Packages

trait Expr[+T] extends Equals with Serializable

Expr wraps an abstract syntax tree and tags it with its type. The main source of information about exprs is the scala.reflect.api.Exprs page.

Source
Exprs.scala
Linear Supertypes
java.io.Serializable, Equals, AnyRef, Any
Type Hierarchy
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  2. By Inheritance
Inherited
  1. Expr
  2. Serializable
  3. Equals
  4. AnyRef
  5. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Visibility
  1. Public
  2. Protected

Abstract Value Members

  1. abstract def actualType: Universe.Type

    Type of the wrapped expression tree as found in the underlying tree.

  2. abstract def in[U <: Universe with Singleton](otherMirror: Mirror[U]): in.U.Expr[T]

    Migrates the expression into another mirror, jumping into a different universe if necessary.

  3. abstract val mirror: Universe.Mirror

    Underlying mirror of this expr.

  4. abstract def splice: T

    A dummy method to mark expression splicing in reification.

    A dummy method to mark expression splicing in reification.

    It should only be used within a reify call, which eliminates the splice call and embeds the wrapped tree into the reified surrounding expression. If used alone splice throws an exception when called at runtime.

    If you want to use an Expr in reification of some Scala code, you need to splice it in. For an expr of type Expr[T], where T has a method foo, the following code

    reify{ expr.splice.foo }

    uses splice to turn an expr of type Expr[T] into a value of type T in the context of reify.

    It is equivalent to

    Select( expr.tree, TermName("foo") )

    The following example code however does not compile

    reify{ expr.foo }

    because expr of type Expr[T] itself does not have a method foo.

    Annotations
    @compileTimeOnly("splice must be enclosed within a reify {} block")
  5. abstract def staticType: Universe.Type

    Type of the wrapped expression tree as provided during creation.

    Type of the wrapped expression tree as provided during creation.

    When exprs are created by the compiler, staticType represents a statically known type of the tree as calculated at that point by the compiler.

  6. abstract def tree: Universe.Tree

    The Scala abstract syntax tree representing the wrapped expression.

  7. abstract val value: T

    A dummy value to denote cross-stage path-dependent type dependencies.

    A dummy value to denote cross-stage path-dependent type dependencies.

    For example for the following macro definition:

    class X { type T }
object Macros { def foo(x: X): x.T = macro Impls.foo_impl }

    The corresponding macro implementation should have the following signature (note how the return type denotes path-dependency on x):

    object Impls { def foo_impl(c: Context)(x: c.Expr[X]): c.Expr[x.value.T] = ... }
    Annotations
    @compileTimeOnly("cannot use value except for signatures of macro implementations")

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 Universe.Expr[T] toany2stringadd[Universe.Expr[T]] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (Universe.Expr[T], B)
    Implicit
    This member is added by an implicit conversion from Universe.Expr[T] toArrowAssoc[Universe.Expr[T]] 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 canEqual(x: Any): Boolean
    Definition Classes
    Expr → Equals
  8. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @native()
  9. def ensuring(cond: (Universe.Expr[T]) => Boolean, msg: => Any): Universe.Expr[T]
    Implicit
    This member is added by an implicit conversion from Universe.Expr[T] toEnsuring[Universe.Expr[T]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  10. def ensuring(cond: (Universe.Expr[T]) => Boolean): Universe.Expr[T]
    Implicit
    This member is added by an implicit conversion from Universe.Expr[T] toEnsuring[Universe.Expr[T]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  11. def ensuring(cond: Boolean, msg: => Any): Universe.Expr[T]
    Implicit
    This member is added by an implicit conversion from Universe.Expr[T] toEnsuring[Universe.Expr[T]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  12. def ensuring(cond: Boolean): Universe.Expr[T]
    Implicit
    This member is added by an implicit conversion from Universe.Expr[T] toEnsuring[Universe.Expr[T]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  13. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  14. def equals(x: Any): Boolean
    Definition Classes
    Expr → Equals → AnyRef → Any
  15. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable])
  16. def formatted(fmtstr: String): String
    Implicit
    This member is added by an implicit conversion from Universe.Expr[T] toStringFormat[Universe.Expr[T]] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  17. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  18. def hashCode(): Int
    Definition Classes
    Expr → AnyRef → Any
  19. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  20. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  21. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  22. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  23. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  24. def toString(): String
    Definition Classes
    Expr → AnyRef → Any
  25. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  26. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  27. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()

Deprecated Value Members

  1. def →[B](y: B): (Universe.Expr[T], B)
    Implicit
    This member is added by an implicit conversion from Universe.Expr[T] toArrowAssoc[Universe.Expr[T]] 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 java.io.Serializable

Inherited from Equals

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd fromUniverse.Expr[T] to any2stringadd[Universe.Expr[T]]

Inherited by implicit conversion StringFormat fromUniverse.Expr[T] to StringFormat[Universe.Expr[T]]

Inherited by implicit conversion Ensuring fromUniverse.Expr[T] to Ensuring[Universe.Expr[T]]

Inherited by implicit conversion ArrowAssoc fromUniverse.Expr[T] to ArrowAssoc[Universe.Expr[T]]

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