Struct NestedOpt 

pub struct NestedOpt<T>(pub Option<T>);

A Daml Optional nested inside another Optional. Same runtime meaning as Option, but its LF-JSON encoding is the nested-optional list form (None → [], Some(x) → [x]) instead of null/value.

The Daml-LF JSON spec keeps the top-level Optional as null/value, and uses the list form for an Optional directly inside another, so Some None (encoded []) is distinguishable from None (encoded null).

“Directly” is the whole rule: nesting resets as soon as anything else intervenes. In Optional (List (Optional Text)) the inner Optional is a plain null/value again, because the List broke the chain — the same for a TextMap, a GenMap, or a record field. Only Optional (Optional a) puts the inner one in list form. Codegen applies exactly that rule (map.rs recurses through Optional and nothing else), so wrap a layer in NestedOpt only where its parent is itself an Optional.

The gRPC (Value) encoding is identical to Option (a proto Optional), so only the JSON form differs.

Tuple Fields

0: Option<T>

Implementations

impl<T> NestedOpt<T>

pub fn new(value: Option<T>) -> Self

Wrap an Option.

pub fn into_inner(self) -> Option<T>

Unwrap to the Option.

Trait Implementations

impl<T: Clone> Clone for NestedOpt<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for NestedOpt<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: Default> Default for NestedOpt<T>

fn default() -> Self

Returns the “default value” for a type.

impl<'de, T: Deserialize<'de>> Deserialize<'de> for NestedOpt<T>

fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error>

Deserialize this value from the given Serde deserializer.

impl<T: Eq> Eq for NestedOpt<T>

impl<T> From<NestedOpt<T>> for Option<T>

fn from(value: NestedOpt<T>) -> Self

Converts to this type from the input type.

impl<T> From<Option<T>> for NestedOpt<T>

fn from(value: Option<T>) -> Self

Converts to this type from the input type.

impl<T: FromValue> FromValue for NestedOpt<T>

fn from_value(value: &Value) -> Result<Self, ValueError>

Decode a wire Value into Self.

impl<T: PartialEq> PartialEq for NestedOpt<T>

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl<T: Serialize> Serialize for NestedOpt<T>

fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error>

Serialize this value into the given Serde serializer.

impl<T: PartialEq> StructuralPartialEq for NestedOpt<T>

impl<T: ToValue> ToValue for NestedOpt<T>

fn to_value(&self) -> Value

Encode self as a wire Value.