Scala Reflection Library 2.13.16 - scala.reflect.api.Types.ExistentialTypeExtractor
Keywords: Scala Reflection Library 2.13.16 scala.reflect.api.Types.ExistentialTypeExtractor

Scala Reflection Library2.13.16 < 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 Types extends AnyRef

  EXPERIMENTAL

  EXPERIMENTAL

  A trait that defines types and operations on them.

  Type instances represent information about the type of a corresponding symbol. This includes its members (methods, fields, type parameters, nested classes, traits, etc.) either declared directly or inherited, its base types, its erasure and so on. Types also provide operations to test for type conformance or equivalence or for widening.

  To instantiate a type, most of the time, the scala.reflect.api.TypeTags#typeOf method can be used. It takes a type argument and produces a `Type` instance which represents that argument. For example:

      scala> typeOf[List[Int]]
      res0: reflect.runtime.universe.Type = scala.List[Int]

  In this example, a scala.reflect.api.Types#TypeRef is returned, which corresponds to the type constructor `List` applied to the type argument `Int`.

  In the case of a generic type, you can also combine it with other types using scala.reflect.api.Types#appliedType. For example:

      scala> val intType = typeOf[Int]
      intType: reflect.runtime.universe.Type = Int

      scala> val listType = typeOf[List[_]]
      listType: reflect.runtime.universe.Type = List[_]

      scala> appliedType(listType.typeConstructor, intType)
      res0: reflect.runtime.universe.Type = List[Int]

  Note: Method `typeOf` does not work for types with type parameters, such as `typeOf[List[A]]` where `A` is a type parameter. In this case, use scala.reflect.api.TypeTags#weakTypeOf instead.

  For other ways to instantiate types, see the corresponding section of the Reflection Guide.

  ##### Common Operations on Types

  Types are typically used for type conformance tests or are queried for declarations of members or inner types.

  - Subtyping Relationships can be tested using `<:<` and `weak_<:<`.
  - Type Equality can be checked with `=:=`. It's important to note that `==` should not be used to compare types for equality-- `==` can't check for type equality in the presence of type aliases, while `=:=` can.

  Types can be queried for members and declarations by using the `members` and `declarations` methods (along with their singular counterparts `member` and `declaration`), which provide the list of definitions associated with that type. For example, to look up the `map` method of `List`, one can do:

      scala> typeOf[List[_]].member(TermName("map"))
      res1: reflect.runtime.universe.Symbol = method map

  For more information about `Type`s, see the Reflection Guide: Symbols, Trees, and Types

  Definition Classes
    api
- AnnotatedType
- AnnotatedTypeApi
- AnnotatedTypeExtractor
- BoundedWildcardType
- BoundedWildcardTypeApi
- BoundedWildcardTypeExtractor
- ClassInfoType
- ClassInfoTypeApi
- ClassInfoTypeExtractor
- CompoundType
- CompoundTypeApi
- ConstantType
- ConstantTypeApi
- ConstantTypeExtractor
- ExistentialType
- ExistentialTypeApi
- ExistentialTypeExtractor
- MethodType
- MethodTypeApi
- MethodTypeExtractor
- NullaryMethodType
- NullaryMethodTypeApi
- NullaryMethodTypeExtractor
- PolyType
- PolyTypeApi
- PolyTypeExtractor
- RefinedType
- RefinedTypeApi
- RefinedTypeExtractor
- SingleType
- SingleTypeApi
- SingleTypeExtractor
- SingletonType
- SingletonTypeApi
- SuperType
- SuperTypeApi
- SuperTypeExtractor
- ThisType
- ThisTypeApi
- ThisTypeExtractor
- Type
- TypeApi
- TypeBounds
- TypeBoundsApi
- TypeBoundsExtractor
- TypeRef
- TypeRefApi
- TypeRefExtractor

c

scala.reflect.api.Types

# ExistentialTypeExtractor

###

#### abstract class ExistentialTypeExtractor extends AnyRef

An extractor class to create and pattern match with syntax `ExistentialType(quantified, underlying)`. Here, `quantified` are the type variables bound by the existential type and `underlying` is the type that's existentially quantified.

