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fix: add more mostly-adequate examples and solutions

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Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>
This commit is contained in:
Dr. Carsten Leue
2023-09-07 17:21:39 +02:00
parent 3ccafb5302
commit 53f4e5ebd7
9 changed files with 386 additions and 37 deletions
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23
option/sequence.go
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@ -19,13 +19,22 @@ import (
F "github.com/IBM/fp-go/function"
)
// HKTA = HKT<A>
// HKTOA = HKT<Option<A>>
//
// Sequence converts an option of some higher kinded type into the higher kinded type of an option
// Sequence converts an [Option] of some higher kinded type into the higher kinded type of an [Option]
func Sequence[A, HKTA, HKTOA any](
_of func(Option[A]) HKTOA,
_map func(HKTA, func(A) Option[A]) HKTOA,
mof func(Option[A]) HKTOA,
mmap func(func(A) Option[A]) func(HKTA) HKTOA,
) func(Option[HKTA]) HKTOA {
return Fold(F.Nullary2(None[A], _of), F.Bind2nd(_map, Some[A]))
return Fold(F.Nullary2(None[A], mof), mmap(Some[A]))
}
// Traverse converts an [Option] of some higher kinded type into the higher kinded type of an [Option]
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 {
onNone := F.Nullary2(None[B], mof)
onSome := mmap(Some[B])
return func(f func(A) HKTB) func(Option[A]) HKTOB {
return Fold(onNone, F.Flow2(f, onSome))
}
}