option

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 Go to latest Published: Nov 23, 2024 License: Apache-2.0 Imports: 22 Imported by: 24

Documentation

Overview

Package option defines the Option datastructure and its monadic operations

package option implements the Option monad, a data type that can have a defined value or none

Index

Examples

Constants

This section is empty.

Variables

This section is empty.

Functions

func Alt 

func Alt[A any](that func() Option[A]) func(Option[A]) Option[A]

func AltMonoid added in v1.0.40 

func AltMonoid[A any]() M.Monoid[Option[A]]

AltMonoid is the alternative Monoid for an Option

func AlternativeMonoid added in v1.0.40 

func AlternativeMonoid[A any](m M.Monoid[A]) M.Monoid[Option[A]]

AlternativeMonoid is the alternative Monoid for an Option

func Ap 

func Ap[B, A any](fa Option[A]) func(Option[func(A) B]) Option[B]

Ap is the applicative functor of Option

func ApS added in v1.0.107 

func ApS[S1, S2, T any](
	setter func(T) func(S1) S2,
	fa Option[T],
) func(Option[S1]) Option[S2]

ApS attaches a value to a context [S1] to produce a context [S2] by considering the context and the value concurrently

func ApplicativeMonoid 

func ApplicativeMonoid[A any](m M.Monoid[A]) M.Monoid[Option[A]]

ApplicativeMonoid returns a Monoid that concatenates Option instances via their applicative

func ApplySemigroup 

func ApplySemigroup[A any](s S.Semigroup[A]) S.Semigroup[Option[A]]

func Bind added in v1.0.107 

func Bind[S1, S2, A any](
	setter func(A) func(S1) S2,
	f func(S1) Option[A],
) func(Option[S1]) Option[S2]

Bind attaches the result of a computation to a context [S1] to produce a context [S2]

func BindTo added in v1.0.107 

func BindTo[S1, T any](
	setter func(T) S1,
) func(Option[T]) Option[S1]

BindTo initializes a new state [S1] from a value [T]

func Chain 

func Chain[A, B any](f func(A) Option[B]) func(Option[A]) Option[B]

func ChainFirst 

func ChainFirst[A, B any](f func(A) Option[B]) func(Option[A]) Option[A]

func ChainTo 

func ChainTo[A, B any](mb Option[B]) func(Option[A]) Option[B]

func CompactArray added in v1.0.26 

func CompactArray[A any](fa []Option[A]) []A

CompactArray discards the none values and keeps the some values

func CompactArrayG added in v1.0.26 

func CompactArrayG[A1 ~[]Option[A], A2 ~[]A, A any](fa A1) A2

CompactArrayG discards the none values and keeps the some values

func CompactRecord added in v1.0.26 

func CompactRecord[K comparable, A any](m map[K]Option[A]) map[K]A

CompactRecord discards the noe values and keeps the some values

func CompactRecordG added in v1.0.26 

func CompactRecordG[M1 ~map[K]Option[A], M2 ~map[K]A, K comparable, A any](m M1) M2

CompactRecordG discards the noe values and keeps the some values

func Eq 

func Eq[A any](a EQ.Eq[A]) EQ.Eq[Option[A]]

Constructs an equal predicate for an `Option`

func Filter 

func Filter[A any](pred func(A) bool) func(Option[A]) Option[A]

Filter converts an optional onto itself if it is some and the predicate is true

func Flap added in v1.0.39 

func Flap[B, A any](a A) func(Option[func(A) B]) Option[B]

func Fold 

func Fold[A, B any](onNone func() B, onSome func(a A) B) func(ma Option[A]) B

func FromPredicate 

func FromPredicate[A any](pred func(A) bool) func(A) Option[A]

func FromStrictCompare added in v1.0.19 

func FromStrictCompare[A C.Ordered]() ord.Ord[Option[A]]

FromStrictCompare constructs an Ord from the canonical comparison function

func FromStrictEquals 

func FromStrictEquals[A comparable]() EQ.Eq[Option[A]]

FromStrictEquals constructs an [EQ.Eq] from the canonical comparison function

func FromValidation 

func FromValidation[A, B any](f func(A) (B, bool)) func(A) Option[B]

func Functor added in v1.0.145 

func Functor[A, B any]() functor.Functor[A, B, Option[A], Option[B]]

Functor implements the functoric operations for Option

func GetOrElse 

func GetOrElse[A any](onNone func() A) func(Option[A]) A

func IsNone 

func IsNone[T any](val Option[T]) bool

func IsSome 

func IsSome[T any](val Option[T]) bool

func Let added in v1.0.107 

func Let[S1, S2, B any](
	key func(B) func(S1) S2,
	f func(S1) B,
) func(Option[S1]) Option[S2]

