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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Type Members
-
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
Test two objects for inequality.
Test two objects for inequality.
- returns
true
if !(this == that), false otherwise.
- Definition Classes
- AnyRef → Any
-
final
def
##(): Int
Equivalent to
x.hashCode
except for boxed numeric types andnull
.Equivalent to
x.hashCode
except for boxed numeric types andnull
. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. Fornull
returns a hashcode wherenull.hashCode
throws aNullPointerException
.- returns
a hash value consistent with ==
- Definition Classes
- AnyRef → Any
- def +(other: String): String
- def ->[B](y: B): (Internals, B)
-
final
def
==(arg0: Any): Boolean
The expression
x == that
is equivalent toif (x eq null) that eq null else x.equals(that)
.The expression
x == that
is equivalent toif (x eq null) that eq null else x.equals(that)
.- returns
true
if the receiver object is equivalent to the argument;false
otherwise.
- Definition Classes
- AnyRef → Any
-
final
def
asInstanceOf[T0]: T0
Cast the receiver object to be of type
T0
.Cast the receiver object to be of type
T0
.Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression
1.asInstanceOf[String]
will throw aClassCastException
at runtime, while the expressionList(1).asInstanceOf[List[String]]
will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.- returns
the receiver object.
- Definition Classes
- Any
- Exceptions thrown
ClassCastException
if the receiver object is not an instance of the erasure of typeT0
.
-
def
clone(): AnyRef
Create a copy of the receiver object.
Create a copy of the receiver object.
The default implementation of the
clone
method is platform dependent.- returns
a copy of the receiver object.
- Attributes
- protected[java.lang]
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
- Note
not specified by SLS as a member of AnyRef
- 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
Tests whether the argument (
that
) is a reference to the receiver object (this
).Tests whether the argument (
that
) is a reference to the receiver object (this
).The
eq
method implements an equivalence relation on non-null instances ofAnyRef
, and has three additional properties:- It is consistent: for any non-null instances
x
andy
of typeAnyRef
, multiple invocations ofx.eq(y)
consistently returnstrue
or consistently returnsfalse
. - For any non-null instance
x
of typeAnyRef
,x.eq(null)
andnull.eq(x)
returnsfalse
. null.eq(null)
returnstrue
.
When overriding the
equals
orhashCode
methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2
), they should be equal to each other (o1 == o2
) and they should hash to the same value (o1.hashCode == o2.hashCode
).- returns
true
if the argument is a reference to the receiver object;false
otherwise.
- Definition Classes
- AnyRef
- It is consistent: for any non-null instances
-
def
equals(arg0: Any): Boolean
The equality method for reference types.
-
def
finalize(): Unit
Called by the garbage collector on the receiver object when there are no more references to the object.
Called by the garbage collector on the receiver object when there are no more references to the object.
The details of when and if the
finalize
method is invoked, as well as the interaction betweenfinalize
and non-local returns and exceptions, are all platform dependent.- Attributes
- protected[java.lang]
- Definition Classes
- AnyRef
- Annotations
- @throws( classOf[java.lang.Throwable] )
- Note
not specified by SLS as a member of AnyRef
- def formatted(fmtstr: String): String
-
final
def
getClass(): Class[_]
Returns the runtime class representation of the object.
Returns the runtime class representation of the object.
- returns
a class object corresponding to the runtime type of the receiver.
- Definition Classes
- AnyRef → Any
-
def
hashCode(): Int
The hashCode method for reference types.
-
final
def
isInstanceOf[T0]: Boolean
Test whether the dynamic type of the receiver object is
T0
.Test whether the dynamic type of the receiver object is
T0
.Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression
1.isInstanceOf[String]
will returnfalse
, while the expressionList(1).isInstanceOf[List[String]]
will returntrue
. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.- returns
true
if the receiver object is an instance of erasure of typeT0
;false
otherwise.
- Definition Classes
- Any
-
final
def
ne(arg0: AnyRef): Boolean
Equivalent to
!(this eq that)
.Equivalent to
!(this eq that)
.- returns
true
if the argument is not a reference to the receiver object;false
otherwise.
- Definition Classes
- AnyRef
-
final
def
notify(): Unit
Wakes up a single thread that is waiting on the receiver object's monitor.
Wakes up a single thread that is waiting on the receiver object's monitor.
- Definition Classes
- AnyRef
- Note
not specified by SLS as a member of AnyRef
-
final
def
notifyAll(): Unit
Wakes up all threads that are waiting on the receiver object's monitor.
Wakes up all threads that are waiting on the receiver object's monitor.
- Definition Classes
- AnyRef
- Note
not specified by SLS as a member of AnyRef
-
final
def
synchronized[T0](arg0: ⇒ T0): T0
- Definition Classes
- AnyRef
-
def
toString(): String
Creates a String representation of this object.
Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.
- returns
a String representation of the object.
- Definition Classes
- AnyRef → Any
-
final
def
wait(): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
-
final
def
wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
-
final
def
wait(arg0: Long): Unit
- Definition Classes
- AnyRef
- Annotations
- @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