Traverse

Companion object Traverse

trait Traverse[F[_]] extends Functor[F] with Foldable[F]

Idiomatic traversal of a structure, as described in The Essence of the Iterator Pattern.

Self Type: Traverse[F]
Source: Traverse.scala
See also: scalaz.Traverse.TraverseLaw

Linear Supertypes

Foldable[F], Functor[F], InvariantFunctor[F], AnyRef, Any

Known Subclasses

IsomorphismTraverse, IsomorphismTraverse1, Traverse1

Ordering

Alphabetic
By Inheritance

Inherited

Traverse
Foldable
Functor
InvariantFunctor
AnyRef
Any

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Visibility

Public
All

Type Members

trait FoldableLaw extends AnyRef

Definition Classes
Foldable
trait FunctorLaw extends InvariantFunctorLaw

Definition Classes
Functor
trait InvariantFunctorLaw extends AnyRef

Definition Classes
InvariantFunctor
class Traversal [G[_]] extends AnyRef
trait TraverseLaw extends FunctorLaw

Abstract Value Members

abstract def traverseImpl[G[_], A, B](fa: F[A])(f: (A) ⇒ G[B])(implicit arg0: Applicative[G]): G[F[B]]
Transform fa using f, collecting all the Gs with ap.

Concrete Value Members

final def !=(arg0: Any): Boolean

Definition Classes
AnyRef → Any
final def ##(): Int

Definition Classes
AnyRef → Any
final def ==(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def all[A](fa: F[A])(p: (A) ⇒ Boolean): Boolean
Whether all As in fa yield true from p.
Whether all As in fa yield true from p.

Definition Classes
Foldable
def allM[G[_], A](fa: F[A])(p: (A) ⇒ G[Boolean])(implicit G: Monad[G]): G[Boolean]
all with monadic traversal.
all with monadic traversal.

Definition Classes
Foldable
def any[A](fa: F[A])(p: (A) ⇒ Boolean): Boolean
Whether any As in fa yield true from p.
Whether any As in fa yield true from p.

Definition Classes
Foldable
def anyM[G[_], A](fa: F[A])(p: (A) ⇒ G[Boolean])(implicit G: Monad[G]): G[Boolean]
any with monadic traversal.
any with monadic traversal.

Definition Classes
Foldable
def apply[A, B](fa: F[A])(f: (A) ⇒ B): F[B]
Alias for map.
Alias for map.

Definition Classes
Functor
final def asInstanceOf[T0]: T0

Definition Classes
Any
def bicompose[G[_, _]](implicit arg0: Bitraverse[G]): Bitraverse[[α, β]F[G[α, β]]]
The composition of Traverse F and Bitraverse G, [x, y]F[G[x, y]], is a Bitraverse
def bicompose[G[_, _]](implicit arg0: Bifoldable[G]): Bifoldable[[α, β]F[G[α, β]]]
The composition of Foldable F and Bifoldable G, [x, y]F[G[x, y]], is a Bifoldable
The composition of Foldable F and Bifoldable G, [x, y]F[G[x, y]], is a Bifoldable

Definition Classes
Foldable
def bicompose[G[_, _]](implicit arg0: Bifunctor[G]): Bifunctor[[α, β]F[G[α, β]]]
The composition of Functor F and Bifunctor G, [x, y]F[G[x, y]], is a Bifunctor
The composition of Functor F and Bifunctor G, [x, y]F[G[x, y]], is a Bifunctor

Definition Classes
Functor
def clone(): AnyRef

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( ... )
def collapse[X[_], A](x: F[A])(implicit A: ApplicativePlus[X]): X[A]

Definition Classes
Foldable
def compose[G[_]](implicit G0: Traverse[G]): Traverse[[α]F[G[α]]]
The composition of Traverses F and G, [x]F[G[x]], is a Traverse
def compose[G[_]](implicit G0: Foldable[G]): Foldable[[α]F[G[α]]]
The composition of Foldables F and G, [x]F[G[x]], is a Foldable
The composition of Foldables F and G, [x]F[G[x]], is a Foldable

Definition Classes
Foldable
def compose[G[_]](implicit G0: Functor[G]): Functor[[α]F[G[α]]]
The composition of Functors F and G, [x]F[G[x]], is a Functor
The composition of Functors F and G, [x]F[G[x]], is a Functor

Definition Classes
Functor
final def count[A](fa: F[A]): Int
Alias for length.
Alias for length.