Let attaches the result of a computation to a context [S1] to produce a context [S2]

func LetTo added in v1.0.107 

func LetTo[S1, S2, B any](
	key func(B) func(S1) S2,
	b B,
) func(Option[S1]) Option[S2]

LetTo attaches the a value to a context [S1] to produce a context [S2]

func Logger 

func Logger[A any](loggers ...*log.Logger) func(string) func(Option[A]) Option[A]

func Map 

func Map[A, B any](f func(a A) B) func(Option[A]) Option[B]

func MapTo 

func MapTo[A, B any](b B) func(Option[A]) Option[B]

func Monad added in v1.0.113 

func Monad[A, B any]() monad.Monad[A, B, Option[A], Option[B], Option[func(A) B]]

Monad implements the monadic operations for Option

func MonadFold 

func MonadFold[A, B any](ma Option[A], onNone func() B, onSome func(A) B) B

func MonadGetOrElse added in v1.0.58 

func MonadGetOrElse[A any](fa Option[A], onNone func() A) A

func Monoid 

func Monoid[A any]() func(S.Semigroup[A]) M.Monoid[Option[A]]

Monoid returning the left-most non-`None` value. If both operands are `Some`s then the inner values are concatenated using the provided `Semigroup`

| x | y | concat(x, y) | | ------- | ------- | ------------------ | | none | none | none | | some(a) | none | some(a) | | none | some(b) | some(b) | | some(a) | some(b) | some(concat(a, b)) |

func Optionize0 

func Optionize0[F ~func() (R, bool), R any](f F) func() Option[R]

Optionize0 converts a function with 0 parameters returning a tuple of a return value R and a boolean into a function with 0 parameters returning an Option[R]

func Optionize1 

func Optionize1[F ~func(T0) (R, bool), T0, R any](f F) func(T0) Option[R]

Optionize1 converts a function with 1 parameters returning a tuple of a return value R and a boolean into a function with 1 parameters returning an Option[R]

func Optionize10 

func Optionize10[F ~func(T0, T1, T2, T3, T4, T5, T6, T7, T8, T9) (R, bool), T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, R any](f F) func(T0, T1, T2, T3, T4, T5, T6, T7, T8, T9) Option[R]

Optionize10 converts a function with 10 parameters returning a tuple of a return value R and a boolean into a function with 10 parameters returning an Option[R]

func Optionize2 

func Optionize2[F ~func(T0, T1) (R, bool), T0, T1, R any](f F) func(T0, T1) Option[R]

Optionize2 converts a function with 2 parameters returning a tuple of a return value R and a boolean into a function with 2 parameters returning an Option[R]

func Optionize3 

func Optionize3[F ~func(T0, T1, T2) (R, bool), T0, T1, T2, R any](f F) func(T0, T1, T2) Option[R]

Optionize3 converts a function with 3 parameters returning a tuple of a return value R and a boolean into a function with 3 parameters returning an Option[R]

func Optionize4 

func Optionize4[F ~func(T0, T1, T2, T3) (R, bool), T0, T1, T2, T3, R any](f F) func(T0, T1, T2, T3) Option[R]

Optionize4 converts a function with 4 parameters returning a tuple of a return value R and a boolean into a function with 4 parameters returning an Option[R]

func Optionize5 

func Optionize5[F ~func(T0, T1, T2, T3, T4) (R, bool), T0, T1, T2, T3, T4, R any](f F) func(T0, T1, T2, T3, T4) Option[R]

Optionize5 converts a function with 5 parameters returning a tuple of a return value R and a boolean into a function with 5 parameters returning an Option[R]

func Optionize6 

func Optionize6[F ~func(T0, T1, T2, T3, T4, T5) (R, bool), T0, T1, T2, T3, T4, T5, R any](f F) func(T0, T1, T2, T3, T4, T5) Option[R]

Optionize6 converts a function with 6 parameters returning a tuple of a return value R and a boolean into a function with 6 parameters returning an Option[R]

func Optionize7 

func Optionize7[F ~func(T0, T1, T2, T3, T4, T5, T6) (R, bool), T0, T1, T2, T3, T4, T5, T6, R any](f F) func(T0, T1, T2, T3, T4, T5, T6) Option[R]

Optionize7 converts a function with 7 parameters returning a tuple of a return value R and a boolean into a function with 7 parameters returning an Option[R]

func Optionize8 

func Optionize8[F ~func(T0, T1, T2, T3, T4, T5, T6, T7) (R, bool), T0, T1, T2, T3, T4, T5, T6, T7, R any](f F) func(T0, T1, T2, T3, T4, T5, T6, T7) Option[R]

