Scala Compiler2.12.10 < 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
- Debugging
- Interface
- Lit
- Logic
- MatchAnalysis
- MatchApproximation
- MatchCodeGen
- MatchCps
- MatchOptimization
- MatchTranslation
- MatchTreeMaking
- MatchWarnings
- PatternExpansion
- PatternMatching
- PatternMatchingStats
- ScalaLogic
- Solving
- TreeAndTypeAnalysis

t

scala.tools.nsc.transform.patmat

# MatchOptimization 

###

#### trait MatchOptimization extends MatchTreeMaking with MatchAnalysis

Optimize and analyze matches based on their TreeMaker-representation.

The patmat translation doesn't rely on this, so it could be disabled in principle.

- well, not quite: the backend crashes if we emit duplicates in switches (e.g. scala/bug#7290)

Source
  MatchOptimization.scala

Linear Supertypes
MatchAnalysis, MatchApproximation, ScalaLogic, Logic, TreeAndTypeAnalysis, MatchTreeMaking, Debugging, MatchCodeGen, Interface, TreeDSL, AnyRef, Any
Known Subclasses
patmat, PatternMatching
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Ordering

1. Alphabetic
2. By Inheritance

Inherited

1. MatchOptimization
2. MatchAnalysis
3. MatchApproximation
4. ScalaLogic
5. Logic
6. TreeAndTypeAnalysis
7. MatchTreeMaking
8. Debugging
9. MatchCodeGen
10. Interface
11. TreeDSL
12. AnyRef
13. Any

Implicitly

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

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Visibility

1. Public
2. All

### Type Members

1.  trait MatchMonadInterface extends AnyRef

   Interface with user-defined match monad? if there's a `__match` in scope, we use this as the match strategy, assuming it conforms to MatchStrategy as defined below:

   Interface with user-defined match monad? if there's a `__match` in scope, we use this as the match strategy, assuming it conforms to MatchStrategy as defined below:

       type Matcher[P[_], M[+_], A] = {
         def flatMap[B](f: P[A] => M[B]): M[B]
         def orElse[B >: A](alternative: => M[B]): M[B]
       }

       abstract class MatchStrategy[P[_], M[+_]] {
         // runs the matcher on the given input
         def runOrElse[T, U](in: P[T])(matcher: P[T] => M[U]): P[U]

         def zero: M[Nothing]
         def one[T](x: P[T]): M[T]
         def guard[T](cond: P[Boolean], then: => P[T]): M[T]
       }

   P and M are derived from one's signature (`def one[T](x: P[T]): M[T]`)

   if no `__match` is found, we assume the following implementation (and generate optimized code accordingly)

       object __match extends MatchStrategy[({type Id[x] = x})#Id, Option] {
         def zero = None
         def one[T](x: T) = Some(x)
         // NOTE: guard's return type must be of the shape M[T], where M is the monad in which the pattern match should be interpreted
         def guard[T](cond: Boolean, then: => T): Option[T] = if(cond) Some(then) else None
         def runOrElse[T, U](x: T)(f: T => Option[U]): U = f(x) getOrElse (throw new MatchError(x))
       }

   Definition Classes
     Interface
2.  trait TypedSubstitution extends MatchMonadInterface
   Definition Classes
     Interface
3.  trait PropositionalLogic extends AnyRef
   Definition Classes
     Logic
4.  trait MatchAnalyzer extends MatchApproximator
   Definition Classes
     MatchAnalysis
5.  trait MatchApproximator extends TreeMakers with TreesAndTypesDomain

   Represent a match as a formula in propositional logic that encodes whether the match matches (abstractly: we only consider types)

   Represent a match as a formula in propositional logic that encodes whether the match matches (abstractly: we only consider types)

   Definition Classes
     MatchApproximation
6.  trait CodegenCore extends MatchMonadInterface
   Definition Classes
     MatchCodeGen
7.  trait OptimizedCodegen extends CodegenCore with TypedSubstitution with MatchMonadInterface
   Definition Classes
     MatchCodeGen
8.  trait PureCodegen extends CodegenCore with PureMatchMonadInterface
   Definition Classes
     MatchCodeGen
9.  trait PureMatchMonadInterface extends MatchMonadInterface
   Definition Classes
     MatchCodeGen
10.  trait CommonSubconditionElimination extends OptimizedCodegen with MatchApproximator
11.  trait MatchOptimizer extends OptimizedCodegen with SwitchEmission with CommonSubconditionElimination
12.  trait SwitchEmission extends TreeMakers with MatchMonadInterface
13.  final case class Suppression(suppressExhaustive: Boolean, suppressUnreachable: Boolean) extends Product with Serializable
    Definition Classes
      MatchTreeMaking
14.  trait TreeMakers extends TypedSubstitution with CodegenCore
    Definition Classes
      MatchTreeMaking
15.  trait TreesAndTypesDomain extends PropositionalLogic with CheckableTreeAndTypeAnalysis
    Definition Classes
      ScalaLogic
16.  trait CheckableTreeAndTypeAnalysis extends AnyRef
    Definition Classes
      TreeAndTypeAnalysis