Definition Classes
Foldable
def counzip[A, B](a: \/[F[A], F[B]]): F[\/[A, B]]

Definition Classes
Functor
def distinct[A](fa: F[A])(implicit A: Order[A]): IList[A]
O(n log n) complexity
O(n log n) complexity

Definition Classes
Foldable
def distinctE[A](fa: F[A])(implicit A: Equal[A]): IList[A]
O(n²) complexity
O(n²) complexity

Definition Classes
Foldable
def element[A](fa: F[A], a: A)(implicit arg0: Equal[A]): Boolean
Whether a is an element of fa.
Whether a is an element of fa.

Definition Classes
Foldable
def empty[A](fa: F[A]): Boolean
Deforested alias for toStream(fa).isEmpty.
Deforested alias for toStream(fa).isEmpty.

Definition Classes
Foldable
final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def equals(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def finalize(): Unit

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
def findLeft[A](fa: F[A])(f: (A) ⇒ Boolean): Option[A]

Definition Classes
Foldable
final def findMapM[M[_], A, B](fa: F[A])(f: (A) ⇒ M[Option[B]])(implicit arg0: Monad[M]): M[Option[B]]
map elements in a Foldable with a monadic function and return the first element that is mapped successfully
map elements in a Foldable with a monadic function and return the first element that is mapped successfully

Definition Classes
Foldable
def findRight[A](fa: F[A])(f: (A) ⇒ Boolean): Option[A]

Definition Classes
Foldable
def fold[M](t: F[M])(implicit arg0: Monoid[M]): M
Combine the elements of a structure using a monoid.
Combine the elements of a structure using a monoid.

Definition Classes
Foldable
def foldLShape[A, B](fa: F[A], z: B)(f: (B, A) ⇒ B): (B, F[Unit])
def foldLeft[A, B](fa: F[A], z: B)(f: (B, A) ⇒ B): B
Left-associative fold of a structure.
Left-associative fold of a structure.

Definition Classes
Traverse → Foldable
def foldLeft1Opt[A](fa: F[A])(f: (A, A) ⇒ A): Option[A]

Definition Classes
Foldable
def foldLeftM[G[_], A, B](fa: F[A], z: B)(f: (B, A) ⇒ G[B])(implicit M: Monad[G]): G[B]
Left-associative, monadic fold of a structure.
Left-associative, monadic fold of a structure.

Definition Classes
Foldable
def foldMap[A, B](fa: F[A])(f: (A) ⇒ B)(implicit F: Monoid[B]): B
Map each element of the structure to a scalaz.Monoid, and combine the results.
Map each element of the structure to a scalaz.Monoid, and combine the results.

Definition Classes
Traverse → Foldable
def foldMap1Opt[A, B](fa: F[A])(f: (A) ⇒ B)(implicit F: Semigroup[B]): Option[B]
As foldMap but returning None if the foldable is empty and Some otherwise
As foldMap but returning None if the foldable is empty and Some otherwise

Definition Classes
Foldable
def foldMapLeft1Opt[A, B](fa: F[A])(z: (A) ⇒ B)(f: (B, A) ⇒ B): Option[B]

Definition Classes
Foldable
def foldMapM[G[_], A, B](fa: F[A])(f: (A) ⇒ G[B])(implicit B: Monoid[B], G: Monad[G]): G[B]
Specialization of foldRightM when B has a Monoid.
Specialization of foldRightM when B has a Monoid.

Definition Classes
Foldable
def foldMapRight1Opt[A, B](fa: F[A])(z: (A) ⇒ B)(f: (A, ⇒ B) ⇒ B): Option[B]

Definition Classes
Foldable
def foldRight[A, B](fa: F[A], z: ⇒ B)(f: (A, ⇒ B) ⇒ B): B
Right-associative fold of a structure.
Right-associative fold of a structure.