Optionize8 converts a function with 8 parameters returning a tuple of a return value R and a boolean into a function with 8 parameters returning an Option[R]

func Optionize9 

func Optionize9[F ~func(T0, T1, T2, T3, T4, T5, T6, T7, T8) (R, bool), T0, T1, T2, T3, T4, T5, T6, T7, T8, R any](f F) func(T0, T1, T2, T3, T4, T5, T6, T7, T8) Option[R]

Optionize9 converts a function with 9 parameters returning a tuple of a return value R and a boolean into a function with 9 parameters returning an Option[R]

func Ord added in v1.0.19 

func Ord[A any](a ord.Ord[A]) ord.Ord[Option[A]]

Constructs an order for Option

func Pointed added in v1.0.145 

func Pointed[A any]() pointed.Pointed[A, Option[A]]

Pointed implements the Pointed operations for Option

func Reduce 

func Reduce[A, B any](f func(B, A) B, initial B) func(Option[A]) B

func Semigroup 

func Semigroup[A any]() func(S.Semigroup[A]) S.Semigroup[Option[A]]

func Sequence 

func Sequence[A, HKTA, HKTOA any](
	mof func(Option[A]) HKTOA,
	mmap func(func(A) Option[A]) func(HKTA) HKTOA,
) func(Option[HKTA]) HKTOA

Sequence converts an Option of some higher kinded type into the higher kinded type of an Option

func Sequence2 

func Sequence2[T1, T2, R any](f func(T1, T2) Option[R]) func(Option[T1], Option[T2]) Option[R]

func Traverse added in v1.0.24 

func Traverse[A, B, HKTB, HKTOB any](
	mof func(Option[B]) HKTOB,
	mmap func(func(B) Option[B]) func(HKTB) HKTOB,
) func(func(A) HKTB) func(Option[A]) HKTOB

Traverse converts an Option of some higher kinded type into the higher kinded type of an Option

func TraverseArray 

func TraverseArray[A, B any](f func(A) Option[B]) func([]A) Option[[]B]

TraverseArray transforms an array

func TraverseArrayG 

func TraverseArrayG[GA ~[]A, GB ~[]B, A, B any](f func(A) Option[B]) func(GA) Option[GB]

TraverseArray transforms an array

func TraverseArrayWithIndex added in v1.0.29 

func TraverseArrayWithIndex[A, B any](f func(int, A) Option[B]) func([]A) Option[[]B]

TraverseArrayWithIndex transforms an array

func TraverseArrayWithIndexG added in v1.0.29 

func TraverseArrayWithIndexG[GA ~[]A, GB ~[]B, A, B any](f func(int, A) Option[B]) func(GA) Option[GB]

TraverseArrayWithIndexG transforms an array

func TraverseRecord 

func TraverseRecord[K comparable, A, B any](f func(A) Option[B]) func(map[K]A) Option[map[K]B]

TraverseRecord transforms a record of options into an option of a record

func TraverseRecordG 

func TraverseRecordG[GA ~map[K]A, GB ~map[K]B, K comparable, A, B any](f func(A) Option[B]) func(GA) Option[GB]

TraverseRecordG transforms a record of options into an option of a record

func TraverseRecordWithIndex added in v1.0.29 

func TraverseRecordWithIndex[K comparable, A, B any](f func(K, A) Option[B]) func(map[K]A) Option[map[K]B]

TraverseRecordWithIndex transforms a record of options into an option of a record

func TraverseRecordWithIndexG added in v1.0.29 

func TraverseRecordWithIndexG[GA ~map[K]A, GB ~map[K]B, K comparable, A, B any](f func(K, A) Option[B]) func(GA) Option[GB]

TraverseRecordWithIndexG transforms a record of options into an option of a record

func TraverseTuple1 

func TraverseTuple1[F1 ~func(A1) Option[T1], A1, T1 any](f1 F1) func(T.Tuple1[A1]) Option[T.Tuple1[T1]]

TraverseTuple1 converts a [Tuple1] of [A] via transformation functions transforming [A] to [Option[A]] into a [Option[Tuple1]].

func TraverseTuple10 

func TraverseTuple10[F1 ~func(A1) Option[T1], F2 ~func(A2) Option[T2], F3 ~func(A3) Option[T3], F4 ~func(A4) Option[T4], F5 ~func(A5) Option[T5], F6 ~func(A6) Option[T6], F7 ~func(A7) Option[T7], F8 ~func(A8) Option[T8], F9 ~func(A9) Option[T9], F10 ~func(A10) Option[T10], A1, T1, A2, T2, A3, T3, A4, T4, A5, T5, A6, T6, A7, T7, A8, T8, A9, T9, A10, T10 any](f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7, f8 F8, f9 F9, f10 F10) func(T.Tuple10[A1, A2, A3, A4, A5, A6, A7, A8, A9, A10]) Option[T.Tuple10[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10]]

