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Files
fp-go/internal/array/traverse.go
Dr. Carsten Leue c07df5c771 initial checkin
Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>
2023-07-07 22:31:06 +02:00

71 lines
1.6 KiB
Go

package array
import (
F "github.com/ibm/fp-go/function"
)
/*
*
We need to pass the members of the applicative explicitly, because golang does neither support higher kinded types nor template methods on structs or interfaces
HKTRB = HKT<GB>
HKTB = HKT<B>
HKTAB = HKT<func(A)B>
*/
func MonadTraverse[GA ~[]A, GB ~[]B, A, B, HKTB, HKTAB, HKTRB any](
_of func(GB) HKTRB,
_map func(HKTRB, func(GB) func(B) GB) HKTAB,
_ap func(HKTAB, HKTB) HKTRB,
ta GA,
f func(A) HKTB) HKTRB {
return MonadTraverseReduce(_of, _map, _ap, ta, f, Append[GB, B], Empty[GB]())
}
func Traverse[GA ~[]A, GB ~[]B, A, B, HKTB, HKTAB, HKTRB any](
_of func(GB) HKTRB,
_map func(HKTRB, func(GB) func(B) GB) HKTAB,
_ap func(HKTAB, HKTB) HKTRB,
f func(A) HKTB) func(GA) HKTRB {
return func(ma GA) HKTRB {
return MonadTraverse(_of, _map, _ap, ma, f)
}
}
func MonadTraverseReduce[GA ~[]A, GB, A, B, HKTB, HKTAB, HKTRB any](
_of func(GB) HKTRB,
_map func(HKTRB, func(GB) func(B) GB) HKTAB,
_ap func(HKTAB, HKTB) HKTRB,
ta GA,
transform func(A) HKTB,
reduce func(GB, B) GB,
initial GB,
) HKTRB {
mmap := F.Bind2nd(_map, F.Curry2(reduce))
return Reduce(ta, func(r HKTRB, a A) HKTRB {
return _ap(
mmap(r),
transform(a),
)
}, _of(initial))
}
func TraverseReduce[GA ~[]A, GB, A, B, HKTB, HKTAB, HKTRB any](
_of func(GB) HKTRB,
_map func(HKTRB, func(GB) func(B) GB) HKTAB,
_ap func(HKTAB, HKTB) HKTRB,
transform func(A) HKTB,
reduce func(GB, B) GB,
initial GB,
) func(GA) HKTRB {
return func(ta GA) HKTRB {
return MonadTraverseReduce(_of, _map, _ap, ta, transform, reduce, initial)
}
}