Packages

trait FlatMap[F[_]] extends Apply[F]

FlatMap type class gives us flatMap, which allows us to have a value in a context (F[A]) and then feed that into a function that takes a normal value and returns a value in a context (A => F[B]).

One motivation for separating this out from Monad is that there are situations where we can implement flatMap but not pure. For example, we can implement map or flatMap that transforms the values of Map[K, *], but we can't implement pure (because we wouldn't know what key to use when instantiating the new Map).

Annotations
@implicitNotFound( ... ) @typeclass( ... , ... )
Source
FlatMap.scala
See also

See https://github.com/typelevel/cats/issues/3 for some discussion. Must obey the laws defined in cats.laws.FlatMapLaws.

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Inherited
  1. FlatMap
  2. Apply
  3. ApplyArityFunctions
  4. InvariantSemigroupal
  5. Semigroupal
  6. Functor
  7. Invariant
  8. Serializable
  9. Serializable
  10. AnyRef
  11. Any
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Visibility
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Abstract Value Members

  1. abstract def flatMap[A, B](fa: F[A])(f: (A) ⇒ F[B]): F[B]
  2. abstract def map[A, B](fa: F[A])(f: (A) ⇒ B): F[B]
    Definition Classes
    Functor
  3. abstract def tailRecM[A, B](a: A)(f: (A) ⇒ F[Either[A, B]]): F[B]

    Keeps calling f until a scala.util.Right[B] is returned.

    Keeps calling f until a scala.util.Right[B] is returned.

    Based on Phil Freeman's Stack Safety for Free.

    Implementations of this method should use constant stack space relative to f.

Concrete Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##(): Int
    Definition Classes
    AnyRef → Any
  3. final def *>[A, B](fa: F[A])(fb: F[B]): F[B]

    Alias for productR.

    Alias for productR.

    Definition Classes
    Apply
    Annotations
    @inline()
  4. final def <*[A, B](fa: F[A])(fb: F[B]): F[A]

    Alias for productL.

    Alias for productL.

    Definition Classes
    Apply
    Annotations
    @inline()
  5. final def <*>[A, B](ff: F[(A) ⇒ B])(fa: F[A]): F[B]

    Alias for ap.

    Alias for ap.

    Definition Classes
    Apply
    Annotations
    @inline()
  6. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  7. def ap[A, B](ff: F[(A) ⇒ B])(fa: F[A]): F[B]

    Given a value and a function in the Apply context, applies the function to the value.

    Given a value and a function in the Apply context, applies the function to the value.

    Example:

    scala> import cats.implicits._
    
    scala> val someF: Option[Int => Long] = Some(_.toLong + 1L)
    scala> val noneF: Option[Int => Long] = None
    scala> val someInt: Option[Int] = Some(3)
    scala> val noneInt: Option[Int] = None
    
    scala> Apply[Option].ap(someF)(someInt)
    res0: Option[Long] = Some(4)
    
    scala> Apply[Option].ap(noneF)(someInt)
    res1: Option[Long] = None
    
    scala> Apply[Option].ap(someF)(noneInt)
    res2: Option[Long] = None
    
    scala> Apply[Option].ap(noneF)(noneInt)
    res3: Option[Long] = None
    Definition Classes
    FlatMapApply
  8. def ap10[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, Z](f: F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9]): F[Z]

    Definition Classes
    ApplyArityFunctions
  9. def ap11[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, Z](f: F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10]): F[Z]

    Definition Classes
    ApplyArityFunctions
  10. def ap12[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, Z](f: F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11]): F[Z]

    Definition Classes
    ApplyArityFunctions
  11. def ap13[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, Z](f: F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12]): F[Z]

    Definition Classes
    ApplyArityFunctions
  12. def ap14[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, Z](f: F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13]): F[Z]

    Definition Classes
    ApplyArityFunctions
  13. def ap15[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, Z](f: F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14]): F[Z]

    Definition Classes
    ApplyArityFunctions
  14. def ap16[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, Z](f: F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15]): F[Z]

    Definition Classes
    ApplyArityFunctions
  15. def ap17[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, Z](f: F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16]): F[Z]

    Definition Classes
    ApplyArityFunctions
  16. def ap18[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, Z](f: F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16], f17: F[A17]): F[Z]

    Definition Classes
    ApplyArityFunctions
  17. def ap19[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, Z](f: F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16], f17: F[A17], f18: F[A18]): F[Z]

    Definition Classes
    ApplyArityFunctions
  18. def ap2[A, B, Z](ff: F[(A, B) ⇒ Z])(fa: F[A], fb: F[B]): F[Z]

    ap2 is a binary version of ap, defined in terms of ap.

    ap2 is a binary version of ap, defined in terms of ap.