TraverseTuple10 converts a [Tuple10] of [A] via transformation functions transforming [A] to [Option[A]] into a [Option[Tuple10]].

func TraverseTuple2 

func TraverseTuple2[F1 ~func(A1) Option[T1], F2 ~func(A2) Option[T2], A1, T1, A2, T2 any](f1 F1, f2 F2) func(T.Tuple2[A1, A2]) Option[T.Tuple2[T1, T2]]

TraverseTuple2 converts a [Tuple2] of [A] via transformation functions transforming [A] to [Option[A]] into a [Option[Tuple2]].

func TraverseTuple3 

func TraverseTuple3[F1 ~func(A1) Option[T1], F2 ~func(A2) Option[T2], F3 ~func(A3) Option[T3], A1, T1, A2, T2, A3, T3 any](f1 F1, f2 F2, f3 F3) func(T.Tuple3[A1, A2, A3]) Option[T.Tuple3[T1, T2, T3]]

TraverseTuple3 converts a [Tuple3] of [A] via transformation functions transforming [A] to [Option[A]] into a [Option[Tuple3]].

func TraverseTuple4 

func TraverseTuple4[F1 ~func(A1) Option[T1], F2 ~func(A2) Option[T2], F3 ~func(A3) Option[T3], F4 ~func(A4) Option[T4], A1, T1, A2, T2, A3, T3, A4, T4 any](f1 F1, f2 F2, f3 F3, f4 F4) func(T.Tuple4[A1, A2, A3, A4]) Option[T.Tuple4[T1, T2, T3, T4]]

TraverseTuple4 converts a [Tuple4] of [A] via transformation functions transforming [A] to [Option[A]] into a [Option[Tuple4]].

func TraverseTuple5 

func TraverseTuple5[F1 ~func(A1) Option[T1], F2 ~func(A2) Option[T2], F3 ~func(A3) Option[T3], F4 ~func(A4) Option[T4], F5 ~func(A5) Option[T5], A1, T1, A2, T2, A3, T3, A4, T4, A5, T5 any](f1 F1, f2 F2, f3 F3, f4 F4, f5 F5) func(T.Tuple5[A1, A2, A3, A4, A5]) Option[T.Tuple5[T1, T2, T3, T4, T5]]

TraverseTuple5 converts a [Tuple5] of [A] via transformation functions transforming [A] to [Option[A]] into a [Option[Tuple5]].

func TraverseTuple6 

func TraverseTuple6[F1 ~func(A1) Option[T1], F2 ~func(A2) Option[T2], F3 ~func(A3) Option[T3], F4 ~func(A4) Option[T4], F5 ~func(A5) Option[T5], F6 ~func(A6) Option[T6], A1, T1, A2, T2, A3, T3, A4, T4, A5, T5, A6, T6 any](f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6) func(T.Tuple6[A1, A2, A3, A4, A5, A6]) Option[T.Tuple6[T1, T2, T3, T4, T5, T6]]

TraverseTuple6 converts a [Tuple6] of [A] via transformation functions transforming [A] to [Option[A]] into a [Option[Tuple6]].

func TraverseTuple7 

func TraverseTuple7[F1 ~func(A1) Option[T1], F2 ~func(A2) Option[T2], F3 ~func(A3) Option[T3], F4 ~func(A4) Option[T4], F5 ~func(A5) Option[T5], F6 ~func(A6) Option[T6], F7 ~func(A7) Option[T7], A1, T1, A2, T2, A3, T3, A4, T4, A5, T5, A6, T6, A7, T7 any](f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7) func(T.Tuple7[A1, A2, A3, A4, A5, A6, A7]) Option[T.Tuple7[T1, T2, T3, T4, T5, T6, T7]]

TraverseTuple7 converts a [Tuple7] of [A] via transformation functions transforming [A] to [Option[A]] into a [Option[Tuple7]].

func TraverseTuple8 

func TraverseTuple8[F1 ~func(A1) Option[T1], F2 ~func(A2) Option[T2], F3 ~func(A3) Option[T3], F4 ~func(A4) Option[T4], F5 ~func(A5) Option[T5], F6 ~func(A6) Option[T6], F7 ~func(A7) Option[T7], F8 ~func(A8) Option[T8], A1, T1, A2, T2, A3, T3, A4, T4, A5, T5, A6, T6, A7, T7, A8, T8 any](f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7, f8 F8) func(T.Tuple8[A1, A2, A3, A4, A5, A6, A7, A8]) Option[T.Tuple8[T1, T2, T3, T4, T5, T6, T7, T8]]

