std: refactor optional cast to package

std/ndn/spec_2022/spec.go

@@ -101,7 +101,7 @@ func (d *Data) Name() enc.Name {
 
 func (d *Data) ContentType() (val optional.Optional[ndn.ContentType]) {
 	if d.MetaInfo != nil {
-		return utils.ConvIntOpt[uint64, ndn.ContentType](d.MetaInfo.ContentType)
+		return optional.CastInt[uint64, ndn.ContentType](d.MetaInfo.ContentType)
 	}
 	return val
 }
@@ -233,7 +233,7 @@ func (Spec) MakeData(name enc.Name, config *ndn.DataConfig, content enc.Wire, si
 	data := &Data{
 		NameV: name,
 		MetaInfo: &MetaInfo{
-			ContentType:     utils.ConvIntOpt[ndn.ContentType, uint64](config.ContentType),
+			ContentType:     optional.CastInt[ndn.ContentType, uint64](config.ContentType),
 			FreshnessPeriod: config.Freshness,
 			FinalBlockID:    finalBlock,
 		},

std/types/optional/optional.go

@@ -1,45 +1,64 @@
 package optional
 
+import "golang.org/x/exp/constraints"
+
+// Optional is a type that represents an optional value
 type Optional[T any] struct {
 	value T
 	isSet bool
 }
 
+// IsSet returns true if the optional value is set
 func (o Optional[T]) IsSet() bool {
 	return o.isSet
 }
 
+// Set sets the optional value
 func (o *Optional[T]) Set(v T) {
 	o.value = v
 	o.isSet = true
 }
 
+// Unset unsets the optional value
 func (o *Optional[T]) Unset() {
 	o.isSet = false
 }
 
+// Get returns the optional value and a boolean indicating if the value is set
 func (o Optional[T]) Get() (T, bool) {
 	return o.value, o.isSet
 }
 
+// GetOr returns the optional value or a default value if the value is not set
 func (o Optional[T]) GetOr(def T) T {
 	if o.isSet {
 		return o.value
 	}
 	return def
 }
 
+// Unwrap returns the optional value or panics if the value is not set
 func (o Optional[T]) Unwrap() T {
 	if o.isSet {
 		return o.value
 	}
 	panic("Optional value is not set")
 }
 
+// Some creates an optional value with the given value
 func Some[T any](v T) Optional[T] {
 	return Optional[T]{value: v, isSet: true}
 }
 
+// None creates an optional value with no value set
 func None[T any]() Optional[T] {
 	return Optional[T]{isSet: false}
 }
+
+// CastInt converts an integer optional value to another type
+func CastInt[A, B constraints.Integer](a Optional[A]) (out Optional[B]) {
+	if a.IsSet() {
+		out.Set(B(a.Unwrap()))
+	}
+	return out
+}

std/utils/utils.go

@@ -26,14 +26,6 @@ func ConvIntPtr[A, B constraints.Integer](a *A) *B {
 	}
 }
 
-// ConvOptional converts an optional value to another type
-func ConvIntOpt[A, B constraints.Integer](a optional.Optional[A]) (out optional.Optional[B]) {
-	if a.IsSet() {
-		out.Set(B(a.Unwrap()))
-	}
-	return out
-}
-
 func MakeTimestamp(t time.Time) uint64 {
 	return uint64(t.UnixNano() / int64(time.Millisecond))
 }