scala.tools.nsc.transform.patmat.PatternMatching

# PureMatchTranslator

#### class PureMatchTranslator extends MatchTranslator with PureCodegen

Source
  PatternMatching.scala

Linear Supertypes
PatternMatching.PureCodegen, PatternMatching.PureMatchMonadInterface, PatternMatching.MatchTranslator, PatternMatching.TreeMakerWarnings, PatternMatching.TreeMakers, PatternMatching.CodegenCore, PatternMatching.TypedSubstitution, PatternMatching.MatchMonadInterface, AnyRef, Any
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Inherited

1. PureMatchTranslator
2. PureCodegen
3. PureMatchMonadInterface
4. MatchTranslator
5. TreeMakerWarnings
6. TreeMakers
7. CodegenCore
8. TypedSubstitution
9. MatchMonadInterface
10. AnyRef
11. Any

Implicitly

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

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### Instance Constructors

1. #### new PureMatchTranslator(typer: (analyzer)#Typer, matchStrategy: Global.Tree)

### Type Members

1. #### trait AbsCodegen extends AnyRef

   Definition Classes
     CodegenCore

2. #### case class AlternativesTreeMaker(prevBinder: Global.Symbol, altss: List[List[TreeMaker]], pos: Global.Position) extends TreeMaker with NoNewBinders with Product with Serializable

   Definition Classes
     TreeMakers

3. #### case class BodyTreeMaker(body: Global.Tree, matchPt: Global.Type) extends TreeMaker with NoNewBinders with Product with Serializable

   Definition Classes
     TreeMakers

4. #### final case class BoundTree(binder: Global.Symbol, tree: Global.Tree) extends Product with Serializable

   Definition Classes
     MatchTranslator

5. #### trait Casegen extends AbsCodegen

   Definition Classes
     CodegenCore

6. #### abstract class CommonCodegen extends AbsCodegen

   Definition Classes
     CodegenCore

7. #### sealed abstract class CondTreeMaker extends FunTreeMaker

   Definition Classes
     TreeMakers

8. #### case class EqualityTestTreeMaker(prevBinder: Global.Symbol, patTree: Global.Tree, pos: Global.Position) extends CondTreeMaker with Product with Serializable

   Definition Classes
     TreeMakers

9. #### abstract class ExtractorCall extends AnyRef

   Definition Classes
     MatchTranslator

10. #### class ExtractorCallProd extends ExtractorCall

    Definition Classes
      MatchTranslator

11. #### class ExtractorCallRegular extends ExtractorCall

    Definition Classes
      MatchTranslator

12. #### case class ExtractorTreeMaker(extractor: Global.Tree, extraCond: Option[Global.Tree], nextBinder: Global.Symbol)(subPatBinders: List[Global.Symbol], subPatRefs: List[Global.Tree], extractorReturnsBoolean: Boolean, checkedLength: Option[Int], prevBinder: Global.Symbol, ignoredSubPatBinders: Set[Global.Symbol]) extends FunTreeMaker with PreserveSubPatBinders with Product with Serializable

    Make a TreeMaker that will result in an extractor call specified by `extractor` the next TreeMaker (here, we don't know which it'll be) is chained after this one by flatMap'ing a function with binder `nextBinder` over our extractor's result the function's body is determined by the next TreeMaker (furthermore, the interpretation of `flatMap` depends on the codegen instance we're using).

    Make a TreeMaker that will result in an extractor call specified by `extractor` the next TreeMaker (here, we don't know which it'll be) is chained after this one by flatMap'ing a function with binder `nextBinder` over our extractor's result the function's body is determined by the next TreeMaker (furthermore, the interpretation of `flatMap` depends on the codegen instance we're using).

    The values for the subpatterns, as computed by the extractor call in `extractor`, are stored in local variables that re-use the symbols in `subPatBinders`. This makes extractor patterns more debuggable (SI-5739).