TraverseTuple8 converts a [Tuple8] of [A] via transformation functions transforming [A] to [Option[A]] into a [Option[Tuple8]].

func TraverseTuple9 

func TraverseTuple9[F1 ~func(A1) Option[T1], F2 ~func(A2) Option[T2], F3 ~func(A3) Option[T3], F4 ~func(A4) Option[T4], F5 ~func(A5) Option[T5], F6 ~func(A6) Option[T6], F7 ~func(A7) Option[T7], F8 ~func(A8) Option[T8], F9 ~func(A9) Option[T9], A1, T1, A2, T2, A3, T3, A4, T4, A5, T5, A6, T6, A7, T7, A8, T8, A9, T9 any](f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7, f8 F8, f9 F9) func(T.Tuple9[A1, A2, A3, A4, A5, A6, A7, A8, A9]) Option[T.Tuple9[T1, T2, T3, T4, T5, T6, T7, T8, T9]]

TraverseTuple9 converts a [Tuple9] of [A] via transformation functions transforming [A] to [Option[A]] into a [Option[Tuple9]].

func Unoptionize0 

func Unoptionize0[F ~func() Option[R], R any](f F) func() (R, bool)

Unoptionize0 converts a function with 0 parameters returning a tuple of a return value R and a boolean into a function with 0 parameters returning an Option[R]

func Unoptionize1 

func Unoptionize1[F ~func(T0) Option[R], T0, R any](f F) func(T0) (R, bool)

Unoptionize1 converts a function with 1 parameters returning a tuple of a return value R and a boolean into a function with 1 parameters returning an Option[R]

func Unoptionize10 

func Unoptionize10[F ~func(T0, T1, T2, T3, T4, T5, T6, T7, T8, T9) Option[R], T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, R any](f F) func(T0, T1, T2, T3, T4, T5, T6, T7, T8, T9) (R, bool)

Unoptionize10 converts a function with 10 parameters returning a tuple of a return value R and a boolean into a function with 10 parameters returning an Option[R]

func Unoptionize2 

func Unoptionize2[F ~func(T0, T1) Option[R], T0, T1, R any](f F) func(T0, T1) (R, bool)

Unoptionize2 converts a function with 2 parameters returning a tuple of a return value R and a boolean into a function with 2 parameters returning an Option[R]

func Unoptionize3 

func Unoptionize3[F ~func(T0, T1, T2) Option[R], T0, T1, T2, R any](f F) func(T0, T1, T2) (R, bool)

Unoptionize3 converts a function with 3 parameters returning a tuple of a return value R and a boolean into a function with 3 parameters returning an Option[R]

func Unoptionize4 

func Unoptionize4[F ~func(T0, T1, T2, T3) Option[R], T0, T1, T2, T3, R any](f F) func(T0, T1, T2, T3) (R, bool)

Unoptionize4 converts a function with 4 parameters returning a tuple of a return value R and a boolean into a function with 4 parameters returning an Option[R]

func Unoptionize5 

func Unoptionize5[F ~func(T0, T1, T2, T3, T4) Option[R], T0, T1, T2, T3, T4, R any](f F) func(T0, T1, T2, T3, T4) (R, bool)

Unoptionize5 converts a function with 5 parameters returning a tuple of a return value R and a boolean into a function with 5 parameters returning an Option[R]

func Unoptionize6 

func Unoptionize6[F ~func(T0, T1, T2, T3, T4, T5) Option[R], T0, T1, T2, T3, T4, T5, R any](f F) func(T0, T1, T2, T3, T4, T5) (R, bool)

Unoptionize6 converts a function with 6 parameters returning a tuple of a return value R and a boolean into a function with 6 parameters returning an Option[R]

func Unoptionize7 

func Unoptionize7[F ~func(T0, T1, T2, T3, T4, T5, T6) Option[R], T0, T1, T2, T3, T4, T5, T6, R any](f F) func(T0, T1, T2, T3, T4, T5, T6) (R, bool)

Unoptionize7 converts a function with 7 parameters returning a tuple of a return value R and a boolean into a function with 7 parameters returning an Option[R]

func Unoptionize8 

func Unoptionize8[F ~func(T0, T1, T2, T3, T4, T5, T6, T7) Option[R], T0, T1, T2, T3, T4, T5, T6, T7, R any](f F) func(T0, T1, T2, T3, T4, T5, T6, T7) (R, bool)