Definition Classes
Traverse → Foldable
def foldRight1Opt[A](fa: F[A])(f: (A, ⇒ A) ⇒ A): Option[A]

Definition Classes
Foldable
def foldRightM[G[_], A, B](fa: F[A], z: ⇒ B)(f: (A, ⇒ B) ⇒ G[B])(implicit M: Monad[G]): G[B]
Right-associative, monadic fold of a structure.
Right-associative, monadic fold of a structure.

Definition Classes
Foldable
def foldableLaw: FoldableLaw

Definition Classes
Foldable
val foldableSyntax: FoldableSyntax[F]

Definition Classes
Foldable
final def foldl[A, B](fa: F[A], z: B)(f: (B) ⇒ (A) ⇒ B): B
Curried version of foldLeft
Curried version of foldLeft

Definition Classes
Foldable
def foldl1Opt[A](fa: F[A])(f: (A) ⇒ (A) ⇒ A): Option[A]

Definition Classes
Foldable
final def foldlM[G[_], A, B](fa: F[A], z: ⇒ B)(f: (B) ⇒ (A) ⇒ G[B])(implicit M: Monad[G]): G[B]
Curried version of foldLeftM
Curried version of foldLeftM

Definition Classes
Foldable
final def foldr[A, B](fa: F[A], z: ⇒ B)(f: (A) ⇒ (⇒ B) ⇒ B): B
Curried version of foldRight
Curried version of foldRight

Definition Classes
Foldable
def foldr1Opt[A](fa: F[A])(f: (A) ⇒ (⇒ A) ⇒ A): Option[A]

Definition Classes
Foldable
final def foldrM[G[_], A, B](fa: F[A], z: ⇒ B)(f: (A) ⇒ (⇒ B) ⇒ G[B])(implicit M: Monad[G]): G[B]
Curried version of foldRightM
Curried version of foldRightM

Definition Classes
Foldable
def fpair[A](fa: F[A]): F[(A, A)]
Twin all As in fa.
Twin all As in fa.

Definition Classes
Functor
def fproduct[A, B](fa: F[A])(f: (A) ⇒ B): F[(A, B)]
Pair all As in fa with the result of function application.
Pair all As in fa with the result of function application.

Definition Classes
Functor
def functorLaw: FunctorLaw

Definition Classes
Functor
val functorSyntax: FunctorSyntax[F]

Definition Classes
Functor
final def getClass(): Class[_]

Definition Classes
AnyRef → Any
def hashCode(): Int

Definition Classes
AnyRef → Any
def icompose[G[_]](implicit G0: Contravariant[G]): Contravariant[[α]F[G[α]]]
The composition of Functor F and Contravariant G, [x]F[G[x]], is contravariant.
The composition of Functor F and Contravariant G, [x]F[G[x]], is contravariant.

Definition Classes
Functor
def index[A](fa: F[A], i: Int): Option[A]
returns
the element at index i in a Some, or None if the given index falls outside of the range

Definition Classes
Foldable
def indexOr[A](fa: F[A], default: ⇒ A, i: Int): A
returns
the element at index i, or default if the given index falls outside of the range

Definition Classes
Foldable
def indexed[A](fa: F[A]): F[(Int, A)]
def intercalate[A](fa: F[A], a: A)(implicit A: Monoid[A]): A
Insert an A between every A, yielding the sum.
Insert an A between every A, yielding the sum.

Definition Classes
Foldable
def invariantFunctorLaw: InvariantFunctorLaw

Definition Classes
InvariantFunctor
val invariantFunctorSyntax: InvariantFunctorSyntax[F]

Definition Classes
InvariantFunctor
final def isInstanceOf[T0]: Boolean

Definition Classes
Any
def length[A](fa: F[A]): Int
Deforested alias for toStream(fa).size.
Deforested alias for toStream(fa).size.

Definition Classes
Foldable
def lift[A, B](f: (A) ⇒ B): (F[A]) ⇒ F[B]
Lift f into F.
Lift f into F.