    Definition Classes
    FlatMapApply
  19. def ap20[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, Z](f: F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16], f17: F[A17], f18: F[A18], f19: F[A19]): F[Z]

    Definition Classes
    ApplyArityFunctions
  20. def ap21[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, Z](f: F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16], f17: F[A17], f18: F[A18], f19: F[A19], f20: F[A20]): F[Z]

    Definition Classes
    ApplyArityFunctions
  21. def ap22[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, Z](f: F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16], f17: F[A17], f18: F[A18], f19: F[A19], f20: F[A20], f21: F[A21]): F[Z]

    Definition Classes
    ApplyArityFunctions
  22. def ap3[A0, A1, A2, Z](f: F[(A0, A1, A2) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2]): F[Z]

    Definition Classes
    ApplyArityFunctions
  23. def ap4[A0, A1, A2, A3, Z](f: F[(A0, A1, A2, A3) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3]): F[Z]

    Definition Classes
    ApplyArityFunctions
  24. def ap5[A0, A1, A2, A3, A4, Z](f: F[(A0, A1, A2, A3, A4) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4]): F[Z]

    Definition Classes
    ApplyArityFunctions
  25. def ap6[A0, A1, A2, A3, A4, A5, Z](f: F[(A0, A1, A2, A3, A4, A5) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5]): F[Z]

    Definition Classes
    ApplyArityFunctions
  26. def ap7[A0, A1, A2, A3, A4, A5, A6, Z](f: F[(A0, A1, A2, A3, A4, A5, A6) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6]): F[Z]

    Definition Classes
    ApplyArityFunctions
  27. def ap8[A0, A1, A2, A3, A4, A5, A6, A7, Z](f: F[(A0, A1, A2, A3, A4, A5, A6, A7) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7]): F[Z]

    Definition Classes
    ApplyArityFunctions
  28. def ap9[A0, A1, A2, A3, A4, A5, A6, A7, A8, Z](f: F[(A0, A1, A2, A3, A4, A5, A6, A7, A8) ⇒ Z])(f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8]): F[Z]

    Definition Classes
    ApplyArityFunctions
  29. def as[A, B](fa: F[A], b: B): F[B]

    Replaces the A value in F[A] with the supplied value.

    Replaces the A value in F[A] with the supplied value.

    Example:

    scala> import cats.Functor
    scala> import cats.implicits.catsStdInstancesForList
    
    scala> Functor[List].as(List(1,2,3), "hello")
    res0: List[String] = List(hello, hello, hello)
    Definition Classes
    Functor
  30. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  31. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... ) @native()
  32. def compose[G[_]](implicit arg0: Apply[G]): Apply[[α]F[G[α]]]

    Compose an Apply[F] and an Apply[G] into an Apply[λ[α => F[G[α]]]].

    Compose an Apply[F] and an Apply[G] into an Apply[λ[α => F[G[α]]]].

    Example:

    scala> import cats.implicits._
    
    scala> val alo = Apply[List].compose[Option]
    
    scala> alo.product(List(None, Some(true), Some(false)), List(Some(2), None))
    res1: List[Option[(Boolean, Int)]] = List(None, None, Some((true,2)), None, Some((false,2)), None)
    Definition Classes
    Apply
  33. def compose[G[_]](implicit arg0: Functor[G]): Functor[[α]F[G[α]]]
    Definition Classes
    Functor
  34. def compose[G[_]](implicit arg0: Invariant[G]): Invariant[[α]F[G[α]]]

    Compose Invariant F[_] and G[_] then produce Invariant[F[G[_]]] using their imap.

    Compose Invariant F[_] and G[_] then produce Invariant[F[G[_]]] using their imap.

