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 PatternExpander [Pattern, Type] extends AnyRef

    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, ...

    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.

    Definition Classes
    patmat
  • Aligned
  • Extractor
  • NoRepeated
  • Patterns
  • Repeated
  • TypedPat

final case class Extractor(whole: Type, fixed: List[Type], repeated: Repeated, typeOfSinglePattern: Type) extends Product with Serializable

An 'extractor' can be a case class or an unapply or unapplySeq method. Decoding what it is that they extract takes place before we arrive here, so that this class can concentrate only on the relationship between patterns and types.

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.

In other words, this case class and unapply are encoded the same:

case class Foo(x: Int, y: Int, zs: Char*) def unapplySeq(x: Foo): Option[(Int, Int, Seq[Char])]

Both are Extractor(Foo, Int :: Int :: Nil, Repeated(Seq[Char], Char, Char*))

whole

The type in its unextracted form

fixed

The non-sequence types which are extracted

repeated

The sequence type which is extracted

Source
PatternExpander.scala
Linear Supertypes
Serializable, java.io.Serializable, Product, Equals, AnyRef, Any
Type Hierarchy
Ordering
  1. Alphabetic
  2. By Inheritance
Inherited
  1. Extractor
  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
  1. Hide All
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Visibility
  1. Public
  2. All

Instance Constructors

  1. new Extractor(whole: Type, fixed: List[Type], repeated: Repeated, typeOfSinglePattern: Type)

    whole

    The type in its unextracted form

    fixed

    The non-sequence types which are extracted

    repeated

    The sequence type which is extracted

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 Extractor to any2stringadd[Extractor] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (Extractor, B)
    Implicit
    This member is added by an implicit conversion from Extractor to ArrowAssoc[Extractor] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  6. def allTypes: collection.immutable.List[Type]
  7. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  8. def asSinglePattern: Extractor

    A pattern with arity-1 that doesn't match the arity of the Product-like result of the get method, will match that result in its entirety.

    A pattern with arity-1 that doesn't match the arity of the Product-like result of the get method, will match that result in its entirety. Example:

    warning: there was one deprecation warning; re-run with -deprecation for details
scala> object Extractor { def unapply(a: Any): Option[(Int, String)] = Some((1, "2")) }
defined object Extractor

scala> "" match { case Extractor(x: Int, y: String) => }

scala> "" match { case Extractor(xy : (Int, String)) => }
warning: there was one deprecation warning; re-run with -deprecation for details
  9. def clone(): AnyRef
    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  10. def elementType: Type
  11. def ensuring(cond: (Extractor) ⇒ Boolean, msg: ⇒ Any): Extractor
    Implicit
    This member is added by an implicit conversion from Extractor to Ensuring[Extractor] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  12. def ensuring(cond: (Extractor) ⇒ Boolean): Extractor
    Implicit
    This member is added by an implicit conversion from Extractor to Ensuring[Extractor] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  13. def ensuring(cond: Boolean, msg: ⇒ Any): Extractor
    Implicit
    This member is added by an implicit conversion from Extractor to Ensuring[Extractor] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  14. def ensuring(cond: Boolean): Extractor
    Implicit
    This member is added by an implicit conversion from Extractor to Ensuring[Extractor] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  15. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  16. def finalize(): Unit
    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
  17. val fixed: List[Type]
  18. def formatted(fmtstr: String): String
    Implicit
    This member is added by an implicit conversion from Extractor to StringFormat[Extractor] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  19. final def getClass(): Class[_]
    Definition Classes
    AnyRef → Any
  20. def hasSeq: Boolean
  21. def isErroneous: Boolean
  22. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  23. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  24. final def notify(): Unit
    Definition Classes
    AnyRef
  25. final def notifyAll(): Unit
    Definition Classes
    AnyRef
  26. def offeringString: String
  27. def productArity: Int
    Definition Classes
    Extractor → Product
  28. val repeated: Repeated
  29. def sequenceType: Type
  30. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  31. def toString(): String
    Definition Classes
    Extractor → AnyRef → Any
  32. val typeOfSinglePattern: Type
  33. def varargsTypes: collection.immutable.List[Type]
  34. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  35. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  36. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  37. val whole: Type
  38. def →[B](y: B): (Extractor, B)
    Implicit
    This member is added by an implicit conversion from Extractor to ArrowAssoc[Extractor] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc

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 Extractor to any2stringadd[Extractor]

Inherited by implicit conversion StringFormat from Extractor to StringFormat[Extractor]

Inherited by implicit conversion Ensuring from Extractor to Ensuring[Extractor]

Inherited by implicit conversion ArrowAssoc from Extractor to ArrowAssoc[Extractor]

Ungrouped