Scala Compiler2.13.18 < Back
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# 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 PatternMatching extends SubComponent with Transform with TypingTransformers with Debugging with Interface with MatchTranslation with MatchTreeMaking with MatchCodeGen with MatchCps with ScalaLogic with Solving with MatchAnalysis with MatchOptimization with MatchWarnings with PatternExpansion

  Translate pattern matching.

  Translate pattern matching.

  Either into optimized if/then/else's, or virtualized as method calls (these methods form a zero-plus monad), similar in spirit to how for-comprehensions are compiled.

  For each case, express all patterns as extractor calls, guards as 0-ary extractors, and sequence them using `flatMap` (lifting the body of the case into the monad using `one`).

  Cases are combined into a pattern match using the `orElse` combinator (the implicit failure case is expressed using the monad's `zero`).

  TODO:

  - DCE (on irrefutable patterns)
  - update spec and double check it's implemented correctly (see TODO's)

  (longer-term) TODO:

  - user-defined unapplyProd
  - recover GADT typing by locally inserting implicit witnesses to type equalities derived from the current case, and considering these witnesses during subtyping (?)
  - recover exhaustivity/unreachability of user-defined extractors by partitioning the types they match on using an HList or similar type-level structure
  Definition Classes
    patmat
- CNF
- CODE
- CheckableTreeAndTypeAnalysis
- CodegenCore
- CommonSubconditionElimination
- ExtractorAlignment
- ExtractorSubPatternAlignment
- MatchAnalyzer
- MatchApproximator
- MatchMonadInterface
- MatchOptimizer
- MatchTransformer
- MatchTranslator
- OptimizedCodegen
- OptimizingMatchTranslator
- Phase
- PropositionalLogic
- Solver
- StdPhase
- Suppression
- SwitchEmission
- ThicketTransformer
- TreeMakerWarnings
- TreeMakers
- TreesAndTypesDomain
- TypedSubstitution
- TypingTransformer
- debug

c

scala.tools.nsc.transform.patmat.PatternMatching

# OptimizingMatchTranslator

###

#### class OptimizingMatchTranslator extends MatchTranslator with MatchOptimizer with MatchAnalyzer with Solver

Source
  PatternMatching.scala

Linear Supertypes
PatternMatching.Solver, PatternMatching.CNF, PatternMatching.MatchAnalyzer, PatternMatching.MatchOptimizer, PatternMatching.CommonSubconditionElimination, PatternMatching.MatchApproximator, PatternMatching.TreesAndTypesDomain, PatternMatching.CheckableTreeAndTypeAnalysis, PatternMatching.PropositionalLogic, PatternMatching.SwitchEmission, PatternMatching.OptimizedCodegen, PatternMatching.MatchTranslator, PatternMatching.TreeMakerWarnings, PatternMatching.TreeMakers, PatternMatching.CodegenCore, PatternMatching.TypedSubstitution, PatternMatching.MatchMonadInterface, AnyRef, Any
Type Hierarchy

Ordering

1. Alphabetic
2. By Inheritance

Inherited

1. OptimizingMatchTranslator
2. Solver
3. CNF
4. MatchAnalyzer
5. MatchOptimizer
6. CommonSubconditionElimination
7. MatchApproximator
8. TreesAndTypesDomain
9. CheckableTreeAndTypeAnalysis
10. PropositionalLogic
11. SwitchEmission
12. OptimizedCodegen
13. MatchTranslator
14. TreeMakerWarnings
15. TreeMakers
16. CodegenCore
17. TypedSubstitution
18. MatchMonadInterface
19. AnyRef
20. 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 OptimizingMatchTranslator(typer: (analyzer)#Typer, selectorPos: Global.Position, inForceDesugar: Boolean)