    Example:

    scala> import cats.implicits._
    scala> import scala.concurrent.duration._
    
    scala> val durSemigroupList: Semigroup[List[FiniteDuration]] =
         | Invariant[Semigroup].compose[List].imap(Semigroup[List[Long]])(Duration.fromNanos)(_.toNanos)
    scala> durSemigroupList.combine(List(2.seconds, 3.seconds), List(4.seconds))
    res1: List[FiniteDuration] = List(2 seconds, 3 seconds, 4 seconds)
    Definition Classes
    Invariant
  35. def composeApply[G[_]](implicit arg0: Apply[G]): InvariantSemigroupal[[α]F[G[α]]]
    Definition Classes
    InvariantSemigroupal
  36. def composeContravariant[G[_]](implicit arg0: Contravariant[G]): Contravariant[[α]F[G[α]]]

    Compose Invariant F[_] and Contravariant G[_] then produce Invariant[F[G[_]]] using F's imap and G's contramap.

    Compose Invariant F[_] and Contravariant G[_] then produce Invariant[F[G[_]]] using F's imap and G's contramap.

    Example:

    scala> import cats.implicits._
    scala> import scala.concurrent.duration._
    
    scala> type ToInt[T] = T => Int
    scala> val durSemigroupToInt: Semigroup[ToInt[FiniteDuration]] =
         | Invariant[Semigroup]
         |   .composeContravariant[ToInt]
         |   .imap(Semigroup[ToInt[Long]])(Duration.fromNanos)(_.toNanos)
    // semantically equal to (2.seconds.toSeconds.toInt + 1) + (2.seconds.toSeconds.toInt * 2) = 7
    scala> durSemigroupToInt.combine(_.toSeconds.toInt + 1, _.toSeconds.toInt * 2)(2.seconds)
    res1: Int = 7
    Definition Classes
    FunctorInvariant
  37. def composeFunctor[G[_]](implicit arg0: Functor[G]): Invariant[[α]F[G[α]]]

    Compose Invariant F[_] and Functor G[_] then produce Invariant[F[G[_]]] using F's imap and G's map.

    Compose Invariant F[_] and Functor G[_] then produce Invariant[F[G[_]]] using F's imap and G's map.

    Example:

    scala> import cats.implicits._
    scala> import scala.concurrent.duration._
    
    scala> val durSemigroupList: Semigroup[List[FiniteDuration]] =
         | Invariant[Semigroup]
         |   .composeFunctor[List]
         |   .imap(Semigroup[List[Long]])(Duration.fromNanos)(_.toNanos)
    scala> durSemigroupList.combine(List(2.seconds, 3.seconds), List(4.seconds))
    res1: List[FiniteDuration] = List(2 seconds, 3 seconds, 4 seconds)
    Definition Classes
    Invariant
  38. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  39. def equals(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  40. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
  41. def flatTap[A, B](fa: F[A])(f: (A) ⇒ F[B]): F[A]

    Apply a monadic function and discard the result while keeping the effect.

    Apply a monadic function and discard the result while keeping the effect.

    scala> import cats._, implicits._
    scala> Option(1).flatTap(_ => None)
    res0: Option[Int] = None
    scala> Option(1).flatTap(_ => Some("123"))
    res1: Option[Int] = Some(1)
    scala> def nCats(n: Int) = List.fill(n)("cat")
    nCats: (n: Int)List[String]
    scala> List[Int](0).flatTap(nCats)
    res2: List[Int] = List()
    scala> List[Int](4).flatTap(nCats)
    res3: List[Int] = List(4, 4, 4, 4)
  42. def flatten[A](ffa: F[F[A]]): F[A]

    "flatten" a nested F of F structure into a single-layer F structure.

    "flatten" a nested F of F structure into a single-layer F structure.

    This is also commonly called join.

    Example:

    scala> import cats.Eval
    scala> import cats.implicits._
    
    scala> val nested: Eval[Eval[Int]] = Eval.now(Eval.now(3))
    scala> val flattened: Eval[Int] = nested.flatten
    scala> flattened.value
    res0: Int = 3
  43. final def fmap[A, B](fa: F[A])(f: (A) ⇒ B): F[B]

    Alias for map, since map can't be injected as syntax if the implementing type already had a built-in .map method.

    Alias for map, since map can't be injected as syntax if the implementing type already had a built-in .map method.

    Example:

    scala> import cats.implicits._
    
    scala> val m: Map[Int, String] = Map(1 -> "hi", 2 -> "there", 3 -> "you")
    
    scala> m.fmap(_ ++ "!")
    res0: Map[Int,String] = Map(1 -> hi!, 2 -> there!, 3 -> you!)
    Definition Classes
    Functor
  44. def foreverM[A, B](fa: F[A]): F[B]

    Like an infinite loop of >> calls.