    Definition Classes
      TreeMakers

13. #### sealed abstract class FunTreeMaker extends TreeMaker

    Definition Classes
      TreeMakers

14. #### case class GuardTreeMaker(guardTree: Global.Tree) extends TreeMaker with NoNewBinders with Product with Serializable

    Definition Classes
      TreeMakers

15. #### sealed trait NoNewBinders extends TreeMaker

    Definition Classes
      TreeMakers

16. #### sealed trait PreserveSubPatBinders extends TreeMaker

    Definition Classes
      TreeMakers

17. #### case class ProductExtractorTreeMaker(prevBinder: Global.Symbol, extraCond: Option[Global.Tree])(subPatBinders: List[Global.Symbol], subPatRefs: List[Global.Tree], mutableBinders: List[Global.Symbol], binderKnownNonNull: Boolean, ignoredSubPatBinders: Set[Global.Symbol]) extends FunTreeMaker with PreserveSubPatBinders with Product with Serializable

    An optimized version of ExtractorTreeMaker for Products.

    An optimized version of ExtractorTreeMaker for Products. For now, this is hard-coded to case classes, and we simply extract the case class fields.

    The values for the subpatterns, as specified by the case class fields at the time of extraction, are stored in local variables that re-use the symbols in `subPatBinders`. This makes extractor patterns more debuggable (SI-5739) as well as avoiding mutation after the pattern has been matched (SI-5158, SI-6070)

    TODO: make this user-definable as follows When a companion object defines a method `def unapply_1(x: T): U_1`, but no `def unapply` or `def unapplySeq`, the extractor is considered to match any non-null value of type T the pattern is expected to have as many sub-patterns as there are `def unapply_I(x: T): U_I` methods, and the type of the I'th sub-pattern is `U_I`. The same exception for Seq patterns applies: if the last extractor is of type `Seq[U_N]`, the pattern must have at least N arguments (exactly N if the last argument is annotated with `: _*`). The arguments starting at N (and beyond) are taken from the sequence returned by apply_N, and it is checked that that sequence has enough elements to provide values for all expected sub-patterns.

    For a case class C, the implementation is assumed to be `def unapply_I(x: C) = x._I`, and the extractor call is inlined under that assumption.

    Definition Classes
      TreeMakers

18. #### case class SubstOnlyTreeMaker(prevBinder: Global.Symbol, nextBinder: Global.Symbol) extends TreeMaker with Product with Serializable

    Definition Classes
      TreeMakers

19. #### class Substitution extends AnyRef

    Definition Classes
      TypedSubstitution

20. #### final case class TranslationStep(makers: List[MatchTranslator.TreeMaker], subpatterns: List[BoundTree]) extends Product with Serializable

    Definition Classes
      MatchTranslator

21. #### abstract class TreeMaker extends AnyRef

    Definition Classes
      TreeMakers

22. #### case class TrivialTreeMaker(tree: Global.Tree) extends TreeMaker with NoNewBinders with Product with Serializable

    Definition Classes
      TreeMakers

23. #### case class TypeTestTreeMaker(prevBinder: Global.Symbol, testedBinder: Global.Symbol, expectedTp: Global.Type, nextBinderTp: Global.Type)(pos: Global.Position, extractorArgTypeTest: Boolean = false) extends CondTreeMaker with Product with Serializable

    implements the run-time aspects of (§8.2) (typedPattern has already done the necessary type transformations)

    implements the run-time aspects of (§8.2) (typedPattern has already done the necessary type transformations)

    Type patterns consist of types, type variables, and wildcards. A type pattern T is of one of the following forms:

