Scala Reflection Library2.12.2-20170504-135222-21d12e9 < 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
- Annotations
- Constants
- Exprs
- FlagSets
- ImplicitTags
- Internals
- JavaUniverse
- Liftables
- Mirror
- Mirrors
- Names
- Position
- Positions
- Printers
- Quasiquotes
- Scopes
- StandardDefinitions
- StandardLiftables
- StandardNames
- Symbols
- TreeCreator
- Trees
- TypeCreator
- TypeTags
- Types
- Universe

t

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(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

Self Type
  Universe
Source
  Symbols.scala

Linear Supertypes
AnyRef, Any
Known Subclasses
JavaUniverse, Universe, Universe
Type Hierarchy
Content Hierarchy
 
Ordering

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

1. Hide All
2. Show All

Visibility

1. Public
2. All

### 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
     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
     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
     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
     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
      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
      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
      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
      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