    Like an infinite loop of >> calls. This is most useful effect loops that you want to run forever in for instance a server.

    This will be an infinite loop, or it will return an F[Nothing].

    Be careful using this. For instance, a List of length k will produce a list of length k^n at iteration n. This means if k = 0, we return an empty list, if k = 1, we loop forever allocating single element lists, but if we have a k > 1, we will allocate exponentially increasing memory and very quickly OOM.

    Annotations
    @noop()
  45. def fproduct[A, B](fa: F[A])(f: (A) ⇒ B): F[(A, B)]

    Tuple the values in fa with the result of applying a function with the value

    Tuple the values in fa with the result of applying a function with the value

    Example:

    scala> import cats.Functor
    scala> import cats.implicits.catsStdInstancesForOption
    
    scala> Functor[Option].fproduct(Option(42))(_.toString)
    res0: Option[(Int, String)] = Some((42,42))
    Definition Classes
    Functor
  46. def fproductLeft[A, B](fa: F[A])(f: (A) ⇒ B): F[(B, A)]

    Pair the result of function application with A.

    Pair the result of function application with A.

    Example:

    scala> import cats.Functor
    scala> import cats.implicits.catsStdInstancesForOption
    
    scala> Functor[Option].fproductLeft(Option(42))(_.toString)
    res0: Option[(String, Int)] = Some((42,42))
    Definition Classes
    Functor
  47. final def getClass(): Class[_]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  48. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  49. def ifA[A](fcond: F[Boolean])(ifTrue: F[A], ifFalse: F[A]): F[A]

    An if-then-else lifted into the F context.

    An if-then-else lifted into the F context. This function combines the effects of the fcond condition and of the two branches, in the order in which they are given.

    The value of the result is, depending on the value of the condition, the value of the first argument, or the value of the second argument.

    Example:

    scala> import cats.implicits._
    
    scala> val b1: Option[Boolean] = Some(true)
    scala> val asInt1: Option[Int] = Apply[Option].ifA(b1)(Some(1), Some(0))
    scala> asInt1.get
    res0: Int = 1
    
    scala> val b2: Option[Boolean] = Some(false)
    scala> val asInt2: Option[Int] = Apply[Option].ifA(b2)(Some(1), Some(0))
    scala> asInt2.get
    res1: Int = 0
    
    scala> val b3: Option[Boolean] = Some(true)
    scala> val asInt3: Option[Int] = Apply[Option].ifA(b3)(Some(1), None)
    asInt2: Option[Int] = None
    Definition Classes
    Apply
    Annotations
    @noop()
  50. def ifF[A](fb: F[Boolean])(ifTrue: ⇒ A, ifFalse: ⇒ A): F[A]

    Lifts if to Functor

    Lifts if to Functor

    Example:

    scala> import cats.Functor
    scala> import cats.implicits.catsStdInstancesForList
    
    scala> Functor[List].ifF(List(true, false, false))(1, 0)
    res0: List[Int] = List(1, 0, 0)
    Definition Classes
    Functor
    Annotations
    @noop()
  51. def ifM[B](fa: F[Boolean])(ifTrue: ⇒ F[B], ifFalse: ⇒ F[B]): F[B]

    if lifted into monad.

    if lifted into monad.

    Annotations
    @noop()
  52. def imap[A, B](fa: F[A])(f: (A) ⇒ B)(g: (B) ⇒ A): F[B]

    Transform an F[A] into an F[B] by providing a transformation from A to B and one from B to A.

    Transform an F[A] into an F[B] by providing a transformation from A to B and one from B to A.

    Example:

    scala> import cats.implicits._
    scala> import scala.concurrent.duration._
    
    scala> val durSemigroup: Semigroup[FiniteDuration] =
         | Invariant[Semigroup].imap(Semigroup[Long])(Duration.fromNanos)(_.toNanos)
    scala> durSemigroup.combine(2.seconds, 3.seconds)
    res1: FiniteDuration = 5 seconds
    Definition Classes
    FunctorInvariant
  53. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  54. def iterateForeverM[A, B](a: A)(f: (A) ⇒ F[A]): F[B]

    iterateForeverM is almost exclusively useful for effect types.

    iterateForeverM is almost exclusively useful for effect types. For instance, A may be some state, we may take the current state, run some effect to get a new state and repeat.

