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scala.reflect.api

Internals

trait Internals extends AnyRef

EXPERIMENTAL

This trait assembles APIs occasionally necessary for performing low-level operations on reflection artifacts. See Internals#InternalApi for more information about nature, usefulness and compatibility guarantees of these APIs.

Self Type
Universe
Source
Internals.scala
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  1. Internals
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Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Visibility
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Type Members

  1. abstract type FreeTermSymbol >: Null <: Universe.FreeTermSymbolApi with Universe.TermSymbol

    The type of free terms introduced by reification.

  2. trait FreeTermSymbolApi extends Universe.TermSymbolApi

    The API of free term symbols.

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

    $SYMACCESSORS

  3. abstract type FreeTypeSymbol >: Null <: Universe.FreeTypeSymbolApi with Universe.TypeSymbol

    The type of free types introduced by reification.

  4. trait FreeTypeSymbolApi extends Universe.TypeSymbolApi

    The API of free type symbols.

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

    $SYMACCESSORS

  5. trait Importer extends AnyRef

    This trait provides support for importers, a facility to migrate reflection artifacts between universes.

    This trait provides support for importers, a facility to migrate reflection artifacts between universes. Note: this trait should typically be used only rarely.

    Reflection artifacts, such as Symbols and Types, are contained in Universes. Typically all processing happens within a single Universe (e.g. a compile-time macro Universe or a runtime reflection Universe), but sometimes there is a need to migrate artifacts from one Universe to another. For example, runtime compilation works by importing runtime reflection trees into a runtime compiler universe, compiling the importees and exporting the result back.

    Reflection artifacts are firmly grounded in their Universes, which is reflected by the fact that types of artifacts from different universes are not compatible. By using Importers, however, they be imported from one universe into another. For example, to import foo.bar.Baz from the source Universe to the target Universe, an importer will first check whether the entire owner chain exists in the target Universe. If it does, then nothing else will be done. Otherwise, the importer will recreate the entire owner chain and will import the corresponding type signatures into the target Universe.

    Since importers match Symbol tables of the source and the target Universes using plain string names, it is programmer's responsibility to make sure that imports don't distort semantics, e.g., that foo.bar.Baz in the source Universe means the same that foo.bar.Baz does in the target Universe.

    Example

    Here's how one might implement a macro that performs compile-time evaluation of its argument by using a runtime compiler to compile and evaluate a tree that belongs to a compile-time compiler:

    def staticEval[T](x: T) = macro staticEval[T]
    
    def staticEval[T](c: scala.reflect.macros.blackbox.Context)(x: c.Expr[T]) = {
      // creates a runtime reflection universe to host runtime compilation
      import scala.reflect.runtime.{universe => ru}
      val mirror = ru.runtimeMirror(c.libraryClassLoader)
      import scala.tools.reflect.ToolBox
      val toolBox = mirror.mkToolBox()
    
      // runtime reflection universe and compile-time macro universe are different
      // therefore an importer is needed to bridge them
      // currently mkImporter requires a cast to correctly assign the path-dependent types
      val importer0 = ru.internal.mkImporter(c.universe)
      val importer = importer0.asInstanceOf[ru.internal.Importer { val from: c.universe.type }]
    
      // the created importer is used to turn a compiler tree into a runtime compiler tree
      // both compilers use the same classpath, so semantics remains intact
      val imported = importer.importTree(tree)
    
      // after the tree is imported, it can be evaluated as usual
      val tree = toolBox.untypecheck(imported.duplicate)
      val valueOfX = toolBox.eval(imported).asInstanceOf[T]
      ...
    }
  6. abstract type Internal <: Universe.InternalApi

    See also

    InternalApi

  7. trait InternalApi extends AnyRef

    Reflection API exhibits a tension inherent to experimental things: on the one hand we want it to grow into a beautiful and robust API, but on the other hand we have to deal with immaturity of underlying mechanisms by providing not very pretty solutions to enable important use cases.

    Reflection API exhibits a tension inherent to experimental things: on the one hand we want it to grow into a beautiful and robust API, but on the other hand we have to deal with immaturity of underlying mechanisms by providing not very pretty solutions to enable important use cases.

    In Scala 2.10, which was our first stab at reflection API, we didn't have a systematic approach to dealing with this tension, sometimes exposing too much of internals (e.g. Symbol.deSkolemize) and sometimes exposing too little (e.g. there's still no facility to change owners, to do typing transformations, etc). This resulted in certain confusion with some internal APIs living among public ones, scaring the newcomers, and some internal APIs only available via casting, which requires intimate knowledge of the compiler and breaks compatibility guarantees.

    This led to creation of the internal API module for the reflection API, which provides advanced APIs necessary for macros that push boundaries of the state of the art, clearly demarcating them from the more or less straightforward rest and providing compatibility guarantees on par with the rest of the reflection API (full compatibility within minor releases, best effort towards backward compatibility within major releases, clear replacement path in case of rare incompatible changes in major releases).

    The internal module itself (the value that implements InternalApi) isn't defined here, in scala.reflect.api.Universe, but is provided on per-implementation basis. Runtime API endpoint (scala.reflect.runtime.universe) provides universe.compat: InternalApi, whereas compile-time API endpoints (instances of scala.reflect.macros.Context) provide c.compat: ContextInternalApi, which extends InternalApi with additional universe-specific and context-specific functionality.