### Type Members

1.  class Substitution extends AnyRef
   Definition Classes
     TypedSubstitution
2.  trait AbsVar extends AnyRef
   Definition Classes
     PropositionalLogic
3.  final case class And(ops: LogicLinkedHashSet[Prop]) extends Prop with Product with Serializable
   Definition Classes
     PropositionalLogic
4.  final case class AtMostOne(ops: List[Sym]) extends Prop with Product with Serializable
   Definition Classes
     PropositionalLogic
5.  final case class Eq(p: Var, q: Const) extends Prop with Product with Serializable
   Definition Classes
     PropositionalLogic
6.  final case class Not(a: Prop) extends Prop with Product with Serializable
   Definition Classes
     PropositionalLogic
7.  final case class Or(ops: LogicLinkedHashSet[Prop]) extends Prop with Product with Serializable
   Definition Classes
     PropositionalLogic
8.  sealed abstract class Prop extends AnyRef
   Definition Classes
     PropositionalLogic
9.  trait PropMap extends AnyRef
   Definition Classes
     PropositionalLogic
10.  trait PropTraverser extends AnyRef
    Definition Classes
      PropositionalLogic
11.  final case class Solution(model: Model, unassigned: List[Sym]) extends Product with Serializable
    Definition Classes
      PropositionalLogic
12.  final class Sym extends Prop
    Definition Classes
      PropositionalLogic
13.  trait TypeConstExtractor extends AnyRef
    Definition Classes
      PropositionalLogic
14.  trait ValueConstExtractor extends AnyRef
    Definition Classes
      PropositionalLogic
15.  trait VarExtractor extends AnyRef
    Definition Classes
      PropositionalLogic
16.  case class ConstructorExample(cls: Global.Symbol, ctorArgs: List[CounterExample]) extends CounterExample with Product with Serializable
    Definition Classes
      MatchAnalyzer
17.  class CounterExample extends AnyRef
    Definition Classes
      MatchAnalyzer
18.  case class ListExample(ctorArgs: List[CounterExample]) extends CounterExample with Product with Serializable
    Definition Classes
      MatchAnalyzer
19.  case class NegativeExample(eqTo: MatchAnalyzer.Const, nonTrivialNonEqualTo: List[MatchAnalyzer.Const]) extends CounterExample with Product with Serializable
    Definition Classes
      MatchAnalyzer
20.  case class TupleExample(ctorArgs: List[CounterExample]) extends CounterExample with Product with Serializable
    Definition Classes
      MatchAnalyzer
21.  case class TypeExample(c: MatchAnalyzer.Const) extends CounterExample with Product with Serializable
    Definition Classes
      MatchAnalyzer
22.  case class ValueExample(c: MatchAnalyzer.ValueConst) extends CounterExample with Product with Serializable
    Definition Classes
      MatchAnalyzer
23.  case class Test(prop: MatchApproximator.Prop, treeMaker: MatchApproximator.TreeMaker) extends Product with Serializable
    Definition Classes
      MatchApproximator
24.  class TreeMakersToProps extends AnyRef
    Definition Classes
      MatchApproximator
25.  trait AbsCodegen extends AnyRef
    Definition Classes
      CodegenCore
26.  trait Casegen extends AbsCodegen
    Definition Classes
      CodegenCore
27.  abstract class CommonCodegen extends AbsCodegen
    Definition Classes
      CodegenCore
28.  class ReusedCondTreeMaker extends TreeMaker
    Definition Classes
      CommonSubconditionElimination
29.  case class ReusingCondTreeMaker(sharedPrefix: List[CommonSubconditionElimination.Test], reusesTest: (CommonSubconditionElimination.Test) => Option[CommonSubconditionElimination.Test], toReused: (CommonSubconditionElimination.TreeMaker) => CommonSubconditionElimination.TreeMaker) extends TreeMaker with Product with Serializable
    Definition Classes
      CommonSubconditionElimination
30.  class RegularSwitchMaker extends SwitchMaker
    Definition Classes
      SwitchEmission
31.  abstract class SwitchMaker extends AnyRef
    Definition Classes
      SwitchEmission
32.  final case class BoundTree(binder: Global.Symbol, tree: Global.Tree) extends Product with Serializable
    Definition Classes
      MatchTranslator
33.  abstract class ExtractorCall extends PatternMatching.ExtractorAlignment
    Definition Classes
      MatchTranslator
34.  class ExtractorCallProd extends ExtractorCall
    Definition Classes
      MatchTranslator
35.  class ExtractorCallRegular extends ExtractorCall