    Annotations
    @noop()
  55. def lift[A, B](f: (A) ⇒ B): (F[A]) ⇒ F[B]

    Lift a function f to operate on Functors

    Lift a function f to operate on Functors

    Example:

    scala> import cats.Functor
    scala> import cats.implicits.catsStdInstancesForOption
    
    scala> val o = Option(42)
    scala> Functor[Option].lift((x: Int) => x + 10)(o)
    res0: Option[Int] = Some(52)
    Definition Classes
    Functor
  56. def map10[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9])(f: (A0, A1, A2, A3, A4, A5, A6, A7, A8, A9) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  57. def map11[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10])(f: (A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  58. def map12[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11])(f: (A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  59. def map13[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12])(f: (A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  60. def map14[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13])(f: (A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  61. def map15[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14])(f: (A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  62. def map16[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15])(f: (A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  63. def map17[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16])(f: (A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  64. def map18[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16], f17: F[A17])(f: (A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  65. def map19[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16], f17: F[A17], f18: F[A18])(f: (A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  66. def map2[A, B, Z](fa: F[A], fb: F[B])(f: (A, B) ⇒ Z): F[Z]

    Applies the pure (binary) function f to the effectful values fa and fb.

    Applies the pure (binary) function f to the effectful values fa and fb.

    map2 can be seen as a binary version of cats.Functor#map.

    Example:

    scala> import cats.implicits._
    
    scala> val someInt: Option[Int] = Some(3)
    scala> val noneInt: Option[Int] = None
    scala> val someLong: Option[Long] = Some(4L)
    scala> val noneLong: Option[Long] = None
    
    scala> Apply[Option].map2(someInt, someLong)((i, l) => i.toString + l.toString)
    res0: Option[String] = Some(34)
    
    scala> Apply[Option].map2(someInt, noneLong)((i, l) => i.toString + l.toString)
    res0: Option[String] = None
    
    scala> Apply[Option].map2(noneInt, noneLong)((i, l) => i.toString + l.toString)
    res0: Option[String] = None
    
    scala> Apply[Option].map2(noneInt, someLong)((i, l) => i.toString + l.toString)
    res0: Option[String] = None
    Definition Classes
    FlatMapApply
  67. def map20[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16], f17: F[A17], f18: F[A18], f19: F[A19])(f: (A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  68. def map21[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16], f17: F[A17], f18: F[A18], f19: F[A19], f20: F[A20])(f: (A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  69. def map22[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16], f17: F[A17], f18: F[A18], f19: F[A19], f20: F[A20], f21: F[A21])(f: (A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  70. def map2Eval[A, B, Z](fa: F[A], fb: Eval[F[B]])(f: (A, B) ⇒ Z): Eval[F[Z]]

    Similar to map2 but uses Eval to allow for laziness in the F[B] argument.

    Similar to map2 but uses Eval to allow for laziness in the F[B] argument. This can allow for "short-circuiting" of computations.

    NOTE: the default implementation of map2Eval does not short-circuit computations. For data structures that can benefit from laziness, Apply instances should override this method.

    In the following example, x.map2(bomb)(_ + _) would result in an error, but map2Eval "short-circuits" the computation. x is None and thus the result of bomb doesn't even need to be evaluated in order to determine that the result of map2Eval should be None.

    scala> import cats.{Eval, Later}
    scala> import cats.implicits._
    scala> val bomb: Eval[Option[Int]] = Later(sys.error("boom"))
    scala> val x: Option[Int] = None
    scala> x.map2Eval(bomb)(_ + _).value
    res0: Option[Int] = None
    Definition Classes
    Apply
  71. def map3[A0, A1, A2, Z](f0: F[A0], f1: F[A1], f2: F[A2])(f: (A0, A1, A2) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  72. def map4[A0, A1, A2, A3, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3])(f: (A0, A1, A2, A3) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  73. def map5[A0, A1, A2, A3, A4, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4])(f: (A0, A1, A2, A3, A4) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  74. def map6[A0, A1, A2, A3, A4, A5, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5])(f: (A0, A1, A2, A3, A4, A5) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  75. def map7[A0, A1, A2, A3, A4, A5, A6, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6])(f: (A0, A1, A2, A3, A4, A5, A6) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  76. def map8[A0, A1, A2, A3, A4, A5, A6, A7, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7])(f: (A0, A1, A2, A3, A4, A5, A6, A7) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  77. def map9[A0, A1, A2, A3, A4, A5, A6, A7, A8, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8])(f: (A0, A1, A2, A3, A4, A5, A6, A7, A8) ⇒ Z): F[Z]

    Definition Classes
    ApplyArityFunctions
  78. def mproduct[A, B](fa: F[A])(f: (A) ⇒ F[B]): F[(A, B)]

    Pair A with the result of function application.

