Packages

  • package root
    Definition Classes
    root
  • package cats

    The cats root package contains all the trait signatures of most Scala type classes.

    The cats root package contains all the trait signatures of most Scala type classes.

    Cats type classes are implemented using the approach from the "Type classes as objects and implicits" article.

    For each type class, cats provides four pieces:

    • Its signature: a trait that is polymorphic on a type parameter. Type class traits inherit from other type classes to indicate that any implementation of the lower type class (e.g. Applicative) can also serve as an instance for the higher type class (e.g. Functor).
    • Type class instances, which are classes and objects that implement one or more type class signatures for some specific types. Type class instances for several data types from the Java or Scala standard libraries are declared in the subpackage cats.instances.
    • Syntax extensions, each of which provides the methods of the type class defined as extension methods (which in Scala 2 are encoded as implicit classes) for values of any type F; given that an instance of the type class for the receiver type (this) is in the implicit scope. Syntax extensions are declared in the cats.syntax package.
    • A set of laws, that are also generic on the type of the class, and are only defined on the operations of the type class. The purpose of these laws is to declare some algebraic relations (equations) between Scala expressions involving the operations of the type class, and test (but not verify) that implemented instances satisfy those equations. Laws are defined in the cats.laws package.

    Although most of cats type classes are declared in this package, some are declared in other packages:

    • type classes that operate on base types (kind *), and their implementations for standard library types, are contained in cats.kernel, which is a different SBT project. However, they are re-exported from this package.
    • type classes of kind F[_, _], such as cats.arrow.Profunctor or cats.arrow.Arrow, which are relevant for Functional Reactive Programming or optics, are declared in the cats.arrow package.
    • Also, those type classes that abstract over (pure or impure) functional runtime effects are declared in the cats-effect library.
    • Some type classes for which no laws can be provided are left out of the main road, in a small and dirty alley. These are the alleycats.
    Definition Classes
    root
  • object Foldable extends Serializable
    Definition Classes
    cats
  • AllOps
  • Ops
  • ToFoldableOps
  • nonInheritedOps
  • ops

trait Ops[F[_], A] extends Serializable

Source
Foldable.scala
Linear Supertypes
Serializable, AnyRef, Any
Known Subclasses
AllOps, AllOps, AllOps, AllOps
Type Hierarchy
Ordering
  1. Alphabetic
  2. By Inheritance
Inherited
  1. Ops
  2. Serializable
  3. AnyRef
  4. Any
  1. Hide All
  2. Show All
Visibility
  1. Public
  2. Protected

Type Members

  1. abstract type TypeClassType <: Foldable[F]

Abstract Value Members

  1. abstract def self: F[A]
  2. abstract val typeClassInstance: TypeClassType

Concrete Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##: Int
    Definition Classes
    AnyRef → Any
  3. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  4. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  5. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @native()
  6. def collectFirst[B](pf: PartialFunction[A, B]): Option[B]
  7. def collectFirstSome[B](f: (A) => Option[B]): Option[B]
  8. def collectFoldSome[B](f: (A) => Option[B])(implicit B: Monoid[B]): B
  9. def combineAll(implicit arg0: Monoid[A]): A
  10. def combineAllOption(implicit ev: Semigroup[A]): Option[A]
  11. def dropWhile_(p: (A) => Boolean): List[A]
  12. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  13. def equals(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef → Any
  14. def existsM[G[_]](p: (A) => G[Boolean])(implicit G: Monad[G]): G[Boolean]
  15. def filter_(p: (A) => Boolean): List[A]
  16. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable])
  17. def find(f: (A) => Boolean): Option[A]
  18. def fold(implicit A: Monoid[A]): A
  19. def foldK[G[_], B](implicit arg0: <:<[A, G[B]], G: MonoidK[G]): G[B]
  20. def foldLeft[B](b: B)(f: (B, A) => B): B
  21. final def foldLeftM[G[_], B](z: B)(f: (B, A) => G[B])(implicit G: Monad[G]): G[B]
  22. def foldM[G[_], B](z: B)(f: (B, A) => G[B])(implicit G: Monad[G]): G[B]
  23. def foldMap[B](f: (A) => B)(implicit B: Monoid[B]): B
  24. def foldMapA[G[_], B](f: (A) => G[B])(implicit G: Applicative[G], B: Monoid[B]): G[B]
  25. def foldMapM[G[_], B](f: (A) => G[B])(implicit G: Monad[G], B: Monoid[B]): G[B]
  26. def foldRight[B](lb: Eval[B])(f: (A, Eval[B]) => Eval[B]): Eval[B]
  27. def foldRightDefer[G[_], B](gb: G[B])(fn: (A, G[B]) => G[B])(implicit arg0: Defer[G]): G[B]
  28. def forallM[G[_]](p: (A) => G[Boolean])(implicit G: Monad[G]): G[Boolean]
  29. def get(idx: Long): Option[A]
  30. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  31. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  32. def intercalate(a: A)(implicit A: Monoid[A]): A
  33. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  34. def maximumByList[B](f: (A) => B)(implicit arg0: Order[B]): List[A]
  35. def maximumByOption[B](f: (A) => B)(implicit arg0: Order[B]): Option[A]
  36. def maximumList(implicit A: Order[A]): List[A]
  37. def maximumOption(implicit A: Order[A]): Option[A]
  38. def minimumByList[B](f: (A) => B)(implicit arg0: Order[B]): List[A]
  39. def minimumByOption[B](f: (A) => B)(implicit arg0: Order[B]): Option[A]
  40. def minimumList(implicit A: Order[A]): List[A]
  41. def minimumOption(implicit A: Order[A]): Option[A]
  42. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  43. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  44. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  45. def partitionEither[B, C](f: (A) => Either[B, C])(implicit A: Alternative[F]): (F[B], F[C])
  46. def productAll(implicit A: Numeric[A]): A
  47. def reduceLeftOption(f: (A, A) => A): Option[A]
  48. def reduceLeftToOption[B](f: (A) => B)(g: (B, A) => B): Option[B]
  49. def reduceRightOption(f: (A, Eval[A]) => Eval[A]): Eval[Option[A]]
  50. def reduceRightToOption[B](f: (A) => B)(g: (A, Eval[B]) => Eval[B]): Eval[Option[B]]
  51. def sequenceVoid[G[_], B](implicit arg0: <:<[A, G[B]], arg1: Applicative[G]): G[Unit]
  52. def sequence_[G[_], B](implicit arg0: <:<[A, G[B]], arg1: Applicative[G]): G[Unit]
  53. def sumAll(implicit A: Numeric[A]): A
  54. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  55. def takeWhile_(p: (A) => Boolean): List[A]
  56. def toIterable: Iterable[A]
  57. def toList: List[A]
  58. def toString(): String
    Definition Classes
    AnyRef → Any
  59. def traverseVoid[G[_], B](f: (A) => G[B])(implicit G: Applicative[G]): G[Unit]
  60. def traverse_[G[_], B](f: (A) => G[B])(implicit G: Applicative[G]): G[Unit]
  61. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  62. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  63. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()

Inherited from Serializable

Inherited from AnyRef

Inherited from Any

Ungrouped