    - A reference to a class C, p.C, or T#C. This type pattern matches any non-null instance of the given class. Note that the prefix of the class, if it is given, is relevant for determining class instances. For instance, the pattern p.C matches only instances of classes C which were created with the path p as prefix. The bottom types scala.Nothing and scala.Null cannot be used as type patterns, because they would match nothing in any case.
    - A singleton type p.type. This type pattern matches only the value denoted by the path p (that is, a pattern match involved a comparison of the matched value with p using method eq in class AnyRef). // TODO: the actual pattern matcher uses ==, so that's what I'm using for now // https://issues.scala-lang.org/browse/SI-4577 "pattern matcher, still disappointing us at equality time"
    - A compound type pattern T1 with ... with Tn where each Ti is a type pat- tern. This type pattern matches all values that are matched by each of the type patterns Ti.
    - A parameterized type pattern T[a1,...,an], where the ai are type variable patterns or wildcards _. This type pattern matches all values which match T for some arbitrary instantiation of the type variables and wildcards. The bounds or alias type of these type variable are determined as described in (§8.3).
    - A parameterized type pattern scala.Array[T1], where T1 is a type pattern. // TODO This type pattern matches any non-null instance of type scala.Array[U1], where U1 is a type matched by T1.
    Definition Classes
      TreeMakers

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

4. #### def ->[B](y: B): (PureMatchTranslator, B)

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

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

   Definition Classes
     AnyRef → Any

6. #### object EmptySubstitution extends Substitution

   Definition Classes
     TypedSubstitution

7. #### object ExtractorCall

   Definition Classes
     MatchTranslator

8. #### object IrrefutableExtractorTreeMaker

   Definition Classes
     TreeMakers

9. #### object PatternBoundToUnderscore

   Definition Classes
     MatchTranslator

10. #### object Substitution

    Definition Classes
      TypedSubstitution

11. #### object SymbolBound

    Definition Classes
      MatchTranslator

12. #### object TypeTestTreeMaker extends Serializable

    Definition Classes
      TreeMakers

13. #### object WildcardPattern

    A conservative approximation of which patterns do not discern anything.

    A conservative approximation of which patterns do not discern anything. They are discarded during the translation.

    Definition Classes
      MatchTranslator

14. #### def _match(n: Global.Name): SelectStart

    Definition Classes
      PureMatchMonadInterface

15. #### def analyzeCases(prevBinder: Global.Symbol, cases: List[List[TreeMaker]], pt: Global.Type, suppression: PatternMatching.Suppression): Unit

    Definition Classes
      PureMatchTranslator → TreeMakers

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

    Definition Classes
      Any

17. #### def checkMatchVariablePatterns(cases: List[Global.CaseDef]): Unit

    Definition Classes
      TreeMakerWarnings

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

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

19. #### def codegen: AbsCodegen

    Definition Classes
      PureCodegen → CodegenCore

20. #### def combineCases(scrut: Global.Tree, scrutSym: Global.Symbol, casesRaw: List[List[TreeMaker]], pt: Global.Type, owner: Global.Symbol, matchFailGenOverride: Option[(Global.Tree) ⇒ Global.Tree]): Global.Tree

    Definition Classes
      TreeMakers

21. #### def combineCasesNoSubstOnly(scrut: Global.Tree, scrutSym: Global.Symbol, casesNoSubstOnly: List[List[TreeMaker]], pt: Global.Type, owner: Global.Symbol, matchFailGenOverride: Option[(Global.Tree) ⇒ Global.Tree]): Global.Tree

    Definition Classes
      TreeMakers

22. #### def combineExtractors(treeMakers: List[TreeMaker])(casegen: Casegen): Global.Tree

    Definition Classes
      TreeMakers

23. #### val debugInfoEmitVars: Boolean

    Attributes
      protected
    Definition Classes
      TreeMakers

24. #### def emitSwitch(scrut: Global.Tree, scrutSym: Global.Symbol, cases: List[List[TreeMaker]], pt: Global.Type, matchFailGenOverride: Option[(Global.Tree) ⇒ Global.Tree], unchecked: Boolean): Option[Global.Tree]

    Definition Classes
      TreeMakers

25. #### def emitTypeSwitch(bindersAndCases: List[(Global.Symbol, List[TreeMaker])], pt: Global.Type): Option[List[Global.CaseDef]]

