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 transform
    Definition Classes
    nsc
  • package patmat
    Definition Classes
    transform
  • trait PatternExpansion extends AnyRef

    An 'extractor' can be a case class or an unapply or unapplySeq method.

    An 'extractor' can be a case class or an unapply or unapplySeq method.

    In a case class, the class is the unextracted type and the fixed and repeated types are derived from its constructor parameters.

    In an unapply, this is reversed: the parameter to the unapply is the unextracted type, and the other types are derived based on the return type of the unapply method.

    An extractor returns: F1, F2, ..., Fi, opt[Seq[E] or E*] A case matches: P1, P2, ..., Pj, opt[Seq[E]] Put together: P1/F1, P2/F2, ... Pi/Fi, Pi+1/E, Pi+2/E, ... Pj/E, opt[Seq[E]]

    Here Pm/Fi is the last pattern to match the fixed arity section.

    productArity: the value of i, i.e. the number of non-sequence types in the extractor nonStarArity: the value of j, i.e. the number of non-star patterns in the case definition elementArity: j - i, i.e. the number of non-star patterns which must match sequence elements starArity: 1 or 0 based on whether there is a star (sequence-absorbing) pattern totalArity: nonStarArity + starArity, i.e. the number of patterns in the case definition

    Note that productArity is a function only of the extractor, and nonStar/star/totalArity are all functions of the patterns. The key value for aligning and typing the patterns is elementArity, as it is derived from both sets of information.

    If elementArity is...

    • zero: A perfect match between extractor and the fixed patterns. If there is a star pattern it will match any sequence.
    • positive: There are more patterns than products. There will have to be a sequence which can populate at least elementArity patterns.
    • negative: There are more products than patterns: compile time error.
    Definition Classes
    patmat
  • ExtractorAlignment
  • ExtractorSubPatternAlignment

class ExtractorAlignment extends ExtractorSubPatternAlignment

Source
PatternExpansion.scala
Linear Supertypes
ExtractorSubPatternAlignment, AnyRef, Any
Known Subclasses
ExtractorCall, ExtractorCallProd, ExtractorCallRegular
Type Hierarchy
Ordering
  1. Alphabetic
  2. By Inheritance
Inherited
  1. ExtractorAlignment
  2. ExtractorSubPatternAlignment
  3. AnyRef
  4. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
  1. Hide All
  2. Show All
Visibility
  1. Public
  2. Protected

Instance Constructors

  1. new ExtractorAlignment(fun: Global.Tree, args: List[Global.Tree])(context: Context)

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 ExtractorAlignment toany2stringadd[ExtractorAlignment] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (ExtractorAlignment, B)
    Implicit
    This member is added by an implicit conversion from ExtractorAlignment toArrowAssoc[ExtractorAlignment] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  6. val args: List[Global.Tree]

    Args will be broken down into the concatenation of: productArity product patterns (fixed length, corresponding to fields in case class or tuple components in classic unapply, or product selectors in product-based unapply) elementArity element patterns (explicit patterns that pick off the prefix of the final sequence-valued component of the unapply, or a repeated case constructor arg) starArity star patterns (0 or 1, absorbs the remaining variable-length components)

    Args will be broken down into the concatenation of: productArity product patterns (fixed length, corresponding to fields in case class or tuple components in classic unapply, or product selectors in product-based unapply) elementArity element patterns (explicit patterns that pick off the prefix of the final sequence-valued component of the unapply, or a repeated case constructor arg) starArity star patterns (0 or 1, absorbs the remaining variable-length components)

    Definition Classes
    ExtractorAlignment → ExtractorSubPatternAlignment
  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 elementArity: Int
  10. def ensuring(cond: (ExtractorAlignment) => Boolean, msg: => Any): ExtractorAlignment
    Implicit
    This member is added by an implicit conversion from ExtractorAlignment toEnsuring[ExtractorAlignment] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  11. def ensuring(cond: (ExtractorAlignment) => Boolean): ExtractorAlignment
    Implicit
    This member is added by an implicit conversion from ExtractorAlignment toEnsuring[ExtractorAlignment] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  12. def ensuring(cond: Boolean, msg: => Any): ExtractorAlignment
    Implicit
    This member is added by an implicit conversion from ExtractorAlignment toEnsuring[ExtractorAlignment] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  13. def ensuring(cond: Boolean): ExtractorAlignment
    Implicit
    This member is added by an implicit conversion from ExtractorAlignment toEnsuring[ExtractorAlignment] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  14. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  15. def equals(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef → Any
  16. def expectedExtractedType: Global.Type
  17. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable])
  18. val fun: Global.Tree
  19. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  20. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  21. def isBool: Boolean
  22. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  23. def isSeq: Boolean
  24. def isSingle: Boolean
  25. val isStar: Boolean
    Definition Classes
    ExtractorSubPatternAlignment
  26. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  27. val nonStarArity: Int
    Definition Classes
    ExtractorSubPatternAlignment
  28. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  29. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  30. def productArity: Int
  31. def resultInMonad(extractedBinder: Global.Symbol): Global.Type
  32. def starArity: Int
    Definition Classes
    ExtractorSubPatternAlignment
  33. def subPatTypes(extractedBinder: Global.Symbol): List[Global.Type]
  34. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  35. def toString(): String
    Definition Classes
    AnyRef → Any
  36. def totalArity: Int
    Definition Classes
    ExtractorSubPatternAlignment
  37. def unapplyFormals: List[Global.Type]
  38. def unapplySelector: Global.Symbol
  39. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  40. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  41. 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 ExtractorAlignment toStringFormat[ExtractorAlignment] 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): (ExtractorAlignment, B)
    Implicit
    This member is added by an implicit conversion from ExtractorAlignment toArrowAssoc[ExtractorAlignment] 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 ExtractorSubPatternAlignment

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd fromExtractorAlignment to any2stringadd[ExtractorAlignment]

Inherited by implicit conversion StringFormat fromExtractorAlignment to StringFormat[ExtractorAlignment]

Inherited by implicit conversion Ensuring fromExtractorAlignment to Ensuring[ExtractorAlignment]

Inherited by implicit conversion ArrowAssoc fromExtractorAlignment to ArrowAssoc[ExtractorAlignment]

Ungrouped