  8. abstract type ReferenceToBoxed >: Null <: Universe.ReferenceToBoxedApi with Universe.TermTree

    Marks underlying reference to id as boxed.

    Marks underlying reference to id as boxed.

    Precondition:<\b> id must refer to a captured variable A reference such marked will refer to the boxed entity, no dereferencing with `.elem` is done on it. This tree node can be emitted by macros such as reify that call referenceCapturedVariable. It is eliminated in LambdaLift, where the boxing conversion takes place.

  9. trait ReferenceToBoxedApi extends Universe.TermTreeApi

    The API that all references support

  10. abstract class ReferenceToBoxedExtractor extends AnyRef

    An extractor class to create and pattern match with syntax ReferenceToBoxed(ident).

    An extractor class to create and pattern match with syntax ReferenceToBoxed(ident). This AST node does not have direct correspondence to Scala code, and is emitted by macros to reference capture vars directly without going through elem.

    For example:

    var x = ... fun { x }

    Will emit:

    Ident(x)

    Which gets transformed to:

    Select(Ident(x), "elem")

    If ReferenceToBoxed were used instead of Ident, no transformation would be performed.

  11. trait ReificationSupportApi extends AnyRef

    This is an internal implementation class.

Deprecated Type Members

  1. abstract type Compat <: Universe.CompatApi

    Annotations
    @deprecated
    Deprecated

    (Since version 2.13.0) compatibility with Scala 2.10 EOL

    See also

    compat

  2. trait CompatApi extends AnyRef

    Annotations
    @deprecated
    Deprecated

    (Since version 2.13.0) compatibility with Scala 2.10 EOL

    See also

    compat

  3. class CompatToken extends AnyRef

    Presence of an implicit value of this type in scope indicates that source compatibility with Scala 2.10 has been enabled.

    Presence of an implicit value of this type in scope indicates that source compatibility with Scala 2.10 has been enabled.

    Annotations
    @implicitNotFound("This method has been removed from the public API. Import compat._ or migrate away.") @deprecated
    Deprecated

    (Since version 2.13.0) compatibility with Scala 2.10 EOL

Abstract Value Members

  1. implicit abstract val FreeTermSymbolTag: ClassTag[Universe.FreeTermSymbol]

    Tag that preserves the identity of FreeTermSymbol in the face of erasure.

    Tag that preserves the identity of FreeTermSymbol in the face of erasure. Can be used for pattern matching, instance tests, serialization and the like.

  2. implicit abstract val FreeTypeSymbolTag: ClassTag[Universe.FreeTypeSymbol]

    Tag that preserves the identity of FreeTermSymbol in the face of erasure.

    Tag that preserves the identity of FreeTermSymbol in the face of erasure. Can be used for pattern matching, instance tests, serialization and the like.

  3. abstract val ReferenceToBoxed: Universe.ReferenceToBoxedExtractor

    The constructor/extractor for ReferenceToBoxed instances.

  4. implicit abstract val ReferenceToBoxedTag: ClassTag[Universe.ReferenceToBoxed]

    Tag that preserves the identity of ReferenceToBoxed in the face of erasure.

    Tag that preserves the identity of ReferenceToBoxed in the face of erasure. Can be used for pattern matching, instance tests, serialization and the like.

  5. abstract val internal: Universe.Internal

    See also

    InternalApi

  6. abstract val compat: Universe.Compat

    Provides enrichments to ensure source compatibility between Scala 2.10 and Scala 2.11.

    Provides enrichments to ensure source compatibility between Scala 2.10 and Scala 2.11. If in your reflective program for Scala 2.10 you've used something that's now become an internal API, a single compat._ import will fix things for you.

    Annotations
    @deprecated
    Deprecated

    (Since version 2.13.0) compatibility with Scala 2.10 EOL

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 Internals toany2stringadd[Internals] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (Internals, B)
    Implicit
    This member is added by an implicit conversion from Internals toArrowAssoc[Internals] 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: (Internals) => Boolean, msg: => Any): Internals
    Implicit
    This member is added by an implicit conversion from Internals toEnsuring[Internals] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  9. def ensuring(cond: (Internals) => Boolean): Internals
    Implicit
    This member is added by an implicit conversion from Internals toEnsuring[Internals] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  10. def ensuring(cond: Boolean, msg: => Any): Internals
    Implicit
    This member is added by an implicit conversion from Internals toEnsuring[Internals] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  11. def ensuring(cond: Boolean): Internals
    Implicit
    This member is added by an implicit conversion from Internals toEnsuring[Internals] 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. def formatted(fmtstr: String): String
    Implicit
    This member is added by an implicit conversion from Internals toStringFormat[Internals] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  16. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  17. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  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
    Annotations
    @native()
  21. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  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(classOf[java.lang.InterruptedException])
  25. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  26. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()

Deprecated Value Members

  1. def mkImporter(from0: Universe): Universe.Importer { val from: from0.type }
    Annotations
    @deprecated
    Deprecated

    (Since version 2.11.0) use internal.createImporter instead

  2. def [B](y: B): (Internals, B)
    Implicit
    This member is added by an implicit conversion from Internals toArrowAssoc[Internals] 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 fromInternals to any2stringadd[Internals]

Inherited by implicit conversion StringFormat fromInternals to StringFormat[Internals]

Inherited by implicit conversion Ensuring fromInternals to Ensuring[Internals]

Inherited by implicit conversion ArrowAssoc fromInternals to ArrowAssoc[Internals]

Internal

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