    Definition Classes
      TreeMakers

26. #### def ensuring(cond: (PureMatchTranslator) ⇒ Boolean, msg: ⇒ Any): PureMatchTranslator

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

27. #### def ensuring(cond: (PureMatchTranslator) ⇒ Boolean): PureMatchTranslator

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

28. #### def ensuring(cond: Boolean, msg: ⇒ Any): PureMatchTranslator

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

29. #### def ensuring(cond: Boolean): PureMatchTranslator

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

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

    Definition Classes
      AnyRef

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

    Definition Classes
      AnyRef → Any

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

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

33. #### def fixerUpper(origOwner: Global.Symbol, pos: Global.Position): Global.Traverser

    Attributes
      protected
    Definition Classes
      TreeMakers

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

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

35. #### def freshName(prefix: String): Global.TermName

    Definition Classes
      CodegenCore

36. #### def freshSym(pos: Global.Position, tp: Global.Type = NoType, prefix: String = "x"): Global.TermSymbol

    Definition Classes
      CodegenCore

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

    Definition Classes
      AnyRef → Any

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

    Definition Classes
      AnyRef → Any

39. #### final def isInstanceOf[T0]: Boolean

    Definition Classes
      Any

40. #### val matchOwner: Global.Symbol

    Definition Classes
      MatchMonadInterface

41. #### val matchStrategy: Global.Tree

    Definition Classes
      PureMatchTranslator → PureMatchMonadInterface

42. #### final def ne(arg0: AnyRef): Boolean

    Definition Classes
      AnyRef

43. #### def newBoundTree(tree: Global.Tree, pt: Global.Type): BoundTree

    Definition Classes
      MatchTranslator

44. #### def newSynthCaseLabel(name: String): Global.MethodSymbol

    Definition Classes
      CodegenCore

45. #### final def notify(): Unit

    Definition Classes
      AnyRef

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

    Definition Classes
      AnyRef

47. #### def optimizeCases(prevBinder: Global.Symbol, cases: List[List[TreeMaker]], pt: Global.Type): (List[List[TreeMaker]], collection.immutable.Nil.type)

    Definition Classes
      PureMatchTranslator → TreeMakers

48. #### def propagateSubstitution(treeMakers: List[TreeMaker], initial: Substitution): List[TreeMaker]

    Definition Classes
      TreeMakers

49. #### object pureCodegen extends CommonCodegen with Casegen

    Definition Classes
      PureCodegen

50. #### def pureType(tp: Global.Type): Global.Type

    Definition Classes
      PureMatchMonadInterface → MatchMonadInterface

51. #### def removeSubstOnly(makers: List[TreeMaker]): collection.immutable.List[TreeMaker]

    Definition Classes
      TreeMakers

52. #### def reportMissingCases(pos: Global.Position, counterExamples: List[String]): Unit

    Definition Classes
      MatchMonadInterface

53. #### def reportUnreachable(pos: Global.Position): Unit

    Definition Classes
      MatchMonadInterface

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

    Definition Classes
      AnyRef

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

    Definition Classes
      AnyRef → Any

56. #### def translateBody(body: Global.Tree, matchPt: Global.Type): TreeMaker

    Definition Classes
      MatchTranslator

57. #### def translateCase(scrutSym: Global.Symbol, pt: Global.Type)(caseDef: Global.CaseDef): collection.immutable.List[TreeMaker]

    The translation of `pat if guard => body` has two aspects: 1) the substitution due to the variables bound by patterns 2) the combination of the extractor calls using `flatMap`.

    The translation of `pat if guard => body` has two aspects: 1) the substitution due to the variables bound by patterns 2) the combination of the extractor calls using `flatMap`.