    Definition Classes
      MatchTranslator
36.  final case class TranslationStep(makers: List[MatchTranslator.TreeMaker], subpatterns: List[BoundTree]) extends Product with Serializable
    Definition Classes
      MatchTranslator
37.  case class AlternativesTreeMaker(prevBinder: Global.Symbol, altss: List[List[TreeMaker]], pos: Global.Position) extends TreeMaker with NoNewBinders with Product with Serializable
    Definition Classes
      TreeMakers
38.  case class BodyTreeMaker(body: Global.Tree, matchPt: Global.Type) extends TreeMaker with NoNewBinders with Product with Serializable
    Definition Classes
      TreeMakers
39.  sealed abstract class CondTreeMaker extends FunTreeMaker
    Definition Classes
      TreeMakers
40.  case class EqualityTestTreeMaker(prevBinder: Global.Symbol, patTree: Global.Tree, pos: Global.Position) extends CondTreeMaker with Product with Serializable
    Definition Classes
      TreeMakers
41.  case class ExtractorTreeMaker(extractor: Global.Tree, extraCond: Option[Global.Tree], nextBinder: Global.Symbol)(subPatBinders: List[Global.Symbol], subPatRefs: List[Global.Tree], potentiallyMutableBinders: Set[Global.Symbol], 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 (scala/bug#5739).

    Definition Classes
      TreeMakers
42.  sealed abstract class FunTreeMaker extends TreeMaker
    Definition Classes
      TreeMakers
43.  case class GuardTreeMaker(guardTree: Global.Tree) extends TreeMaker with NoNewBinders with Product with Serializable
    Definition Classes
      TreeMakers
44.  sealed trait NoNewBinders extends TreeMaker
    Definition Classes
      TreeMakers
45.  case class NonNullTestTreeMaker(prevBinder: Global.Symbol, expectedTp: Global.Type, pos: Global.Position) extends FunTreeMaker with Product with Serializable

    Make a TreeMaker that performs null check.

    Make a TreeMaker that performs null check. This is called prior to extractor call.

    Definition Classes
      TreeMakers
46.  sealed trait PreserveSubPatBinders extends TreeMaker
    Definition Classes
      TreeMakers
47.  case class ProductExtractorTreeMaker(prevBinder: Global.Symbol, extraCond: Option[Global.Tree])(subPatBinders: List[Global.Symbol], subPatRefs: List[Global.Tree], mutableBinders: List[Global.Symbol], 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 (scala/bug#5739) as well as avoiding mutation after the pattern has been matched (scala/bug#5158, scala/bug#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
48.  case class SubstOnlyTreeMaker(prevBinder: Global.Symbol, nextBinder: Global.Symbol) extends TreeMaker with Product with Serializable
    Definition Classes
      TreeMakers
49.  abstract class TreeMaker extends AnyRef
    Definition Classes
      TreeMakers
50.  case class TrivialTreeMaker(tree: Global.Tree) extends TreeMaker with NoNewBinders with Product with Serializable
    Definition Classes
      TreeMakers
51.  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://github.com/scala/bug/issues/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
52.  type Clause = Set[Lit]
    Definition Classes
      CNF
53.  type Cnf = Array[Clause]

    Conjunctive normal form (of a Boolean formula).

    Conjunctive normal form (of a Boolean formula). A formula in this form is amenable to a SAT solver (i.e., solver that decides satisfiability of a formula).

    Definition Classes
      CNF
54.  type Model = Map[Sym, Boolean]
    Definition Classes
      PropositionalLogic
55.  type Tree = Global.Tree
    Definition Classes
      TreesAndTypesDomain → PropositionalLogic
56.  type TseitinModel = collection.immutable.List[Lit]
    Definition Classes
      Solver
57.  type TseitinSearch = collection.immutable.List[(Array[Clause], List[Lit])]
    Definition Classes
      Solver
58.  type Type = Global.Type
    Definition Classes
      TreesAndTypesDomain → PropositionalLogic
59.  type VarAssignment = Map[Var, (Seq[Const], Seq[Const])]
    Definition Classes
      MatchAnalyzer
60.  sealed abstract class Const extends AnyRef
    Definition Classes
      TreesAndTypesDomain
61.  sealed class TypeConst extends Const
    Definition Classes
      TreesAndTypesDomain
62.  sealed class ValueConst extends Const
    Definition Classes
      TreesAndTypesDomain
63.  class Var extends AbsVar
    Definition Classes
      TreesAndTypesDomain
64.  class AlreadyInCNF extends AnyRef
    Definition Classes
      CNF
65.  trait CnfBuilder extends AnyRef
    Definition Classes
      CNF
66.  trait LitApi extends AnyRef
    Definition Classes
      CNF
67.  trait LitModule extends AnyRef
    Definition Classes
      CNF
68.  final case class Solvable(cnf: Cnf, symbolMapping: SymbolMapping) extends Product with Serializable
    Definition Classes
      CNF
69.  class SymbolMapping extends AnyRef
    Definition Classes
      CNF
70.  class TransformToCnf extends CnfBuilder