Unoptionize8 converts a function with 8 parameters returning a tuple of a return value R and a boolean into a function with 8 parameters returning an Option[R]

func Unoptionize9 

func Unoptionize9[F ~func(T0, T1, T2, T3, T4, T5, T6, T7, T8) Option[R], T0, T1, T2, T3, T4, T5, T6, T7, T8, R any](f F) func(T0, T1, T2, T3, T4, T5, T6, T7, T8) (R, bool)

Unoptionize9 converts a function with 9 parameters returning a tuple of a return value R and a boolean into a function with 9 parameters returning an Option[R]

func Unwrap 

func Unwrap[A any](ma Option[A]) (A, bool)

Types

type Option 

type Option[A any] struct {
	// contains filtered or unexported fields
}

Option defines a data structure that logically holds a value or not

Example (Creation) 
// Build an Option
none1 := None[int]()
some1 := Some("value")

// Build from a value
fromNillable := FromNillable[string]
nonFromNil := fromNillable(nil) // None[*string]
value := "value"
someFromPointer := fromNillable(&value) // Some[*string](xxx)

// some predicate
isEven := func(num int) bool {
	return num%2 == 0
}

fromEven := FromPredicate(isEven)
noneFromPred := fromEven(3) // None[int]
someFromPred := fromEven(4) // Some[int](4)

fmt.Println(none1)
fmt.Println(some1)
fmt.Println(nonFromNil)
fmt.Println(IsSome(someFromPointer))
fmt.Println(noneFromPred)
fmt.Println(someFromPred)

Output:

None[int]
Some[string](value)
None[*string]
true
None[int]
Some[int](4)
Example (Extraction) 
noneValue := None[int]()
someValue := Of(42)

// Convert Option[T] to T
fromNone, okFromNone := Unwrap(noneValue) // 0, false
fromSome, okFromSome := Unwrap(someValue) // 42, true

// Convert Option[T] with a default value
noneWithDefault := GetOrElse(F.Constant(0))(noneValue) // 0
someWithDefault := GetOrElse(F.Constant(0))(someValue) // 42

// Apply a different function on None/Some(...)
doubleOrZero := Fold(
	F.Constant(0), // none case
	N.Mul(2),      // some case
) // func(ma Option[int]) int

doubleFromNone := doubleOrZero(noneValue) // 0
doubleFromSome := doubleOrZero(someValue) // 84

// Pro-tip: Fold is short for the following:
doubleOfZeroBis := F.Flow2(
	Map(N.Mul(2)),            // some case
	GetOrElse(F.Constant(0)), // none case
)
doubleFromNoneBis := doubleOfZeroBis(noneValue) // 0
doubleFromSomeBis := doubleOfZeroBis(someValue) // 84

fmt.Printf("%d, %t\n", fromNone, okFromNone)
fmt.Printf("%d, %t\n", fromSome, okFromSome)
fmt.Println(noneWithDefault)
fmt.Println(someWithDefault)
fmt.Println(doubleFromNone)
fmt.Println(doubleFromSome)
fmt.Println(doubleFromNoneBis)
fmt.Println(doubleFromSomeBis)

Output:

0, false
42, true
0
42
0
84
0
84

func Do added in v1.0.107 

func Do[S any](
	empty S,
) Option[S]

Bind creates an empty context of type [S] to be used with the Bind operation

func Flatten 

func Flatten[A any](mma Option[Option[A]]) Option[A]

func FromNillable 

func FromNillable[A any](a *A) Option[*A]

func MonadAlt added in v1.0.40 

func MonadAlt[A any](fa Option[A], that func() Option[A]) Option[A]

func MonadAp 

func MonadAp[B, A any](fab Option[func(A) B], fa Option[A]) Option[B]

MonadAp is the applicative functor of Option

func MonadChain 

func MonadChain[A, B any](fa Option[A], f func(A) Option[B]) Option[B]

func MonadChainFirst 

func MonadChainFirst[A, B any](ma Option[A], f func(A) Option[B]) Option[A]

func MonadChainTo 

func MonadChainTo[A, B any](_ Option[A], mb Option[B]) Option[B]

func MonadFlap added in v1.0.39 

func MonadFlap[B, A any](fab Option[func(A) B], a A) Option[B]

func MonadMap 

func MonadMap[A, B any](fa Option[A], f func(A) B) Option[B]

func MonadMapTo 

func MonadMapTo[A, B any](fa Option[A], b B) Option[B]

func MonadSequence2 

func MonadSequence2[T1, T2, R any](o1 Option[T1], o2 Option[T2], f func(T1, T2) Option[R]) Option[R]

func None 

func None[T any]() Option[T]

func Of 

func Of[T any](value T) Option[T]

func SequenceArray 

func SequenceArray[A any](ma []Option[A]) Option[[]A]