    Pair A with the result of function application.

    Example:

    scala> import cats.implicits._
    scala> List("12", "34", "56").mproduct(_.toList)
    res0: List[(String, Char)] = List((12,1), (12,2), (34,3), (34,4), (56,5), (56,6))
  79. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  80. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  81. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  82. def product[A, B](fa: F[A], fb: F[B]): F[(A, B)]

    Combine an F[A] and an F[B] into an F[(A, B)] that maintains the effects of both fa and fb.

    Combine an F[A] and an F[B] into an F[(A, B)] that maintains the effects of both fa and fb.

    Example:

    scala> import cats.implicits._
    
    scala> val noneInt: Option[Int] = None
    scala> val some3: Option[Int] = Some(3)
    scala> val noneString: Option[String] = None
    scala> val someFoo: Option[String] = Some("foo")
    
    scala> Semigroupal[Option].product(noneInt, noneString)
    res0: Option[(Int, String)] = None
    
    scala> Semigroupal[Option].product(noneInt, someFoo)
    res1: Option[(Int, String)] = None
    
    scala> Semigroupal[Option].product(some3, noneString)
    res2: Option[(Int, String)] = None
    
    scala> Semigroupal[Option].product(some3, someFoo)
    res3: Option[(Int, String)] = Some((3,foo))
    Definition Classes
    FlatMapApplySemigroupal
  83. def productL[A, B](fa: F[A])(fb: F[B]): F[A]

    Compose two actions, discarding any value produced by the second.

    Compose two actions, discarding any value produced by the second.

    Definition Classes
    FlatMapApply
    See also

    productR to discard the value of the first instead. Example:

    scala> import cats.implicits._
    scala> import cats.data.Validated
    scala> import Validated.{Valid, Invalid}
    
    scala> type ErrOr[A] = Validated[String, A]
    
    scala> val validInt: ErrOr[Int] = Valid(3)
    scala> val validBool: ErrOr[Boolean] = Valid(true)
    scala> val invalidInt: ErrOr[Int] = Invalid("Invalid int.")
    scala> val invalidBool: ErrOr[Boolean] = Invalid("Invalid boolean.")
    
    scala> Apply[ErrOr].productL(validInt)(validBool)
    res0: ErrOr[Int] = Valid(3)
    
    scala> Apply[ErrOr].productL(invalidInt)(validBool)
    res1: ErrOr[Int] = Invalid(Invalid int.)
    
    scala> Apply[ErrOr].productL(validInt)(invalidBool)
    res2: ErrOr[Int] = Invalid(Invalid boolean.)
    
    scala> Apply[ErrOr].productL(invalidInt)(invalidBool)
    res3: ErrOr[Int] = Invalid(Invalid int.Invalid boolean.)
  84. def productLEval[A, B](fa: F[A])(fb: Eval[F[B]]): F[A]

    Sequentially compose two actions, discarding any value produced by the second.

    Sequentially compose two actions, discarding any value produced by the second. This variant of productL also lets you define the evaluation strategy of the second action. For instance you can evaluate it only after the first action has finished:

    scala> import cats.Eval
    scala> import cats.implicits._
    scala> var count = 0
    scala> val fa: Option[Int] = Some(3)
    scala> def fb: Option[Unit] = Some(count += 1)
    scala> fa.productLEval(Eval.later(fb))
    res0: Option[Int] = Some(3)
    scala> assert(count == 1)
    scala> none[Int].productLEval(Eval.later(fb))
    res1: Option[Int] = None
    scala> assert(count == 1)
  85. def productR[A, B](fa: F[A])(fb: F[B]): F[B]

    Compose two actions, discarding any value produced by the first.

    Compose two actions, discarding any value produced by the first.

