

    Does this symbol represent a java annotation interface?

    Does this symbol represent a java annotation interface?

    Definition Classes
      SymbolApi
16.  abstract def isJavaEnum: Boolean

    Does this symbol represent a java enum class or a java enum value?

    Does this symbol represent a java enum class or a java enum value?

    Definition Classes
      SymbolApi
17.  abstract def isMacro: Boolean

    Is this symbol a macro?

    Is this symbol a macro?

    Definition Classes
      SymbolApi
18.  abstract def isPackage: Boolean

    Does this symbol represent the definition of a package? Known issues: https://github.com/scala/bug/issues/6732.

    Does this symbol represent the definition of a package? Known issues: https://github.com/scala/bug/issues/6732.

    Definition Classes
      SymbolApi
19.  abstract def isPackageClass: Boolean

    Does this symbol represent a package class? If yes, `isClass` is also guaranteed to be true.

    Does this symbol represent a package class? If yes, `isClass` is also guaranteed to be true.

    Definition Classes
      SymbolApi
20.  abstract def isParameter: Boolean

    Is this symbol a parameter (either a method parameter or a type parameter)?

    Is this symbol a parameter (either a method parameter or a type parameter)?

    Definition Classes
      SymbolApi
21.  abstract def isPrivate: Boolean

    Does this symbol represent a private declaration or definition? If yes, `privateWithin` might tell more about this symbol's visibility scope.

    Does this symbol represent a private declaration or definition? If yes, `privateWithin` might tell more about this symbol's visibility scope.

    Definition Classes
      SymbolApi
22.  abstract def isPrivateThis: Boolean

    Does this symbol represent a declaration or definition written in a source file as `private[this]` or generated in tree/symbol form with the combination of flags LOCAL and PRIVATE? If yes, `isPrivate` is guaranteed to be true.

    Does this symbol represent a declaration or definition written in a source file as `private[this]` or generated in tree/symbol form with the combination of flags LOCAL and PRIVATE? If yes, `isPrivate` is guaranteed to be true.

    Definition Classes
      SymbolApi
23.  abstract def isProtected: Boolean

    Does this symbol represent a protected declaration or definition? If yes, `privateWithin` might tell more about this symbol's visibility scope.

    Does this symbol represent a protected declaration or definition? If yes, `privateWithin` might tell more about this symbol's visibility scope.

    Definition Classes
      SymbolApi
24.  abstract def isProtectedThis: Boolean

    Does this symbol represent a declaration or definition written in a source file as `protected[this]` or generated in tree/symbol form with the combination of flags LOCAL and PROTECTED? If yes, `isProtected` is guaranteed to be true,

    Does this symbol represent a declaration or definition written in a source file as `protected[this]` or generated in tree/symbol form with the combination of flags LOCAL and PROTECTED? If yes, `isProtected` is guaranteed to be true,

    Definition Classes
      SymbolApi
25.  abstract def isPublic: Boolean

    Does this symbol represent a public declaration or definition?

    Does this symbol represent a public declaration or definition?

    Definition Classes
      SymbolApi
26.  abstract def isSpecialized: Boolean

    Is this symbol a specialized type parameter or a generated specialized member?

    Is this symbol a specialized type parameter or a generated specialized member?

    Definition Classes
      SymbolApi
27.  abstract def isStatic: Boolean

    Is this symbol static (i.e.

    Is this symbol static (i.e. with no outer instance)? Q: When exactly is a sym marked as STATIC? A: If it's a member of a toplevel object, or of an object contained in a toplevel object, or any number of levels deep. https://groups.google.com/group/scala-internals/browse_thread/thread/d385bcd60b08faf6

    Definition Classes
      SymbolApi
28.  abstract def isSynthetic: Boolean

    Does this symbol represent a synthetic (i.e.

    Does this symbol represent a synthetic (i.e. a compiler-generated) entity? Examples of synthetic entities are accessors for vals and vars.

    Definition Classes
      SymbolApi
29.  abstract def map(f: (Universe.Symbol) => Universe.Symbol): Universe.Symbol

    If this is a NoSymbol, returns NoSymbol, otherwise returns the result of applying `f` to this symbol.

    If this is a NoSymbol, returns NoSymbol, otherwise returns the result of applying `f` to this symbol.

    Definition Classes
      SymbolApi
30.  abstract def name: NameType

    The name of the symbol as a member of the `Name` type.

    The name of the symbol as a member of the `Name` type.