SequenceArray converts a homogeneous sequence of either into an either of sequence

func SequenceArrayG 

func SequenceArrayG[GA ~[]A, GOA ~[]Option[A], A any](ma GOA) Option[GA]

func SequencePair added in v1.0.128 

func SequencePair[T1, T2 any](t P.Pair[Option[T1], Option[T2]]) Option[P.Pair[T1, T2]]

SequencePair converts a [Pair] of [Option[T]] into an [Option[Pair]].

func SequenceRecord 

func SequenceRecord[K comparable, A any](ma map[K]Option[A]) Option[map[K]A]

SequenceRecord converts a homogeneous sequence of either into an either of sequence

func SequenceRecordG 

func SequenceRecordG[GA ~map[K]A, GOA ~map[K]Option[A], K comparable, A any](ma GOA) Option[GA]

func SequenceT1 

func SequenceT1[T1 any](t1 Option[T1]) Option[T.Tuple1[T1]]

SequenceT1 converts 1 parameters of [Option[T]] into a [Option[Tuple1]].

func SequenceT10 

func SequenceT10[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10 any](t1 Option[T1], t2 Option[T2], t3 Option[T3], t4 Option[T4], t5 Option[T5], t6 Option[T6], t7 Option[T7], t8 Option[T8], t9 Option[T9], t10 Option[T10]) Option[T.Tuple10[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10]]

SequenceT10 converts 10 parameters of [Option[T]] into a [Option[Tuple10]].

func SequenceT2 

func SequenceT2[T1, T2 any](t1 Option[T1], t2 Option[T2]) Option[T.Tuple2[T1, T2]]

SequenceT2 converts 2 parameters of [Option[T]] into a [Option[Tuple2]].

func SequenceT3 

func SequenceT3[T1, T2, T3 any](t1 Option[T1], t2 Option[T2], t3 Option[T3]) Option[T.Tuple3[T1, T2, T3]]

SequenceT3 converts 3 parameters of [Option[T]] into a [Option[Tuple3]].

func SequenceT4 

func SequenceT4[T1, T2, T3, T4 any](t1 Option[T1], t2 Option[T2], t3 Option[T3], t4 Option[T4]) Option[T.Tuple4[T1, T2, T3, T4]]

SequenceT4 converts 4 parameters of [Option[T]] into a [Option[Tuple4]].

func SequenceT5 

func SequenceT5[T1, T2, T3, T4, T5 any](t1 Option[T1], t2 Option[T2], t3 Option[T3], t4 Option[T4], t5 Option[T5]) Option[T.Tuple5[T1, T2, T3, T4, T5]]

SequenceT5 converts 5 parameters of [Option[T]] into a [Option[Tuple5]].

func SequenceT6 

func SequenceT6[T1, T2, T3, T4, T5, T6 any](t1 Option[T1], t2 Option[T2], t3 Option[T3], t4 Option[T4], t5 Option[T5], t6 Option[T6]) Option[T.Tuple6[T1, T2, T3, T4, T5, T6]]

SequenceT6 converts 6 parameters of [Option[T]] into a [Option[Tuple6]].

func SequenceT7 

func SequenceT7[T1, T2, T3, T4, T5, T6, T7 any](t1 Option[T1], t2 Option[T2], t3 Option[T3], t4 Option[T4], t5 Option[T5], t6 Option[T6], t7 Option[T7]) Option[T.Tuple7[T1, T2, T3, T4, T5, T6, T7]]

SequenceT7 converts 7 parameters of [Option[T]] into a [Option[Tuple7]].

func SequenceT8 

func SequenceT8[T1, T2, T3, T4, T5, T6, T7, T8 any](t1 Option[T1], t2 Option[T2], t3 Option[T3], t4 Option[T4], t5 Option[T5], t6 Option[T6], t7 Option[T7], t8 Option[T8]) Option[T.Tuple8[T1, T2, T3, T4, T5, T6, T7, T8]]

SequenceT8 converts 8 parameters of [Option[T]] into a [Option[Tuple8]].

func SequenceT9 

func SequenceT9[T1, T2, T3, T4, T5, T6, T7, T8, T9 any](t1 Option[T1], t2 Option[T2], t3 Option[T3], t4 Option[T4], t5 Option[T5], t6 Option[T6], t7 Option[T7], t8 Option[T8], t9 Option[T9]) Option[T.Tuple9[T1, T2, T3, T4, T5, T6, T7, T8, T9]]