    Definition Classes
    FlatMapApply
    See also

    productL to discard the value of the second instead. Example:

    scala> import cats.implicits._
    scala> import cats.data.Validated
    scala> import Validated.{Valid, Invalid}
    
    scala> type ErrOr[A] = Validated[String, A]
    
    scala> val validInt: ErrOr[Int] = Valid(3)
    scala> val validBool: ErrOr[Boolean] = Valid(true)
    scala> val invalidInt: ErrOr[Int] = Invalid("Invalid int.")
    scala> val invalidBool: ErrOr[Boolean] = Invalid("Invalid boolean.")
    
    scala> Apply[ErrOr].productR(validInt)(validBool)
    res0: ErrOr[Boolean] = Valid(true)
    
    scala> Apply[ErrOr].productR(invalidInt)(validBool)
    res1: ErrOr[Boolean] = Invalid(Invalid int.)
    
    scala> Apply[ErrOr].productR(validInt)(invalidBool)
    res2: ErrOr[Boolean] = Invalid(Invalid boolean.)
    
    scala> Apply[ErrOr].productR(invalidInt)(invalidBool)
    res3: ErrOr[Boolean] = Invalid(Invalid int.Invalid boolean.)
  86. def productREval[A, B](fa: F[A])(fb: Eval[F[B]]): F[B]

    Sequentially compose two actions, discarding any value produced by the first.

    Sequentially compose two actions, discarding any value produced by the first. This variant of productR also lets you define the evaluation strategy of the second action. For instance you can evaluate it only after the first action has finished:

    scala> import cats.Eval
    scala> import cats.implicits._
    scala> val fa: Option[Int] = Some(3)
    scala> def fb: Option[String] = Some("foo")
    scala> fa.productREval(Eval.later(fb))
    res0: Option[String] = Some(foo)
  87. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  88. def toString(): String
    Definition Classes
    AnyRef → Any
  89. def tuple10[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9]): F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9)]

    Definition Classes
    ApplyArityFunctions
  90. def tuple11[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10]): F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10)]

    Definition Classes
    ApplyArityFunctions
  91. def tuple12[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11]): F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11)]

    Definition Classes
    ApplyArityFunctions
  92. def tuple13[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12]): F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12)]

    Definition Classes
    ApplyArityFunctions
  93. def tuple14[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13]): F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13)]

    Definition Classes
    ApplyArityFunctions
  94. def tuple15[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14]): F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14)]

    Definition Classes
    ApplyArityFunctions
  95. def tuple16[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15]): F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15)]

    Definition Classes
    ApplyArityFunctions
  96. def tuple17[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16]): F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16)]

    Definition Classes
    ApplyArityFunctions
  97. def tuple18[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16], f17: F[A17]): F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17)]

    Definition Classes
    ApplyArityFunctions
  98. def tuple19[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16], f17: F[A17], f18: F[A18]): F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18)]

    Definition Classes
    ApplyArityFunctions
  99. def tuple2[A, B](f1: F[A], f2: F[B]): F[(A, B)]
    Definition Classes
    ApplyArityFunctions
  100. def tuple20[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16], f17: F[A17], f18: F[A18], f19: F[A19]): F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19)]

    Definition Classes
    ApplyArityFunctions
  101. def tuple21[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16], f17: F[A17], f18: F[A18], f19: F[A19], f20: F[A20]): F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20)]

    Definition Classes
    ApplyArityFunctions
  102. def tuple22[A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8], f9: F[A9], f10: F[A10], f11: F[A11], f12: F[A12], f13: F[A13], f14: F[A14], f15: F[A15], f16: F[A16], f17: F[A17], f18: F[A18], f19: F[A19], f20: F[A20], f21: F[A21]): F[(A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21)]

    Definition Classes
    ApplyArityFunctions
  103. def tuple3[A0, A1, A2, Z](f0: F[A0], f1: F[A1], f2: F[A2]): F[(A0, A1, A2)]

    Definition Classes
    ApplyArityFunctions
  104. def tuple4[A0, A1, A2, A3, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3]): F[(A0, A1, A2, A3)]

    Definition Classes
    ApplyArityFunctions
  105. def tuple5[A0, A1, A2, A3, A4, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4]): F[(A0, A1, A2, A3, A4)]

    Definition Classes
    ApplyArityFunctions
  106. def tuple6[A0, A1, A2, A3, A4, A5, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5]): F[(A0, A1, A2, A3, A4, A5)]

    Definition Classes
    ApplyArityFunctions
  107. def tuple7[A0, A1, A2, A3, A4, A5, A6, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6]): F[(A0, A1, A2, A3, A4, A5, A6)]