### Abstract Value Members

1.  abstract val global: Global
   Definition Classes
     Debugging

### Concrete Value Members

1.  object CODE
   Definition Classes
     TreeDSL
2.  object debug
   Definition Classes
     Debugging
3.  object vpmName
   Definition Classes
     Interface
4.  final def !=(arg0: Any): Boolean
   Definition Classes
     AnyRef → Any
5.  final def ##(): Int
   Definition Classes
     AnyRef → Any
6.  def +(other: String): String
   Implicit
     This member is added by an implicit conversion from MatchOptimization to any2stringadd[MatchOptimization] performed by method any2stringadd in scala.Predef.
   Definition Classes
     any2stringadd
7.  def ->[B](y: B): (MatchOptimization, B)
   Implicit
     This member is added by an implicit conversion from MatchOptimization to ArrowAssoc[MatchOptimization] performed by method ArrowAssoc in scala.Predef.
   Definition Classes
     ArrowAssoc
   Annotations
     @inline()
8.  final def ==(arg0: Any): Boolean
   Definition Classes
     AnyRef → Any
9.  def alignAcrossRows(xss: List[List[Any]], sep: String, lineSep: String = "\n"): String
   Definition Classes
     Logic
10.  final def asInstanceOf[T0]: T0
    Definition Classes
      Any
11.  def binderTypeImpliedByPattern(pat: Global.Tree, pt: Global.Type, binder: Global.Symbol): Global.Type

    Compute the type T implied for a value `v` matched by a pattern `pat` (with expected type `pt`).

    Compute the type T implied for a value `v` matched by a pattern `pat` (with expected type `pt`).

    Usually, this is the pattern's type because pattern matching implies instance-of checks.

    However, Stable Identifier and Literal patterns are matched using `==`, which does not imply a type for the binder that binds the matched value.

    See scala/bug#1503, scala/bug#5024: don't cast binders to types we're not sure they have

    TODO: update spec as follows (deviation between `**`):

    A pattern binder x@p consists of a pattern variable x and a pattern p. The type of the variable x is the static type T **IMPLIED BY** the pattern p. This pattern matches any value v matched by the pattern p **Deleted: , provided the run-time type of v is also an instance of T, ** and it binds the variable name to that value.

    Addition: A pattern `p` _implies_ a type `T` if the pattern matches only values of the type `T`.

    Definition Classes
      TreeAndTypeAnalysis
12.  def clone(): AnyRef
    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( ... ) @native()
13.  final def dealiasWiden(tp: Global.Type): Global.Type
    Attributes
      protected
    Definition Classes
      Interface
14.  def ensuring(cond: (MatchOptimization) ⇒ Boolean, msg: ⇒ Any): MatchOptimization
    Implicit
      This member is added by an implicit conversion from MatchOptimization to Ensuring[MatchOptimization] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
15.  def ensuring(cond: (MatchOptimization) ⇒ Boolean): MatchOptimization
    Implicit
      This member is added by an implicit conversion from MatchOptimization to Ensuring[MatchOptimization] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
16.  def ensuring(cond: Boolean, msg: ⇒ Any): MatchOptimization
    Implicit
      This member is added by an implicit conversion from MatchOptimization to Ensuring[MatchOptimization] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
17.  def ensuring(cond: Boolean): MatchOptimization
    Implicit
      This member is added by an implicit conversion from MatchOptimization to Ensuring[MatchOptimization] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
18.  final def eq(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
19.  def equals(arg0: Any): Boolean
    Definition Classes
      AnyRef → Any
20.  def equivalentTree(a: Global.Tree, b: Global.Tree): Boolean
    Definition Classes
      TreeAndTypeAnalysis
21.  def finalize(): Unit
    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( classOf[java.lang.Throwable] )
22.  def formatted(fmtstr: String): String
    Implicit
      This member is added by an implicit conversion from MatchOptimization to StringFormat[MatchOptimization] performed by method StringFormat in scala.Predef.
    Definition Classes
      StringFormat
    Annotations
      @inline()
23.  final def getClass(): Class[_]
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
24.  final def hasStableSymbol(p: Global.Tree): Boolean
    Attributes
      protected
    Definition Classes
      Interface
25.  def hashCode(): Int
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
26.  def instanceOfTpImplies(tp: Global.Type, tpImplied: Global.Type): Boolean
    Definition Classes
      TreeAndTypeAnalysis
27.  final def isInstanceOf[T0]: Boolean
    Definition Classes
      Any
28.  final def mkFALSE: Global.Literal
    Attributes
      protected
    Definition Classes
      Interface
29.  final def mkTRUE: Global.Literal
    Attributes
      protected
    Definition Classes
      Interface
30.  final def ne(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
31.  final def notify(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
32.  final def notifyAll(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
33.  final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
      AnyRef
34.  def toString(): String
    Definition Classes
      AnyRef → Any
35.  final def wait(): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
36.  final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
37.  final def wait(arg0: Long): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... ) @native()
38.  def →[B](y: B): (MatchOptimization, B)
    Implicit
      This member is added by an implicit conversion from MatchOptimization to ArrowAssoc[MatchOptimization] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
      ArrowAssoc
39.  object Suppression extends Serializable
    Definition Classes
      MatchTreeMaking

### Inherited from MatchAnalysis

### Inherited from MatchApproximation

### Inherited from ScalaLogic

### Inherited from Logic

### Inherited from TreeAndTypeAnalysis

### Inherited from MatchTreeMaking

### Inherited from Debugging

### Inherited from MatchCodeGen

### Inherited from Interface

### Inherited from TreeDSL

### Inherited from AnyRef

### Inherited from Any

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

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

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

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

### Ungrouped