scala.reflect.api

# Symbols

#### trait Symbols extends AnyRef

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(newTermName("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

Self Type
  Universe
Source
  Symbols.scala

Linear Supertypes
AnyRef, Any
Known Subclasses
JavaUniverse, Universe, Universe
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1. Grouped
2. Alphabetic
3. By inheritance

Inherited

1. Symbols
2. AnyRef
3. Any

Implicitly

1. by any2stringadd
2. by StringFormat
3. by Ensuring
4. by ArrowAssoc

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1. Public
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### Type Members

1. #### abstract type ClassSymbol >: Null <: Universe.ClassSymbolApi with Universe.TypeSymbol

   The type of class symbols representing class and trait definitions.

2. #### trait ClassSymbolApi extends Universe.TypeSymbolApi

   The API of class symbols.

   The API of class symbols. The main source of information about symbols is the Symbols page.

   Class Symbol defines `isXXX` test methods such as `isPublic` or `isFinal`, `params` and `returnType` methods for method symbols, `baseClasses` for class symbols and so on. Some of these methods don't make sense for certain subclasses of `Symbol` and return `NoSymbol`, `Nil` or other empty values.

3. #### abstract type MethodSymbol >: Null <: Universe.MethodSymbolApi with Universe.TermSymbol

   The type of method symbols representing def declarations.

4. #### trait MethodSymbolApi extends Universe.TermSymbolApi

   The API of method symbols.

   The API of method symbols. The main source of information about symbols is the Symbols page.

   Class Symbol defines `isXXX` test methods such as `isPublic` or `isFinal`, `params` and `returnType` methods for method symbols, `baseClasses` for class symbols and so on. Some of these methods don't make sense for certain subclasses of `Symbol` and return `NoSymbol`, `Nil` or other empty values.

5. #### abstract type ModuleSymbol >: Null <: Universe.ModuleSymbolApi with Universe.TermSymbol

   The type of module symbols representing object declarations.

6. #### trait ModuleSymbolApi extends Universe.TermSymbolApi

   The API of module symbols.

   The API of module symbols. The main source of information about symbols is the Symbols page.

   Class Symbol defines `isXXX` test methods such as `isPublic` or `isFinal`, `params` and `returnType` methods for method symbols, `baseClasses` for class symbols and so on. Some of these methods don't make sense for certain subclasses of `Symbol` and return `NoSymbol`, `Nil` or other empty values.

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

   The type of symbols representing declarations.

8. #### trait SymbolApi extends AnyRef

   The API of symbols.

   The API of symbols. The main source of information about symbols is the Symbols page.

   Class Symbol defines `isXXX` test methods such as `isPublic` or `isFinal`, `params` and `returnType` methods for method symbols, `baseClasses` for class symbols and so on. Some of these methods don't make sense for certain subclasses of `Symbol` and return `NoSymbol`, `Nil` or other empty values.

9. #### abstract type TermSymbol >: Null <: Universe.TermSymbolApi with Universe.Symbol

   The type of term symbols representing val, var, def, and object declarations as well as packages and value parameters.

10. #### trait TermSymbolApi extends Universe.SymbolApi

    The API of term symbols.

    The API of term symbols. The main source of information about symbols is the Symbols page.

    Class Symbol defines `isXXX` test methods such as `isPublic` or `isFinal`, `params` and `returnType` methods for method symbols, `baseClasses` for class symbols and so on. Some of these methods don't make sense for certain subclasses of `Symbol` and return `NoSymbol`, `Nil` or other empty values.

11. #### abstract type TypeSymbol >: Null <: Universe.TypeSymbolApi with Universe.Symbol

    The type of type symbols representing type, class, and trait declarations, as well as type parameters.

12. #### trait TypeSymbolApi extends Universe.SymbolApi

    The API of type symbols.

    The API of type symbols. The main source of information about symbols is the Symbols page.

    Class Symbol defines `isXXX` test methods such as `isPublic` or `isFinal`, `params` and `returnType` methods for method symbols, `baseClasses` for class symbols and so on. Some of these methods don't make sense for certain subclasses of `Symbol` and return `NoSymbol`, `Nil` or other empty values.