    Plaisted transformation: used for conversion of a propositional formula into conjunctive normal form (CNF) (input format for SAT solver).

    Plaisted transformation: used for conversion of a propositional formula into conjunctive normal form (CNF) (input format for SAT solver). A simple conversion into CNF via Shannon expansion would also be possible but it's worst-case complexity is exponential (in the number of variables) and thus even simple problems could become untractable. The Plaisted transformation results in an _equisatisfiable_ CNF-formula (it generates auxiliary variables) but runs with linear complexity. The common known Tseitin transformation uses bi-implication, whereas the Plaisted transformation uses implication only, thus the resulting CNF formula has (on average) only half of the clauses of a Tseitin transformation. The Plaisted transformation uses the polarities of sub-expressions to figure out which part of the bi-implication can be omitted. However, if all sub-expressions have positive polarity (e.g., after transformation into negation normal form) then the conversion is rather simple and the pseudo-normalization via NNF increases chances only one side of the bi-implication is needed.

    Definition Classes
      CNF
71.  case class Lit(v: Int) extends LitApi with Product with Serializable
    Definition Classes
      Solver

### Value Members

1.  object EmptySubstitution extends Substitution
   Definition Classes
     TypedSubstitution
2.  object Substitution
   Definition Classes
     TypedSubstitution
3.  object AnalysisBudget
   Definition Classes
     PropositionalLogic
4.  object And extends java.io.Serializable
   Definition Classes
     PropositionalLogic
5.  case object False extends Prop with Product with Serializable
   Definition Classes
     PropositionalLogic
6.  object Or extends java.io.Serializable
   Definition Classes
     PropositionalLogic
7.  object Sym
   Definition Classes
     PropositionalLogic
8.  case object True extends Prop with Product with Serializable
   Definition Classes
     PropositionalLogic
9.  object CounterExample
   Definition Classes
     MatchAnalyzer
10.  case object NoExample extends CounterExample with Product with Serializable
    Definition Classes
      MatchAnalyzer
11.  case object WildcardExample extends CounterExample with Product with Serializable
    Definition Classes
      MatchAnalyzer
12.  object Test extends java.io.Serializable
    Definition Classes
      MatchApproximator
13.  object optimizedCodegen extends CommonCodegen
    Definition Classes
      OptimizedCodegen
14.  object ReusedCondTreeMaker
    Definition Classes
      CommonSubconditionElimination
15.  object ExtractorCall
    Definition Classes
      MatchTranslator
16.  object PatternBoundToUnderscore
    Definition Classes
      MatchTranslator
17.  object SymbolBound
    Definition Classes
      MatchTranslator
18.  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
19.  case object DummyTreeMaker extends TreeMaker with NoNewBinders with Product with Serializable

    A dummy tree maker used to mark wildcard patterns.

    A dummy tree maker used to mark wildcard patterns. This is later used to back off from exhaustivity checking.