    Definition Classes
      SymbolApi
31.  abstract def orElse(alt: => Universe.Symbol): Universe.Symbol

    Provides an alternate if symbol is a NoSymbol.

    Provides an alternate if symbol is a NoSymbol.

    Definition Classes
      SymbolApi
32.  abstract def overrides: List[Universe.Symbol]

    Returns all symbols overridden by this symbol.

    Returns all symbols overridden by this symbol.

    Definition Classes
      SymbolApi
33.  abstract def owner: Universe.Symbol

    The owner of this symbol.

    The owner of this symbol. This is the symbol that directly contains the current symbol's definition. The `NoSymbol` symbol does not have an owner, and calling this method on one causes an internal error. The owner of the Scala root class scala.reflect.api.Mirror.RootClass and the Scala root object scala.reflect.api.Mirror.RootPackage is `NoSymbol`. Every other symbol has a chain of owners that ends in scala.reflect.api.Mirror.RootClass.

    Definition Classes
      SymbolApi
34.  abstract def pos: Universe.Position

    Position of the tree.

    Position of the tree.

    Definition Classes
      SymbolApi
35.  abstract def privateWithin: Universe.Symbol

    Set when symbol has a modifier of the form private[X] or protected[X], NoSymbol otherwise.

    Set when symbol has a modifier of the form private[X] or protected[X], NoSymbol otherwise.

    Access level encoding: there are three scala flags (PRIVATE, PROTECTED, and LOCAL) which combine with value privateWithin (the "foo" in private[foo]) to define from where an entity can be accessed. The meanings are as follows:

    PRIVATE access restricted to class only. PROTECTED access restricted to class and subclasses only. LOCAL can only be set in conjunction with PRIVATE or PROTECTED. Further restricts access to the same object instance.

    In addition, privateWithin can be used to set a visibility barrier. When set, everything contained in the named enclosing package or class has access. It is incompatible with PRIVATE or LOCAL, but is additive with PROTECTED (i.e. if either the flags or privateWithin allow access, then it is allowed.)

    The java access levels translate as follows:

    java private: isPrivate && (privateWithin == NoSymbol) java package: !isPrivate && !isProtected && (privateWithin == enclosingPackage) java protected: isProtected && (privateWithin == enclosingPackage) java public: !isPrivate && !isProtected && (privateWithin == NoSymbol)

    Definition Classes
      SymbolApi
36.  abstract def suchThat(cond: (Universe.Symbol) => Boolean): Universe.Symbol

    Does the same as `filter`, but crashes if there are multiple matches.

    Does the same as `filter`, but crashes if there are multiple matches.

    Definition Classes
      SymbolApi
37.  abstract def typeSignature: Universe.Type

    Definition Classes
      SymbolApi
    See also

      info

38.  abstract def typeSignatureIn(site: Universe.Type): Universe.Type

    Definition Classes
      SymbolApi
    See also

      infoIn

39.  abstract def allOverriddenSymbols: List[Universe.Symbol]

    Definition Classes
      SymbolApi
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) use `overrides` instead

    See also

      overrides

40.  abstract def associatedFile: AbstractFile

    Source file if this symbol is created during this compilation run, or a class file if this symbol is loaded from a *.class or *.jar.

    Source file if this symbol is created during this compilation run, or a class file if this symbol is loaded from a *.class or *.jar.

    The return type is `scala.reflect.io.AbstractFile`, which belongs to an experimental part of Scala reflection. It should not be used unless you know what you are doing. In subsequent releases, this API will be refined and exposed as a part of scala.reflect.api.

    Definition Classes
      SymbolApi
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) use `pos.source.file` instead

41.  abstract def companionSymbol: Universe.Symbol

    For a class: the module or case class factory with the same name in the same package.

    For a class: the module or case class factory with the same name in the same package. For a module: the class with the same name in the same package. For all others: NoSymbol.

    This API may return unexpected results for module classes, packages and package classes. Use `companion` instead in order to get predictable results.

    Definition Classes
      SymbolApi
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) use `companion` instead, but beware of possible changes in behavior

### Concrete Value Members

1.  final def !=(arg0: Any): Boolean
   Definition Classes
     AnyRef → Any
2.  final def ##: Int
   Definition Classes
     AnyRef → Any
3.  final def ==(arg0: Any): Boolean
   Definition Classes
     AnyRef → Any
4.  def asClass: Universe.ClassSymbol

   This symbol cast to a ClassSymbol representing a class or trait.

   This symbol cast to a ClassSymbol representing a class or trait.

