Trait scala.reflect.api.Exprs

trait Exprs extends AnyRef

EXPERIMENTAL

A trait that defines strongly-typed tree wrappers and operations on them for use in Scala Reflection.

Expr wraps an abstract syntax tree (scala.reflect.api.Trees#Tree) and tags it with its type (scala.reflect.api.Types#Type).

Usually Exprs are created via scala.reflect.api.Universe#reify, in which case a compiler produces a scala.reflect.api.TreeCreator for the provided expression and also creates a complementary scala.reflect.api.TypeTags#WeakTypeTag that corresponds to the type of that expression.

Exprs can also be created manually via the Expr companion object, but then the burden of providing a TreeCreator lies on the programmer. Compile-time reflection via macros, as described in scala.reflect.macros.Aliases, provides an easier way to instantiate exprs manually. Manual creation, however, is very rarely needed when working with runtime reflection.

Expr can be migrated from one mirror to another by using the in method. Migration means that all symbolic references to classes/objects/packages in the expression are re-resolved within the new mirror (typically using that mirror's classloader). The default universe of an Expr is typically scala.reflect.runtime#universe, the default mirror is typically scala.reflect.runtime#currentMirror.

Self Type
Universe
Source
Exprs.scala
Linear Supertypes
Known Subclasses

Type Members

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.

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 Exprs to any2stringadd[Exprs] performed by method any2stringadd in scala.Predef.
Definition Classes
any2stringadd

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

Implicit
This member is added by an implicit conversion from Exprs to ArrowAssoc[Exprs] 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[lang]
Definition Classes
AnyRef
Annotations
@throws( ... ) @native()

def ensuring(cond: (Exprs) ⇒ Boolean, msg: ⇒ Any): Exprs

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

def ensuring(cond: (Exprs) ⇒ Boolean): Exprs

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

def ensuring(cond: Boolean, msg: ⇒ Any): Exprs

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

def ensuring(cond: Boolean): Exprs

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

final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef

def equals(arg0: Any): Boolean

Definition Classes
AnyRef → Any

def finalize(): Unit

Attributes
protected[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 Exprs to StringFormat[Exprs] performed by method StringFormat in scala.Predef.
Definition Classes
StringFormat
Annotations
@inline()

final def getClass(): Class[_]

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( ... )

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

Definition Classes
AnyRef
Annotations
@throws( ... )

final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... ) @native()

def [B](y: B): (Exprs, B)

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

object Expr extends Serializable

Constructor/Extractor for Expr.

Can be useful, when having a tree and wanting to splice it in reify call, in which case the tree first needs to be wrapped in an expr.

The main source of information about exprs is the scala.reflect.api.Exprs page.

© 2002-2019 EPFL, with contributions from Lightbend.
Licensed under the Apache License, Version 2.0.
https://www.scala-lang.org/api/2.12.9/scala-reflect/scala/reflect/api/Exprs.html