Scala Reflection Library2.12.21 < Back
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# Packages

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

  EXPERIMENTAL

  EXPERIMENTAL

  The Scala Reflection API (located in scala-reflect.jar).

  In Scala 2.10.0, the Scala Reflection API and its implementation have an "experimental" status. This means that the API and the docs are not complete and can be changed in binary- and source-incompatible manner in 2.10.1. This also means that the implementation has some known issues.

  The following types are the backbone of the Scala Reflection API, and serve as a good starting point for information about Scala Reflection:

  - scala.reflect.api.Symbols
  - scala.reflect.api.Types
  - scala.reflect.api.Mirrors
  - scala.reflect.api.Universe

  For more information about Scala Reflection, see the Reflection Guide

  Definition Classes
    reflect
-  trait Printers extends AnyRef

  EXPERIMENTAL

  EXPERIMENTAL

  Utilities for nicely printing scala.reflect.api.Trees and scala.reflect.api.Types.

  ##### Printing Trees

  The method `show` displays the "prettified" representation of reflection artifacts. This representation provides one with the desugared Java representation of Scala code. For example:

      scala> import scala.reflect.runtime.universe._
      import scala.reflect.runtime.universe._

      scala> def tree = reify{ final class C { def x = 2 } }.tree
      tree: reflect.runtime.universe.Tree

      scala> show(tree)
      res0: String =
      {
        final class C extends AnyRef {
          def <init>() = {
            super.<init>();
            ()
          };
          def x = 2
        };
        ()
      }

  The method `showRaw` displays internal structure of a given reflection object as a Scala abstract syntax tree (AST), the representation that the Scala typechecker operates on.

  Note, that while this representation appears to generate correct trees that one might think would be possible to use in a macro implementation, this is not usually the case. Symbols aren't fully represented (only their names are). Thus, this method is best-suited for use simply inspecting ASTs given some valid Scala code.

      scala> showRaw(tree)
      res1: String = Block(List(
        ClassDef(Modifiers(FINAL), TypeName("C"), List(), Template(
          List(Ident(TypeName("AnyRef"))),
          noSelfType,
          List(
            DefDef(Modifiers(), nme.CONSTRUCTOR, List(), List(List()), TypeTree(),
              Block(List(
                Apply(Select(Super(This(tpnme.EMPTY), tpnme.EMPTY), nme.CONSTRUCTOR), List())),
                Literal(Constant(())))),
            DefDef(Modifiers(), TermName("x"), List(), List(), TypeTree(),
              Literal(Constant(2))))))),
        Literal(Constant(())))

  The method `showRaw` can also print scala.reflect.api.Types next to the artifacts being inspected

      scala> import scala.tools.reflect.ToolBox // requires scala-compiler.jar
      import scala.tools.reflect.ToolBox

      scala> import scala.reflect.runtime.{currentMirror => cm}
      import scala.reflect.runtime.{currentMirror=>cm}

      scala> showRaw(cm.mkToolBox().typecheck(tree), printTypes = true)
      res2: String = Block[1](List(
        ClassDef[2](Modifiers(FINAL), TypeName("C"), List(), Template[3](
          List(Ident[4](TypeName("AnyRef"))),
          noSelfType,
          List(
            DefDef[2](Modifiers(), nme.CONSTRUCTOR, List(), List(List()), TypeTree[3](),
              Block[1](List(
                Apply[4](Select[5](Super[6](This[3](TypeName("C")), tpnme.EMPTY), ...))),
                Literal[1](Constant(())))),
            DefDef[2](Modifiers(), TermName("x"), List(), List(), TypeTree[7](),
              Literal[8](Constant(2))))))),
        Literal[1](Constant(())))
      [1] TypeRef(ThisType(scala), scala.Unit, List())
      [2] NoType
      [3] TypeRef(NoPrefix, TypeName("C"), List())
      [4] TypeRef(ThisType(java.lang), java.lang.Object, List())
      [5] MethodType(List(), TypeRef(ThisType(java.lang), java.lang.Object, List()))
      [6] SuperType(ThisType(TypeName("C")), TypeRef(... java.lang.Object ...))
      [7] TypeRef(ThisType(scala), scala.Int, List())
      [8] ConstantType(Constant(2))

  ##### Printing Types

  The method `show`

      scala> import scala.reflect.runtime.universe._
      import scala.reflect.runtime.universe._

      scala> def tpe = typeOf[{ def x: Int; val y: List[Int] }]
      tpe: reflect.runtime.universe.Type

      scala> show(tpe)
      res0: String = scala.AnyRef{def x: Int; val y: scala.List[Int]}

  Like the method `showRaw` for scala.reflect.api.Trees, `showRaw` for scala.reflect.api.Types provides a visualization of the Scala AST operated on by the Scala typechecker.

