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fix: use endomorphism in optics

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Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>
This commit is contained in:
Dr. Carsten Leue
2023-12-18 09:28:36 +01:00
parent 6d043d2752
commit a87de2f644
10 changed files with 162 additions and 101 deletions
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9
optics/optional/optional.go
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@@ -18,6 +18,7 @@
package optional
import (
EM "github.com/IBM/fp-go/endomorphism"
F "github.com/IBM/fp-go/function"
O "github.com/IBM/fp-go/option"
)
@@ -25,12 +26,12 @@ import (
// Optional is an optional reference to a subpart of a data type
type Optional[S, A any] struct {
GetOption func(s S) O.Option[A]
Set func(a A) func(S) S
Set func(a A) EM.Endomorphism[S]
}
// setCopy wraps a setter for a pointer into a setter that first creates a copy before
// modifying that copy
func setCopy[S, A any](setter func(*S, A) *S) func(s *S, a A) *S {
func setCopy[SET ~func(*S, A) *S, S, A any](setter SET) func(s *S, a A) *S {
return func(s *S, a A) *S {
copy := *s
return setter(&copy, a)
@@ -41,7 +42,7 @@ func setCopy[S, A any](setter func(*S, A) *S) func(s *S, a A) *S {
// data. This happens automatically if the data is passed by value. For pointers consider to use `MakeOptionalRef`
// and for other kinds of data structures that are copied by reference make sure the setter creates the copy.
func MakeOptional[S, A any](get func(S) O.Option[A], set func(S, A) S) Optional[S, A] {
return Optional[S, A]{GetOption: get, Set: F.Curry2(F.Swap(set))}
return Optional[S, A]{GetOption: get, Set: EM.Curry2(F.Swap(set))}
}
// MakeOptionalRef creates an Optional based on a getter and a setter function. The setter passed in does not have to create a shallow
@@ -168,7 +169,7 @@ func ichain[S, A, B any](sa Optional[S, A], ab func(A) O.Option[B], ba func(B) O
return MakeOptional(
F.Flow2(sa.GetOption, O.Chain(ab)),
func(s S, b B) S {
return O.MonadFold(ba(b), F.Constant(F.Identity[S]), sa.Set)(s)
return O.MonadFold(ba(b), EM.Identity[S], sa.Set)(s)
},
)
}