   Definition Classes
     SymbolApi
   Exceptions thrown

     `ScalaReflectionException` if `isClass` is false.

5.  final def asInstanceOf[T0]: T0
   Definition Classes
     Any
6.  def asMethod: Universe.MethodSymbol

   This symbol cast to a MethodSymbol.

   This symbol cast to a MethodSymbol.

   Definition Classes
     SymbolApi
   Exceptions thrown

     `ScalaReflectionException` if `isMethod` is false.

7.  def asModule: Universe.ModuleSymbol

   This symbol cast to a ModuleSymbol defined by an object definition.

   This symbol cast to a ModuleSymbol defined by an object definition.

   Definition Classes
     SymbolApi
   Exceptions thrown

     `ScalaReflectionException` if `isModule` is false.

8.  def asTerm: Universe.TermSymbol

   This symbol cast to a TermSymbol.

   This symbol cast to a TermSymbol.

   Definition Classes
     SymbolApi
   Exceptions thrown

     `ScalaReflectionException` if `isTerm` is false.

9.  def asType: Universe.TypeSymbol

   This symbol cast to a TypeSymbol.

   This symbol cast to a TypeSymbol.

   Definition Classes
     SymbolApi
   Exceptions thrown

     `ScalaReflectionException` if `isType` is false.

10.  def clone(): AnyRef
    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.CloneNotSupportedException]) @native()
11.  final def eq(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
12.  def equals(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef → Any
13.  def finalize(): Unit
    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.Throwable])
14.  final def getClass(): Class[_ <: AnyRef]
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
15.  def hashCode(): Int
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
16.  def isClass: Boolean

    Does this symbol represent the definition of a class or trait? If yes, `isType` is also guaranteed to be true.

    Does this symbol represent the definition of a class or trait? If yes, `isType` is also guaranteed to be true.

    Definition Classes
      SymbolApi
17.  final def isInstanceOf[T0]: Boolean
    Definition Classes
      Any
18.  def isMethod: Boolean

    Does this symbol represent the definition of a method? If yes, `isTerm` is also guaranteed to be true.

    Does this symbol represent the definition of a method? If yes, `isTerm` is also guaranteed to be true.

    Definition Classes
      SymbolApi
19.  def isModule: Boolean

    Does this symbol represent the definition of a module (i.e.

    Does this symbol represent the definition of a module (i.e. it results from an object definition?). If yes, `isTerm` is also guaranteed to be true.

    Definition Classes
      SymbolApi
20.  def isModuleClass: Boolean

    Does this symbol represent the definition of a class implicitly associated with an object definition (module class in scala compiler parlance)? If yes, `isType` is also guaranteed to be true.

    Does this symbol represent the definition of a class implicitly associated with an object definition (module class in scala compiler parlance)? If yes, `isType` is also guaranteed to be true.

    Definition Classes
      SymbolApi
21.  def isOverloadedMethod: Boolean

    Used to provide a better error message for `asMethod`.

    Used to provide a better error message for `asMethod`.

    Attributes
      protected
    Definition Classes
      SymbolApi
22.  def isTerm: Boolean

    Does this symbol represent the definition of a term? Note that every symbol is either a term or a type.

    Does this symbol represent the definition of a term? Note that every symbol is either a term or a type. So for every symbol `sym` (except for `NoSymbol`), either `sym.isTerm` is true or `sym.isType` is true.

    Definition Classes
      SymbolApi
23.  def isType: Boolean

    Does this symbol represent the definition of a type? Note that every symbol is either a term or a type.

    Does this symbol represent the definition of a type? Note that every symbol is either a term or a type. So for every symbol `sym` (except for `NoSymbol`), either `sym.isTerm` is true or `sym.isType` is true.

    Definition Classes
      SymbolApi
24.  final def ne(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
25.  final def notify(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
26.  final def notifyAll(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
27.  final def synchronized[T0](arg0: => T0): T0
    Definition Classes
      AnyRef
28.  def toString(): String
    Definition Classes
      AnyRef → Any
29.  final def wait(): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.InterruptedException])
30.  final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.InterruptedException])
31.  final def wait(arg0: Long): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.InterruptedException]) @native()

### Inherited from Universe.SymbolApi

### Inherited from AnyRef

### Inherited from Any

### Method Symbol Members

### Symbol Basic Information

### Symbol Type Tests

### Symbol Conversions

### Iteration Helpers

These methods enable collections-like operations on symbols.

### Ungrouped