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scala.tools.nsc.transform.patmat

MatchApproximation

trait MatchApproximation extends TreeAndTypeAnalysis with ScalaLogic with MatchTreeMaking

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  1. MatchApproximation
  2. MatchTreeMaking
  3. MatchCodeGen
  4. ScalaLogic
  5. Logic
  6. Interface
  7. TreeDSL
  8. TreeAndTypeAnalysis
  9. Debugging
  10. AnyRef
  11. Any
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  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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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 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)

  5. trait CodegenCore extends MatchMonadInterface
    Definition Classes
    MatchCodeGen
  6. trait OptimizedCodegen extends CodegenCore with TypedSubstitution with MatchMonadInterface
    Definition Classes
    MatchCodeGen
  7. trait PureCodegen extends CodegenCore with PureMatchMonadInterface
    Definition Classes
    MatchCodeGen
  8. trait PureMatchMonadInterface extends MatchMonadInterface
    Definition Classes
    MatchCodeGen
  9. final case class Suppression(suppressExhaustive: Boolean, suppressUnreachable: Boolean) extends Product with Serializable
    Definition Classes
    MatchTreeMaking
  10. trait TreeMakers extends TypedSubstitution with CodegenCore
    Definition Classes
    MatchTreeMaking
  11. trait TreesAndTypesDomain extends PropositionalLogic with CheckableTreeAndTypeAnalysis
    Definition Classes
    ScalaLogic
  12. trait CheckableTreeAndTypeAnalysis extends AnyRef
    Definition Classes
    TreeAndTypeAnalysis

Abstract Value Members

  1. abstract val global: Global
    Definition Classes
    TreeDSL

Concrete Value Members

  1. object CODE
    Definition Classes
    TreeDSL
  2. object debug
    Definition Classes
    Debugging
  3. object vpmName
    Definition Classes
    Interface
  4. def alignAcrossRows(xss: List[List[Any]], sep: String, lineSep: String = "\n"): String
    Definition Classes
    Logic
  5. 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
  6. def equivalentTree(a: Global.Tree, b: Global.Tree): Boolean
    Definition Classes
    TreeAndTypeAnalysis
  7. def instanceOfTpImplies(tp: Global.Type, tpImplied: Global.Type): Boolean
    Definition Classes
    TreeAndTypeAnalysis
  8. object Suppression extends Serializable
    Definition Classes
    MatchTreeMaking