    Definition Classes
      TreeMakers
20.  object TypeTestTreeMaker extends java.io.Serializable
    Definition Classes
      TreeMakers
21.  final def !=(arg0: Any): Boolean
    Definition Classes
      AnyRef → Any
22.  final def ##: Int
    Definition Classes
      AnyRef → Any
23.  def +(other: String): String
    Implicit
      This member is added by an implicit conversion from OptimizingMatchTranslator toany2stringadd[OptimizingMatchTranslator] performed by method any2stringadd in scala.Predef.
    Definition Classes
      any2stringadd
24.  def ->[B](y: B): (OptimizingMatchTranslator, B)
    Implicit
      This member is added by an implicit conversion from OptimizingMatchTranslator toArrowAssoc[OptimizingMatchTranslator] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
      ArrowAssoc
    Annotations
      @inline()
25.  def /\(props: Iterable[Prop]): Prop
    Definition Classes
      PropositionalLogic
26.  final def ==(arg0: Any): Boolean
    Definition Classes
      AnyRef → Any
27.  val ArrayOfFalse: Array[Clause]
    Definition Classes
      CNF
28.  val EmptyModel: Map[Sym, Boolean]
    Definition Classes
      Solver → PropositionalLogic
29.  val NoClauses: Array[Clause]
    Definition Classes
      CNF
30.  val NoModel: Model
    Definition Classes
      Solver → PropositionalLogic
31.  val NoTseitinModel: TseitinModel
    Definition Classes
      Solver
32.  def \/(props: Iterable[Prop]): Prop
    Definition Classes
      PropositionalLogic
33.  def analyzeCases(prevBinder: Global.Symbol, cases: List[List[TreeMaker]], pt: Type, suppression: PatternMatching.Suppression): Unit
    Definition Classes
      MatchAnalyzer → TreeMakers
34.  def approximateMatchConservative(root: Global.Symbol, cases: List[List[TreeMaker]]): List[List[Test]]
    Definition Classes
      MatchApproximator
35.  final def asInstanceOf[T0]: T0
    Definition Classes
      Any
36.  final def caseWithoutBodyToProp(tests: List[Test]): Prop
    Attributes
      protected
    Definition Classes
      MatchApproximator
37.  def checkMatchVariablePatterns(cases: List[Global.CaseDef]): Unit
    Definition Classes
      TreeMakerWarnings
38.  def checkableType(tp: Global.Type): Global.Type
    Definition Classes
      CheckableTreeAndTypeAnalysis
39.  def clause(ls: IterableOnce[Lit]): Clause
    Definition Classes
      CNF
40.  def clause(l: Lit, l2: Lit, ls: Lit*): Clause
    Definition Classes
      CNF
41.  def clause(l: Lit, l2: Lit): Clause
    Definition Classes
      CNF
42.  def clause(l: Lit): Clause
    Definition Classes
      CNF
43.  def clause(): Clause
    Definition Classes
      CNF
44.  def clone(): AnyRef
    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.CloneNotSupportedException]) @native()
45.  def cnfString(f: Array[Clause]): String
    Definition Classes
      Solver → CNF
46.  def codegen: AbsCodegen
    Definition Classes
      OptimizedCodegen → CodegenCore
47.  def combineCases(scrut: Global.Tree, scrutSym: Global.Symbol, cases: List[List[TreeMaker]], pt: Global.Type, selectorPos: Global.Position, owner: Global.Symbol, matchFailGenOverride: Option[(Global.Tree) => Global.Tree], suppression: PatternMatching.Suppression): Global.Tree
    Definition Classes
      TreeMakers
48.  def combineExtractors(treeMakers: List[TreeMaker])(casegen: Casegen): Global.Tree
    Definition Classes
      TreeMakers
49.  val debugInfoEmitVars: Boolean
    Attributes
      protected
    Definition Classes
      TreeMakers
50.  def doCSE(prevBinder: Global.Symbol, cases: List[List[TreeMaker]], pt: Type, selectorPos: Global.Position): List[List[TreeMaker]]

    a flow-sensitive, generalised, common sub-expression elimination reuse knowledge from performed tests the only sub-expressions we consider are the conditions and results of the three tests (type, type&equality, equality) when a sub-expression is shared, it is stored in a mutable variable the variable is floated up so that its scope includes all of the program that shares it we generalize sharing to implication, where b reuses a if a => b and priors(a) => priors(b) (the priors of a sub expression form the path through the decision tree)

    a flow-sensitive, generalised, common sub-expression elimination reuse knowledge from performed tests the only sub-expressions we consider are the conditions and results of the three tests (type, type&equality, equality) when a sub-expression is shared, it is stored in a mutable variable the variable is floated up so that its scope includes all of the program that shares it we generalize sharing to implication, where b reuses a if a => b and priors(a) => priors(b) (the priors of a sub expression form the path through the decision tree)