SequenceT9 converts 9 parameters of [Option[T]] into a [Option[Tuple9]].

func SequenceTuple1 

func SequenceTuple1[T1 any](t T.Tuple1[Option[T1]]) Option[T.Tuple1[T1]]

SequenceTuple1 converts a [Tuple1] of [Option[T]] into an [Option[Tuple1]].

func SequenceTuple10 

func SequenceTuple10[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10 any](t T.Tuple10[Option[T1], Option[T2], Option[T3], Option[T4], Option[T5], Option[T6], Option[T7], Option[T8], Option[T9], Option[T10]]) Option[T.Tuple10[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10]]

SequenceTuple10 converts a [Tuple10] of [Option[T]] into an [Option[Tuple10]].

func SequenceTuple2 

func SequenceTuple2[T1, T2 any](t T.Tuple2[Option[T1], Option[T2]]) Option[T.Tuple2[T1, T2]]

SequenceTuple2 converts a [Tuple2] of [Option[T]] into an [Option[Tuple2]].

func SequenceTuple3 

func SequenceTuple3[T1, T2, T3 any](t T.Tuple3[Option[T1], Option[T2], Option[T3]]) Option[T.Tuple3[T1, T2, T3]]

SequenceTuple3 converts a [Tuple3] of [Option[T]] into an [Option[Tuple3]].

func SequenceTuple4 

func SequenceTuple4[T1, T2, T3, T4 any](t T.Tuple4[Option[T1], Option[T2], Option[T3], Option[T4]]) Option[T.Tuple4[T1, T2, T3, T4]]

SequenceTuple4 converts a [Tuple4] of [Option[T]] into an [Option[Tuple4]].

func SequenceTuple5 

func SequenceTuple5[T1, T2, T3, T4, T5 any](t T.Tuple5[Option[T1], Option[T2], Option[T3], Option[T4], Option[T5]]) Option[T.Tuple5[T1, T2, T3, T4, T5]]

SequenceTuple5 converts a [Tuple5] of [Option[T]] into an [Option[Tuple5]].

func SequenceTuple6 

func SequenceTuple6[T1, T2, T3, T4, T5, T6 any](t T.Tuple6[Option[T1], Option[T2], Option[T3], Option[T4], Option[T5], Option[T6]]) Option[T.Tuple6[T1, T2, T3, T4, T5, T6]]

SequenceTuple6 converts a [Tuple6] of [Option[T]] into an [Option[Tuple6]].

func SequenceTuple7 

func SequenceTuple7[T1, T2, T3, T4, T5, T6, T7 any](t T.Tuple7[Option[T1], Option[T2], Option[T3], Option[T4], Option[T5], Option[T6], Option[T7]]) Option[T.Tuple7[T1, T2, T3, T4, T5, T6, T7]]

SequenceTuple7 converts a [Tuple7] of [Option[T]] into an [Option[Tuple7]].

func SequenceTuple8 

func SequenceTuple8[T1, T2, T3, T4, T5, T6, T7, T8 any](t T.Tuple8[Option[T1], Option[T2], Option[T3], Option[T4], Option[T5], Option[T6], Option[T7], Option[T8]]) Option[T.Tuple8[T1, T2, T3, T4, T5, T6, T7, T8]]

SequenceTuple8 converts a [Tuple8] of [Option[T]] into an [Option[Tuple8]].

func SequenceTuple9 

func SequenceTuple9[T1, T2, T3, T4, T5, T6, T7, T8, T9 any](t T.Tuple9[Option[T1], Option[T2], Option[T3], Option[T4], Option[T5], Option[T6], Option[T7], Option[T8], Option[T9]]) Option[T.Tuple9[T1, T2, T3, T4, T5, T6, T7, T8, T9]]

SequenceTuple9 converts a [Tuple9] of [Option[T]] into an [Option[Tuple9]].

func Some 

func Some[T any](value T) Option[T]

func ToAny 

func ToAny[T any](src T) Option[any]

func ToType 

func ToType[T any](src any) Option[T]

func TryCatch 

func TryCatch[A any](f func() (A, error)) Option[A]

func (Option[A]) Format 

func (s Option[A]) Format(f fmt.State, c rune)

Format prints some debug info for the object

func (Option[A]) MarshalJSON 

func (s Option[A]) MarshalJSON() ([]byte, error)

func (Option[A]) String 

func (s Option[A]) String() string

String prints some debug info for the object

func (*Option[A]) UnmarshalJSON 

func (s *Option[A]) UnmarshalJSON(data []byte) error

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