Scala Reflection Library 2.13.16 - scala.reflect.macros.Attachments
Keywords: Scala Reflection Library 2.13.16 scala.reflect.macros.Attachments

Scala Reflection Library2.13.16 < Back
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# Packages

-  package root
  Definition Classes
    root
-  package scala
  Definition Classes
    root
-  package reflect
  Definition Classes
    scala
-  package macros

  EXPERIMENTAL

  EXPERIMENTAL

  The base package for Scala macros.

  Macros are functions that are called by the compiler during compilation. Within these functions the programmer has access to compiler APIs. For example, it is possible to generate, analyze and typecheck code.

  See the Macros Guide on how to get started with Scala macros.

  Definition Classes
    reflect
-  package blackbox
  Definition Classes
    macros
-  package whitebox
  Definition Classes
    macros
- Aliases
- Attachments
- Enclosures
- Evals
- ExprUtils
- FrontEnds
- Infrastructure
- Internals
- Names
- ParseException
- Parsers
- ReificationException
- Reifiers
- TypecheckException
- Typers
- UnexpectedReificationException
- Universe

c

scala.reflect.macros

# Attachments

###

#### abstract class Attachments extends AnyRef

EXPERIMENTAL

Attachments provide a way to associate custom metadata with symbols and trees.

Along with `symbol` and `tpe`, which represent core metadata of trees, each tree carries the `attachments` field that can store other metadata: compiler-defined (e.g. positions) or user-defined. Same story is true for symbols, which also have extensible metadata by the virtue of the same `attachments` field.

Typically attachments just store a scala.reflect.api.Position, but they can be extended to encompass arbitrary payloads. Payloads are stored in type-indexed slots, which can be read with `get[T]` and written with `update[T]` and `remove[T]`.

This API doesn't have much use in the runtime reflection API (the scala.reflect.api package), but it might be of help for macro writers, providing a way to coordinate multiple macros operating on the same code. Therefore the `attachments` field is only declared in trees and symbols belonging to scala.reflect.macros.Universe.

Self Type
  Attachments
Source
  Attachments.scala

Linear Supertypes
AnyRef, Any
Known Subclasses
Position
Type Hierarchy
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Ordering

1. Alphabetic
2. By Inheritance

Inherited

1. Attachments
2. AnyRef
3. Any

Implicitly

1. by any2stringadd
2. by StringFormat
3. by Ensuring
4. by ArrowAssoc

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Visibility

1. Public
2. Protected

### Instance Constructors

1.  new Attachments()

### Type Members

1.  abstract type Pos >: Null

   The position type of this attachment

### Abstract Value Members

1.  abstract def all: Set[Any]

   The underlying payload with the guarantee that no two elements have the same type.

2.  abstract def isEmpty: Boolean
3.  abstract def pos: Pos

   The underlying position

4.  abstract def withPos(newPos: Pos): Attachments { type Pos = Attachments.this.Pos }

   Creates a copy of this attachment with the position replaced by `newPos`

### 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 Attachments toany2stringadd[Attachments] performed by method any2stringadd in scala.Predef.
   Definition Classes
     any2stringadd
4.  def ->[B](y: B): (Attachments, B)
   Implicit
     This member is added by an implicit conversion from Attachments toArrowAssoc[Attachments] 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 addElement[T](attachment: T): Attachments { type Pos = Attachments.this.Pos }

   Creates a copy of this attachment with the given element added.

7.  final def asInstanceOf[T0]: T0
   Definition Classes
     Any
8.  def clone(): AnyRef
   Attributes
     protected[lang]
   Definition Classes
     AnyRef
   Annotations
     @throws(classOf[java.lang.CloneNotSupportedException]) @native()
9.  def cloneAttachments: Attachments { type Pos = Attachments.this.Pos }
10.  def contains[T](implicit arg0: ClassTag[T]): Boolean

    Check underlying payload contains an instance of type `T`.

11.  final def containsElement(element: Any): Boolean

    Tests if the given element is attached.

12.  def ensuring(cond: (Attachments) => Boolean, msg: => Any): Attachments
    Implicit
      This member is added by an implicit conversion from Attachments toEnsuring[Attachments] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
13.  def ensuring(cond: (Attachments) => Boolean): Attachments
    Implicit
      This member is added by an implicit conversion from Attachments toEnsuring[Attachments] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
14.  def ensuring(cond: Boolean, msg: => Any): Attachments
    Implicit
      This member is added by an implicit conversion from Attachments toEnsuring[Attachments] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
15.  def ensuring(cond: Boolean): Attachments
    Implicit
      This member is added by an implicit conversion from Attachments toEnsuring[Attachments] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
16.  final def eq(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
17.  def equals(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef → Any
18.  def finalize(): Unit
    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.Throwable])
19.  def get[T](implicit arg0: ClassTag[T]): Option[T]

    An underlying payload of the given class type `T`.

20.  final def getClass(): Class[_ <: AnyRef]
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
21.  def hashCode(): Int
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
22.  final def isInstanceOf[T0]: Boolean
    Definition Classes
      Any
23.  final def ne(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
24.  final def notify(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
25.  final def notifyAll(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
26.  def remove[T](implicit arg0: ClassTag[T]): Attachments { type Pos = Attachments.this.Pos }

    Creates a copy of this attachment with the payload of the given class type `T` removed.

27.  final def removeElement[T](attachment: T): Attachments { type Pos = Attachments.this.Pos }

    Creates a copy of this attachment with the given element removed.

28.  final def synchronized[T0](arg0: => T0): T0
    Definition Classes
      AnyRef
29.  def toString(): String
    Definition Classes
      AnyRef → Any
30.  def update[T](attachment: T)(implicit arg0: ClassTag[T]): Attachments { type Pos = Attachments.this.Pos }

    Creates a copy of this attachment with the payload slot of T added/updated with the provided value.

    Creates a copy of this attachment with the payload slot of T added/updated with the provided value. Replaces an existing payload of the same type, if exists.

31.  final def wait(): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.InterruptedException])
32.  final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.InterruptedException])
33.  final def wait(arg0: Long): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.InterruptedException]) @native()

### Deprecated Value Members

1.  def formatted(fmtstr: String): String
   Implicit
     This member is added by an implicit conversion from Attachments toStringFormat[Attachments] performed by method StringFormat in scala.Predef.
   Definition Classes
     StringFormat
   Annotations
     @deprecated @inline()
   Deprecated

     (Since version 2.12.16) Use `formatString.format(value)` instead of `value.formatted(formatString)`, or use the `f""` string interpolator. In Java 15 and later, `formatted` resolves to the new method in String which has reversed parameters.

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

### Inherited by implicit conversion StringFormat fromAttachments to StringFormat[Attachments]

### Inherited by implicit conversion Ensuring fromAttachments to Ensuring[Attachments]

### Inherited by implicit conversion ArrowAssoc fromAttachments to ArrowAssoc[Attachments]

### Ungrouped