Source
  Types.scala

Linear Supertypes
AnyRef, Any
Type Hierarchy

Ordering

1. Alphabetic
2. By Inheritance

Inherited

1. ExistentialTypeExtractor
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. Protected

### Instance Constructors

1.  new ExistentialTypeExtractor()

### Abstract Value Members

1.  abstract def unapply(tpe: Universe.ExistentialType): Option[(List[Universe.Symbol], Universe.Type)]

### 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 Universe.ExistentialTypeExtractor toany2stringadd[Universe.ExistentialTypeExtractor] performed by method any2stringadd in scala.Predef.
   Definition Classes
     any2stringadd
4.  def ->[B](y: B): (Universe.ExistentialTypeExtractor, B)
   Implicit
     This member is added by an implicit conversion from Universe.ExistentialTypeExtractor toArrowAssoc[Universe.ExistentialTypeExtractor] 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[lang]
   Definition Classes
     AnyRef
   Annotations
     @throws(classOf[java.lang.CloneNotSupportedException]) @native()
8.  def ensuring(cond: (Universe.ExistentialTypeExtractor) => Boolean, msg: => Any): Universe.ExistentialTypeExtractor
   Implicit
     This member is added by an implicit conversion from Universe.ExistentialTypeExtractor toEnsuring[Universe.ExistentialTypeExtractor] performed by method Ensuring in scala.Predef.
   Definition Classes
     Ensuring
9.  def ensuring(cond: (Universe.ExistentialTypeExtractor) => Boolean): Universe.ExistentialTypeExtractor
   Implicit
     This member is added by an implicit conversion from Universe.ExistentialTypeExtractor toEnsuring[Universe.ExistentialTypeExtractor] performed by method Ensuring in scala.Predef.
   Definition Classes
     Ensuring
10.  def ensuring(cond: Boolean, msg: => Any): Universe.ExistentialTypeExtractor
    Implicit
      This member is added by an implicit conversion from Universe.ExistentialTypeExtractor toEnsuring[Universe.ExistentialTypeExtractor] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
11.  def ensuring(cond: Boolean): Universe.ExistentialTypeExtractor
    Implicit
      This member is added by an implicit conversion from Universe.ExistentialTypeExtractor toEnsuring[Universe.ExistentialTypeExtractor] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
12.  final def eq(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
13.  def equals(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef → Any
14.  def finalize(): Unit
    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.Throwable])
15.  final def getClass(): Class[_ <: AnyRef]
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
16.  def hashCode(): Int
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
17.  final def isInstanceOf[T0]: Boolean
    Definition Classes
      Any
18.  final def ne(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
19.  final def notify(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
20.  final def notifyAll(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
21.  final def synchronized[T0](arg0: => T0): T0
    Definition Classes
      AnyRef
22.  def toString(): String
    Definition Classes
      AnyRef → Any
23.  final def wait(): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.InterruptedException])
24.  final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.InterruptedException])
25.  final def wait(arg0: Long): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.InterruptedException]) @native()

### Deprecated Value Members

1.  def apply(quantified: List[Universe.Symbol], underlying: Universe.Type)(implicit token: Universe.CompatToken): Universe.ExistentialType

   Annotations
     @deprecated
   Deprecated

     (Since version 2.11.0) use `internal.existentialType` instead

   See also

     Internals.InternalApi.existentialType

2.  def formatted(fmtstr: String): String
   Implicit
     This member is added by an implicit conversion from Universe.ExistentialTypeExtractor toStringFormat[Universe.ExistentialTypeExtractor] performed by method StringFormat in scala.Predef.
   Definition Classes
     StringFormat
   Annotations
     @deprecated @inline()
   Deprecated

     (Since version 2.12.16) Use `formatString.format(value)` instead of `value.formatted(formatString)`, or use the `f""` string interpolator. In Java 15 and later, `formatted` resolves to the new method in String which has reversed parameters.

3.  def →[B](y: B): (Universe.ExistentialTypeExtractor, B)
   Implicit
     This member is added by an implicit conversion from Universe.ExistentialTypeExtractor toArrowAssoc[Universe.ExistentialTypeExtractor] performed by method ArrowAssoc in scala.Predef.
   Definition Classes
     ArrowAssoc
   Annotations
     @deprecated
   Deprecated

     (Since version 2.13.0) Use `->` instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.

### Inherited from AnyRef

### Inherited from Any

### Inherited by implicit conversion any2stringadd fromUniverse.ExistentialTypeExtractor to any2stringadd[Universe.ExistentialTypeExtractor]

### Inherited by implicit conversion StringFormat fromUniverse.ExistentialTypeExtractor to StringFormat[Universe.ExistentialTypeExtractor]

### Inherited by implicit conversion Ensuring fromUniverse.ExistentialTypeExtractor to Ensuring[Universe.ExistentialTypeExtractor]

### Inherited by implicit conversion ArrowAssoc fromUniverse.ExistentialTypeExtractor to ArrowAssoc[Universe.ExistentialTypeExtractor]

### Ungrouped