    Definition Classes
      CommonSubconditionElimination
51.  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
      SwitchEmission → TreeMakers
52.  def emitTypeSwitch(bindersAndCases: List[(Global.Symbol, List[TreeMaker])], pt: Global.Type): Option[List[Global.CaseDef]]
    Definition Classes
      SwitchEmission → TreeMakers
53.  def ensuring(cond: (OptimizingMatchTranslator) => Boolean, msg: => Any): OptimizingMatchTranslator
    Implicit
      This member is added by an implicit conversion from OptimizingMatchTranslator toEnsuring[OptimizingMatchTranslator] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
54.  def ensuring(cond: (OptimizingMatchTranslator) => Boolean): OptimizingMatchTranslator
    Implicit
      This member is added by an implicit conversion from OptimizingMatchTranslator toEnsuring[OptimizingMatchTranslator] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
55.  def ensuring(cond: Boolean, msg: => Any): OptimizingMatchTranslator
    Implicit
      This member is added by an implicit conversion from OptimizingMatchTranslator toEnsuring[OptimizingMatchTranslator] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
56.  def ensuring(cond: Boolean): OptimizingMatchTranslator
    Implicit
      This member is added by an implicit conversion from OptimizingMatchTranslator toEnsuring[OptimizingMatchTranslator] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
57.  def enumerateSubtypes(tp: Global.Type, grouped: Boolean): List[List[Global.Type]]
    Definition Classes
      CheckableTreeAndTypeAnalysis
58.  final def eq(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
59.  def eqFreePropToSolvable(p: Prop): Solvable
    Definition Classes
      CNF → PropositionalLogic
60.  def equals(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef → Any
61.  def exhaustive(prevBinder: Global.Symbol, cases: List[List[TreeMaker]], pt: Type): List[String]
    Definition Classes
      MatchAnalyzer
62.  def expandModel(solution: Solution): List[VarAssignment]

    The models we get from the DPLL solver need to be mapped back to counter examples.

    The models we get from the DPLL solver need to be mapped back to counter examples. However there's no precalculated mapping model -> counter example. Even worse, not every valid model corresponds to a valid counter example. The reason is that restricting the valid models further would for example require a quadratic number of additional clauses. So to keep the optimistic case fast (i.e., all cases are covered in a pattern match), the infeasible counter examples are filtered later.

    The DPLL procedure keeps the literals that do not contribute to the solution unassigned, e.g., for `(a \/ b)` only {a = true} or {b = true} is required and the other variable can have any value.

    This function does a smart expansion of the model and avoids models that have conflicting mappings.

    For example for in case of the given set of symbols (taken from `t7020.scala`): "V2=2#16" "V2=6#19" "V2=5#18" "V2=4#17" "V2=7#20"

    One possibility would be to group the symbols by domain but this would only work for equality tests and would not be compatible with type tests. Another observation leads to a much simpler algorithm: Only one of these symbols can be set to true, since `V2` can at most be equal to one of {2,6,5,4,7}.

