Packages

  • package root

    The Scala compiler and reflection APIs.

    The Scala compiler and reflection APIs.

    Definition Classes
    root
  • package scala
    Definition Classes
    root
  • package tools
    Definition Classes
    scala
  • package nsc
    Definition Classes
    tools
  • package typechecker
    Definition Classes
    nsc
  • trait Macros extends MacroRuntimes with Traces with Helpers

    Code to deal with macros, namely with: * Compilation of macro definitions * Expansion of macro applications

    Code to deal with macros, namely with: * Compilation of macro definitions * Expansion of macro applications

    Say we have in a class C:

    def foo[T](xs: List[T]): T = macro fooBar

    Then fooBar needs to point to a static method of the following form:

    def fooBar[T: c.WeakTypeTag] // type tag annotation is optional (c: scala.reflect.macros.blackbox.Context) (xs: c.Expr[List[T]]) : c.Expr[T] = { ... }

    Then, if foo is called in qual.foo[Int](elems), where qual: D, the macro application is expanded to a reflective invocation of fooBar with parameters:

    (simpleMacroContext{ type PrefixType = D; val prefix = qual }) (Expr(elems)) (TypeTag(Int))

    Definition Classes
    typechecker
  • DefMacroExpander
  • Delayed
  • Failure
  • Fallback
  • JavaReflectionResolvers
  • MacroArgs
  • MacroExpander
  • MacroImplBinding
  • MacroRuntimeResolver
  • MacroStatus
  • Skipped
  • Success

abstract class MacroExpander extends AnyRef

Performs macro expansion:

Expandable trees

A term of one of the following shapes:

Ident(<term macro>) Select(<any qualifier>, <term macro>) TypeApply(<any of the above>, <targs>) Apply(...Apply(<any of the above>, <args1>)...<argsN>)

Macro expansion

First of all macroExpandXXX: 1) If necessary desugars the expandee to fit into the default expansion scheme that is understood by macroExpandWithRuntime / macroExpandWithoutRuntime

Then macroExpandWithRuntime: 2) Checks whether the expansion needs to be delayed 3) Loads macro implementation using macroMirror 4) Synthesizes invocation arguments for the macro implementation 5) Checks that the result is a tree or an expr bound to this universe

Finally macroExpandXXX: 6) Validates the expansion against the white list of supported tree shapes 7) Typechecks the result as required by the circumstances of the macro application

If -Ymacro-debug-lite is enabled, you will get basic notifications about macro expansion along with macro expansions logged in the form that can be copy/pasted verbatim into REPL.

If -Ymacro-debug-verbose is enabled, you will get detailed log of how exactly this function performs class loading and method resolution in order to load the macro implementation. The log will also include other non-trivial steps of macro expansion.

returns

the expansion result if the expansion has been successful, the fallback tree if the expansion has been unsuccessful, but there is a fallback, the expandee unchanged if the expansion has been delayed, the expandee fully expanded if the expansion has been delayed before and has been expanded now, the expandee with an error marker set if the expansion has been cancelled due malformed arguments or implementation the expandee with an error marker set if there has been an error

Source
Macros.scala
Linear Supertypes
AnyRef, Any
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Inherited
  1. MacroExpander
  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. All

Instance Constructors

  1. new MacroExpander(typer: Analyzer.Typer, expandee: Global.Tree)

Abstract Value Members

  1. abstract def onFallback(expanded: Global.Tree): Global.Tree
  2. abstract def onSuccess(expanded: Global.Tree): Global.Tree

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 Analyzer.MacroExpander toany2stringadd[Analyzer.MacroExpander] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (Analyzer.MacroExpander, B)
    Implicit
    This member is added by an implicit conversion from Analyzer.MacroExpander toArrowAssoc[Analyzer.MacroExpander] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  6. def apply(desugared: Global.Tree): Global.Tree
  7. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  8. def clone(): AnyRef
    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @native()
  9. def ensuring(cond: (Analyzer.MacroExpander) => Boolean, msg: => Any): Analyzer.MacroExpander
    Implicit
    This member is added by an implicit conversion from Analyzer.MacroExpander toEnsuring[Analyzer.MacroExpander] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  10. def ensuring(cond: (Analyzer.MacroExpander) => Boolean): Analyzer.MacroExpander
    Implicit
    This member is added by an implicit conversion from Analyzer.MacroExpander toEnsuring[Analyzer.MacroExpander] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  11. def ensuring(cond: Boolean, msg: => Any): Analyzer.MacroExpander
    Implicit
    This member is added by an implicit conversion from Analyzer.MacroExpander toEnsuring[Analyzer.MacroExpander] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  12. def ensuring(cond: Boolean): Analyzer.MacroExpander
    Implicit
    This member is added by an implicit conversion from Analyzer.MacroExpander toEnsuring[Analyzer.MacroExpander] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  13. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  14. def equals(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef → Any
  15. def expand(desugared: Global.Tree): Global.Tree
    Attributes
    protected
  16. val expandee: Global.Tree
  17. def finalize(): Unit
    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable])
  18. def formatted(fmtstr: String): String
    Implicit
    This member is added by an implicit conversion from Analyzer.MacroExpander toStringFormat[Analyzer.MacroExpander] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  19. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  20. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  21. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  22. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  23. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  24. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  25. def onDelayed(expanded: Global.Tree): Global.Tree
  26. def onFailure(expanded: Global.Tree): Global.Tree
  27. def onSkipped(expanded: Global.Tree): Global.Tree
  28. def onSuppressed(expandee: Global.Tree): Global.Tree
  29. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  30. def toString(): String
    Definition Classes
    AnyRef → Any
  31. val typer: Analyzer.Typer
  32. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  33. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  34. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()

Deprecated Value Members

  1. def [B](y: B): (Analyzer.MacroExpander, B)
    Implicit
    This member is added by an implicit conversion from Analyzer.MacroExpander toArrowAssoc[Analyzer.MacroExpander] 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 fromAnalyzer.MacroExpander to any2stringadd[Analyzer.MacroExpander]

Inherited by implicit conversion StringFormat fromAnalyzer.MacroExpander to StringFormat[Analyzer.MacroExpander]

Inherited by implicit conversion Ensuring fromAnalyzer.MacroExpander to Ensuring[Analyzer.MacroExpander]

Inherited by implicit conversion ArrowAssoc fromAnalyzer.MacroExpander to ArrowAssoc[Analyzer.MacroExpander]

Ungrouped