Trait/Object

izumi.reflect

Tag

Related Docs: object Tag | package reflect

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trait Tag[T] extends AnyTag

Like scala.reflect.api.TypeTags.TypeTag, but supports higher-kinded type tags via TagK type class.

In context of DI this lets you define modules parameterized by higher-kinded type parameters. This is especially helpful for applying tagless final style

Example:

import distage.ModuleDef

class MyModule[F[_]: Monad: TagK] extends ModuleDef {
  make[MyService[F]]
  make[F[Int]].named("lucky-number").from(Monad[F].pure(7))
}

Without a TagK constraint above, this example would fail with no TypeTag available for MyService[F] error

Currently some limitations apply as to when a Tag will be correctly constructed: * Type Parameters do not yet resolve inside structural refinements, e.g. T in 

Tag[{ def x: T}]

* TagK* does not resolve for constructors with bounded parameters, e.g. S in 

class Abc[S <: String]; TagK[Abc]

(You can still have a bound in partial application: e.g. 

class Abc[S <: String, A]; TagK[Abc["hi", ?]]

* Further details at https://github.com/7mind/izumi/issues/374

Annotations
@implicitNotFound( ... )
See also

izumi.reflect.macrortti.LTag.Weak - summoner for izumi.reflect.macrortti.LightTypeTag that does not resolve type parameters and allows unresolved ("weak") type parameters to be part of a tag

izumi.reflect.macrortti.LTag - summoner for izumi.reflect.macrortti.LightTypeTag that does not resolve type parameters

"Lightweight Scala Reflection and why Dotty needs TypeTags reimplemented" https://blog.7mind.io/lightweight-reflection.html

Linear Supertypes
AnyTag, AnyRef, Any
Ordering
  1. Alphabetic
  2. By Inheritance
Inherited
  1. Tag
  2. AnyTag
  3. AnyRef
  4. Any
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Visibility
  1. Public
  2. All

Abstract Value Members

  1. abstract def closestClass: Class[_]

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    Closest class found for the type or for a LUB of all intersection members in case of an intersection type.

    Closest class found for the type or for a LUB of all intersection members in case of an intersection type.

    A Scala type may not have an associated JVM class, as such this class may not be sufficient to create instances of T

    Only if tag.hasPreciseClass returns true it may be safe to reflect on closestClass

    Definition Classes
    Tag → AnyTag

  2. abstract def tag: LightTypeTag

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    Definition Classes
    Tag → AnyTag

Concrete Value Members

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

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    Definition Classes
    AnyRef → Any

  2. final def ##(): Int

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    Definition Classes
    AnyRef → Any

  3. final def ==(arg0: Any): Boolean

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    Definition Classes
    AnyRef → Any

  4. final def asInstanceOf[T0]: T0

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    Definition Classes
    Any

  5. def clone(): AnyRef

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

  6. final def eq(arg0: AnyRef): Boolean

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    Definition Classes
    AnyRef

  7. final def equals(that: Any): Boolean

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    Definition Classes
    AnyTag → AnyRef → Any

  8. final def getClass(): Class[_]

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    Definition Classes
    AnyRef → Any
    Annotations
    @HotSpotIntrinsicCandidate()

  9. final def hasPreciseClass: Boolean

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    Definition Classes
    AnyTag

  10. final def hashCode(): Int

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    Definition Classes
    AnyTag → AnyRef → Any

  11. final def isInstanceOf[T0]: Boolean

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    Definition Classes
    Any

  12. final def ne(arg0: AnyRef): Boolean

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    Definition Classes
    AnyRef

  13. final def notify(): Unit

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    Definition Classes
    AnyRef
    Annotations
    @HotSpotIntrinsicCandidate()

  14. final def notifyAll(): Unit

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    Definition Classes
    AnyRef
    Annotations
    @HotSpotIntrinsicCandidate()

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

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    Definition Classes
    AnyRef

  16. final def toString(): String

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    Definition Classes
    Tag → AnyRef → Any

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

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    Definition Classes
    AnyRef
    Annotations
    @throws( ... )

  18. final def wait(arg0: Long): Unit

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    Definition Classes
    AnyRef
    Annotations
    @throws( ... )

  19. final def wait(): Unit

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    Definition Classes
    AnyRef
    Annotations
    @throws( ... )

Deprecated Value Members

  1. def finalize(): Unit

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

    (Since version ) see corresponding Javadoc for more information.

Inherited from AnyTag

Inherited from AnyRef

Inherited from Any

Ungrouped