### Abstract Value Members

1. #### abstract val NoSymbol: Universe.Symbol

   A special "missing" symbol.

   A special "missing" symbol. Commonly used in the API to denote a default or empty value.

### Concrete Value Members

1. #### final def !=(arg0: Any): Boolean

   Definition Classes
     AnyRef → Any

2. #### final def ##(): Int

   Definition Classes
     AnyRef → Any

3. #### def +(other: String): String

   Implicit information
     This member is added by an implicit conversion from Symbols to any2stringadd[Symbols] performed by method any2stringadd in scala.Predef.
   Definition Classes
     any2stringadd

4. #### def ->[B](y: B): (Symbols, B)

   Implicit information
     This member is added by an implicit conversion from Symbols to ArrowAssoc[Symbols] performed by method ArrowAssoc in scala.Predef.
   Definition Classes
     ArrowAssoc
   Annotations
     @inline()

5. #### final def ==(arg0: Any): Boolean

   Definition Classes
     AnyRef → Any

6. #### final def asInstanceOf[T0]: T0

   Definition Classes
     Any

7. #### def clone(): AnyRef

   Attributes
     protected[java.lang]
   Definition Classes
     AnyRef
   Annotations
     @throws( ... )

8. #### def ensuring(cond: (Symbols) ⇒ Boolean, msg: ⇒ Any): Symbols

   Implicit information
     This member is added by an implicit conversion from Symbols to Ensuring[Symbols] performed by method Ensuring in scala.Predef.
   Definition Classes
     Ensuring

9. #### def ensuring(cond: (Symbols) ⇒ Boolean): Symbols

   Implicit information
     This member is added by an implicit conversion from Symbols to Ensuring[Symbols] performed by method Ensuring in scala.Predef.
   Definition Classes
     Ensuring

10. #### def ensuring(cond: Boolean, msg: ⇒ Any): Symbols

    Implicit information
      This member is added by an implicit conversion from Symbols to Ensuring[Symbols] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring

11. #### def ensuring(cond: Boolean): Symbols

    Implicit information
      This member is added by an implicit conversion from Symbols to Ensuring[Symbols] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring

12. #### final def eq(arg0: AnyRef): Boolean

    Definition Classes
      AnyRef

13. #### def equals(arg0: Any): Boolean

    Definition Classes
      AnyRef → Any

14. #### def finalize(): Unit

    Attributes
      protected[java.lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( classOf[java.lang.Throwable] )

15. #### def formatted(fmtstr: String): String

    Implicit information
      This member is added by an implicit conversion from Symbols to StringFormat[Symbols] performed by method StringFormat in scala.Predef.
    Definition Classes
      StringFormat
    Annotations
      @inline()

16. #### final def getClass(): Class[_]

    Definition Classes
      AnyRef → Any

17. #### def hashCode(): Int

    Definition Classes
      AnyRef → Any

18. #### final def isInstanceOf[T0]: Boolean

    Definition Classes
      Any

19. #### final def ne(arg0: AnyRef): Boolean

    Definition Classes
      AnyRef

20. #### final def notify(): Unit

    Definition Classes
      AnyRef

21. #### final def notifyAll(): Unit

    Definition Classes
      AnyRef

22. #### final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
      AnyRef

23. #### def toString(): String

    Definition Classes
      AnyRef → Any

24. #### final def wait(): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

25. #### final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

26. #### final def wait(arg0: Long): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

27. #### def →[B](y: B): (Symbols, B)

    Implicit information
      This member is added by an implicit conversion from Symbols to ArrowAssoc[Symbols] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
      ArrowAssoc

### Inherited from AnyRef

### Inherited from Any

### Inherited by implicit conversion any2stringadd from Symbols to any2stringadd[Symbols]

### Inherited by implicit conversion StringFormat from Symbols to StringFormat[Symbols]

### Inherited by implicit conversion Ensuring from Symbols to Ensuring[Symbols]

### Inherited by implicit conversion ArrowAssoc from Symbols to ArrowAssoc[Symbols]

### Symbols

### API

The methods available for each reflection entity, without the implementation. Since the reflection entities are later overridden by runtime reflection and macros, their API counterparts guarantee a minimum set of methods that are implemented.

### Ungrouped