    2) is easy -- it looks like: `translatePattern_1.flatMap(translatePattern_2....flatMap(translatePattern_N.flatMap(translateGuard.flatMap((x_i) => success(Xbody(x_i)))))...)` this must be right-leaning tree, as can be seen intuitively by considering the scope of bound variables: variables bound by pat_1 must be visible from the function inside the left-most flatMap right up to Xbody all the way on the right 1) is tricky because translatePattern_i determines the shape of translatePattern_i+1: zoom in on `translatePattern_1.flatMap(translatePattern_2)` for example -- it actually looks more like: `translatePattern_1(x_scrut).flatMap((x_1) => {y_i -> x_1._i}translatePattern_2)`

    `x_1` references the result (inside the monad) of the extractor corresponding to `pat_1`, this result holds the values for the constructor arguments, which translatePattern_1 has extracted from the object pointed to by `x_scrut`. The `y_i` are the symbols bound by `pat_1` (in order) in the scope of the remainder of the pattern, and they must thus be replaced by:

    - (for 1-ary unapply) x_1
    - (for n-ary unapply, n > 1) selection of the i'th tuple component of `x_1`
    - (for unapplySeq) x_1.apply(i)

    in the treemakers,

    Thus, the result type of `translatePattern_i`'s extractor must conform to `M[(T_1,..., T_n)]`.

    Operationally, phase 1) is a foldLeft, since we must consider the depth-first-flattening of the transformed patterns from left to right. For every pattern ast node, it produces a transformed ast and a function that will take care of binding and substitution of the next ast (to the right).

    Definition Classes
      MatchTranslator

58. #### def translateGuard(guard: Global.Tree): List[TreeMaker]

    Definition Classes
      MatchTranslator

59. #### def translateMatch(match_: Global.Match): Global.Tree

    Implement a pattern match by turning its cases (including the implicit failure case) into the corresponding (monadic) extractors, and combining them with the `orElse` combinator.

    Implement a pattern match by turning its cases (including the implicit failure case) into the corresponding (monadic) extractors, and combining them with the `orElse` combinator.

    For `scrutinee match { case1 ... caseN }`, the resulting tree has the shape `runOrElse(scrutinee)(x => translateCase1(x).orElse(translateCase2(x)).....orElse(zero))`

    NOTE: the resulting tree is not type checked, nor are nested pattern matches transformed thus, you must typecheck the result (and that will in turn translate nested matches) this could probably optimized... (but note that the matchStrategy must be solved for each nested patternmatch)

    Definition Classes
      MatchTranslator

60. #### def translatePattern(bound: BoundTree): List[TreeMaker]

    Definition Classes
      MatchTranslator

61. #### def translateTry(caseDefs: List[Global.CaseDef], pt: Global.Type, pos: Global.Position): List[Global.CaseDef]

    Definition Classes
      MatchTranslator

62. #### val typer: (analyzer)#Typer

    Definition Classes
      PureMatchTranslator → MatchMonadInterface

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

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

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

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

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

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

66. #### def →[B](y: B): (PureMatchTranslator, B)

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

### Inherited from PatternMatching.PureCodegen

### Inherited from PatternMatching.PureMatchMonadInterface

### Inherited from PatternMatching.MatchTranslator

### Inherited from PatternMatching.TreeMakerWarnings

### Inherited from PatternMatching.TreeMakers

### Inherited from PatternMatching.CodegenCore

### Inherited from PatternMatching.TypedSubstitution

### Inherited from PatternMatching.MatchMonadInterface

### Inherited from AnyRef

### Inherited from Any

### Inherited by implicit conversion any2stringadd from PureMatchTranslator to any2stringadd[PureMatchTranslator]

### Inherited by implicit conversion StringFormat from PureMatchTranslator to StringFormat[PureMatchTranslator]

### Inherited by implicit conversion Ensuring from PureMatchTranslator to Ensuring[PureMatchTranslator]

### Inherited by implicit conversion ArrowAssoc from PureMatchTranslator to ArrowAssoc[PureMatchTranslator]

### Ungrouped