    Definition Classes
    ApplyArityFunctions
  108. def tuple8[A0, A1, A2, A3, A4, A5, A6, A7, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7]): F[(A0, A1, A2, A3, A4, A5, A6, A7)]

    Definition Classes
    ApplyArityFunctions
  109. def tuple9[A0, A1, A2, A3, A4, A5, A6, A7, A8, Z](f0: F[A0], f1: F[A1], f2: F[A2], f3: F[A3], f4: F[A4], f5: F[A5], f6: F[A6], f7: F[A7], f8: F[A8]): F[(A0, A1, A2, A3, A4, A5, A6, A7, A8)]

    Definition Classes
    ApplyArityFunctions
  110. def tupleLeft[A, B](fa: F[A], b: B): F[(B, A)]

    Tuples the A value in F[A] with the supplied B value, with the B value on the left.

    Tuples the A value in F[A] with the supplied B value, with the B value on the left.

    Example:

    scala> import scala.collection.immutable.Queue
    scala> import cats.Functor
    scala> import cats.implicits.catsStdInstancesForQueue
    
    scala> Functor[Queue].tupleLeft(Queue("hello", "world"), 42)
    res0: scala.collection.immutable.Queue[(Int, String)] = Queue((42,hello), (42,world))
    Definition Classes
    Functor
  111. def tupleRight[A, B](fa: F[A], b: B): F[(A, B)]

    Tuples the A value in F[A] with the supplied B value, with the B value on the right.

    Tuples the A value in F[A] with the supplied B value, with the B value on the right.

    Example:

    scala> import scala.collection.immutable.Queue
    scala> import cats.Functor
    scala> import cats.implicits.catsStdInstancesForQueue
    
    scala> Functor[Queue].tupleRight(Queue("hello", "world"), 42)
    res0: scala.collection.immutable.Queue[(String, Int)] = Queue((hello,42), (world,42))
    Definition Classes
    Functor
  112. def untilDefinedM[A](foa: F[Option[A]]): F[A]

    This repeats an F until we get defined values.

    This repeats an F until we get defined values. This can be useful for polling type operations on State (or RNG) Monads, or in effect monads.

    Annotations
    @noop()
  113. def unzip[A, B](fab: F[(A, B)]): (F[A], F[B])

    Un-zips an F[(A, B)] consisting of element pairs or Tuple2 into two separate F's tupled.

    Un-zips an F[(A, B)] consisting of element pairs or Tuple2 into two separate F's tupled.

    NOTE: Check for effect duplication, possibly memoize before

    scala> import cats.Functor
    scala> import cats.implicits.catsStdInstancesForList
    
    scala> Functor[List].unzip(List((1,2), (3, 4)))
    res0: (List[Int], List[Int]) = (List(1, 3),List(2, 4))
    Definition Classes
    Functor
    Annotations
    @noop()
  114. def void[A](fa: F[A]): F[Unit]

    Empty the fa of the values, preserving the structure

    Empty the fa of the values, preserving the structure

    Example:

    scala> import cats.Functor
    scala> import cats.implicits.catsStdInstancesForList
    
    scala> Functor[List].void(List(1,2,3))
    res0: List[Unit] = List((), (), ())
    Definition Classes
    Functor
  115. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  116. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  117. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... ) @native()
  118. def widen[A, B >: A](fa: F[A]): F[B]

    Lifts natural subtyping covariance of covariant Functors.

    Lifts natural subtyping covariance of covariant Functors.

    NOTE: In certain (perhaps contrived) situations that rely on universal equality this can result in a ClassCastException, because it is implemented as a type cast. It could be implemented as map(identity), but according to the functor laws, that should be equal to fa, and a type cast is often much more performant. See this example of widen creating a ClassCastException.

    Example:

    scala> import cats.Functor
    scala> import cats.implicits.catsStdInstancesForOption
    
    scala> val s = Some(42)
    scala> Functor[Option].widen(s)
    res0: Option[Int] = Some(42)
    Definition Classes
    Functor

Inherited from Apply[F]

Inherited from ApplyArityFunctions[F]

Inherited from InvariantSemigroupal[F]

Inherited from Semigroupal[F]

Inherited from Functor[F]

Inherited from Invariant[F]

Inherited from Serializable

Inherited from Serializable

Inherited from AnyRef

Inherited from Any

Ungrouped

ap arity

Higher-arity ap methods

map arity

Higher-arity map methods

tuple arity

Higher-arity tuple methods