scala.tools.nsc.transform.patmat

# PatternExpander

#### 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, ... 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.

Linear Supertypes
AnyRef, Any
Known Subclasses
ScalacPatternExpander, alignPatterns
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Inherited

1. PatternExpander
2. AnyRef
3. Any

Implicitly

1. by any2stringadd
2. by StringFormat
3. by Ensuring
4. by ArrowAssoc

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### Type Members

1. #### final case class Aligned(patterns: Patterns, extractor: Extractor) extends Product with Serializable

   If elementArity is.

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

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

3. #### final case class Patterns(fixed: List[Pattern], star: Pattern) extends Product with Serializable

4. #### sealed case class Repeated(sequenceType: Type, elementType: Type, repeatedType: Type) extends Product with Serializable

   It's not optimal that we're carrying both sequence and repeated type here, but the implementation requires more unraveling before it can be avoided.

5. #### final case class TypedPat(pat: Pattern, tpe: Type) extends Product with Serializable

### Abstract Value Members

1. #### abstract def NoPattern: Pattern

   You'll note we're not inside the cake.

   You'll note we're not inside the cake. "Pattern" and "Type" are arbitrary types here, and NoPattern and NoType arbitrary values.

2. #### abstract def NoType: Type

### 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 information
     This member is added by an implicit conversion from PatternExpander[Pattern, Type] to any2stringadd[PatternExpander[Pattern, Type]] performed by method any2stringadd in scala.Predef.
   Definition Classes
     any2stringadd

4. #### def ->[B](y: B): (PatternExpander[Pattern, Type], B)

   Implicit information
     This member is added by an implicit conversion from PatternExpander[Pattern, Type] to ArrowAssoc[PatternExpander[Pattern, Type]] performed by method ArrowAssoc in scala.Predef.
   Definition Classes
     ArrowAssoc
   Annotations
     @inline()

5. #### final def ==(arg0: Any): Boolean

   Definition Classes
     AnyRef → Any

6. #### object NoRepeated extends Repeated

7. #### final def asInstanceOf[T0]: T0

   Definition Classes
     Any

8. #### def clone(): AnyRef

   Attributes
     protected[java.lang]
   Definition Classes
     AnyRef
   Annotations
     @throws( ... )

9. #### def ensuring(cond: (PatternExpander[Pattern, Type]) ⇒ Boolean, msg: ⇒ Any): PatternExpander[Pattern, Type]

   Implicit information
     This member is added by an implicit conversion from PatternExpander[Pattern, Type] to Ensuring[PatternExpander[Pattern, Type]] performed by method Ensuring in scala.Predef.
   Definition Classes
     Ensuring

10. #### def ensuring(cond: (PatternExpander[Pattern, Type]) ⇒ Boolean): PatternExpander[Pattern, Type]

    Implicit information
      This member is added by an implicit conversion from PatternExpander[Pattern, Type] to Ensuring[PatternExpander[Pattern, Type]] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring

11. #### def ensuring(cond: Boolean, msg: ⇒ Any): PatternExpander[Pattern, Type]

    Implicit information
      This member is added by an implicit conversion from PatternExpander[Pattern, Type] to Ensuring[PatternExpander[Pattern, Type]] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring

12. #### def ensuring(cond: Boolean): PatternExpander[Pattern, Type]

    Implicit information
      This member is added by an implicit conversion from PatternExpander[Pattern, Type] to Ensuring[PatternExpander[Pattern, Type]] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring

13. #### final def eq(arg0: AnyRef): Boolean

    Definition Classes
      AnyRef

14. #### def equals(arg0: Any): Boolean

    Definition Classes
      AnyRef → Any

15. #### def finalize(): Unit

    Attributes
      protected[java.lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( classOf[java.lang.Throwable] )

16. #### def formatted(fmtstr: String): String

    Implicit information
      This member is added by an implicit conversion from PatternExpander[Pattern, Type] to StringFormat[PatternExpander[Pattern, Type]] performed by method StringFormat in scala.Predef.
    Definition Classes
      StringFormat
    Annotations
      @inline()

17. #### final def getClass(): Class[_]

    Definition Classes
      AnyRef → Any

18. #### def hashCode(): Int

    Definition Classes
      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

22. #### final def notifyAll(): Unit

    Definition Classes
      AnyRef

23. #### final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
      AnyRef

24. #### def toString(): String

    Definition Classes
      AnyRef → Any

25. #### final def wait(): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

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

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

27. #### final def wait(arg0: Long): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

28. #### def →[B](y: B): (PatternExpander[Pattern, Type], B)

    Implicit information
      This member is added by an implicit conversion from PatternExpander[Pattern, Type] to ArrowAssoc[PatternExpander[Pattern, Type]] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
      ArrowAssoc

### Inherited from AnyRef

### Inherited from Any

### Inherited by implicit conversion any2stringadd from PatternExpander[Pattern, Type] to any2stringadd[PatternExpander[Pattern, Type]]

### Inherited by implicit conversion StringFormat from PatternExpander[Pattern, Type] to StringFormat[PatternExpander[Pattern, Type]]

### Inherited by implicit conversion Ensuring from PatternExpander[Pattern, Type] to Ensuring[PatternExpander[Pattern, Type]]

### Inherited by implicit conversion ArrowAssoc from PatternExpander[Pattern, Type] to ArrowAssoc[PatternExpander[Pattern, Type]]

### Ungrouped