Definition Classes
Functor
def longDigits[A](fa: F[A])(implicit d: <:<[A, Digit]): Long

Definition Classes
Foldable
def map[A, B](fa: F[A])(f: (A) ⇒ B): F[B]
Lift f into F and apply to F[A].
Lift f into F and apply to F[A].

Definition Classes
Traverse → Functor
def mapAccumL[S, A, B](fa: F[A], z: S)(f: (S, A) ⇒ (S, B)): (S, F[B])
def mapAccumR[S, A, B](fa: F[A], z: S)(f: (S, A) ⇒ (S, B)): (S, F[B])
def mapply[A, B](a: A)(f: F[(A) ⇒ B]): F[B]
Lift apply(a), and apply the result to f.
Lift apply(a), and apply the result to f.

Definition Classes
Functor
def maximum[A](fa: F[A])(implicit arg0: Order[A]): Option[A]
The greatest element of fa, or None if fa is empty.
The greatest element of fa, or None if fa is empty.

Definition Classes
Foldable
def maximumBy[A, B](fa: F[A])(f: (A) ⇒ B)(implicit arg0: Order[B]): Option[A]
The element a of fa which yields the greatest value of f(a), or None if fa is empty.
The element a of fa which yields the greatest value of f(a), or None if fa is empty.

Definition Classes
Foldable
def maximumOf[A, B](fa: F[A])(f: (A) ⇒ B)(implicit arg0: Order[B]): Option[B]
The greatest value of f(a) for each element a of fa, or None if fa is empty.
The greatest value of f(a) for each element a of fa, or None if fa is empty.

Definition Classes
Foldable
def minimum[A](fa: F[A])(implicit arg0: Order[A]): Option[A]
The smallest element of fa, or None if fa is empty.
The smallest element of fa, or None if fa is empty.

Definition Classes
Foldable
def minimumBy[A, B](fa: F[A])(f: (A) ⇒ B)(implicit arg0: Order[B]): Option[A]
The element a of fa which yields the smallest value of f(a), or None if fa is empty.
The element a of fa which yields the smallest value of f(a), or None if fa is empty.

Definition Classes
Foldable
def minimumOf[A, B](fa: F[A])(f: (A) ⇒ B)(implicit arg0: Order[B]): Option[B]
The smallest value of f(a) for each element a of fa, or None if fa is empty.
The smallest value of f(a) for each element a of fa, or None if fa is empty.

Definition Classes
Foldable
def msuml[G[_], A](fa: F[G[A]])(implicit G: PlusEmpty[G]): G[A]

Definition Classes
Foldable
final def ne(arg0: AnyRef): Boolean

Definition Classes
AnyRef
final def notify(): Unit

Definition Classes
AnyRef
final def notifyAll(): Unit

Definition Classes
AnyRef
def product[G[_]](implicit G0: Traverse[G]): Traverse[[α](F[α], G[α])]
The product of Traverses F and G, [x](F[x], G[x]]), is a Traverse
def product[G[_]](implicit G0: Foldable[G]): Foldable[[α](F[α], G[α])]
The product of Foldables F and G, [x](F[x], G[x]]), is a Foldable
The product of Foldables F and G, [x](F[x], G[x]]), is a Foldable

Definition Classes
Foldable
def product[G[_]](implicit G0: Functor[G]): Functor[[α](F[α], G[α])]
The product of Functors F and G, [x](F[x], G[x]]), is a Functor
The product of Functors F and G, [x](F[x], G[x]]), is a Functor

Definition Classes
Functor
def product0[G[_]](implicit G0: Traverse1[G]): Traverse1[[α](F[α], G[α])]
The product of Traverse F and Traverse1 G, [x](F[x], G[x]]), is a Traverse1
def product0[G[_]](implicit G0: Foldable1[G]): Foldable1[[α](F[α], G[α])]
The product of Foldable F and Foldable1 G, [x](F[x], G[x]]), is a Foldable1
The product of Foldable F and Foldable1 G, [x](F[x], G[x]]), is a Foldable1

Definition Classes
Foldable
def reverse[A](fa: F[A]): F[A]
def runTraverseS[S, A, B](fa: F[A], s: S)(f: (A) ⇒ State[S, B]): (S, F[B])
def selectSplit[A](fa: F[A])(p: (A) ⇒ Boolean): List[NonEmptyList[A]]
Selects groups of elements that satisfy p and discards others.
Selects groups of elements that satisfy p and discards others.

