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fix: try a more efficient implementation of standard interfaces

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Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>
This commit is contained in:
Dr. Carsten Leue
2024-02-07 13:26:17 +01:00
parent d86cf55a3d
commit a774d63e66
3 changed files with 71 additions and 28 deletions
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64
option/core.go
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@@ -19,52 +19,72 @@ import (
"bytes"
"encoding/json"
"fmt"
"reflect"
)
var (
// jsonNull is the cached representation of the `null` serialization in JSON
jsonNull = []byte("null")
)
// Option defines a data structure that logically holds a value or not
type Option[A any] struct {
isSome bool
some A
value A
}
// optString prints some debug info for the object
func optString(isSome bool, value any) string {
if isSome {
return fmt.Sprintf("Some[%T](%v)", value, value)
}
return fmt.Sprintf("None[%T]", value)
}
// optFormat prints some debug info for the object
func optFormat(isSome bool, value any, f fmt.State, c rune) {
switch c {
case 's':
fmt.Fprint(f, optString(isSome, value))
default:
fmt.Fprint(f, optString(isSome, value))
}
}
// String prints some debug info for the object
func (s Option[A]) String() string {
if s.isSome {
return fmt.Sprintf("Some[%T](%v)", s.some, s.some)
}
return fmt.Sprintf("None[%T]", s.some)
return optString(s.isSome, s.value)
}
// Format prints some debug info for the object
func (s Option[A]) Format(f fmt.State, c rune) {
switch c {
case 's':
fmt.Fprint(f, s.String())
default:
fmt.Fprint(f, s.String())
}
optFormat(s.isSome, s.value, f, c)
}
func (s Option[A]) MarshalJSON() ([]byte, error) {
if IsSome(s) {
return json.Marshal(s.some)
func optMarshalJSON(isSome bool, value any) ([]byte, error) {
if isSome {
return json.Marshal(value)
}
return jsonNull, nil
}
func (s *Option[A]) UnmarshalJSON(data []byte) error {
func (s Option[A]) MarshalJSON() ([]byte, error) {
return optMarshalJSON(s.isSome, s.value)
}
func optUnmarshalJSON(isSome *bool, value any, data []byte) error {
// decode the value
if bytes.Equal(data, jsonNull) {
s.isSome = false
s.some = *new(A)
*isSome = false
reflect.ValueOf(value).Elem().SetZero()
return nil
}
s.isSome = true
return json.Unmarshal(data, &s.some)
*isSome = true
return json.Unmarshal(data, value)
}
func (s *Option[A]) UnmarshalJSON(data []byte) error {
return optUnmarshalJSON(&s.isSome, &s.value, data)
}
func IsNone[T any](val Option[T]) bool {
@@ -72,7 +92,7 @@ func IsNone[T any](val Option[T]) bool {
}
func Some[T any](value T) Option[T] {
return Option[T]{isSome: true, some: value}
return Option[T]{isSome: true, value: value}
}
func Of[T any](value T) Option[T] {
@@ -89,11 +109,11 @@ func IsSome[T any](val Option[T]) bool {
func MonadFold[A, B any](ma Option[A], onNone func() B, onSome func(A) B) B {
if IsSome(ma) {
return onSome(ma.some)
return onSome(ma.value)
}
return onNone()
}
func Unwrap[A any](ma Option[A]) (A, bool) {
return ma.some, ma.isSome
return ma.value, ma.isSome
}