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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abstract
type
Compat <: Universe.CompatApi
- See also
-
trait
CompatApi extends AnyRef
- See also
-
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( ... )
-
abstract
type
FreeTermSymbol >: Null <: Universe.FreeTermSymbolApi with Universe.TermSymbol
The type of free terms introduced by reification.
-
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
-
abstract
type
FreeTypeSymbol >: Null <: Universe.FreeTypeSymbolApi with Universe.TypeSymbol
The type of free types introduced by reification.
-
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
-
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 macroUniverse
or a runtime reflectionUniverse
), but sometimes there is a need to migrate artifacts from oneUniverse
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
Universe
s, which is reflected by the fact that types of artifacts from different universes are not compatible. By usingImporter
s, however, they be imported from one universe into another. For example, to importfoo.bar.Baz
from the sourceUniverse
to the targetUniverse
, an importer will first check whether the entire owner chain exists in the targetUniverse
. 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 targetUniverse
.Since importers match
Symbol
tables of the source and the targetUniverse
s using plain string names, it is programmer's responsibility to make sure that imports don't distort semantics, e.g., thatfoo.bar.Baz
in the sourceUniverse
means the same thatfoo.bar.Baz
does in the targetUniverse
.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] ... }
-
abstract
type
Internal <: Universe.InternalApi
- See also
-
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) providesuniverse.compat: InternalApi
, whereas compile-time API endpoints (instances of scala.reflect.macros.Context) providec.compat: ContextInternalApi
, which extendsInternalApi
with additional universe-specific and context-specific functionality. -
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.
-
trait
ReferenceToBoxedApi extends Universe.TermTreeApi
The API that all references support
-
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 throughelem
.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. -
trait
ReificationSupportApi extends AnyRef
This is an internal implementation class.
-
type
BuildApi = Universe.ReificationSupportApi
- Annotations
- @deprecated
- Deprecated
(Since version 2.11.0) use
internal.ReificationSupportApi
instead
Abstract Value Members
-
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. -
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. -
abstract
val
ReferenceToBoxed: Universe.ReferenceToBoxedExtractor
The constructor/extractor for
ReferenceToBoxed
instances. -
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. -
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. -
abstract
val
internal: Universe.Internal
- See also
-
abstract
val
build: Universe.ReificationSupportApi
- Annotations
- @deprecated
- Deprecated
(Since version 2.11.0) use
internal.reificationSupport
instead
Concrete Value Members
-
final
def
!=(arg0: Any): Boolean
- Definition Classes
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-
final
def
##(): Int
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- def +(other: String): String
- def ->[B](y: B): (Internals, B)
-
final
def
==(arg0: Any): Boolean
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final
def
asInstanceOf[T0]: T0
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def
clone(): AnyRef
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- @native() @throws( ... )
- def ensuring(cond: (Internals) ⇒ Boolean, msg: ⇒ Any): Internals
- def ensuring(cond: (Internals) ⇒ Boolean): Internals
- def ensuring(cond: Boolean, msg: ⇒ Any): Internals
- def ensuring(cond: Boolean): Internals
-
final
def
eq(arg0: AnyRef): Boolean
- Definition Classes
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-
def
equals(arg0: Any): Boolean
- Definition Classes
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-
def
finalize(): Unit
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- protected[java.lang]
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- @throws( classOf[java.lang.Throwable] )
- def formatted(fmtstr: String): String
-
final
def
getClass(): Class[_]
- Definition Classes
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-
def
hashCode(): Int
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final
def
isInstanceOf[T0]: Boolean
- Definition Classes
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-
final
def
ne(arg0: AnyRef): Boolean
- Definition Classes
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final
def
notify(): Unit
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final
def
notifyAll(): Unit
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final
def
synchronized[T0](arg0: ⇒ T0): T0
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def
toString(): String
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final
def
wait(): Unit
- Definition Classes
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- @throws( ... )
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final
def
wait(arg0: Long, arg1: Int): Unit
- Definition Classes
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- @throws( ... )
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final
def
wait(arg0: Long): Unit
- Definition Classes
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- @native() @throws( ... )
- def →[B](y: B): (Internals, B)
Deprecated Value Members
-
def
mkImporter(from0: Universe): Universe.Importer { val from: from0.type }
- Annotations
- @deprecated
- Deprecated
(Since version 2.11.0) use
internal.createImporter
instead