    Definition Classes
      MatchAnalyzer
63.  def finalize(): Unit
    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.Throwable])
64.  def findAllModelsFor(solvable: Solvable, owner: Global.Symbol): List[Solution]
    Definition Classes
      Solver → PropositionalLogic
65.  def findTseitinModelFor(clauses: Array[Clause]): TseitinModel
    Definition Classes
      Solver
66.  def fixerUpper(origOwner: Global.Symbol, pos: Global.Position): Global.InternalTraverser
    Attributes
      protected
    Definition Classes
      TreeMakers
67.  def freshName(prefix: String): Global.TermName
    Definition Classes
      CodegenCore
68.  def freshSym(pos: Global.Position, tp: Global.Type = NoType, prefix: String = "x"): Global.TermSymbol
    Definition Classes
      CodegenCore
69.  def gatherSymbols(p: Prop): Set[Sym]
    Definition Classes
      PropositionalLogic
70.  def gatherVariables(p: Prop): Set[Var]
    Definition Classes
      PropositionalLogic
71.  final def getClass(): Class[_ <: AnyRef]
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
72.  def getSuppression(scrut: Global.Tree): PatternMatching.Suppression
    Definition Classes
      TreeMakers
73.  def hasModel(solvable: Solvable): Boolean
    Definition Classes
      Solver → PropositionalLogic
74.  def hashCode(): Int
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
75.  val inForceDesugar: Boolean
    Definition Classes
      OptimizingMatchTranslator → SwitchEmission
76.  final def isInstanceOf[T0]: Boolean
    Definition Classes
      Any
77.  val matchOwner: Global.Symbol
    Definition Classes
      MatchMonadInterface
78.  def modelToCounterExample(scrutVar: Var)(varAssignment: VarAssignment): Option[CounterExample]
    Definition Classes
      MatchAnalyzer
79.  def modelToVarAssignment(model: Model): VarAssignment
    Definition Classes
      MatchAnalyzer
80.  final def ne(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
81.  def newSynthCaseLabel(name: String): Global.MethodSymbol
    Definition Classes
      CodegenCore
82.  final def notify(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
83.  final def notifyAll(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
84.  def optimizeCases(prevBinder: Global.Symbol, cases: List[List[TreeMaker]], pt: Type, selectorPos: Global.Position): (List[List[TreeMaker]], List[Tree])
    Definition Classes
      MatchOptimizer → TreeMakers
85.  def prepareNewAnalysis(): Unit
    Definition Classes
      TreesAndTypesDomain → PropositionalLogic
86.  def propToSolvable(p: Prop): Solvable
    Definition Classes
      PropositionalLogic
87.  def propagateSubstitution(treeMakers: List[TreeMaker], initial: Substitution): List[TreeMaker]
    Definition Classes
      TreeMakers
88.  def removeDummy(makers: List[TreeMaker]): collection.immutable.List[TreeMaker]
    Definition Classes
      TreeMakers
89.  def removeSubstOnly(makers: List[TreeMaker]): collection.immutable.List[TreeMaker]
    Definition Classes
      TreeMakers
90.  def removeVarEq(props: List[Prop], modelNull: Boolean = false): (Prop, List[Prop])
    Definition Classes
      PropositionalLogic
91.  def reportMissingCases(pos: Global.Position, counterExamples: List[String]): Unit
    Definition Classes
      MatchMonadInterface
92.  def reportUnreachable(pos: Global.Position): Unit
    Definition Classes
      MatchMonadInterface
93.  def reportWarning(message: String): Unit
    Definition Classes
      MatchAnalyzer → PropositionalLogic
94.  def requiresSwitch(scrut: Global.Tree, cases: List[List[TreeMaker]]): Boolean
    Definition Classes
      TreeMakers
95.  val selectorPos: Global.Position
    Definition Classes
      OptimizingMatchTranslator → MatchTranslator
96.  def showTreeMakers(cases: List[List[TreeMaker]]): Unit
    Definition Classes
      MatchApproximator
97.  def simplify(f: Prop): Prop

    Simplifies propositional formula according to the following rules: - eliminate double negation (avoids unnecessary Tseitin variables) - flatten trees of same connectives (avoids unnecessary Tseitin variables) - removes constants and connectives that are in fact constant because of their operands - eliminates duplicate operands - convert formula into NNF: all sub-expressions have a positive polarity which makes them amenable for the subsequent Plaisted transformation and increases chances to figure out that the formula is already in CNF

    Simplifies propositional formula according to the following rules: - eliminate double negation (avoids unnecessary Tseitin variables) - flatten trees of same connectives (avoids unnecessary Tseitin variables) - removes constants and connectives that are in fact constant because of their operands - eliminates duplicate operands - convert formula into NNF: all sub-expressions have a positive polarity which makes them amenable for the subsequent Plaisted transformation and increases chances to figure out that the formula is already in CNF

    Complexity: DFS over formula tree

    See https://www.decision-procedures.org/slides/propositional_logic-2x3.pdf

    Definition Classes
      PropositionalLogic
98.  final def synchronized[T0](arg0: => T0): T0
    Definition Classes
      AnyRef
99.  def toString(): String
    Definition Classes
      AnyRef → Any
100.  def translateBody(body: Global.Tree, matchPt: Global.Type): TreeMaker
     Definition Classes
       MatchTranslator
101.  def translateCase(scrutSym: Global.Symbol, pt: Global.Type)(caseDef: Global.CaseDef): 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
102.  def translateGuard(guard: Global.Tree): List[TreeMaker]
     Definition Classes
       MatchTranslator
103.  def translateMatch(match_: Global.Match): Global.Tree

     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 be optimized...