Definition Classes
Foldable
def sequence[G[_], A](fga: F[G[A]])(implicit arg0: Applicative[G]): G[F[A]]
Traverse with the identity function.
def sequenceF_[M[_], A](ffa: F[Free[M, A]]): Free[M, Unit]
sequence_ for Free.
sequence_ for Free. collapses into a single Free *

Definition Classes
Foldable
def sequenceS[S, A](fga: F[State[S, A]]): State[S, F[A]]
Traverse with State.
def sequenceS_[S, A](fga: F[State[S, A]]): State[S, Unit]
sequence_ specialized to State *
sequence_ specialized to State *

Definition Classes
Foldable
final def sequenceU[A](self: F[A])(implicit G: Unapply[Applicative, A]): M[F[A]]
A version of sequence that infers the nested type constructor.
def sequence_[M[_], A](fa: F[M[A]])(implicit a: Applicative[M]): M[Unit]
Strict sequencing in an applicative functor M that ignores the value in fa.
Strict sequencing in an applicative functor M that ignores the value in fa.

Definition Classes
Foldable
def splitWith[A](fa: F[A])(p: (A) ⇒ Boolean): List[NonEmptyList[A]]
Splits the elements into groups that alternatively satisfy and don't satisfy the predicate p.
Splits the elements into groups that alternatively satisfy and don't satisfy the predicate p.

Definition Classes
Foldable
def strengthL[A, B](a: A, f: F[B]): F[(A, B)]
Inject a to the left of Bs in f.
Inject a to the left of Bs in f.

Definition Classes
Functor
def strengthR[A, B](f: F[A], b: B): F[(A, B)]
Inject b to the right of As in f.
Inject b to the right of As in f.

Definition Classes
Functor
def suml[A](fa: F[A])(implicit A: Monoid[A]): A

Definition Classes
Foldable
def suml1Opt[A](fa: F[A])(implicit A: Semigroup[A]): Option[A]

Definition Classes
Foldable
def sumr[A](fa: F[A])(implicit A: Monoid[A]): A

Definition Classes
Foldable
def sumr1Opt[A](fa: F[A])(implicit A: Semigroup[A]): Option[A]

Definition Classes
Foldable
final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
def to[A, G[_]](fa: F[A])(implicit c: CanBuildFrom[Nothing, A, G[A]]): G[A]

Definition Classes
Foldable
def toEphemeralStream[A](fa: F[A]): EphemeralStream[A]

Definition Classes
Foldable
def toIList[A](fa: F[A]): IList[A]

Definition Classes
Foldable
def toList[A](fa: F[A]): List[A]

Definition Classes
Foldable
def toSet[A](fa: F[A]): Set[A]

Definition Classes
Foldable
def toStream[A](fa: F[A]): Stream[A]

Definition Classes
Foldable
def toString(): String

Definition Classes
AnyRef → Any
def toVector[A](fa: F[A]): Vector[A]

Definition Classes
Foldable
def traversal[G[_]](implicit arg0: Applicative[G]): Traversal[G]
def traversalS[S]: Traversal[[β$0$]IndexedStateT[[X]X, S, S, β$0$]]
def traverse[G[_], A, B](fa: F[A])(f: (A) ⇒ G[B])(implicit arg0: Applicative[G]): G[F[B]]
def traverseKTrampoline[S, G[_], A, B](fa: F[A])(f: (A) ⇒ Kleisli[G, S, B])(implicit arg0: Applicative[G]): Kleisli[G, S, F[B]]
Traverse fa with a Kleisli[G, S, B], internally using a Trampoline to avoid stack overflow.
def traverseLaw: TraverseLaw
final def traverseM[A, G[_], B](fa: F[A])(f: (A) ⇒ G[F[B]])(implicit G: Applicative[G], F: Bind[F]): G[F[B]]
A version of traverse where a subsequent monadic join is applied to the inner result.
def traverseS[S, A, B](fa: F[A])(f: (A) ⇒ State[S, B]): State[S, F[B]]
Traverse with State.
def traverseSTrampoline[S, G[_], A, B](fa: F[A])(f: (A) ⇒ State[S, G[B]])(implicit arg0: Applicative[G]): State[S, G[F[B]]]
Traverse fa with a State[S, G[B]], internally using a Trampoline to avoid stack overflow.
def traverseS_[S, A, B](fa: F[A])(f: (A) ⇒ State[S, B]): State[S, Unit]
traverse_ specialized to State *
traverse_ specialized to State *

