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/Scala 2.13 Reflection

Trait scala.reflect.macros.Enclosures

trait Enclosures extends AnyRef

EXPERIMENTAL

A slice of the Scala macros context that exposes enclosing trees (method, class, compilation unit and currently compiled macro application), the enclosing position of the macro expansion, as well as macros and implicits that are currently in-flight.

Starting from Scala 2.11.0, the APIs to get the trees enclosing by the current macro application are deprecated, and the reasons for that are two-fold. Firstly, we would like to move towards the philosophy of locally-expanded macros, as it has proven to be important for understanding of code. Secondly, within the current architecture of scalac, we are unable to have c.enclosingTree-style APIs working robustly. Required changes to the typechecker would greatly exceed the effort that we would like to expend on this feature given the existence of more pressing concerns at the moment. This is somewhat aligned with the overall evolution of macros during the 2.11 development cycle, where we played with c.introduceTopLevel and c.introduceMember, but at the end of the day decided to reject them.

If you're relying on the now deprecated APIs, consider using the new c.internal.enclosingOwner method that can be used to obtain the names of enclosing definitions. Alternatively try reformulating your macros in terms of completely local expansion and/or joining a discussion of a somewhat related potential language feature at https://groups.google.com/forum/#!topic/scala-debate/f4CLmYShX6Q. We also welcome questions and suggestions on our mailing lists, where we would be happy to further discuss this matter.

Self Type
blackbox.Context
Source
Enclosures.scala
Linear Supertypes
AnyRef, Any
Known Subclasses
Context, Context

Abstract Value Members

abstract def enclosingMacros: List[blackbox.Context]

Contexts that represent macros in-flight, including the current one. Very much like a stack trace, but for macros only. Can be useful for interoperating with other macros and for imposing compiler-friendly limits on macro expansion.

Is also priceless for emitting sane error messages for macros that are called by other macros on synthetic (i.e. position-less) trees. In that dire case navigate the enclosingMacros stack, and it will most likely contain at least one macro with a position-ful macro application. See enclosingPosition for a default implementation of this logic.

Unlike openMacros, this is a val, which means that it gets initialized when the context is created and always stays the same regardless of whatever happens during macro expansion.

abstract def enclosingPosition: blackbox.Context.Position

Tries to guess a position for the enclosing application. But that is simple, right? Just dereference pos of macroApplication? Not really. If we're in a synthetic macro expansion (no positions), we must do our best to infer the position of something that triggered this expansion. Surprisingly, quite often we can do this by navigation the enclosingMacros stack.

abstract def macroApplication: blackbox.Context.Tree

The tree that undergoes macro expansion. Can be useful to get an offset or a range position of the entire tree being processed.

abstract def enclosingClass: blackbox.Context.Tree

Tree that corresponds to the enclosing class, or EmptyTree if not applicable.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

See also

scala.reflect.macros.Enclosures

abstract def enclosingDef: Universe.DefDef

Tree that corresponds to the enclosing DefDef tree. Throws EnclosureException if there's no such enclosing tree.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

See also

scala.reflect.macros.Enclosures

abstract def enclosingImpl: Universe.ImplDef

Tree that corresponds to the enclosing ImplDef tree (i.e. either ClassDef or ModuleDef). Throws EnclosureException if there's no such enclosing tree.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

See also

scala.reflect.macros.Enclosures

abstract def enclosingMethod: blackbox.Context.Tree

Tree that corresponds to the enclosing method, or EmptyTree if not applicable.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

See also

scala.reflect.macros.Enclosures

abstract def enclosingPackage: Universe.PackageDef

Tree that corresponds to the enclosing PackageDef tree. Throws EnclosureException if there's no such enclosing tree.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

See also

scala.reflect.macros.Enclosures

abstract def enclosingRun: blackbox.Context.Run

Compilation run that contains this macro application.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

See also

scala.reflect.macros.Enclosures

abstract def enclosingTemplate: Universe.Template

Tree that corresponds to the enclosing Template tree. Throws EnclosureException if there's no such enclosing tree.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

See also

scala.reflect.macros.Enclosures

abstract def enclosingUnit: blackbox.Context.CompilationUnit

Compilation unit that contains this macro application.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

See also

scala.reflect.macros.Enclosures

Concrete Value Members

final def !=(arg0: Any): Boolean

Definition Classes
AnyRef → Any

final def ##(): Int

Definition Classes
AnyRef → Any

def +(other: String): String

Implicit
This member is added by an implicit conversion from Enclosures toany2stringadd[Enclosures] performed by method any2stringadd in scala.Predef.
Definition Classes
any2stringadd

def ->[B](y: B): (Enclosures, B)

Implicit
This member is added by an implicit conversion from Enclosures toArrowAssoc[Enclosures] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc
Annotations
@inline()

final def ==(arg0: Any): Boolean

Definition Classes
AnyRef → Any

final def asInstanceOf[T0]: T0

Definition Classes
Any

def clone(): AnyRef

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.CloneNotSupportedException]) @native()

def ensuring(cond: (Enclosures) => Boolean, msg: => Any): Enclosures

Implicit
This member is added by an implicit conversion from Enclosures toEnsuring[Enclosures] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: (Enclosures) => Boolean): Enclosures

Implicit
This member is added by an implicit conversion from Enclosures toEnsuring[Enclosures] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: Boolean, msg: => Any): Enclosures

Implicit
This member is added by an implicit conversion from Enclosures toEnsuring[Enclosures] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: Boolean): Enclosures

Implicit
This member is added by an implicit conversion from Enclosures toEnsuring[Enclosures] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef

def equals(arg0: AnyRef): Boolean

Definition Classes
AnyRef → Any

def finalize(): Unit

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

def formatted(fmtstr: String): String

Implicit
This member is added by an implicit conversion from Enclosures toStringFormat[Enclosures] performed by method StringFormat in scala.Predef.
Definition Classes
StringFormat
Annotations
@inline()

final def getClass(): Class[_ <: AnyRef]

Definition Classes
AnyRef → Any
Annotations
@native()

def hashCode(): Int

Definition Classes
AnyRef → Any
Annotations
@native()

final def isInstanceOf[T0]: Boolean

Definition Classes
Any

final def ne(arg0: AnyRef): Boolean

Definition Classes
AnyRef

final def notify(): Unit

Definition Classes
AnyRef
Annotations
@native()

final def notifyAll(): Unit

Definition Classes
AnyRef
Annotations
@native()

final def synchronized[T0](arg0: => T0): T0

Definition Classes
AnyRef

def toString(): String

Definition Classes
AnyRef → Any

final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.InterruptedException])

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

Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.InterruptedException])

final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.InterruptedException]) @native()

© 2002-2019 EPFL, with contributions from Lightbend.
Licensed under the Apache License, Version 2.0.
https://www.scala-lang.org/api/2.13.0/scala-reflect/scala/reflect/macros/Enclosures.html