     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 be optimized...

     Definition Classes
       MatchTranslator
104.  def translatePattern(bound: BoundTree): List[TreeMaker]
     Definition Classes
       MatchTranslator
105.  def translateTry(caseDefs: List[Global.CaseDef], pt: Global.Type, pos: Global.Position): List[Global.CaseDef]
     Definition Classes
       MatchTranslator
106.  val typer: (analyzer)#Typer
     Definition Classes
       OptimizingMatchTranslator → CheckableTreeAndTypeAnalysis → MatchMonadInterface
107.  def uncheckableType(tp: Global.Type): Boolean
     Definition Classes
       CheckableTreeAndTypeAnalysis
108.  def uncheckedWarning(pos: Global.Position, msg: String, site: Global.Symbol): Unit
     Definition Classes
       MatchAnalyzer → PropositionalLogic
109.  def unreachableCase(prevBinder: Global.Symbol, cases: List[List[TreeMaker]], pt: Type): Option[Int]
     Definition Classes
       MatchAnalyzer
110.  def unreachableTypeSwitchCase(cases: List[Global.CaseDef]): Option[Global.CaseDef]
     Definition Classes
       SwitchEmission → TreeMakers
111.  def varAssignmentString(varAssignment: VarAssignment): String
     Definition Classes
       MatchAnalyzer
112.  final def wait(): Unit
     Definition Classes
       AnyRef
     Annotations
       @throws(classOf[java.lang.InterruptedException])
113.  final def wait(arg0: Long, arg1: Int): Unit
     Definition Classes
       AnyRef
     Annotations
       @throws(classOf[java.lang.InterruptedException])
114.  final def wait(arg0: Long): Unit
     Definition Classes
       AnyRef
     Annotations
       @throws(classOf[java.lang.InterruptedException]) @native()
115.  def warn(pos: Global.Position, ex: Logic.PropositionalLogic.AnalysisBudget.Exception, kind: String, site: Global.Symbol): Unit
     Definition Classes
       MatchAnalyzer
116.  object Const
     Definition Classes
       TreesAndTypesDomain
117.  case object NullConst extends Const with Product with Serializable
     Definition Classes
       TreesAndTypesDomain → PropositionalLogic
118.  object TypeConst extends TypeConstExtractor
     Definition Classes
       TreesAndTypesDomain → PropositionalLogic
119.  object ValueConst extends ValueConstExtractor
     Definition Classes
       TreesAndTypesDomain → PropositionalLogic
120.  object Var extends VarExtractor
     Definition Classes
       TreesAndTypesDomain → PropositionalLogic
121.  object Lit extends LitModule with java.io.Serializable
     Definition Classes
       Solver → CNF

### Deprecated Value Members

1.  def formatted(fmtstr: String): String
   Implicit
     This member is added by an implicit conversion from OptimizingMatchTranslator toStringFormat[OptimizingMatchTranslator] 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): (OptimizingMatchTranslator, B)
   Implicit
     This member is added by an implicit conversion from OptimizingMatchTranslator toArrowAssoc[OptimizingMatchTranslator] 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 PatternMatching.Solver

### Inherited from PatternMatching.CNF

### Inherited from PatternMatching.MatchAnalyzer

### Inherited from PatternMatching.MatchOptimizer

### Inherited from PatternMatching.CommonSubconditionElimination

### Inherited from PatternMatching.MatchApproximator

### Inherited from PatternMatching.TreesAndTypesDomain

### Inherited from PatternMatching.CheckableTreeAndTypeAnalysis

### Inherited from PatternMatching.PropositionalLogic

### Inherited from PatternMatching.SwitchEmission

### Inherited from PatternMatching.OptimizedCodegen

### 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 fromOptimizingMatchTranslator to any2stringadd[OptimizingMatchTranslator]

### Inherited by implicit conversion StringFormat fromOptimizingMatchTranslator to StringFormat[OptimizingMatchTranslator]

### Inherited by implicit conversion Ensuring fromOptimizingMatchTranslator to Ensuring[OptimizingMatchTranslator]

### Inherited by implicit conversion ArrowAssoc fromOptimizingMatchTranslator to ArrowAssoc[OptimizingMatchTranslator]

### Ungrouped