Definition Classes
Foldable
val traverseSyntax: TraverseSyntax[F]
final def traverseU[A, GB](fa: F[A])(f: (A) ⇒ GB)(implicit G: Unapply[Applicative, GB]): M[F[A]]
A version of traverse that infers the type constructor G.
final def traverseU_[A, GB](fa: F[A])(f: (A) ⇒ GB)(implicit G: Unapply[Applicative, GB]): M[Unit]
A version of traverse_ that infers the type constructor M.
A version of traverse_ that infers the type constructor M.

Definition Classes
Foldable
def traverse_[M[_], A, B](fa: F[A])(f: (A) ⇒ M[B])(implicit a: Applicative[M]): M[Unit]
Strict traversal in an applicative functor M that ignores the result of f.
Strict traversal in an applicative functor M that ignores the result of f.

Definition Classes
Foldable
def void[A](fa: F[A]): F[Unit]
Empty fa of meaningful pure values, preserving its structure.
Empty fa of meaningful pure values, preserving its structure.

Definition Classes
Functor
final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
def widen[A, B](fa: F[A])(implicit ev: <~<[A, B]): F[B]
Functors are covariant by nature, so we can treat an F[A] as an F[B] if A is a subtype of B.
Functors are covariant by nature, so we can treat an F[A] as an F[B] if A is a subtype of B.

Definition Classes
Functor
def xmap[A, B](fa: F[A], f: (A) ⇒ B, g: (B) ⇒ A): F[B]
Converts ma to a value of type F[B] using the provided functions f and g.
Converts ma to a value of type F[B] using the provided functions f and g.

Definition Classes
Functor → InvariantFunctor
def xmapb[A, B](ma: F[A])(b: Bijection[A, B]): F[B]
Converts ma to a value of type F[B] using the provided bijection.
Converts ma to a value of type F[B] using the provided bijection.

Definition Classes
InvariantFunctor
def xmapi[A, B](ma: F[A])(iso: Isomorphism.<=>[A, B]): F[B]
Converts ma to a value of type F[B] using the provided isomorphism.
Converts ma to a value of type F[B] using the provided isomorphism.

Definition Classes
InvariantFunctor
def zipL[A, B](fa: F[A], fb: F[B]): F[(A, Option[B])]
def zipR[A, B](fa: F[A], fb: F[B]): F[(Option[A], B)]
def zipWith[A, B, C](fa: F[A], fb: F[B])(f: (A, Option[B]) ⇒ C): (List[B], F[C])
def zipWithL[A, B, C](fa: F[A], fb: F[B])(f: (A, Option[B]) ⇒ C): F[C]
def zipWithR[A, B, C](fa: F[A], fb: F[B])(f: (Option[A], B) ⇒ C): F[C]

Packages

Traverse

Companion object Traverse

trait Traverse[F[_]] extends Functor[F] with Foldable[F]

Type Members

Abstract Value Members

Concrete Value Members

Inherited from Foldable[F]

Inherited from Functor[F]

Inherited from InvariantFunctor[F]

Inherited from AnyRef

Inherited from Any

Ungrouped

Packages

Traverse 

Companion object Traverse

trait Traverse[F[_]] extends Functor[F] with Foldable[F]

Type Members

Abstract Value Members

Concrete Value Members

Inherited from Foldable[F]

Inherited from Functor[F]

Inherited from InvariantFunctor[F]

Inherited from AnyRef

Inherited from Any

Ungrouped

Traverse