Trait

scala.reflect.macros

Enclosures

Related Doc: package macros

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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
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Type Members

  1. case class EnclosureException(expected: Class[_], enclosingTrees: List[blackbox.Context.Tree]) extends Exception with Product with Serializable

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    Indicates than one of the enclosure methods failed to find a tree of required type among enclosing trees.

    Indicates than one of the enclosure methods failed to find a tree of required type among enclosing trees.

    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 Value Members

  1. abstract def enclosingMacros: List[blackbox.Context]

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    Contexts that represent macros in-flight, including the current one.

    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.

  2. abstract def enclosingPosition: blackbox.Context.Position

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    Tries to guess a position for the enclosing application.

    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.

  3. abstract def macroApplication: blackbox.Context.Tree

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    The tree that undergoes macro expansion.

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

  4. abstract def enclosingClass: blackbox.Context.Tree

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

    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

  5. abstract def enclosingDef: Universe.DefDef

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    Tree that corresponds to the enclosing DefDef tree.

    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

  6. abstract def enclosingImpl: Universe.ImplDef

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    Tree that corresponds to the enclosing ImplDef tree (i.e.

    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

  7. abstract def enclosingMethod: blackbox.Context.Tree

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

    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

  8. abstract def enclosingPackage: Universe.PackageDef

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    Tree that corresponds to the enclosing PackageDef tree.

    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

  9. abstract def enclosingRun: blackbox.Context.Run

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    Compilation run that contains this macro application.

    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

  10. abstract def enclosingTemplate: Universe.Template

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    Tree that corresponds to the enclosing Template tree.

    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

  11. abstract def enclosingUnit: blackbox.Context.CompilationUnit

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    Compilation unit that contains this macro application.

    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

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

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    Test two objects for inequality.

    Test two objects for inequality.

    returns

    true if !(this == that), false otherwise.

    Definition Classes
    AnyRef → Any
  2. final def ##(): Int

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    Equivalent to x.hashCode except for boxed numeric types and null.

    Equivalent to x.hashCode except for boxed numeric types and null. 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. For null returns a hashcode where null.hashCode throws a NullPointerException.

    returns

    a hash value consistent with ==

    Definition Classes
    AnyRef → Any
  3. def +(other: String): String

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    Implicit information
    This member is added by an implicit conversion from Enclosures to any2stringadd[Enclosures] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (Enclosures, B)

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    Implicit information
    This member is added by an implicit conversion from Enclosures to ArrowAssoc[Enclosures] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. final def ==(arg0: Any): Boolean

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    The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

    The expression x == that is equivalent to if (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
  6. final def asInstanceOf[T0]: T0

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    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 a ClassCastException at runtime, while the expression List(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 type T0.

  7. def clone(): AnyRef

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    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

  8. def ensuring(cond: (Enclosures) ⇒ Boolean, msg: ⇒ Any): Enclosures

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    Implicit information
    This member is added by an implicit conversion from Enclosures to Ensuring[Enclosures] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  9. def ensuring(cond: (Enclosures) ⇒ Boolean): Enclosures

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    Implicit information
    This member is added by an implicit conversion from Enclosures to Ensuring[Enclosures] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  10. def ensuring(cond: Boolean, msg: ⇒ Any): Enclosures

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    Implicit information
    This member is added by an implicit conversion from Enclosures to Ensuring[Enclosures] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  11. def ensuring(cond: Boolean): Enclosures

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    Implicit information
    This member is added by an implicit conversion from Enclosures to Ensuring[Enclosures] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  12. final def eq(arg0: AnyRef): Boolean

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    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 of AnyRef, and has three additional properties:

    • It is consistent: for any non-null instances x and y of type AnyRef, multiple invocations of x.eq(y) consistently returns true or consistently returns false.
    • For any non-null instance x of type AnyRef, x.eq(null) and null.eq(x) returns false.
    • null.eq(null) returns true.

    When overriding the equals or hashCode 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
  13. def equals(arg0: Any): Boolean

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    The equality method for reference types.

    The equality method for reference types. Default implementation delegates to eq.

    See also equals in scala.Any.

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    Definition Classes
    AnyRef → Any
  14. def finalize(): Unit

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    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 between finalize 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

  15. def formatted(fmtstr: String): String

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    Implicit information
    This member is added by an implicit conversion from Enclosures to StringFormat[Enclosures] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  16. final def getClass(): Class[_]

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    A representation that corresponds to the dynamic class of the receiver object.

    A representation that corresponds to the dynamic class of the receiver object.

    The nature of the representation is platform dependent.

    returns

    a representation that corresponds to the dynamic class of the receiver object.

    Definition Classes
    AnyRef → Any
    Note

    not specified by SLS as a member of AnyRef

  17. def hashCode(): Int

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    The hashCode method for reference types.

    The hashCode method for reference types. See hashCode in scala.Any.

    returns

    the hash code value for this object.

    Definition Classes
    AnyRef → Any
  18. final def isInstanceOf[T0]: Boolean

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    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 return false, while the expression List(1).isInstanceOf[List[String]] will return true. 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 type T0; false otherwise.

    Definition Classes
    Any
  19. final def ne(arg0: AnyRef): Boolean

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    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
  20. final def notify(): Unit

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    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

  21. final def notifyAll(): Unit

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    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

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

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    Definition Classes
    AnyRef
  23. def toString(): String

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    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
  24. final def wait(): Unit

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    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  25. final def wait(arg0: Long, arg1: Int): Unit

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    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  26. final def wait(arg0: Long): Unit

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    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  27. def [B](y: B): (Enclosures, B)

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

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd from Enclosures to any2stringadd[Enclosures]

Inherited by implicit conversion StringFormat from Enclosures to StringFormat[Enclosures]

Inherited by implicit conversion Ensuring from Enclosures to Ensuring[Enclosures]

Inherited by implicit conversion ArrowAssoc from Enclosures to ArrowAssoc[Enclosures]

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