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 Types, 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

scala.reflect.api.Types

NullaryMethodTypeExtractor