      // showRaw has already been discussed above
      scala> showRaw(tpe)
      res1: String = RefinedType(
        List(TypeRef(ThisType(scala), TypeName("AnyRef"), List())),
        Scope(
          TermName("x"),
          TermName("y")))

  `printIds` and/or `printKinds` can additionally be supplied as arguments in a call to `showRaw` which additionally shows the unique identifiers of symbols.

      scala> showRaw(tpe, printIds = true, printKinds = true)
      res2: String = RefinedType(
        List(TypeRef(ThisType(scala#2043#PK), TypeName("AnyRef")#691#TPE, List())),
        Scope(
          TermName("x")#2540#METH,
          TermName("y")#2541#GET))

  For more details about `Printer`s and other aspects of Scala reflection, see the Reflection Guide

  Definition Classes
    api
- BooleanFlag
- TreePrinter

c

scala.reflect.api.Printers

# BooleanFlag 

###
Companion object BooleanFlag

#### case class BooleanFlag(value: Option[Boolean]) extends Product with Serializable

Source
  Printers.scala

Linear Supertypes
Serializable, java.io.Serializable, Product, Equals, AnyRef, Any
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Ordering

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2. By Inheritance

Inherited

1. BooleanFlag
2. Serializable
3. Serializable
4. Product
5. Equals
6. AnyRef
7. Any

Implicitly

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

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Visibility

1. Public
2. All

### Instance Constructors

1.  new BooleanFlag(value: Option[Boolean])

### 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 Universe.BooleanFlag to any2stringadd[Universe.BooleanFlag] performed by method any2stringadd in scala.Predef.
   Definition Classes
     any2stringadd
4.  def ->[B](y: B): (Universe.BooleanFlag, B)
   Implicit
     This member is added by an implicit conversion from Universe.BooleanFlag to ArrowAssoc[Universe.BooleanFlag] 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 asInstanceOf[T0]: T0
   Definition Classes
     Any
7.  def clone(): AnyRef
   Attributes
     protected[lang]
   Definition Classes
     AnyRef
   Annotations
     @throws( ... ) @native()
8.  def ensuring(cond: (Universe.BooleanFlag) ⇒ Boolean, msg: ⇒ Any): Universe.BooleanFlag
   Implicit
     This member is added by an implicit conversion from Universe.BooleanFlag to Ensuring[Universe.BooleanFlag] performed by method Ensuring in scala.Predef.
   Definition Classes
     Ensuring
9.  def ensuring(cond: (Universe.BooleanFlag) ⇒ Boolean): Universe.BooleanFlag
   Implicit
     This member is added by an implicit conversion from Universe.BooleanFlag to Ensuring[Universe.BooleanFlag] performed by method Ensuring in scala.Predef.
   Definition Classes
     Ensuring
10.  def ensuring(cond: Boolean, msg: ⇒ Any): Universe.BooleanFlag
    Implicit
      This member is added by an implicit conversion from Universe.BooleanFlag to Ensuring[Universe.BooleanFlag] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
11.  def ensuring(cond: Boolean): Universe.BooleanFlag
    Implicit
      This member is added by an implicit conversion from Universe.BooleanFlag to Ensuring[Universe.BooleanFlag] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
12.  final def eq(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
13.  def finalize(): Unit
    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( classOf[java.lang.Throwable] )
14.  final def getClass(): Class[_]
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
15.  final def isInstanceOf[T0]: Boolean
    Definition Classes
      Any
16.  final def ne(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
17.  final def notify(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
18.  final def notifyAll(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
19.  final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
      AnyRef
20.  val value: Option[Boolean]
21.  final def wait(): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
22.  final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
23.  final def wait(arg0: Long): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... ) @native()
24.  def →[B](y: B): (Universe.BooleanFlag, B)
    Implicit
      This member is added by an implicit conversion from Universe.BooleanFlag to ArrowAssoc[Universe.BooleanFlag] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
      ArrowAssoc

### Deprecated Value Members

1.  def formatted(fmtstr: String): String
   Implicit
     This member is added by an implicit conversion from Universe.BooleanFlag to StringFormat[Universe.BooleanFlag] 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.

### Inherited from Serializable

### Inherited from java.io.Serializable

### Inherited from Product

### Inherited from Equals

### Inherited from AnyRef

### Inherited from Any

### Inherited by implicit conversion any2stringadd from Universe.BooleanFlag to any2stringadd[Universe.BooleanFlag]

### Inherited by implicit conversion StringFormat from Universe.BooleanFlag to StringFormat[Universe.BooleanFlag]

### Inherited by implicit conversion Ensuring from Universe.BooleanFlag to Ensuring[Universe.BooleanFlag]

### Inherited by implicit conversion ArrowAssoc from Universe.BooleanFlag to ArrowAssoc[Universe.BooleanFlag]

### Ungrouped